Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The rabies virus infects the central nervous system, ultimately causing disease in the brain and death. It is almost always fatal once symptoms develop.
Radiation sickness, also known as acute radiation syndrome (ARS) or radiation poisoning, is an illness caused by exposure to a high dose of ionizing radiation over a short period of time. The radiation damages the body's cells and tissues, particularly those that divide rapidly, such as those in the bone marrow, digestive tract, and skin. The severity of radiation sickness depends on the dose of radiation received.
Reactive arthritis is a type of arthritis that develops in response to an infection in another part of the body, most often the genitals or intestines. It is an autoimmune condition, meaning the body's immune system mistakenly attacks healthy tissues. It typically affects the joints, eyes, and urinary tract. Reactive arthritis is not contagious.
Difficulty understanding spoken words and sentences.
Trouble following directions or instructions.
Inability to answer questions appropriately.
Misunderstanding jokes or sarcasm.
Difficulty understanding stories or conversations.
Appearing inattentive or disinterested in conversations.
Responding inappropriately to questions or comments.
Requesting frequent repetitions.
Having trouble with reading comprehension.
Delayed language development compared to peers.
Rectal cancer is a type of cancer that begins in the rectum, the last several inches of the large intestine before the anus. It is often grouped together with colon cancer as colorectal cancer, although treatment approaches can differ based on the location of the tumor. Rectal cancer develops when cells in the rectum begin to grow uncontrollably, forming a tumor. These cancerous cells can invade and destroy surrounding tissue and potentially spread (metastasize) to other parts of the body.
Rectal prolapse is a condition in which the rectum (the last part of the large intestine) loses its attachment inside the body and protrudes through the anus. It can range from a small portion of the rectal lining slipping out to the entire rectum protruding externally. It can be uncomfortable and distressing, but is usually treatable. It's more common in older adults, particularly women, but can occur in people of all ages, including children.
A recurring digital mucous cyst is a small, fluid-filled sac (cyst) that develops near the distal interphalangeal (DIP) joint (the joint closest to the fingertip) on the fingers or toes. It's often associated with underlying osteoarthritis in the joint. The cyst is filled with a gelatinous fluid that is similar to the fluid found in joints (synovial fluid). They tend to recur even after treatment.
Recurrent corneal erosion (RCE) is a condition where the outer layer of the cornea (the epithelium) doesn't properly adhere to the underlying basement membrane. This faulty adhesion leads to repeated episodes of corneal surface breakdown, causing pain, light sensitivity, and blurred vision, often upon awakening.
Recurrent laryngeal nerve palsy (RLNP) is a condition that occurs when the recurrent laryngeal nerve, which controls most of the muscles in the larynx (voice box), is damaged or paralyzed. This paralysis can affect voice quality, breathing, and swallowing. RLNP can be unilateral (affecting one side) or bilateral (affecting both sides), with bilateral paralysis posing a greater risk to breathing.
Recurrent Respiratory Papillomatosis (RRP) is a rare disease characterized by the growth of benign tumors (papillomas) in the respiratory tract. These growths most commonly occur in the larynx (voice box) but can also affect other areas, including the trachea, bronchi, and even the lungs. The papillomas are caused by the human papillomavirus (HPV), most often types 6 and 11. The "recurrent" aspect of the disease refers to the tendency for the papillomas to grow back after treatment, often requiring multiple procedures to manage the condition. RRP can cause significant airway obstruction, leading to breathing difficulties and voice changes.
"Red eye" refers to redness or bloodshot appearance of the eye. It's a common condition that can be caused by various factors, ranging from minor irritations to more serious infections or injuries. The redness is typically due to dilated blood vessels on the surface of the sclera (white part of the eye). While often harmless and self-limiting, persistent or severe red eye can indicate a condition requiring medical attention.
Red Man Syndrome (RMS), also known as Vancomycin Flushing Syndrome, is a reaction that occurs most commonly as a result of rapid intravenous infusion of the antibiotic vancomycin. It is characterized by flushing, rash, itching, and other symptoms. While alarming, it is generally not life-threatening if managed appropriately.
Blurred vision (near or far)
Double vision
Hazy vision
Eyestrain
Headaches
Squinting
Difficulty focusing
Glare or halos around lights
Reflex Sympathetic Dystrophy (RSD), now more commonly known as Complex Regional Pain Syndrome (CRPS), is a chronic pain condition that typically develops after an injury, surgery, stroke, or heart attack. It is characterized by disproportionate, persistent pain, often accompanied by changes in skin color, temperature, and swelling in the affected area. The pain is often described as burning, throbbing, or shooting.
Refsum disease is a rare, inherited metabolic disorder characterized by the body's inability to break down phytanic acid, a branched-chain fatty acid found in certain foods. This leads to an accumulation of phytanic acid in the blood and tissues, causing a variety of neurological and other health problems. It is an autosomal recessive condition.
Bringing up undigested food or liquid into the mouth.
Sour or bitter taste in the mouth.
Feeling of a lump in the throat.
Heartburn (burning sensation in the chest).
Difficulty swallowing (dysphagia) in some cases.
Coughing or wheezing, especially at night.
Regional enteritis, also known as Crohn's disease, is a chronic inflammatory bowel disease (IBD) that causes inflammation of the digestive tract. It can affect any part of the digestive tract, from the mouth to the anus, but most commonly affects the small intestine (ileum) and the beginning of the colon. Crohn's disease is characterized by periods of active inflammation (flare-ups) followed by periods of remission when symptoms are minimal or absent. There is no cure for Crohn's disease, but various treatments can help control symptoms and achieve long-term remission.
Reiter's Syndrome, now more commonly referred to as Reactive Arthritis, is a type of arthritis that occurs as a reaction to an infection in the body. Often, the infection is in the urinary tract, genitals, or intestines. It typically affects the joints, eyes, and urethra (the tube that carries urine out of the body). Reactive arthritis is not contagious.
Relapsing fever is a bacterial infection characterized by recurring episodes of fever separated by periods without fever. It is caused by various species of Borrelia bacteria transmitted to humans through the bites of infected ticks or lice. The disease is named for its characteristic pattern of recurring fevers.
REM Sleep Behavior Disorder (RBD) is a parasomnia in which you physically act out vivid, often unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM (rapid eye movement) sleep. Normally, during REM sleep, your brain paralyzes your muscles to prevent you from acting out your dreams. In RBD, this paralysis is incomplete or absent. It can be associated with other neurological conditions, such as Parkinson's disease, Lewy body dementia, and multiple system atrophy. It can be dangerous to both the individual and their bed partner.
Renal artery stenosis (RAS) is the narrowing of one or both of the arteries that carry blood to the kidneys. This narrowing reduces blood flow to the affected kidney(s). Reduced blood flow can lead to kidney damage, high blood pressure, and fluid retention. It can progressively worsen, leading to significant health problems if left untreated.
Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults. It originates in the lining of the proximal convoluted tubule, the portion of the very small tubes in the kidney that filter the blood and remove waste products. Various subtypes exist, with clear cell RCC being the most prevalent. RCC is often discovered incidentally during imaging tests for other conditions.
Symptoms can vary depending on the severity and speed of kidney failure progression. Common symptoms include:
Decreased urine output
Swelling in legs, ankles, or feet (edema)
Fatigue
Shortness of breath
Nausea
Loss of appetite
Confusion
Seizures (in severe cases)
Persistent itching
Muscle cramps
High blood pressure
Renal Tubular Acidosis (RTA) is a group of disorders characterized by a defect in the kidney's ability to properly acidify the urine. This leads to an accumulation of acid in the body (metabolic acidosis) despite normal kidney function in other areas. The specific defect lies in the renal tubules, which are responsible for reabsorbing bicarbonate or excreting acid into the urine. Different types of RTA exist based on the specific part of the tubule affected and the underlying cause.
Renovascular hypertension is high blood pressure caused by narrowed or blocked arteries that supply blood to the kidneys. This narrowing, often due to atherosclerosis or fibromuscular dysplasia, reduces blood flow to the kidneys. In response, the kidneys release hormones that raise blood pressure throughout the body.
Repetitive Strain Injury (RSI), also known as cumulative trauma disorder, is a general term used to describe pain in the muscles, nerves, and tendons caused by repetitive movement and overuse. It commonly affects the wrists, hands, forearms, shoulders, and neck. RSI can encompass a variety of specific conditions like carpal tunnel syndrome, tendinitis, and tenosynovitis. The core issue involves tissue damage resulting from sustained or repeated motions.
Shortness of breath
Fatigue
Confusion
Headache
Sleepiness
Tremors
Cyanosis (bluish discoloration of the skin, lips, and nail beds)
Rapid breathing
Dizziness
Respiratory alkalosis is a condition that occurs when you hyperventilate, breathing out too much carbon dioxide (CO2). This leads to a decrease in the partial pressure of CO2 in the blood (PaCO2), increasing the blood's pH and making it more alkaline. The body attempts to compensate for this imbalance.
1. Summary about disease: Respiratory Distress Syndrome (RDS), also known as Hyaline Membrane Disease (HMD), is a breathing disorder most commonly seen in premature infants. It's caused by a lack of surfactant, a substance that helps the lungs inflate and keeps the air sacs (alveoli) from collapsing. This lack of surfactant leads to stiff lungs, making it difficult for the infant to breathe.
Respiratory Syncytial Virus (RSV) infection is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious, especially for infants and older adults. It is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia in children younger than 1 year in the United States.
Fatigue
Shortness of breath, especially with exertion or when lying flat
Swelling in the ankles, feet, legs, and abdomen (edema)
Weakness
Cough, particularly when lying down
Ascites (fluid accumulation in the abdomen)
Chest pain
Palpitations (feeling of rapid or irregular heartbeats)
Lightheadedness or dizziness
Jugular venous distention (swollen neck veins)
Restless Legs Syndrome (RLS), also known as Willis-Ekbom Disease, is a neurological disorder characterized by an irresistible urge to move the legs, often accompanied by uncomfortable sensations. These sensations are frequently described as creeping, crawling, pulling, throbbing, or itching. The urge to move is typically worse during periods of inactivity, especially in the evening or at night, and is temporarily relieved by movement. This can significantly disrupt sleep and affect daytime functioning.
Reticular dysgenesis (RD), also known as severe combined immunodeficiency with leukopenia (SCID-L), is an extremely rare and severe form of SCID, an inherited immune deficiency disorder. It is characterized by a complete or near-complete absence of lymphocytes (T cells, B cells, and NK cells) and granulocytes (neutrophils), crucial components of the immune system. This leaves affected individuals highly susceptible to severe, recurrent, and life-threatening infections from bacteria, viruses, and fungi. RD is often fatal in early infancy if left untreated.
Context is Key: A reticulocyte count must always be interpreted in the context of the patient's overall clinical picture, including other blood test results, medical history, and physical examination findings.
Normal Ranges Vary: Normal ranges for reticulocyte counts can vary slightly between laboratories.
Relative vs. Absolute Count: Both the relative reticulocyte percentage and the absolute reticulocyte count are important. The absolute count is generally more informative.
Corrected Reticulocyte Count: In cases of anemia, a "corrected" reticulocyte count is often calculated to account for the shortened lifespan of red blood cells and to provide a more accurate assessment of bone marrow activity.
Consultation with a Hematologist: In many cases, consulting a hematologist (a blood specialist) is necessary to properly diagnose and manage the underlying cause of an abnormal reticulocyte count.
Reticulocytosis is a condition characterized by an increased number of reticulocytes in the blood. Reticulocytes are immature red blood cells (RBCs) that are released from the bone marrow into the bloodstream. An elevated reticulocyte count indicates that the bone marrow is producing RBCs at a higher rate than normal, usually in response to anemia or other blood loss. It is a sign that the body is attempting to compensate for a shortage of mature red blood cells.
Reticulum cell sarcoma is an outdated term for what is now classified as Diffuse Large B-cell Lymphoma (DLBCL), a type of non-Hodgkin lymphoma. It's a cancer of the lymphatic system, specifically affecting B lymphocytes (B-cells). DLBCL is an aggressive lymphoma, meaning it can grow and spread quickly, but it's also often curable with appropriate treatment.
Blurred or distorted vision
Decreased night vision
Seeing floaters (small specks or clouds drifting in your vision)
Seeing flashes of light
Loss of peripheral vision
A dark or empty spot in the center of your vision
Sudden vision loss
Retinal artery occlusion (RAO) is a blockage in one of the arteries that carries blood to the retina, the light-sensitive tissue at the back of the eye. This blockage deprives the retina of oxygen, leading to sudden and painless vision loss. RAO is a serious condition that can cause permanent vision impairment if not treated promptly. There are two main types: Central Retinal Artery Occlusion (CRAO), affecting the main retinal artery, and Branch Retinal Artery Occlusion (BRAO), affecting a smaller branch artery.
Retinal detachment is a serious eye condition where the retina, a light-sensitive layer of tissue at the back of the eye, pulls away from its underlying support tissue. This separation deprives the retinal cells of oxygen and nourishment. The longer the retina remains detached, the greater the risk of permanent vision loss. It is a medical emergency requiring prompt treatment.
Retinal Vein Occlusion (RVO) is a blockage of a vein that carries blood away from the retina. This blockage can lead to bleeding and fluid leakage in the retina, potentially causing vision loss. There are two main types: Branch Retinal Vein Occlusion (BRVO), affecting a smaller vein branch, and Central Retinal Vein Occlusion (CRVO), affecting the main central retinal vein. The severity and impact on vision vary depending on the location and extent of the occlusion.
Retinitis refers to inflammation of the retina, the light-sensitive layer of tissue at the back of the eye. It can have various causes, leading to impaired vision. Different types of retinitis exist, including retinitis pigmentosa (RP), a genetic disorder, and cytomegalovirus (CMV) retinitis, an infection that primarily affects individuals with weakened immune systems. The specific effects on vision depend on the cause and location of the inflammation.
Retinitis Pigmentosa (RP) is a group of inherited eye diseases that cause slow, progressive loss of vision. It affects the retina, the light-sensitive tissue at the back of the eye. RP primarily affects the rod photoreceptor cells, which are responsible for vision in low light, and later, the cone photoreceptor cells, which are responsible for color vision and vision in bright light. The disease typically begins with night blindness and a gradual loss of peripheral vision, eventually leading to tunnel vision and, in some cases, legal blindness.
Retinoblastoma is a rare cancer that develops in the retina, the light-sensitive tissue at the back of the eye. It primarily affects young children, but can rarely occur in adults. It can be unilateral (affecting one eye) or bilateral (affecting both eyes). Early detection and treatment are crucial for survival and preserving vision.
Retinopathy of Prematurity (ROP) is an eye disease that can occur in premature babies. It happens when abnormal blood vessels grow in the retina, the light-sensitive tissue at the back of the eye. These abnormal vessels can leak and scar the retina, potentially leading to vision loss or blindness. ROP is a leading cause of childhood blindness.
Retrobulbar neuritis, also known as optic neuritis, is an inflammatory condition that affects the optic nerve, specifically the portion behind the eyeball (retrobulbar). This inflammation damages the myelin sheath that surrounds the nerve fibers, disrupting the transmission of visual information from the eye to the brain. This can lead to a range of visual disturbances, most commonly vision loss and pain with eye movement. It is often associated with multiple sclerosis (MS) but can occur due to other causes or even be idiopathic (cause unknown).
Retroperitoneal fibrosis (RPF) is a rare condition characterized by chronic inflammation and the formation of fibrous tissue in the retroperitoneum, the space behind the abdominal cavity. This fibrous tissue can encase and compress retroperitoneal structures, most commonly the ureters (tubes that carry urine from the kidneys to the bladder), leading to hydronephrosis (swelling of the kidney due to urine build-up) and potential kidney damage.
Reye's syndrome is a rare but serious condition that causes swelling in the liver and brain. It most often affects children and teenagers recovering from a viral infection, such as the flu or chickenpox. While the exact cause is unknown, it's strongly linked to the use of aspirin during these viral illnesses. Reye's syndrome can lead to permanent brain damage or death if not diagnosed and treated promptly.
Rhabdomyolysis is a serious condition caused by the breakdown of damaged skeletal muscle. This breakdown releases muscle cell contents into the bloodstream, including myoglobin, creatine kinase (CK), and electrolytes. High levels of these substances can lead to kidney damage, heart problems, and other complications.
Rhabdomyosarcoma (RMS) is a rare type of cancer that forms in soft tissue, specifically in skeletal muscle tissue (muscle that is attached to bones and helps the body move). RMS can occur at any age, but it's most common in children. RMS can occur in many places in the body, such as the head and neck, groin, abdomen, or in an arm or leg.
Rheumatic fever (RF) is a serious inflammatory condition that can develop as a complication of inadequately treated strep throat or scarlet fever. These infections are caused by bacteria called
Streptococcus pyogenes
(group A streptococcus). Rheumatic fever primarily affects children and adolescents but can affect adults as well. It can damage the heart, joints, brain, and skin. Repeated episodes of RF can lead to rheumatic heart disease, a chronic condition that can cause permanent heart damage, including damaged heart valves.
Rheumatic heart disease (RHD) is a chronic heart condition resulting from rheumatic fever, an inflammatory disease that can develop following inadequately treated strep throat or scarlet fever. Rheumatic fever can damage the heart valves, leading to RHD, which can cause significant morbidity and mortality. The damage to the heart valves restricts blood flow, forcing the heart to work harder.
Rheumatism is an umbrella term for conditions causing chronic or intermittent pain affecting the joints and connective tissues. It's not a specific disease itself, but rather encompasses a variety of disorders like arthritis, bursitis, lupus, and fibromyalgia. The common thread is pain, stiffness, and often limited range of motion in the musculoskeletal system.
Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder that primarily affects the joints. In RA, the body's immune system mistakenly attacks its own tissues, specifically the synovium (the lining of the joints). This leads to inflammation, pain, swelling, stiffness, and eventually, joint damage and disability. RA can also affect other organs, including the skin, eyes, lungs, heart, and blood vessels.
Rheumatoid vasculitis (RV) is a rare but serious complication of long-standing, severe rheumatoid arthritis (RA). It involves inflammation of the blood vessels, leading to damage of organs and tissues supplied by those vessels. It's a systemic condition, meaning it can affect various parts of the body. The severity can range from mild skin rashes to life-threatening organ damage.
Rhinitis is inflammation and irritation of the mucous membrane inside the nose. It's often characterized by a runny nose, nasal congestion, sneezing, and itching. It can be caused by allergies (allergic rhinitis) or non-allergic factors (non-allergic rhinitis). Allergic rhinitis is triggered by allergens like pollen, dust mites, or pet dander, while non-allergic rhinitis can be triggered by irritants, weather changes, or other factors.
Rhinorrhea, commonly known as a runny nose, is the drainage of mucus from the nasal passages. It can be caused by a variety of factors, including infections, allergies, and irritants. While often a minor inconvenience, it can sometimes indicate a more serious underlying condition.
Rhinophyma is a skin disorder characterized by a large, red, bulbous nose. It is a severe subtype of rosacea, a chronic inflammatory skin condition. It results from a thickening of the skin and sebaceous (oil) glands of the nose. While it can be visually prominent and affect self-esteem, it is not life-threatening.
Rhinoscleroma is a chronic, progressive granulomatous infectious disease that primarily affects the nose, but can also involve the pharynx, larynx, trachea, and bronchi. It is caused by the bacterium
Klebsiella rhinoscleromatis
. The disease is characterized by slowly developing, destructive lesions that can lead to disfigurement and airway obstruction if left untreated.
Rhinosporidiosis is a chronic granulomatous infection primarily affecting the mucous membranes of the nose, but can also involve other sites such as the conjunctiva, skin, and genitalia. It is caused by the fungus
Rhinosporidium seeberi
. The disease is characterized by the formation of polypoid masses or lesions that are often friable and bleed easily. It is more common in tropical regions and affects both humans and animals.
Rhizomelic chondrodysplasia punctata (RCDP) is a rare genetic disorder that primarily affects bone and cartilage development, resulting in skeletal abnormalities, intellectual disability, and other health problems. There are multiple types of RCDP, with RCDP type 1 being the most common. "Rhizomelic" refers to shortening of the proximal limbs (humerus and femur). "Chondrodysplasia punctata" indicates abnormalities in cartilage and the presence of stippled calcifications in cartilage, especially around joints, seen on X-rays.
A rib fracture is a break in one or more of the bones in your rib cage. The ribs protect organs in the chest, such as the lungs and heart. Fractured ribs are usually caused by a direct blow to the chest, such as from a car accident or a fall. A severe cough can also fracture ribs. While painful, most fractured ribs heal on their own with rest and pain management.
Riboflavin deficiency, also known as ariboflavinosis, is a condition caused by a lack of riboflavin (vitamin B2) in the diet. Riboflavin is essential for various metabolic processes, including energy production, cellular function, growth, and the metabolism of fats, carbohydrates, and proteins. Deficiency can lead to a variety of health problems, mainly affecting the skin, mucous membranes, eyes, and nervous system. It is usually seen in conjunction with other nutrient deficiencies.
Rickettsialpox is a mild, self-limiting, infectious disease caused by the bacterium
Rickettsia akari
. It's transmitted to humans through the bite of a mite (
Liponyssoides sanguineus
) that infests rodents, primarily house mice. Rickettsialpox is characterized by an initial eschar (a dark, crusty scab) at the site of the mite bite, followed by a generalized papulovesicular rash (small, raised bumps that turn into fluid-filled blisters) accompanied by flu-like symptoms.
Right ventricular failure (RVF), also known as right-sided heart failure, occurs when the right ventricle of the heart has difficulty pumping blood to the lungs. This leads to a backup of blood in the veins, causing fluid retention in the body. RVF can be caused by conditions that increase the workload of the right ventricle, such as lung diseases, left-sided heart failure, or pulmonary hypertension.
Rigidity, in a medical context, refers to stiffness or inflexibility of muscles. It's a resistance to passive movement of a limb, regardless of the speed or direction of the force applied. It can be a symptom of various underlying conditions affecting the brain, spinal cord, or muscles themselves. The severity can range from mild stiffness to severe, debilitating immobility.
Rickets is a condition that affects bone development in children. It's caused by a deficiency of vitamin D, calcium, or phosphate, leading to soft and weakened bones. This can result in skeletal deformities, growth problems, and increased susceptibility to fractures.
Riley-Day syndrome, also known as familial dysautonomia or hereditary sensory and autonomic neuropathy type III (HSAN III), is a rare genetic disorder that primarily affects the development and function of the autonomic nervous system and the sensory nervous system. The autonomic nervous system controls involuntary functions such as heart rate, blood pressure, body temperature, digestion, and sweating. The sensory nervous system is responsible for sensing pain, temperature, and touch. This dysfunction can lead to a wide range of symptoms affecting multiple systems of the body.
Ringworm, despite its name, is not caused by a worm. It's a common fungal infection of the skin, hair, and nails. The infection causes a characteristic ring-shaped rash, hence the name. It's also known by different names depending on the location on the body (e.g., tinea pedis for athlete's foot, tinea capitis for scalp ringworm). Ringworm is generally treatable with antifungal medications.
Ring chromosome is a rare chromosomal abnormality where a chromosome forms a circular structure. This happens when the ends of a chromosome break off and then rejoin to form a ring. The genetic information lost during the breakage can lead to a variety of health problems, depending on which chromosome is affected and how much genetic material is lost. The severity of symptoms can vary widely among affected individuals.
1. Summary about disease: Ritter's disease, also known as Staphylococcal Scalded Skin Syndrome (SSSS), is a severe skin infection primarily affecting infants and young children. It is characterized by widespread blistering and peeling of the skin, resembling a burn. It is caused by toxins produced by certain strains of Staphylococcus aureus bacteria.
1. Summary about disease Roberts syndrome (RBS) is a rare genetic disorder characterized by prenatal and postnatal growth deficiency, limb malformations (affecting all four limbs but often more severely the arms), facial abnormalities, and, in some cases, intellectual disability. The severity of symptoms varies widely among affected individuals. It is also known as pseudothalidomide syndrome because the limb malformations seen in RBS are similar to those caused by the drug thalidomide, which was once prescribed for morning sickness.
Rocky Mountain Spotted Fever (RMSF) is a tick-borne disease caused by the bacterium
Rickettsia rickettsii
. It is a serious illness that can be fatal if not treated early and appropriately. While the name suggests it's limited to the Rocky Mountain region, it occurs throughout North, Central, and South America.
Rod-cone dystrophy (RCD), also known as retinitis pigmentosa (RP), is a group of inherited eye disorders that cause progressive vision loss. It primarily affects the photoreceptor cells in the retina, specifically the rods (responsible for night vision) and cones (responsible for color and central vision). Initially, the rods degenerate, leading to night blindness and loss of peripheral vision. As the disease progresses, the cones also degenerate, resulting in decreased visual acuity, color vision problems, and eventually, central vision loss. The severity and rate of progression vary significantly among individuals.
Romano-Ward syndrome (RWS) is a congenital long QT syndrome (LQTS). It is a genetic disorder affecting the heart's electrical system, specifically the repolarization process after each heartbeat. This prolonged repolarization (QT interval) increases the risk of irregular heartbeats (arrhythmias), which can lead to fainting (syncope), seizures, or sudden cardiac death. It is typically an autosomal dominant condition, meaning only one copy of the affected gene is needed to cause the syndrome.
Turning the head towards the side that is stroked on the cheek or mouth.
Opening the mouth.
Attempting to suck.
Roseola, also known as sixth disease or exanthem subitum, is a mild viral infection common in young children, typically between 6 months and 3 years old. It's characterized by a high fever followed by a distinctive pink or red rash. It's usually a self-limiting illness and rarely causes serious complications.
Rosacea is a common skin condition that causes visible blood vessels and redness in the face. It can also produce small, red, pus-filled bumps. These signs and symptoms may flare up for weeks to months and then go away for a while. Rosacea can be mistaken for acne, other skin problems or natural ruddiness. While there is no cure, treatments can control and reduce the symptoms.
Ross River fever (RRF) is a mosquito-borne viral disease caused by the Ross River virus (RRV). It's primarily characterized by joint pain (arthritis), often accompanied by fever and rash. While not typically life-threatening, the symptoms can be debilitating and persist for months. It is endemic to Australia, Papua New Guinea, and other parts of the South Pacific.
A rotator cuff tear is an injury that affects a group of muscles and tendons that surround the shoulder joint, holding the head of the upper arm bone (humerus) securely in the shallow socket of the shoulder. Tears can occur due to acute injury or develop gradually over time due to repetitive overhead motions or age-related degeneration. This injury can cause pain, weakness, and limited range of motion in the affected shoulder.
Rotavirus infection is a highly contagious viral illness that primarily affects infants and young children. It is the most common cause of severe diarrheal disease in this age group worldwide. The infection causes inflammation of the stomach and intestines (gastroenteritis), leading to symptoms like diarrhea, vomiting, fever, and abdominal pain. While adults can also get rotavirus, the symptoms are usually milder. Vaccination is highly effective in preventing severe rotavirus infection in infants.
Rotor syndrome is a rare, benign, inherited disorder characterized by chronic, predominantly conjugated hyperbilirubinemia (increased bilirubin levels in the blood). It is caused by impaired hepatic uptake and storage of bilirubin, leading to its regurgitation into the circulation. The condition typically presents with mild jaundice but is otherwise asymptomatic and does not usually require treatment.
Rubella, also known as German measles or three-day measles, is a contagious viral infection. It is typically a mild disease, especially in children. However, it poses a serious threat to pregnant women, as it can cause severe birth defects in the developing fetus (Congenital Rubella Syndrome or CRS). Eradication efforts are largely focused on vaccination to prevent CRS.
Rumination syndrome is a functional gastrointestinal disorder characterized by the effortless regurgitation of recently ingested food from the stomach into the mouth, followed by re-chewing and re-swallowing or spitting it out. It is often mistaken for vomiting, but it is not associated with nausea, retching, or forceful contractions. The regurgitation is usually not acidic or bile-stained. Rumination syndrome can occur in infants, children, and adults.
Russell-Silver syndrome (RSS) is a rare genetic disorder characterized primarily by intrauterine growth restriction (IUGR) and/or postnatal growth failure, leading to short stature. Other common features include a distinctive facial appearance, body asymmetry, and feeding difficulties in infancy. The severity of symptoms can vary significantly among individuals.
A ruptured eardrum (tympanic membrane perforation) is a hole or tear in the thin tissue that separates your ear canal from your middle ear. It can cause hearing loss, and make your middle ear vulnerable to infections. Many ruptured eardrums heal within a few weeks without treatment. But some require repair.
Reye's syndrome is a rare but serious condition that causes swelling in the liver and brain. It most often affects children and teenagers recovering from a viral infection, such as the flu or chickenpox. The exact cause is unknown, but it's strongly associated with the use of aspirin during viral illnesses. Reye's syndrome can lead to permanent brain damage or death if not diagnosed and treated promptly.
Rabson-Mendenhall syndrome is a rare, severe genetic disorder characterized by insulin resistance, abnormalities of the pineal gland, and facial and dental abnormalities. Individuals with this condition are resistant to the effects of insulin, a hormone that regulates blood sugar levels. This resistance leads to elevated blood sugar (hyperglycemia) and can result in various health problems.
Radial Tunnel Syndrome (RTS) is a condition caused by compression of the radial nerve in the radial tunnel of the forearm. This tunnel is a narrow space formed by muscles and bone near the elbow. The compression leads to pain in the forearm and elbow, but unlike carpal tunnel syndrome, it rarely causes numbness or weakness. It's often confused with tennis elbow (lateral epicondylitis).
Neck pain or swelling: Tenderness in the thyroid area is common shortly after treatment.
Nausea and vomiting: This is usually mild and temporary.
Dry mouth: RAI can affect the salivary glands.
Taste changes: Metallic or altered taste sensations may occur.
Dry eyes: Similar to dry mouth, RAI can affect tear production.
Fatigue: Feeling tired or weak is frequent.
Hair thinning: Temporary hair loss is possible, but usually grows back.
Changes in menstruation: Women may experience irregular periods.
Infertility: Though usually not permanent, RAI can affect fertility in both men and women.
Hypothyroidism: An underactive thyroid, which requires lifelong thyroid hormone replacement.
Sialadenitis (inflammation of the salivary glands): Can cause pain and swelling in the cheeks.
Rare but serious side effects: Including bone marrow suppression, secondary cancers (very rare).
Radioulnar synostosis is a congenital condition (present at birth) characterized by an abnormal bony or cartilaginous bridge that connects the radius and ulna bones in the forearm. This fusion restricts or completely prevents pronation (turning the palm down) and supination (turning the palm up) movements. It can range in severity from a mild limitation of motion to complete immobility.
Ramsay Hunt Syndrome (RHS), also known as herpes zoster oticus, is a rare neurological disorder characterized by a painful rash around the ear, on the face, or in the mouth. It occurs when the varicella-zoster virus, the same virus that causes chickenpox and shingles, reactivates and affects the facial nerve (cranial nerve VII) and sometimes the auditory nerve (cranial nerve VIII). This reactivation can lead to facial paralysis and hearing problems.
A ranula is a type of mucocele found in the floor of the mouth. It's a cyst-like lesion that develops when a salivary gland (typically the sublingual gland) becomes blocked, causing saliva to leak into the surrounding tissues. This leaked saliva collects, forming a bluish, translucent swelling that can resemble a frog's belly (hence the name "ranula," derived from the Latin word for frog).
Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) is a very rare syndrome characterized by rapid weight gain, usually in childhood, along with problems with the hypothalamus (a brain region controlling many bodily functions), impaired breathing, and dysfunction of the autonomic nervous system.
Rapp-Hodgkin syndrome (RHS), also known as ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome, is a rare genetic disorder characterized by a combination of ectodermal dysplasia (abnormal development of structures derived from the ectoderm, such as skin, hair, nails, and teeth), cleft lip and/or cleft palate, and limb malformations, specifically ectrodactyly (split hand/foot malformation). The severity and specific features can vary greatly between individuals.
Rare blood disorders encompass a diverse group of conditions affecting the blood cells, bone marrow, blood proteins (like clotting factors), and lymphatic system. They can be inherited or acquired. Due to their rarity, diagnosis can be challenging, and treatment options may be limited. They can affect any age group and vary significantly in severity from mild to life-threatening.
Rare anemias are a diverse group of conditions characterized by a lower-than-normal number of red blood cells or hemoglobin in the blood, resulting from a variety of underlying causes, many of which are genetic or acquired. They are considered rare due to their low prevalence in the general population. Some examples include Aplastic Anemia, Diamond-Blackfan Anemia, and Paroxysmal Nocturnal Hemoglobinuria (PNH). The severity and prognosis vary greatly depending on the specific type of rare anemia.
Rare bone diseases encompass a wide variety of conditions that affect the growth, structure, or density of bones. These diseases are often genetic but can also be caused by infections, hormonal imbalances, or unknown factors. Due to their rarity, diagnosis and treatment can be challenging. Examples include Osteogenesis Imperfecta, Fibrous Dysplasia, and Achondroplasia.
Rare brain diseases encompass a wide array of neurological disorders, each characterized by their low prevalence and often complex, poorly understood etiologies. These conditions can affect various parts of the brain, leading to a diverse range of neurological and cognitive impairments. Due to their rarity, diagnosis and treatment can be challenging, often requiring specialized expertise.
Rare cancers are cancers that affect a small number of people compared to more common cancers. There isn't a single definition, but often cancers affecting fewer than 6 per 100,000 people per year are considered rare. Because they are rare, research and treatment options may be limited compared to more common cancers. This can lead to challenges in diagnosis, treatment, and finding specialists. They span a wide range of cancer types affecting various organs and tissues, and can occur at any age.
Rare chromosomal disorders encompass a wide range of conditions resulting from abnormalities in the number or structure of chromosomes. These abnormalities can lead to various developmental and health issues, varying greatly in severity depending on the specific chromosome affected and the nature of the alteration (e.g., deletion, duplication, translocation). Each specific chromosomal disorder is individually rare.
Rare connective tissue diseases (CTDs) are a diverse group of disorders that affect the connective tissues of the body. Connective tissues provide support, structure, and elasticity to various organs and tissues, including skin, joints, blood vessels, and internal organs. Due to their rarity and the broad range of symptoms they can cause, diagnosis can be challenging. Examples include Scleroderma, Ehlers-Danlos Syndrome, Marfan Syndrome, and others. Each specific disease has its own characteristics and prognosis.
Rare corneal dystrophies are a group of inherited eye disorders that cause abnormal deposits to build up in the cornea, the clear front surface of the eye. These deposits can affect the cornea's clarity, leading to vision problems. There are many different types of corneal dystrophies, each with its own unique characteristics and inheritance pattern. The severity and progression of these dystrophies vary greatly.
Erythropoietic Protoporphyria (EPP) is a rare inherited metabolic disorder characterized by extreme sensitivity to sunlight. It results from a deficiency in the enzyme ferrochelatase, which is necessary for the production of heme (a component of hemoglobin). This deficiency leads to the accumulation of protoporphyrin in red blood cells, plasma, and the skin. This excess protoporphyrin reacts with sunlight, causing painful skin reactions.
Rare dental disorders encompass a wide range of conditions affecting the teeth, gums, and oral structures that are infrequent in the general population. These disorders can be genetic, developmental, or acquired, and often have significant implications for oral health, aesthetics, and overall well-being. Examples include Amelogenesis Imperfecta, Dentinogenesis Imperfecta, Ectodermal Dysplasia with dental involvement, and Hypophosphatasia.
Rare developmental disorders encompass a wide range of conditions that arise during development, affecting physical, cognitive, and/or behavioral aspects. These disorders are individually rare, but collectively affect a significant number of individuals. They often involve genetic mutations, chromosomal abnormalities, or environmental factors. Their impact can vary greatly, from mild to severe, and may require lifelong management.
Rare digestive disorders encompass a wide range of conditions affecting the gastrointestinal (GI) tract, each with unique characteristics, prevalence, and impact on overall health. These disorders are considered "rare" because they affect a small percentage of the population, often less than 1 in 2,000 individuals. Due to their rarity, diagnosis can be challenging, and research into effective treatments may be limited. They can affect any part of the GI tract, from the esophagus to the anus, disrupting normal digestive processes such as nutrient absorption, waste elimination, and gut motility. Examples include Eosinophilic Esophagitis, Achalasia, Gastroparesis, and Microscopic Colitis.
Rare endocrine disorders are a diverse group of conditions that affect the endocrine system. The endocrine system is responsible for producing hormones that regulate various bodily functions such as metabolism, growth, reproduction, and mood. These disorders are considered rare because they affect a small percentage of the population. They can result from genetic mutations, autoimmune diseases, tumors, or other unknown factors. Due to the variety of disorders, diagnosis and treatment can be challenging.
This hypothetical rare eye disease,
Ocular Chromatic Aberration Deficiency
(OCAD), is a genetic condition affecting the cone cells in the retina. It primarily impairs color perception and visual acuity, leading to difficulties in distinguishing certain color shades and experiencing blurred vision, particularly in bright light. It affects approximately 1 in 500,000 individuals.
Rare genetic disorders are a diverse group of conditions, each affecting a small number of people, often resulting from a mutation in a single gene or chromosome. They can manifest at any age and affect any part of the body. Due to their rarity, diagnosis and treatment can be challenging. Many have no cure, and management focuses on alleviating symptoms and improving quality of life.
Rare heart conditions encompass a diverse group of cardiac disorders that affect a relatively small number of individuals compared to common heart diseases like coronary artery disease or hypertension. These conditions can be congenital (present at birth) or acquired later in life. They often involve structural abnormalities, electrical conduction issues, or problems with the heart muscle itself. Due to their rarity, diagnosis and treatment can be challenging, requiring specialized expertise. Examples include, but are not limited to, cardiac tumors, arrhythmogenic right ventricular dysplasia (ARVD), and Long QT syndrome.
Rare immunodeficiency syndromes are a diverse group of genetic disorders that impair the immune system's ability to defend the body against infections, autoimmune diseases, and cancers. These syndromes can affect different components of the immune system, leading to varying degrees of immune dysfunction and susceptibility to illness. Because they are rare, diagnosis and treatment can be challenging.
Rare kidney diseases encompass a diverse group of disorders affecting the structure or function of the kidneys that occur infrequently in the general population. These diseases can be genetic, autoimmune, or caused by other underlying conditions. They often lead to chronic kidney disease (CKD) or kidney failure if left untreated. Examples include Alport syndrome, Fabry disease, atypical hemolytic uremic syndrome (aHUS), and primary hyperoxaluria.
Rare liver diseases encompass a wide spectrum of conditions affecting the liver, each with a low prevalence in the general population. These diseases can affect various liver functions, leading to inflammation, scarring (fibrosis), and eventually liver failure if left untreated. Examples include Primary Biliary Cholangitis (PBC), Primary Sclerosing Cholangitis (PSC), Autoimmune Hepatitis (AIH), Wilson's disease, Alpha-1 Antitrypsin Deficiency, and Budd-Chiari syndrome. Due to their rarity, diagnosis can be delayed, and specialized care is often required. The prognosis and management strategies vary greatly depending on the specific disease.
Rare metabolic disorders are a group of individually rare genetic conditions that disrupt normal metabolism. Metabolism involves the chemical processes the body uses to convert food into energy and to build and repair tissues. These disorders often result from enzyme deficiencies, leading to the accumulation of toxic substances or a lack of essential products. The specific symptoms, severity, and treatment options vary widely depending on the specific disorder.
Rare lung diseases encompass a diverse group of conditions affecting the lungs and respiratory system that are uncommon in the general population. Due to their rarity, they often present diagnostic and therapeutic challenges. These diseases can affect different parts of the lungs, including the airways, air sacs (alveoli), blood vessels, and the tissue surrounding these structures. They can be caused by genetic factors, environmental exposures, autoimmune disorders, or unknown reasons. The severity and progression vary widely depending on the specific disease and individual factors.
Rare movement disorders encompass a wide range of neurological conditions that affect a person's ability to control their movements. These disorders can manifest in various ways, including involuntary movements, difficulty initiating movement, slow movement, rigidity, tremor, and problems with balance and coordination. Due to their rarity, many are poorly understood, and diagnosis and treatment can be challenging. Examples include, but are not limited to, chorea, dystonia, myoclonus, ataxia, parkinsonism-plus syndromes, and stiff-person syndrome. The impact on an individual's life can be significant, affecting their ability to perform daily activities and impacting their overall quality of life.
Rare muscle diseases are a diverse group of conditions that affect the muscles responsible for movement and other bodily functions. These diseases can be genetic or acquired, and they can range in severity from mild weakness to life-threatening paralysis. Due to their rarity, diagnosis can be challenging, and research is ongoing to develop effective treatments and cures.
Due to the vast number of rare neurological disorders, providing a summary of "the disease" is impossible. Rare neurological disorders encompass a wide range of conditions affecting the brain, spinal cord, and nerves. They can be genetic, developmental, or acquired, and often present with unique and overlapping symptoms. What unites them is their low prevalence, making diagnosis and treatment challenging. Some examples include: Amyotrophic Lateral Sclerosis (ALS), Huntington's disease, Multiple Sclerosis, Rett syndrome, Batten disease, etc.
1. Summary about disease Rare sleep disorders encompass a wide range of conditions that disrupt normal sleep patterns and often significantly impact daily functioning. These disorders are characterized by their low prevalence in the general population. They can involve difficulties falling asleep or staying asleep (insomnia), excessive daytime sleepiness (hypersomnia), abnormal behaviors during sleep (parasomnias), and disruptions in the sleep-wake cycle. Specific examples include Kleine-Levin Syndrome, Fatal Familial Insomnia, REM Sleep Behavior Disorder, and various types of parasomnias like sleepwalking and sleep terrors in adults. Diagnosis and management of these disorders are often complex and require specialized expertise.
Rare vascular diseases encompass a diverse group of conditions affecting the blood vessels (arteries, veins, and capillaries). These diseases can lead to inflammation, narrowing, or blockage of blood vessels, disrupting blood flow to various organs and tissues. Due to their rarity, diagnosis can be challenging, and specialized care is often required. The impact on the body can range from mild to life-threatening, depending on the specific disease and the extent of the vascular involvement.
Rare skin diseases encompass a wide range of conditions that affect the skin, hair, and nails. These diseases are individually rare, meaning they affect a small number of people compared to more common conditions like eczema or acne. Many are genetic, while others are acquired due to autoimmune reactions, infections, or environmental factors. They often present diagnostic and treatment challenges due to their unfamiliarity and the limited research available.
Rasopathies are a group of genetic syndromes caused by mutations in genes that regulate the RAS/MAPK signaling pathway. This pathway is crucial for cell growth, differentiation, and survival. Disruptions in this pathway can lead to a variety of developmental abnormalities and increased cancer risk. Common rasopathies include Neurofibromatosis Type 1 (NF1), Noonan syndrome (NS), Costello syndrome (CS), and Cardiofaciocutaneous (CFC) syndrome. Each rasopathy presents with a unique set of characteristic features, but they often overlap in symptoms.
Cold fingers or toes
Color changes in the skin in response to cold or stress, usually white, then blue, then red
Numbness, tingling, or stinging pain upon warming or stress relief.
Both types can exhibit irritability, aggression, and difficulty following rules.
Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a severe and rare genetic skin disorder characterized by extremely fragile skin that blisters and tears easily from minor friction or trauma. This blistering can occur both on the surface of the skin and within internal tissues and organs. RDEB is caused by mutations in the
COL7A1
gene, which provides instructions for making type VII collagen, a protein that forms anchoring fibrils necessary for holding the epidermis (outer layer of skin) to the dermis (inner layer of skin). The lack of functional type VII collagen leads to separation of these skin layers and blister formation.
Recurrent Aphthous Stomatitis (RAS), commonly known as canker sores, is a common condition characterized by the repeated appearance of small, shallow ulcers in the mouth. These ulcers are painful and can make eating, drinking, and speaking uncomfortable. RAS is not contagious and typically resolves on its own within a few weeks.
Recurrent Corneal Erosion Syndrome (RCE) is a condition characterized by the repeated breakdown of the corneal epithelium, the outermost layer of the cornea. This breakdown typically occurs spontaneously, often upon waking, and causes sudden, sharp eye pain. It's a chronic condition with periods of remission and exacerbation.
Recurrent Idiopathic Anaphylaxis (RIA) is a condition characterized by repeated episodes of anaphylaxis (a severe, potentially life-threatening allergic reaction) where the trigger cannot be identified despite thorough investigation. "Idiopathic" means "of unknown cause." This means that even with extensive allergy testing and medical evaluation, the specific substance or event that initiates the reaction remains a mystery. Patients with RIA experience the same symptoms as those with known-cause anaphylaxis, but the unpredictable nature of the episodes can be particularly distressing.
Red tide poisoning, more accurately referred to as harmful algal bloom (HAB) poisoning, occurs when humans consume seafood contaminated with toxins produced by certain types of algae. These blooms, often referred to as "red tides" due to the reddish discoloration they can cause in the water, contain algae that produce potent neurotoxins. The primary types of poisoning related to red tides include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), and diarrhetic shellfish poisoning (DSP). The specific toxins involved and the resulting symptoms vary depending on the type of algae and the contaminated seafood consumed.
Skin Leiomyomas (cutaneous leiomyomas): These are typically small, firm, raised bumps or nodules on the skin. They can be painful, especially when touched or exposed to cold. They usually appear on the trunk, limbs, and face.
Uterine Leiomyomas (fibroids): In women, these noncancerous tumors in the uterus can cause heavy menstrual bleeding, pelvic pain, frequent urination, and infertility.
Renal Cell Cancer: Affected individuals have an increased risk of developing renal cell carcinoma, often at a younger age than usual.
Pain: Intense pain in affected areas.
Reflex Neurovascular Dystrophy (RND), now more commonly referred to as Complex Regional Pain Syndrome (CRPS), is a chronic pain condition that usually develops after an injury, surgery, stroke, or heart attack. It's characterized by pain that is out of proportion to the severity of the initial injury. CRPS/RND typically affects one limb (arm, leg, hand, or foot).
Refsum disease is a rare, inherited (genetic) disorder that results in the buildup of phytanic acid in the blood and tissues. Phytanic acid is a branched-chain fatty acid that is normally obtained from the diet, particularly from dairy products, beef, lamb, and certain green vegetables. The accumulation of phytanic acid can damage various organs and tissues, particularly the nervous system, eyes, and bones.
Refsum disease is a rare inherited disorder that results in the buildup of phytanic acid in the blood and tissues. This accumulation primarily affects the nervous system, eyes, and skin. It's caused by a defect in the enzyme that breaks down phytanic acid, which is found in certain foods. Classical Refsum disease is an autosomal recessive disorder, meaning both parents must carry a copy of the defective gene for their child to inherit the condition.
Regional Odontodysplasia (RO) is a rare, non-hereditary developmental anomaly affecting dental hard tissues. It typically involves multiple adjacent teeth in a localized area of the maxilla or mandible, although it can affect the entire dentition. The affected teeth exhibit enamel, dentin, and sometimes pulp malformation, resulting in a characteristic "ghost-like" radiographic appearance.
Symptoms of regressive autism involve a loss of previously acquired skills. These may include:
Loss of spoken language: Child stops using words they previously knew.
Social withdrawal: Child becomes less interested in interacting with others, avoids eye contact, and stops responding to social cues.
Loss of social skills: Loss of reciprocal play, difficulty in showing or understanding facial expressions.
Repetitive behaviors: Increase in repetitive behaviors such as hand flapping, rocking, or fixations on objects.
Loss of interest in playing or interacting with toys.
Decline in motor skills: Some children may show a loss in motor skills like clumsiness or difficulty walking.
Stroke, often referred to as a "brain attack," occurs when blood supply to the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. Within minutes, brain cells begin to die. Stroke can result in lasting brain damage, long-term disability, or even death. Rehabilitation after stroke is a crucial process aimed at helping survivors regain lost skills and improve their quality of life. This often involves a multidisciplinary approach involving physical therapy, occupational therapy, speech therapy, and psychological support. The goal is to maximize independence and functional abilities.
Reiter's Syndrome, now more commonly referred to as Reactive Arthritis, is a type of arthritis that develops as a reaction to an infection in another part of the body. Often, the infection is in the urinary tract, genitals, or intestines. It is characterized by a triad of symptoms: arthritis, inflammation of the eyes (conjunctivitis or uveitis), and urinary or genital inflammation (urethritis or cervicitis). However, not all individuals experience all three symptoms. Reactive arthritis is an autoimmune condition, meaning the body's immune system mistakenly attacks its own tissues.
Renal Angiomyolipoma (AML) is a benign (non-cancerous) tumor of the kidney composed of varying proportions of blood vessels (angio-), smooth muscle (myo-), and fat (lipoma-). While generally benign, larger AMLs can cause symptoms and complications. They are most commonly found in adults and are often associated with genetic conditions like Tuberous Sclerosis Complex (TSC) and Birt-Hogg-Dubé syndrome (BHD). However, they can also occur sporadically (without a known genetic cause).
Relapsing polychondritis (RP) is a rare autoimmune disease characterized by recurrent inflammation and destruction of cartilage in various parts of the body. This inflammation most commonly affects the cartilage of the ears, nose, trachea, and joints, but can also involve the eyes, heart, blood vessels, and skin. The condition is characterized by periods of active inflammation ("flares" or "outbreaks") followed by periods of remission. The long-term prognosis varies depending on the severity and extent of organ involvement, but it can lead to significant morbidity and, in some cases, mortality.
Renal oncocytoma is a benign (non-cancerous) epithelial tumor of the kidney. It originates from the intercalated cells of the collecting ducts. While typically benign, distinguishing it from renal cell carcinoma, particularly chromophobe renal cell carcinoma, can be challenging through imaging alone.
Renal colic is severe pain caused by a kidney stone or stones obstructing the flow of urine. The pain typically starts in the flank and radiates to the groin, often described as one of the most intense pain experiences. It's a common condition affecting a significant portion of the population.
Renpenning syndrome, also known as X-linked intellectual disability-Siderius type (XLID-Siderius type), is a rare genetic disorder primarily affecting males. It is characterized by intellectual disability, short stature, skeletal abnormalities (particularly affecting the arms and hands), and genital hypoplasia (underdevelopment). The severity of symptoms can vary among affected individuals.
Repetitive motion disorders (RMDs), also known as cumulative trauma disorders, overuse syndromes, or repetitive strain injuries (RSIs), are a group of musculoskeletal conditions resulting from repetitive motions, forceful exertions, vibrations, compression, or sustained or awkward postures. These activities can damage tendons, nerves, muscles, and other soft tissues. Common examples include carpal tunnel syndrome, tendinitis, and bursitis.
Reproductive system cancer encompasses a range of cancers affecting the organs involved in reproduction. In women, this includes cancers of the ovaries, uterus (including endometrial and uterine sarcoma), cervix, vagina, and vulva. In men, it includes cancers of the prostate, testicles, and penis. These cancers are characterized by abnormal cell growth within these organs, potentially spreading to other parts of the body if not detected and treated early. The specific type, stage, and grade of the cancer dictate treatment options and prognosis.
1. Summary about disease: Resistance to Thyroid Hormone (RTH) is a rare genetic disorder in which the body's cells do not respond normally to thyroid hormone. This can lead to a complex and variable presentation, with individuals experiencing symptoms of both hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) or sometimes no symptoms at all. The body produces normal or elevated levels of thyroid hormone, but the tissues are less responsive, leading the pituitary gland to produce more TSH (thyroid-stimulating hormone) in an attempt to stimulate thyroid hormone action.
Restless Genital Syndrome (ReGS), also known as Persistent Genital Arousal Disorder (PGAD), is a rare and often distressing condition characterized by persistent, unwanted, and spontaneous feelings of genital arousal in the absence of sexual interest or stimulation. These sensations can be intrusive and significantly impact quality of life. It is important to note that this is a neurological condition, not a sexual one, and it is not the same as hypersexuality or nymphomania.
Reticular Erythematous Mucinosis (REM) is a rare, chronic skin condition characterized by red, slightly raised patches, primarily on the chest and back. It's a form of dermal mucinosis, meaning there's an abnormal accumulation of mucin (a type of connective tissue) in the skin. REM is considered a benign condition, but it can be cosmetically bothersome and persistent. It is not life-threatening.
Retinal vasculitis is an inflammatory condition affecting the blood vessels of the retina. This inflammation can lead to damage and blockage of these vessels, potentially causing vision loss. It can occur as an isolated ocular condition or be associated with systemic inflammatory or infectious diseases.
Retinopathy refers to any non-inflammatory disease of the retina. The retina is the light-sensitive layer of tissue at the back of the eye. Damage to the retina can lead to vision impairment or blindness. Common types include diabetic retinopathy (caused by diabetes), hypertensive retinopathy (caused by high blood pressure), and retinopathy of prematurity (ROP) which affects premature babies.
Retraction pocket cholesteatoma is an abnormal skin growth that occurs in the middle ear, typically behind the eardrum. It is not cancerous but can cause significant damage to the delicate structures of the ear, including the hearing bones (ossicles), leading to hearing loss, balance problems, and other complications. A retraction pocket is an abnormal indentation or pouch in the eardrum, creating a space where dead skin cells and debris can accumulate. Over time, this collection can form a cholesteatoma, which gradually enlarges and erodes the surrounding bone.
Retroperitoneal sarcomas are rare cancers that develop in the retroperitoneum, the space behind the abdominal cavity lining (peritoneum). These sarcomas arise from soft tissues like fat, muscle, nerves, blood vessels, or fibrous tissue located in this area. Due to the retroperitoneum's large volume, tumors can grow significantly before causing noticeable symptoms. They are often large and can displace or encase surrounding organs, making treatment challenging. There are various subtypes, including liposarcoma, leiomyosarcoma, and undifferentiated pleomorphic sarcoma, each with different characteristics and behaviors.
Reversible Posterior Leukoencephalopathy Syndrome (RPLS) is a condition characterized by edema (swelling) in the white matter of the brain, primarily in the posterior regions. It's often associated with high blood pressure, kidney disease, immunosuppressant medications, and other medical conditions. While the name includes "reversible," prompt diagnosis and treatment are crucial to minimize the risk of permanent brain damage.
Reye-like syndrome refers to a group of conditions that mimic the symptoms of Reye's syndrome but are caused by different underlying metabolic disorders. Reye's syndrome is a rare but serious condition that causes swelling in the liver and brain. Reye-like syndromes also involve liver and/or brain dysfunction, but they are not triggered by aspirin use in the context of a viral infection, which is often associated with Reye's syndrome. These syndromes are often related to inborn errors of metabolism that disrupt the body's ability to process fats or amino acids.
Rhabdoid tumors are rare and aggressive cancers that most often occur in young children, although they can occur in adults. These tumors can develop in various parts of the body, but they are most commonly found in the kidneys, brain, and soft tissues. The defining characteristic of a rhabdoid tumor is the presence of "rhabdoid" cells, which are large, atypical cells with eccentric nuclei and prominent nucleoli. These tumors are known for their rapid growth and tendency to spread, making them challenging to treat.
Rh incompatibility, also known as Rh disease, happens when an Rh-negative mother carries an Rh-positive fetus. The mother's immune system can react and produce antibodies against the fetal Rh-positive red blood cells. This can lead to complications for the fetus and newborn, like anemia, jaundice, brain damage, or heart failure. The severity varies, and modern treatments greatly reduce risks.
Rheumatic mitral stenosis (RMS) is a heart valve disorder where the mitral valve, located between the left atrium and left ventricle, narrows. This narrowing obstructs blood flow from the left atrium to the left ventricle, leading to a backup of blood in the left atrium and lungs. It is almost always caused by rheumatic fever, a complication of untreated strep throat or scarlet fever.
Rheumatoid nodules are firm lumps that develop under the skin in people with rheumatoid arthritis (RA). They are a common extra-articular manifestation of RA, meaning they occur outside of the joints. These nodules are typically found near joints affected by RA, but can also occur in other areas of the body. While usually benign, they can sometimes cause discomfort or functional problems depending on their size and location.
Rhinosinusitis, commonly called a sinus infection, is an inflammation or swelling of the tissue lining the sinuses. Healthy sinuses are filled with air. When they become blocked and filled with fluid, germs (bacteria, viruses, and fungi) can grow and cause an infection. Rhinosinusitis can be acute (short-term) or chronic (long-term).
Riboflavin Transporter Deficiency (RTD), also known as Brown-Vialetto-Van Laere Syndrome (BVVLS) and Fazio-Londe disease with auditory neuropathy, is a rare, progressive neurological disorder affecting motor neurons and sensory nerves. It is caused by mutations in genes (SLC52A1, SLC52A2, and SLC52A3) responsible for transporting riboflavin (vitamin B2) into cells. This deficiency leads to impaired cellular energy production, affecting various bodily systems, particularly the nervous system. The condition primarily affects children and young adults.
Ribosomal protein S6 kinase (RSK) deficiency encompasses conditions arising from mutations in genes encoding RSK proteins, particularly RSK2 (encoded by the
RPS6KA3
gene), which leads to Coffin-Lowry Syndrome (CLS). This syndrome is characterized by intellectual disability, skeletal abnormalities, facial dysmorphism, and growth delays. Other, rarer RSK deficiencies may manifest with different, less well-defined phenotypes.
Richner-Hanhart syndrome, also known as Tyrosinemia type II or oculocutaneous tyrosinemia, is a rare inherited metabolic disorder characterized by elevated levels of tyrosine in the blood, urine, and tissues. This leads to the development of skin lesions, eye problems, and sometimes neurological issues. It is caused by a deficiency in the enzyme tyrosine aminotransferase (TAT).
Rickets is a softening and weakening of bones in children, primarily caused by vitamin D deficiency. Vitamin D is crucial for the absorption of calcium and phosphorus from the intestine, which are essential for bone mineralization. Lack of vitamin D, calcium, or phosphate can lead to rickets.
Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) is a heart muscle disease primarily affecting the right ventricle. It's characterized by the replacement of normal heart muscle with fatty and fibrous tissue. This process disrupts the heart's electrical system, leading to arrhythmias (irregular heartbeats) and an increased risk of sudden cardiac death, particularly in young athletes. While primarily affecting the right ventricle, ARVD/C can sometimes involve the left ventricle as well.
Riley-Day syndrome, also known as familial dysautonomia (FD), is a rare genetic disorder that affects the development and function of the autonomic nervous system and the sensory nervous system. These systems control involuntary bodily functions like breathing, digestion, blood pressure, temperature regulation, and pain sensation. FD is primarily found in individuals of Ashkenazi Jewish descent.
Roemheld syndrome, also known as gastrocardiac syndrome, is a condition where gastrointestinal issues (such as bloating, gas, or acid reflux) trigger cardiac symptoms. It is thought to be caused by pressure in the abdomen pressing against the diaphragm, which in turn affects the heart's function through the vagus nerve. It is not a primary heart condition, but rather a heart condition induced by GI issues.
Romberg's syndrome, also known as progressive hemifacial atrophy, is a rare condition characterized by slow and progressive deterioration (atrophy) of the skin and soft tissues, typically affecting one side of the face (hemifacial). It can also involve underlying bone, cartilage, and muscle. The disease usually begins in the first or second decade of life and progresses for several years before stabilizing. The severity of the condition varies greatly among affected individuals.
A root canal infection, also known as a periapical abscess or pulpitis leading to necrosis, is an infection that occurs within the tooth's pulp (the soft tissue containing nerves, blood vessels, and connective tissue) and can extend to the surrounding bone and tissues. It is usually caused by bacteria entering the pulp due to untreated tooth decay, cracks, chips, or previous dental work. Left untreated, it can cause significant pain, swelling, and potential systemic complications.
Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a rare, benign (non-cancerous) disorder characterized by the overproduction and accumulation of histiocytes (a type of immune cell) in lymph nodes and sometimes other tissues throughout the body. It primarily affects children and young adults, although it can occur at any age. While the exact cause is unknown, it is not considered cancerous or typically life-threatening. RDD can resolve spontaneously in some cases, while others may require treatment.
Rothmund-Thomson Syndrome (RTS) is a rare genetic disorder characterized by a distinctive facial rash (poikiloderma), skeletal abnormalities, sparse hair, premature aging, and an increased risk of certain cancers, particularly osteosarcoma. Its severity and specific features can vary considerably among affected individuals.
Rotor syndrome is a rare, benign, inherited disorder characterized by chronic, predominantly conjugated hyperbilirubinemia (elevated bilirubin levels in the blood). It is typically asymptomatic and often discovered incidentally during routine liver function tests. It does not cause liver damage.
Round ligament pain is a common discomfort experienced during pregnancy. It presents as sharp, stabbing, or aching pain, usually in the lower abdomen or groin area. It's caused by the stretching and thickening of the round ligaments, which support the uterus, as the uterus grows during pregnancy. It's generally considered a normal part of pregnancy and is not harmful to the mother or the baby.
Rubella Syndrome, also known as Congenital Rubella Syndrome (CRS), is a serious condition that can occur in a baby if their mother gets a rubella (German measles) infection during pregnancy. The severity of CRS depends on when the mother is infected during the pregnancy, with the greatest risk during the first trimester. CRS can cause a range of birth defects, some of which are permanent and life-threatening. Rubella vaccination is the most effective way to prevent CRS.
Rugger jersey spine, also known as osteosclerosis, is a descriptive term used in radiology to describe a specific appearance of the vertebral bodies on X-rays or other imaging scans. It is not a disease itself, but rather a radiographic finding that indicates increased bone density in the vertebral bodies, typically with alternating bands of sclerosis (increased density) and lucency (decreased density). This pattern gives the spine a striped or banded appearance, reminiscent of a rugby or "rugger" jersey. This pattern is commonly associated with conditions that affect bone marrow and bone remodeling.
Rumination disorder is an eating disorder characterized by the effortless, repetitive regurgitation of recently swallowed food from the stomach into the mouth, where it may be re-chewed, re-swallowed, or spit out. It's not caused by nausea, retching, or disgust, and it differs from vomiting or GERD (gastroesophageal reflux disease). Individuals with rumination disorder don't typically exhibit weight loss or other signs of malnutrition, although this can occur.
1. Summary about disease: A ruptured spleen is a medical emergency that occurs when the spleen's surface breaks open, leading to internal bleeding. The spleen is an organ in the upper left abdomen that filters blood, stores blood cells, and helps fight infection. A ruptured spleen can be life-threatening due to significant blood loss.
Russell's sign refers to the calluses, abrasions, or scars on the knuckles or back of the hand resulting from repeated self-induced vomiting. It is a common physical sign observed in individuals struggling with eating disorders, particularly bulimia nervosa. The repeated insertion of fingers into the mouth to stimulate the gag reflex causes trauma to the skin as it rubs against the teeth. The presence of Russell's sign is a visible indicator of purging behaviors and is often a key factor in diagnosing and treating eating disorders.
There is no known disease officially recognized by the medical community called "Rusty Lung Syndrome." If this term is being used informally, it likely refers to a condition causing lung-related issues with symptoms like coughing up rust-colored sputum (phlegm), suggesting bleeding in the lungs and the presence of iron. Potential underlying conditions could include pneumonia (especially pneumococcal pneumonia), tuberculosis, lung abscess, bronchiectasis, or even lung cancer.
Rutherford's dystrophy, also known as familial corneal dystrophy of Bowman layer type II, is a rare genetic eye disorder affecting the cornea, the clear front surface of the eye. It's characterized by irregular opacities (clouding) in Bowman's layer, a thin layer just beneath the corneal surface. This clouding leads to blurred vision and other visual disturbances. It is usually bilateral, meaning it affects both eyes.
A radius fracture is a break in the radius bone, which is one of the two long bones in the forearm. It is a common injury, often resulting from a fall onto an outstretched hand. Fractures can range in severity from a hairline crack to a complete break, and may be displaced (out of alignment) or non-displaced. The location of the fracture can also vary, with distal radius fractures (near the wrist) being the most common type.
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