Miller Fisher syndrome (MFS) is a rare, acquired nerve disease characterized by the triad of areflexia (absence of reflexes), ataxia (impaired coordination), and ophthalmoplegia (paralysis of eye muscles). It is considered a variant of Guillain-Barré syndrome (GBS).
Madelung disease, also known as multiple symmetric lipomatosis (MSL) or Launois-Bensaude syndrome, is a rare condition characterized by the symmetrical accumulation of non-encapsulated adipose tissue (fat) deposits around the neck, shoulders, upper arms, and upper back. It primarily affects middle-aged men of Mediterranean descent, but cases have been reported in women and other ethnic groups. While generally benign, the excessive fat deposits can cause cosmetic disfigurement and potentially compress surrounding structures, leading to functional impairments.
Muscle cramps, twitches, and spasms
Fatigue and weakness
Numbness or tingling (pins and needles)
Abnormal heart rhythms (arrhythmias)
Personality changes (irritability, anxiety, depression)
Seizures (in severe cases)
Loss of appetite
Nausea and vomiting
Tremors
Major Depressive Disorder (MDD), often simply called depression, is a common and serious mood disorder that negatively affects how you feel, the way you think, and how you act. It causes persistent feelings of sadness, loss of interest, and can lead to a variety of emotional and physical problems. It's more than just feeling "down" or "sad"; it's a clinically significant condition that requires diagnosis and treatment.
Malabsorption syndrome refers to a number of disorders where the small intestine cannot properly absorb nutrients from food. This can include macronutrients (proteins, carbohydrates, fats), micronutrients (vitamins, minerals), or both. It's not a single disease but rather a consequence of various underlying conditions affecting the digestive process. The result is often malnutrition, leading to various health problems.
Malaria is a life-threatening disease caused by parasites that are transmitted to humans through the bites of infected female Anopheles mosquitoes. It is preventable and curable.
Male breast cancer is a rare disease in which malignant (cancer) cells form in the tissue of the male breast. While breast cancer is more commonly associated with women, men do have a small amount of breast tissue that can develop cancer. Early detection and treatment are important.
Problems with sexual function, such as difficulty with ejaculation or decreased sexual desire.
Pain, swelling, or a lump in the testicles.
Recurrent respiratory infections.
Inability to smell.
Abnormal breast growth (gynecomastia).
Decreased facial or body hair.
Low sperm count (oligospermia) or absence of sperm (azoospermia) detected during a semen analysis.
Malignant melanoma is a type of skin cancer that develops from melanocytes, the cells that produce melanin (the pigment responsible for skin color). It is the most serious type of skin cancer because it is more likely to spread to other parts of the body if not detected and treated early. While less common than other skin cancers like basal cell carcinoma and squamous cell carcinoma, melanoma is responsible for the majority of skin cancer deaths. Early detection and treatment are crucial for a positive outcome.
Malignant hyperthermia (MH) is a rare, life-threatening inherited disorder triggered by certain anesthetic agents and, in rare cases, by strenuous exercise in susceptible individuals. It causes a rapid and severe increase in body temperature and muscle rigidity, along with other metabolic abnormalities. It is a pharmacogenetic disorder, meaning it's caused by a genetic predisposition that affects how the body responds to certain drugs.
Downward slanting eyes
Notched lower eyelids (coloboma)
Underdeveloped or absent cheekbones (malar hypoplasia)
Small lower jaw (micrognathia) and chin
Hearing loss (conductive) due to malformed middle ear bones
Absent, small, or malformed ears (microtia or anotia)
Cleft palate
Airway problems (in severe cases)
Dental abnormalities
Malnutrition is a condition that develops when the body doesn't get enough of the nutrients it needs to function properly. This can occur due to insufficient intake of nutrients, impaired nutrient absorption, or excessive nutrient loss. Malnutrition can lead to a wide range of health problems, affecting growth, development, immune function, and overall well-being. It exists in various forms, including undernutrition (deficiencies in calories, protein, or specific micronutrients), overnutrition (excessive intake of calories, leading to obesity), and imbalances in nutrient intake.
Maple Syrup Urine Disease (MSUD) is a rare inherited metabolic disorder. It is characterized by the body's inability to properly break down certain amino acids: leucine, isoleucine, and valine. This leads to a buildup of these amino acids and their toxic byproducts in the blood, resulting in a distinctive sweet odor in the urine, sweat, and earwax, resembling maple syrup. Without treatment, MSUD can cause serious neurological problems, including seizures, coma, and even death.
Marasmus is a severe form of malnutrition characterized by energy deficiency. It primarily affects infants and young children and results in wasting, stunted growth, and significantly reduced muscle mass and subcutaneous fat. It is a serious condition that can be life-threatening if left untreated.
Marburg Virus Disease (MVD), formerly known as Marburg hemorrhagic fever, is a severe and often fatal illness in humans. It is caused by the Marburg virus, a genetically unique zoonotic (animal-borne) RNA virus of the filovirus family, which also includes Ebola virus. The disease is characterized by fever, bleeding, and multi-organ failure. Outbreaks are sporadic and typically associated with exposure to caves or mines inhabited by Rousettus bat colonies, or from contact with infected individuals.
Marchiafava-Bignami disease (MBD) is a rare neurological disorder characterized by demyelination (loss of the myelin sheath, which insulates nerve fibers) and necrosis (cell death) of the corpus callosum, the structure connecting the two hemispheres of the brain. It primarily affects individuals with chronic alcohol abuse but can also occur in malnourished individuals without alcohol dependency. The disease can manifest in acute, subacute, or chronic forms, with variable clinical presentations ranging from subtle cognitive changes to coma and death.
Mania is a state of abnormally elevated arousal, affect, and energy level, or "a state of elevated mood". It is a syndrome associated with mental illnesses, most commonly bipolar disorder, but can also be caused by other conditions or substance use. During a manic episode, individuals may experience racing thoughts, decreased need for sleep, impulsivity, and inflated self-esteem. The severity can range from hypomania (a milder form) to full-blown mania with psychotic features.
Marginal Zone Lymphoma (MZL) is a type of slow-growing (indolent) non-Hodgkin lymphoma (NHL). It develops when B-lymphocytes, a type of white blood cell that fights infection, become abnormal. These abnormal cells multiply uncontrollably and accumulate in the marginal zone of lymphoid tissues such as the spleen, lymph nodes, or other organs. There are three main subtypes of MZL:
Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT lymphoma): The most common type, occurring in organs outside the lymph nodes, often in the stomach, but also in the lungs, eyes, skin, or other areas.
Nodal Marginal Zone Lymphoma (NMZL): Affects the lymph nodes.
Splenic Marginal Zone Lymphoma (SMZL): Primarily affects the spleen, bone marrow, and blood.
Marfan syndrome is a genetic disorder that affects the body's connective tissue. Connective tissue provides support and structure to the body, and it affects many systems, including the skeleton, eyes, heart, and blood vessels. Marfan syndrome is characterized by unusually long limbs, fingers, and toes, as well as potential problems with the heart and aorta (the large artery that carries blood from the heart). The severity of symptoms can vary greatly among individuals.
Marie-Strümpell disease, now more commonly known as ankylosing spondylitis (AS), is a type of arthritis that primarily affects the spine. It causes inflammation of the vertebrae, which can lead to severe, chronic pain and discomfort. In advanced cases, this inflammation can result in new bone formation (ankylosis) causing the spine to fuse in a fixed, immobile position. It's a chronic, progressive condition, meaning it worsens over time.
Marinesco-Sjögren Syndrome (MSS) is a rare, autosomal recessive genetic disorder characterized primarily by cerebellar ataxia, congenital cataracts, intellectual disability, and skeletal abnormalities. The severity of the condition varies significantly among affected individuals. It impacts development and coordination.
Marker chromosomes are extra, structurally abnormal chromosomes. They are often small and cannot be easily identified as any of the normal chromosomes using standard cytogenetic techniques. They can be present in all cells of the body or only in some (mosaicism). The effect of a marker chromosome varies greatly depending on its genetic content; some may cause no noticeable symptoms, while others can lead to developmental delays, intellectual disability, birth defects, and other health problems. The clinical significance of a marker chromosome often depends on its origin and the genes it contains.
Maroteaux-Lamy syndrome, also known as mucopolysaccharidosis type VI (MPS VI), is a rare, inherited metabolic disorder caused by a deficiency of the enzyme arylsulfatase B (ARSB). This enzyme is needed to break down glycosaminoglycans (GAGs), also known as mucopolysaccharides. The buildup of GAGs in various tissues and organs throughout the body leads to a range of symptoms affecting skeletal, cardiac, respiratory, and neurological systems. The severity of symptoms can vary greatly among affected individuals, ranging from mild to severe forms of the disease.
Mast Cell Activation Syndrome (MCAS) is a condition in which mast cells, a type of white blood cell found throughout the body, inappropriately and excessively release mediators (chemical compounds) that cause a variety of symptoms. Unlike mastocytosis, where there's an increased number of mast cells, MCAS involves mast cells that function abnormally and release mediators too easily. This can lead to a wide range of chronic and relapsing symptoms affecting multiple organ systems. The severity and frequency of symptoms can vary significantly from person to person.
Mastitis is an inflammation of breast tissue that can occur in women who are breastfeeding. It can also occur in women who are not breastfeeding, though this is less common. The inflammation can cause breast pain, swelling, warmth, and redness. Sometimes, mastitis can be accompanied by an infection.
Mastocytosis is a rare disorder characterized by an abnormal accumulation of mast cells in one or more tissues of the body. Mast cells are part of the immune system and release substances that cause inflammation and allergic reactions. The symptoms and severity of mastocytosis can vary greatly, ranging from mild skin involvement (cutaneous mastocytosis) to systemic involvement affecting multiple organs.
May-Hegglin Anomaly (MHA) is a rare genetic blood disorder characterized by thrombocytopenia (low platelet count), giant platelets, and the presence of Döhle body-like inclusions in leukocytes (white blood cells). These inclusions are composed of aggregates of myosin heavy chain protein. Many individuals with MHA are asymptomatic or have only mild bleeding tendencies, while others may experience more significant bleeding problems.
McArdle's disease, also known as glycogen storage disease type V (GSD V), is a rare genetic metabolic disorder affecting skeletal muscles. It's caused by a deficiency of the enzyme myophosphorylase (muscle glycogen phosphorylase), which is essential for breaking down glycogen (stored glucose) in muscle cells to provide energy during exercise. This deficiency prevents muscles from properly using glycogen, leading to muscle pain, fatigue, and cramps, particularly during exercise.
McCune-Albright syndrome (MAS) is a rare genetic disorder that affects the bones, skin, and endocrine system. It is characterized by a triad of features: polyostotic fibrous dysplasia (bone abnormalities), café-au-lait skin spots (pigmentation), and precocious puberty (early sexual development). However, not all individuals with MAS exhibit all three features. The severity of the disease can vary greatly from person to person.
Meniere's disease is a disorder of the inner ear that can lead to dizzy spells (vertigo) and hearing loss. In most cases, Meniere's disease affects only one ear. It can occur at any age, but it typically starts between the ages of 20 and 40. The disease is considered chronic, but various treatments can help relieve symptoms and minimize its long-term impact on life.
: Mediastinitis is an inflammation of the mediastinum, the space in the chest between the lungs that contains the heart, esophagus, trachea, major blood vessels, and lymph nodes. It is a serious condition that can be life-threatening if not promptly treated. Mediastinitis can be acute or chronic. Acute mediastinitis usually results from a surgical complication, esophageal perforation, or less commonly, the spread of infection from the neck or lungs. Chronic mediastinitis is often caused by granulomatous diseases like tuberculosis or histoplasmosis, or fibrosing mediastinitis.
Familial Mediterranean Fever (FMF) is an inherited autoinflammatory disease primarily affecting people of Mediterranean ancestry (Sephardic Jews, Turks, Armenians, Arabs, and Italians). It's characterized by recurrent short episodes of fever and painful inflammation in the abdomen, chest, joints, and skin. The underlying cause is a genetic mutation affecting the immune system's regulation of inflammation. While there's no cure, treatment can significantly reduce the frequency and severity of attacks and prevent long-term complications.
Medulloblastoma is a cancerous (malignant) brain tumor that starts in the cerebellum, the area at the back and base of the brain. It is the most common type of malignant brain tumor in children, but can occur in adults as well. These tumors grow rapidly and can spread to other parts of the brain and spinal cord via the cerebrospinal fluid (CSF).
Megacolon refers to an abnormal dilation (widening) of the colon. This enlargement can occur due to various underlying conditions that impair the colon's ability to effectively move stool through the digestive tract. In severe cases, megacolon can lead to significant constipation, abdominal distension, and even life-threatening complications. It can be congenital (present at birth) or acquired later in life.
Meesmann corneal dystrophy (MECD) is a rare, inherited eye disorder that affects the cornea, the clear front part of the eye. It is characterized by tiny, bubble-like cysts in the epithelium, the outermost layer of the cornea. These cysts typically appear in early childhood and can cause varying degrees of discomfort and visual disturbances. It usually progresses slowly and rarely causes severe vision loss.
Megaloblastic anemia is a type of anemia characterized by the production of abnormally large, structurally unusual, immature red blood cells (megaloblasts) in the bone marrow. This is most often due to a deficiency in vitamin B12 or folate, which are essential for DNA synthesis needed for red blood cell production. These large red blood cells are often fewer in number and are unable to carry oxygen effectively, leading to anemia.
Meige syndrome, also known as cranial dystonia, is a rare neurological movement disorder characterized by involuntary and forceful contractions of the muscles of the face, jaw, tongue, and neck. It typically involves blepharospasm (involuntary eye closure) and oromandibular dystonia (involuntary movements of the jaw, face, and tongue). While not life-threatening, it can significantly impair a person's ability to function and impact their quality of life.
Meibomian Gland Dysfunction (MGD) is a chronic condition that occurs when the meibomian glands, located in the eyelids, don't produce enough oil or the oil they produce is of poor quality. These glands are crucial for secreting meibum, an oily substance that forms the outer layer of the tear film. This oily layer prevents the tear film from evaporating too quickly, keeping the eyes moist and comfortable. When MGD occurs, the tear film becomes unstable, leading to dry eye symptoms and potential damage to the ocular surface.
Melancholia is an outdated term historically used to describe a severe form of depression. It is no longer a formal psychiatric diagnosis, but its characteristics are often associated with what is now diagnosed as major depressive disorder with melancholic features. This subtype of depression involves a distinct set of symptoms indicating a profound disturbance in mood and the experience of pleasure.
Melanoma is a type of skin cancer that develops from melanocytes, the cells that produce melanin (the pigment that gives skin its color). It's characterized by the uncontrolled growth of these cells. While less common than other types of skin cancer, melanoma is more dangerous because it's more likely to spread to other parts of the body if not detected and treated early.
Melorheostosis is a rare, non-inherited bone disorder characterized by linear hyperostosis (thickening) of the cortex (outer layer) of bones. This thickening often resembles dripping candle wax on X-rays. The disease can affect one or more bones and can involve a single limb or multiple limbs, and sometimes the axial skeleton (spine, ribs, and skull). It can cause pain, deformity, and limitation of movement. The severity of symptoms varies widely among individuals.
Melkersson-Rosenthal Syndrome (MRS) is a rare neurological disorder characterized by a triad of symptoms: recurring facial paralysis (usually unilateral, affecting one side of the face), facial or oral edema (swelling, particularly of the lips, which may become fissured), and a fissured tongue (also known as lingua plicata, where deep grooves and furrows appear on the tongue). Not all three features are present in every case, and some individuals may only experience one or two of the core symptoms. The condition can manifest in childhood or adulthood and its cause is not fully understood.
Membranoproliferative glomerulonephritis (MPGN), also known as mesangiocapillary glomerulonephritis, is a rare kidney disorder that affects the glomeruli, which are the filtering units of the kidneys. It is characterized by changes in the glomerular basement membrane and an increase in the number of cells in the glomerulus. MPGN can lead to kidney failure and may be associated with other medical conditions.
1. Summary about disease: A meningioma is a tumor that arises from the meninges, the membranes surrounding the brain and spinal cord. Most meningiomas are benign (non-cancerous) and slow-growing, often causing symptoms by pressing on nearby brain tissue, nerves, or vessels. While most are not cancerous, location can make treatment challenging and lead to significant morbidity.
Meningitis is an inflammation of the meninges, the protective membranes covering the brain and spinal cord. It can be caused by bacterial, viral, or fungal infections, as well as by chemical irritation, drug allergies, or tumors. Bacterial meningitis is the most serious type and can be life-threatening if not treated promptly.
In newborns and infants, symptoms may be more subtle and include:
Inactivity or sluggishness
Irritability
Poor feeding
Vomiting
Bulging fontanelle (soft spot on the head)
A meniscal tear is a common knee injury involving damage to one or more of the menisci, which are C-shaped cartilage structures that act as shock absorbers between the femur (thighbone) and tibia (shinbone). Tears can range in severity from minor to severe and can occur due to acute trauma or gradual degeneration over time.
Menopause is a natural biological process that marks the end of a woman's menstrual cycles. It's diagnosed after a woman has gone 12 months without a menstrual period. It signals the decline in estrogen production by the ovaries. While a natural part of aging, the symptoms can disrupt daily life, but treatments are available.
Menorrhagia is the medical term for abnormally heavy or prolonged menstrual bleeding. It is a common condition that can significantly impact a woman's quality of life. The bleeding is often heavy enough to interfere with daily activities and can lead to anemia.
Mental retardation, now more commonly referred to as intellectual disability, is a condition characterized by significant limitations in both intellectual functioning (reasoning, learning, problem-solving) and adaptive behavior (everyday social and practical skills). These limitations originate before the age of 18. The severity of intellectual disability can range from mild to profound, and it impacts individuals' ability to live independently and participate fully in society.
Mercury poisoning is a toxic condition caused by exposure to mercury. Mercury exists in various forms (elemental, inorganic, and organic), each with different routes of exposure and toxicity levels. The effects of mercury poisoning can range from mild to severe, depending on the form of mercury, the dose, the route of exposure, and the duration of exposure. It can affect the nervous system, kidneys, lungs, and other organs.
MERRF (Myoclonic Epilepsy with Ragged Red Fibers) syndrome is a rare mitochondrial disorder affecting multiple systems in the body. It primarily affects the nervous system and muscles. The condition is characterized by myoclonus (sudden, brief muscle jerks), epileptic seizures, ataxia (loss of coordination), muscle weakness, and ragged red fibers (abnormal accumulations of mitochondria) in muscle tissue. The severity and specific symptoms can vary considerably among affected individuals.
Mesothelioma is a rare and aggressive form of cancer that develops in the mesothelium, a protective lining that covers most of the body's internal organs. The most common site is the pleura (lining of the lungs and chest wall), but it can also occur in the peritoneum (lining of the abdomen), pericardium (lining around the heart), and tunica vaginalis (lining around the testicles). Mesothelioma is primarily caused by asbestos exposure.
Metabolic syndrome is a cluster of conditions that occur together, increasing your risk of heart disease, stroke, and type 2 diabetes. These conditions include increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels. Having just one of these conditions doesn't mean you have metabolic syndrome. However, having several of these conditions increases your risk of serious health problems.
Late Infantile MLD (most common and severe): Muscle weakness, stiffness, difficulty walking, loss of motor skills, developmental delays, irritability, vision problems, seizures, and progressive loss of cognitive function.
Juvenile MLD: Behavioral problems, declining school performance, gait disturbances, muscle weakness, speech difficulties, and cognitive decline.
Adult MLD: Psychiatric symptoms (depression, psychosis), cognitive decline, gait abnormalities, muscle weakness, bladder and bowel control issues.
Metaphyseal chondrodysplasia (MCD) is a group of rare genetic disorders that affect the growth of bones, particularly in the metaphyses (the ends of long bones). This leads to skeletal abnormalities, short stature, and sometimes other health issues. Several different types of MCD exist, each with slightly different features and genetic causes.
Metastatic cancer, also known as stage IV cancer, occurs when cancer cells break away from the primary tumor (the original site of cancer) and spread to other parts of the body. These cancer cells travel through the bloodstream or lymphatic system and form new tumors in distant organs or tissues. Metastasis is a complex process, and not all cancers have the same likelihood of spreading. Metastatic cancer is generally more difficult to treat than localized cancer and may be incurable. However, treatment can often help control the disease, extend survival, and improve quality of life.
Metatarsalgia is a condition characterized by pain and inflammation in the ball of the foot, specifically the area under the metatarsal heads (the bones just before the toes). It's not a specific disease, but rather a symptom of other underlying conditions or contributing factors.
Methicillin-Resistant Staphylococcus Aureus (MRSA) is a type of staph bacteria that is resistant to several antibiotics commonly used to treat staph infections. This resistance makes MRSA infections more difficult to treat than regular staph infections. MRSA can cause a range of infections, from skin infections to pneumonia and bloodstream infections.
Methylmalonic acidemia (MMA) is a rare inherited metabolic disorder in which the body is unable to properly process certain amino acids and fats. This leads to a buildup of methylmalonic acid and other harmful substances in the blood, urine, and tissues. There are several different types of MMA, each caused by a specific genetic defect that affects the enzymes involved in the breakdown of these substances. MMA can lead to various health problems, ranging from mild to life-threatening.
Microcephaly is a rare neurological condition where a baby's head is significantly smaller than expected for their age and sex. This is usually due to abnormal brain development, either during pregnancy or after birth. The severity of microcephaly can vary, ranging from mild to severe.
Microphthalmia is a congenital condition in which one or both eyes are abnormally small. It can range in severity, from only slightly smaller than normal to complete absence of the eyeball (anophthalmia, often considered the most extreme form of microphthalmia). Microphthalmia can occur in isolation or in association with other birth defects or genetic syndromes. Vision may be impaired, depending on the degree of malformation and the presence of other ocular abnormalities.
Micturition syncope is a temporary loss of consciousness (fainting) that occurs during or immediately after urination. It's generally considered a type of vasovagal syncope, triggered by a sudden drop in blood pressure.
Midgut volvulus is a life-threatening condition that occurs when the small intestine twists around the superior mesenteric artery, which supplies blood to the intestine. This twisting can obstruct the bowel and cut off blood supply, leading to ischemia, necrosis (tissue death), and potentially bowel perforation. It's a surgical emergency that requires prompt diagnosis and intervention to prevent severe complications. It most commonly occurs in infants, particularly those with malrotation of the intestines (an abnormality present from birth where the intestines do not develop and settle into their proper position).
Migraine is a neurological disorder characterized by recurrent throbbing headaches, often on one side of the head. It's frequently accompanied by symptoms like nausea, vomiting, and extreme sensitivity to light and sound. Migraines can significantly impact daily life.
Mikulicz's syndrome is a rare, chronic condition characterized by symmetrical, painless enlargement of the lacrimal (tear) and salivary glands. It's often associated with other autoimmune disorders like Sjögren's syndrome, lupus, or rheumatoid arthritis. It's considered a historical term, often now categorized under IgG4-related disease, particularly when associated with elevated IgG4 levels.
Mild Cognitive Impairment (MCI) is an intermediate stage between the expected cognitive decline of normal aging and the more serious decline of dementia. It involves problems with memory, language, thinking, and judgment that are greater than normal age-related changes, but not severe enough to significantly interfere with daily activities. Individuals with MCI are at an increased risk of developing dementia, particularly Alzheimer's disease, but not all people with MCI will progress to dementia.
Milk-alkali syndrome is a condition characterized by high levels of calcium in the blood (hypercalcemia), metabolic alkalosis (increased blood pH), and kidney problems (renal insufficiency). It typically occurs due to excessive intake of calcium and absorbable alkali, often from calcium supplements and antacids.
Miller Fisher Syndrome (MFS) is a rare, acquired nerve disease characterized by a triad of symptoms: areflexia (absence of reflexes), ataxia (loss of coordination), and ophthalmoplegia (paralysis of eye muscles). It is considered a variant of Guillain-Barré syndrome (GBS). MFS is an autoimmune disorder where the body's immune system mistakenly attacks its own nerves.
Miller syndrome, also known as postaxial acrofacial dysostosis syndrome (POADS), is a very rare genetic disorder characterized by facial and limb abnormalities. The facial features typically include underdeveloped cheekbones (malar hypoplasia), a small lower jaw (micrognathia), and cleft palate. Limb abnormalities primarily affect the arms and legs, with missing or underdeveloped bones in the forearms and lower legs, as well as missing fingers or toes. Intelligence is usually normal.
Minimal Change Disease (MCD) is a kidney disorder that causes nephrotic syndrome, characterized by excessive protein in the urine (proteinuria), low levels of protein in the blood (hypoalbuminemia), swelling (edema), and high cholesterol levels. It's called "minimal change" because the kidney tissue appears nearly normal under a regular microscope; changes are only visible with more specialized tests like electron microscopy. It's a leading cause of nephrotic syndrome in children.
Miosis, also known as pinpoint pupils, refers to the excessive constriction of the pupils of the eyes. Normally, pupils dilate and constrict in response to light and other stimuli. In miosis, the pupils remain abnormally small, typically less than 2 millimeters in diameter. It is a symptom, not a disease itself, and can indicate various underlying medical conditions or drug use.
Mitochondrial diseases are a group of disorders caused by dysfunctional mitochondria, the energy-producing units within cells. These diseases can affect nearly any part of the body, but organs with high energy demands, such as the brain, heart, muscles, and liver, are often most severely affected. The severity and specific symptoms vary widely depending on the genetic mutations and the affected tissues.
Mitral regurgitation (MR), also known as mitral insufficiency or mitral incompetence, is a heart valve disorder in which the mitral valve doesn't close properly, allowing blood to leak backward into the left atrium when the left ventricle contracts. This reduces the amount of blood that is pumped forward to the body and can lead to various heart problems. The severity can range from mild, often causing no symptoms, to severe, requiring intervention.
Mitral stenosis is a narrowing of the mitral valve opening. This valve normally allows blood to flow from the left atrium to the left ventricle. When the valve is narrowed, it restricts blood flow, leading to a buildup of pressure in the left atrium and potentially affecting the lungs and other organs.
Mitral valve prolapse (MVP) is a condition in which the mitral valve, located between the left atrium and left ventricle of the heart, doesn't close smoothly or evenly during heart contraction. Instead, one or both of the valve flaps (leaflets) bulge (prolapse) backward into the left atrium. In some cases, this can lead to mitral regurgitation, where blood leaks backward into the left atrium. MVP is often benign, causing no symptoms or problems. However, in some individuals, it can lead to complications that require treatment.
Mixed Connective Tissue Disease (MCTD) is a rare autoimmune disorder characterized by a combination of features found in other connective tissue diseases, such as systemic lupus erythematosus (SLE), scleroderma, and polymyositis. It's defined by the presence of a specific antibody in the blood, anti-U1 ribonucleoprotein (anti-U1 RNP). MCTD can affect various organ systems, leading to a wide range of symptoms and disease progression. The severity of the disease varies considerably from person to person.
Möbius Syndrome is a rare neurological disorder characterized primarily by facial paralysis and the inability to move the eyes from side to side. This is usually present at birth (congenital). The condition results from the underdevelopment or absence of the 6th (abducens) and 7th (facial) cranial nerves, which control eye movement and facial expression, respectively. While facial paralysis is a hallmark of the condition, the severity can vary widely. Associated features can include other cranial nerve palsies, limb abnormalities, speech and swallowing difficulties, and occasionally intellectual disability.
Mold allergy symptoms are similar to other respiratory allergies. Common symptoms include:
Sneezing
Runny or stuffy nose
Postnasal drip
Itchy or watery eyes
Coughing
Wheezing
Shortness of breath
Scratchy throat
Skin rash (hives)
Headache
Molluscum contagiosum is a common, usually mild, viral skin infection that causes small, raised, pearly or flesh-colored bumps on the skin. It is most common in children, but can affect people of all ages. The infection is generally self-limiting, meaning it will resolve on its own, but this can take months or even years.
Mondor's disease is a rare condition characterized by thrombophlebitis (inflammation of a vein due to a blood clot) of the superficial veins of the chest wall or upper abdomen. It's generally a benign and self-limiting condition, meaning it usually resolves on its own without significant long-term complications.
A molar pregnancy, also known as hydatidiform mole, is a rare complication of pregnancy characterized by abnormal growth of trophoblasts, the cells that normally develop into the placenta. There are two types: complete molar pregnancy, where there is no fetal tissue, and partial molar pregnancy, where there may be some fetal tissue but it is not viable. It is considered a type of gestational trophoblastic disease (GTD).
Monge's disease, also known as chronic mountain sickness (CMS), is a condition characterized by an excessive production of red blood cells (polycythemia) in individuals living at high altitudes. This leads to increased blood viscosity, which can result in various symptoms and health complications. It is an adaptation gone awry, where the body overcompensates for the lower oxygen levels at high altitudes.
Monilethrix is a rare genetic hair disorder characterized by beaded or "moniliform" hair. The hair shafts have regularly spaced nodes (beads) and constrictions (internodes), making the hair fragile and prone to breakage at the constrictions. This results in sparse, short, and brittle hair, particularly on the scalp.
Mononucleosis, often called "mono" or the "kissing disease," is an infectious illness typically caused by the Epstein-Barr virus (EBV). It's characterized by fatigue, fever, sore throat, and swollen lymph nodes. While generally not serious, symptoms can be debilitating and persist for several weeks.
Symptoms vary depending on the specific mood disorder but can include:
Depressive Symptoms: Persistent sadness, loss of interest or pleasure, changes in appetite or weight, sleep disturbances (insomnia or hypersomnia), fatigue, feelings of worthlessness or guilt, difficulty concentrating, thoughts of death or suicide.
Manic Symptoms (Bipolar Disorder): Elevated mood, inflated self-esteem, decreased need for sleep, racing thoughts, increased talkativeness, distractibility, increased goal-directed activity or agitation, risky behaviors.
Hypomanic Symptoms (Bipolar II Disorder): Similar to manic symptoms, but less severe and shorter in duration.
Mixed Features: Experiencing both depressive and manic/hypomanic symptoms simultaneously.
Morgagni-Stewart-Morel Syndrome (MSM), also known as hyperostosis frontalis interna (HFI), is a rare condition characterized by thickening of the inner table of the frontal bone of the skull, often accompanied by obesity and virilization (development of male characteristics) in females. The full spectrum of the syndrome is not always present, and diagnosis can be challenging.
Moraxella catarrhalis
is a bacterium commonly found in the upper respiratory tract of humans. While often harmless, it can cause infections, particularly in children, the elderly, and individuals with underlying respiratory conditions. These infections commonly include middle ear infections (otitis media), sinus infections (sinusitis), and lower respiratory tract infections like pneumonia or bronchitis.
Morphea is a rare skin condition characterized by localized patches of thickened, discolored skin. These patches can vary in size, shape, and location on the body. Morphea is a form of localized scleroderma, meaning "hard skin," but it typically doesn't affect internal organs like systemic scleroderma does. The condition is not contagious.
Morquio syndrome, also known as mucopolysaccharidosis type IV (MPS IV), is a rare, inherited metabolic disorder caused by a deficiency in enzymes needed to break down certain complex sugar molecules called glycosaminoglycans (GAGs), specifically keratan sulfate and chondroitin-6-sulfate. This leads to an accumulation of these GAGs in various tissues and organs, causing a range of skeletal abnormalities, and other complications. There are two main types: Morquio A and Morquio B, depending on which specific enzyme is deficient.
Moyamoya disease is a rare, progressive cerebrovascular disorder in which the internal carotid arteries in the brain become narrowed and blocked. This narrowing reduces blood flow to the brain. To compensate, the brain develops tiny, abnormal blood vessels (collateral vessels) at the base of the brain. These small vessels are fragile and prone to bleeding or blockage, leading to stroke-like symptoms. The term "moyamoya" means "puff of smoke" in Japanese and refers to the appearance of these tangled vessels on an angiogram.
Mucinous cystadenomas are benign, slow-growing tumors that typically occur in the ovaries but can also occur in other organs like the appendix or pancreas. They are characterized by the presence of cysts filled with thick, gelatinous mucus. While generally benign, there is a small risk of malignant transformation into mucinous cystadenocarcinoma.
A mucocele is a fluid-filled cyst that develops in the mouth, typically on the lower lip. It forms when a salivary gland duct is blocked or damaged, causing saliva to leak into the surrounding tissues. Mucoceles are generally benign and painless, though they can be a nuisance.
Mucoviscidosis, also known as cystic fibrosis (CF), is a genetic disorder that primarily affects the lungs, pancreas, liver, intestines, sinuses, and reproductive organs. It's characterized by the production of abnormally thick and sticky mucus, which clogs these organs and leads to various complications. CF is a progressive disease, meaning it worsens over time. There is currently no cure, but treatments can help manage symptoms and improve quality of life.
Mucositis is the painful inflammation and ulceration of the mucous membranes lining the digestive tract, usually as a side effect of chemotherapy and/or radiation therapy for cancer. It can occur anywhere along the gastrointestinal tract, but it most commonly affects the mouth (oral mucositis). Mucositis can significantly impact a patient's quality of life, leading to pain, difficulty eating, malnutrition, and increased risk of infection.
Multiple Endocrine Neoplasia (MEN) disorders are a group of inherited conditions characterized by the development of tumors in multiple endocrine glands. These tumors can be benign or malignant. The three main types are MEN1, MEN2A, and MEN2B. Each type involves a specific set of glands. The genes responsible for these syndromes are known, and genetic testing is available. The goal of treatment is to manage hormone imbalances and remove or shrink tumors.
Multiple myeloma is a cancer that forms in plasma cells, a type of white blood cell. Healthy plasma cells help you fight infections by making antibodies that recognize and attack germs. In multiple myeloma, cancerous plasma cells accumulate in the bone marrow and crowd out healthy blood cells. Instead of producing helpful antibodies, the cancerous cells produce abnormal proteins that can cause complications.
Multiple Sclerosis (MS) is a chronic, potentially disabling disease of the central nervous system (brain and spinal cord). In MS, the immune system attacks the protective myelin sheath that covers nerve fibers, causing communication problems between the brain and the rest of the body. This can lead to a wide range of symptoms. The disease's progression and severity vary significantly from person to person.
Mumps is a contagious viral infection that primarily affects the salivary glands, particularly the parotid glands, which cause swelling in the cheeks. It is preventable through vaccination.
Munchausen Syndrome (also known as Factitious Disorder Imposed on Self) is a mental disorder in which a person deliberately and consciously feigns, exaggerates, or creates symptoms of a physical or mental illness in order to gain medical attention and play the "sick" role. The primary motivation is not for financial gain, avoiding legal responsibility, or other tangible benefits; it's the psychological need to be seen as ill or injured.
Munchausen Syndrome by Proxy (MSBP), also known as Factitious Disorder Imposed on Another (FDIA), is a mental disorder in which a caregiver, most often a parent (typically the mother), deliberately exaggerates, fabricates, or induces illness in another person, most often a child, to gain attention or sympathy. The caregiver's actions are often manipulative and harmful to the victim. It is considered a form of child abuse.
Mumps orchitis is an inflammation of one or both testicles that can occur as a complication of the mumps virus infection. Mumps is a contagious viral illness characterized by swelling of the salivary glands, particularly the parotid glands (located near the ears). Orchitis, when it occurs, typically develops several days after the onset of mumps. While mumps is now preventable with vaccination, orchitis remains a significant concern for those who contract the disease, especially in post-pubertal males.
Murine typhus, also known as endemic typhus, is a flea-borne illness caused by the bacteria
Rickettsia typhi
. It's primarily transmitted to humans through the bite of infected fleas, most commonly found on rodents like rats. While generally less severe than other forms of typhus, it can still cause significant discomfort and illness.
Sudden, sharp pain in the affected muscle
A hard, palpable lump or knot of muscle tissue
Possible visible twitching or spasms of the muscle
Tenderness in the area after the cramp subsides
Muscular dystrophy (MD) is a group of genetic diseases that cause progressive weakness and degeneration of muscles. The underlying defect interferes with the production of proteins needed to form healthy muscle. There are many different types of MD, each with varying symptoms, age of onset, and severity.
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex, chronic, and debilitating multi-system disease characterized by profound fatigue that is not improved by rest and is worsened by physical or mental exertion (post-exertional malaise - PEM). It affects multiple body systems, including the neurological, immunological, endocrine, and energy metabolism systems. The severity of symptoms can vary greatly among individuals.
Mycetoma is a chronic, progressive, destructive inflammatory disease usually of the foot, but any part of the body can be affected. It is characterized by a triad of painless subcutaneous mass, multiple draining sinuses, and grains containing the causative agent. Mycetoma is caused by true fungi (eumycetoma) or aerobic actinomycetes (actinomycetoma). It's primarily found in tropical and subtropical regions, often affecting rural workers. The disease can lead to significant disability and disfigurement if left untreated.
Mycobacterium Avium Complex (MAC) is a group of bacteria related to tuberculosis. It is commonly found in water, soil, and dust. MAC infections can be localized, affecting a single area of the body, or disseminated, spreading throughout the body. It most often affects people with weakened immune systems, such as those with HIV/AIDS, the elderly, or those with underlying lung conditions. While MAC is common, infection is not.
Mycobacterium marinum infection, also known as "fish tank granuloma" or "swimming pool granuloma," is a chronic granulomatous skin infection caused by the bacterium
Mycobacterium marinum
. This bacterium is commonly found in fresh and saltwater environments, including fish tanks, swimming pools, and natural bodies of water. The infection typically occurs when the bacteria enter the skin through abrasions, cuts, or scrapes.
Mycosis Fungoides (MF) is the most common type of cutaneous T-cell lymphoma (CTCL), a cancer of the T-cells, a type of white blood cell. MF primarily affects the skin, causing rash-like patches, plaques, and sometimes tumors. It progresses slowly over years or even decades. In some cases, it can spread to lymph nodes, blood, and internal organs, but this is less common, especially in the early stages. It is not contagious.
Mydriasis refers to the dilation of the pupil of the eye. This dilation is not due to normal physiological responses to light or accommodation (focusing). It can be unilateral (affecting one eye) or bilateral (affecting both eyes). Mydriasis can be a symptom of an underlying condition, medication side effect, or a response to specific substances. It's generally not a disease in itself but a sign that warrants investigation.
Myelofibrosis is a rare type of bone marrow cancer that disrupts the body's normal production of blood cells. This results in extensive scarring in the bone marrow, leading to anemia, weakness, fatigue, and an enlarged spleen. It is classified as a myeloproliferative neoplasm (MPN).
Myelodysplastic syndromes (MDS) are a group of clonal bone marrow disorders characterized by ineffective hematopoiesis (blood cell production). This leads to cytopenias (deficiencies in one or more types of blood cells), a risk of progressing to acute myeloid leukemia (AML), and significant morbidity and mortality. The bone marrow produces abnormal blood cells that don't mature properly, leading to a shortage of healthy red blood cells, white blood cells, and/or platelets.
Myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow to a part of the heart is blocked for a prolonged period, causing damage to the heart muscle. This blockage is usually due to a blood clot forming on top of plaque buildup in a coronary artery (atherosclerosis). The affected heart muscle cells die because they don't receive enough oxygen. MI is a serious, life-threatening condition requiring immediate medical attention.
Myelopathy refers to any neurological deficit related to the spinal cord. It is not a specific disease itself, but rather a term describing the dysfunction of the spinal cord, leading to various symptoms. The underlying causes can vary widely, ranging from compression (e.g., from spinal stenosis, herniated discs), inflammation, infection, vascular problems, or trauma. Depending on the cause and severity, myelopathy can significantly impact a person's mobility, sensation, and bowel/bladder control.
Myocarditis is an inflammation of the heart muscle (myocardium). This inflammation can weaken the heart, reducing its ability to pump blood effectively. Myocarditis can cause a variety of signs and symptoms, ranging from mild to severe. Severe myocarditis can lead to heart failure, abnormal heart rhythms (arrhythmias), and sudden death.
Myoclonus is a brief, involuntary twitching or jerking of a muscle or a group of muscles. It's not a disease in itself, but rather a symptom of an underlying condition. Myoclonic jerks can occur normally, such as hiccups or sudden jerks when falling asleep (hypnic jerks), or they can be a sign of a nervous system disorder. The severity and frequency of myoclonus can vary greatly.
Myofascial Pain Syndrome (MPS) is a chronic pain condition that affects the musculoskeletal system. It is characterized by the development of trigger points in muscles. These trigger points are hypersensitive spots that can cause localized pain or referred pain in other areas of the body. MPS can be caused by muscle injury or excessive strain. It is not life-threatening but can significantly impact quality of life.
Myositis is a rare inflammatory condition that causes muscle inflammation, weakness, and pain. It can affect muscles throughout the body and, in some cases, may involve the skin, lungs, or heart. The condition can be chronic (long-lasting) or acute (short-term). Different types of myositis exist, including polymyositis, dermatomyositis, inclusion body myositis, and immune-mediated necrotizing myopathy.
Myotonia refers to a group of neuromuscular disorders characterized by delayed relaxation of muscles after voluntary contraction or stimulation. This stiffness can occur in various muscles, affecting movement, speech, and even breathing in severe cases. Myotonia is not a single disease but a symptom of several different genetic conditions.
Myotubular myopathy (MTM) is a rare genetic muscle disorder primarily affecting males. It is characterized by profound muscle weakness present from birth or early infancy. The term "myotubular" refers to the abnormal appearance of the muscle fibers under a microscope, which resemble immature muscle cells (myotubes). The most common and severe form is X-linked myotubular myopathy (XLMTM), caused by mutations in the
MTM1
gene.
Myopia, also known as nearsightedness, is a common refractive error where distant objects appear blurry while close objects are seen clearly. This occurs when the eye's shape causes light rays to refract (bend) incorrectly, focusing images in front of the retina instead of on it. Myopia can range from mild to severe.
Myxedema represents severe hypothyroidism, a condition where the thyroid gland doesn't produce enough thyroid hormone. It's a medical emergency when it progresses to myxedema coma, characterized by decreased mental status, hypothermia, and other systemic complications. Before progressing to coma, it manifests as pronounced symptoms of hypothyroidism.
Myxomatosis is a highly infectious and often fatal disease primarily affecting rabbits. It is caused by the myxoma virus, a poxvirus. The disease is characterized by swelling and tumors on the skin, particularly around the eyes, nose, and genitals. It typically leads to systemic illness and death in susceptible rabbit populations.
Macrocytic anemia is a type of anemia characterized by larger-than-normal red blood cells (macrocytes). This occurs when the bone marrow produces fewer, but larger, red blood cells, reducing the blood's ability to carry oxygen effectively. It can result from deficiencies of vitamin B12 or folate, liver disease, alcoholism, and other conditions.
Macular edema is the swelling and thickening of the macula, the small central area of the retina responsible for sharp, central vision. Fluid leaks from damaged blood vessels in the retina and accumulates in the macula, causing distortion and blurring of vision. Macular edema can occur in various eye diseases and is a common cause of vision loss.
Major trauma refers to severe injuries that have the potential to cause prolonged disability or death. These injuries often result from events like car accidents, falls, violent assaults, or industrial accidents. Management of major trauma requires a rapid, coordinated, and multidisciplinary approach to stabilize the patient, control bleeding, and minimize further damage.
Meralgia paresthetica is a nerve condition characterized by tingling, numbness, and burning pain in the outer thigh. It's caused by compression of the lateral femoral cutaneous nerve (LFCN), a sensory nerve that supplies sensation to the skin on the outer thigh. The condition is usually not serious and often resolves on its own.
Merkel Cell Carcinoma (MCC) is a rare and aggressive skin cancer that originates in Merkel cells, specialized cells near nerve endings in the skin that are involved in the sense of touch. It typically appears as a painless, firm, flesh-colored, or bluish-red nodule on sun-exposed areas of the body, such as the head, neck, and limbs. While relatively uncommon, MCC has a high risk of recurrence and metastasis (spread to other parts of the body) if not treated promptly.
Metabolic alkalosis is a condition in which the body's pH balance is disturbed, resulting in an increased alkalinity of the blood. This occurs when there is an excess of bicarbonate (a base) in the body, or a loss of acid. It's characterized by a pH greater than 7.45 and a bicarbonate level above 28 mEq/L.
Microangiopathic Hemolytic Anemia (MAHA) is a type of hemolytic anemia characterized by damage to red blood cells as they pass through abnormally narrowed or obstructed microvasculature (small blood vessels). This damage leads to fragmentation of the red blood cells (schistocytes) and premature destruction (hemolysis). MAHA is not a disease itself, but rather a finding associated with several underlying conditions.
Middle Cerebral Artery (MCA) Syndrome refers to a range of neurological deficits resulting from the interruption of blood flow through the middle cerebral artery, one of the major arteries supplying the brain. This interruption, most often caused by a stroke (blockage or rupture of a blood vessel), leads to damage to the brain tissue served by the MCA. The specific symptoms and severity depend on the location and extent of the affected area.
A minor stroke, also known as a transient ischemic attack (TIA), is a temporary disruption of blood flow to the brain. It produces stroke-like symptoms, but unlike a full stroke, the symptoms resolve within a short period, usually less than 24 hours, and often within minutes. While the symptoms are temporary, a TIA is a serious warning sign that a full stroke may occur in the future. It requires immediate medical attention to determine the cause and prevent a more significant stroke.
Mixed Anxiety-Depressive Disorder (MADD) is a condition characterized by the presence of both anxiety and depressive symptoms, but these symptoms are not severe enough to meet the full diagnostic criteria for a specific anxiety disorder or a depressive disorder. Individuals with MADD experience a combination of anxious and depressive feelings that cause significant distress or impairment in their daily lives. It is classified as a "specified" or "other specified" depressive disorder in some diagnostic systems, indicating that it doesn't neatly fit into other defined categories.
Morning sickness is a common condition experienced by many pregnant women, characterized by nausea and vomiting. Despite its name, it can occur at any time of the day or night. While often mild and self-limiting, it can sometimes be severe and require medical intervention. It typically begins in the first trimester and resolves by the second, although some women experience it throughout their pregnancy.
Multifocal Motor Neuropathy (MMN) is a rare, slowly progressive neurological disorder that affects motor nerves. It leads to weakness, muscle atrophy, and cramping, primarily in the limbs. Unlike Amyotrophic Lateral Sclerosis (ALS), MMN is not typically fatal and usually responds to treatment. It is considered an autoimmune disorder.
Mucinous adenocarcinoma is a type of adenocarcinoma (cancer that begins in glandular cells) characterized by the production of large amounts of mucin, a major component of mucus. It can occur in various parts of the body, most commonly in the colon and rectum, but also in the appendix, ovaries, lungs, and other organs. The mucin produced by the tumor can accumulate, leading to characteristic features on imaging and sometimes affecting the way the organ functions. Mucinous adenocarcinomas tend to be more aggressive than non-mucinous adenocarcinomas and may have a poorer prognosis in some cases.
Multiple Chemical Sensitivity (MCS), also sometimes referred to as Idiopathic Environmental Intolerance (IEI), is a chronic condition characterized by adverse reactions to low-level exposures to multiple chemicals. These exposures are often well-tolerated by most people. The symptoms vary widely and affect multiple organ systems. There is no universally accepted definition or diagnostic test, and the condition remains controversial within the medical community.
Myelitis refers to inflammation of the spinal cord. This inflammation can damage or destroy myelin, the protective insulation covering nerve fibers, as well as the nerve fibers themselves. This damage disrupts the communication between the brain and the rest of the body, leading to a range of neurological problems. Different types of myelitis exist, classified by the cause and location of the inflammation within the spinal cord. Transverse myelitis, a specific type, involves inflammation across the entire width of the spinal cord.
Musculoskeletal pain refers to pain affecting bones, muscles, ligaments, tendons, and nerves. It can be acute (short-term) or chronic (long-lasting) and can be localized to one area or widespread throughout the body. The severity can range from mild aches to debilitating pain that limits mobility. Musculoskeletal pain is a common condition with many potential underlying causes.
Myeloproliferative neoplasms (MPNs) are a group of rare blood cancers in which the bone marrow makes too many red blood cells, white blood cells, or platelets. These excess cells can thicken the blood, leading to various complications such as blood clots, bleeding problems, enlargement of the spleen, and, in some cases, progression to acute leukemia. The main types of MPNs include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPNs are generally chronic conditions that can be managed but are not always curable.
Bovine Spongiform Encephalopathy (BSE), commonly known as Mad Cow Disease, is a fatal neurodegenerative disease in cattle that causes a spongy degeneration of the brain and spinal cord. It is a prion disease, meaning it is caused by an abnormal, misfolded protein called a prion. It belongs to a group of diseases called transmissible spongiform encephalopathies (TSEs). While primarily affecting cattle, BSE has implications for human health through the related human prion disease, variant Creutzfeldt-Jakob Disease (vCJD), which can be contracted by consuming BSE-contaminated beef products.
Maffucci syndrome is a rare, non-hereditary congenital disorder characterized by multiple enchondromas (benign cartilage tumors that develop within bones) and hemangiomas (abnormal collections of blood vessels) or lymphangiomas (abnormal collections of lymphatic vessels). These lesions can cause skeletal deformities, pain, and an increased risk of developing certain types of cancer, particularly chondrosarcoma (a type of bone cancer).
Magendie-Hertwig Syndrome is a rare genetic disorder primarily affecting the eyes and brain. It is characterized by specific developmental abnormalities, including malformations of the optic nerves and cerebellum. The syndrome leads to visual impairment, neurological issues, and often developmental delays. It is considered a congenital condition, meaning it is present from birth.
A masticator space abscess is a collection of pus within the masticator space, a potential space in the face that contains muscles of mastication (chewing), blood vessels, and nerves. It's typically a serious infection that requires prompt diagnosis and treatment to prevent complications. If left untreated, it can spread to other spaces in the head and neck, leading to life-threatening conditions.
Maxillary sinusitis is an inflammation or swelling of the lining of the maxillary sinuses. These sinuses are located in the cheekbones, on either side of the nose. This inflammation often results from a viral infection, but can also be caused by bacterial or fungal infections. It can be acute (short-term) or chronic (long-term). The condition leads to mucus buildup, pain, and pressure in the face.
A Medial Collateral Ligament (MCL) injury is a tear or sprain to the MCL, a ligament located on the inside of your knee. It connects the femur (thighbone) to the tibia (shinbone) and helps stabilize the knee joint, preventing it from excessive sideways movement. MCL injuries are common, particularly in athletes involved in contact sports. Severity ranges from minor sprains to complete tears, influencing treatment and recovery time.
Melioidosis is an infectious disease caused by the bacterium
Burkholderia pseudomallei
. It's found primarily in tropical climates, especially in Southeast Asia and northern Australia. The bacteria live in soil and water and can infect humans and animals. Melioidosis can manifest in various forms, ranging from localized infections to pneumonia, sepsis, and even chronic infections. It's a serious disease with a high mortality rate, especially if left untreated.
Mesenteric adenitis is an inflammation of the lymph nodes in the mesentery, which is the membrane that attaches the intestines to the abdominal wall. It often mimics appendicitis and is most common in children and adolescents. The condition is usually caused by a viral or bacterial infection. While it can be painful, it typically resolves on its own without serious complications.
Mesenteric ischemia occurs when blood flow to the small intestine is blocked, causing damage due to lack of oxygen and nutrients. This can range from chronic, gradually developing ischemia to acute, sudden-onset ischemia, which is a medical emergency. If not treated promptly, it can lead to bowel infarction (tissue death), sepsis, and death.
Monosomy is a chromosomal abnormality where an individual is missing one chromosome from a pair. Instead of having the usual two chromosomes, they have only one. This can occur with any of the chromosomes, but some monosomies are more common (though still rare) and more survivable than others. The most well-known is Turner syndrome, which is monosomy X (females having only one X chromosome instead of two). Other monosomies are typically lethal before or shortly after birth.
Microcytic anemia is a type of anemia characterized by red blood cells that are smaller than normal. "Microcytic" refers to the small size of the cells, and "anemia" refers to a condition where you have fewer red blood cells than normal, or your red blood cells don't have enough hemoglobin. Hemoglobin is an iron-rich protein that carries oxygen throughout the body. The main consequence is reduced oxygen delivery to tissues.
Motion sickness is a common condition that occurs when there is a mismatch between what your inner ear, eyes, and other parts of your body sense. This sensory conflict leads to symptoms like nausea, vomiting, dizziness, and fatigue. It's often triggered by travel in cars, boats, airplanes, or amusement park rides.
Morton's neuroma is a painful condition that affects the ball of your foot, most commonly the area between your third and fourth toes. It involves a thickening of the tissue around one of the nerves leading to your toes. This thickening, or neuroma, can cause sharp, burning pain, numbness, and tingling in the affected toes. It's not actually a tumor, but a benign growth of nerve tissue.
Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders caused by the absence or malfunction of specific lysosomal enzymes needed to break down complex sugar molecules called glycosaminoglycans (GAGs), formerly known as mucopolysaccharides. Because the body can't break down these GAGs, they accumulate in cells, blood, and connective tissues. This storage leads to progressive cellular damage and organ dysfunction, resulting in a variety of physical and mental problems. Different types of MPS exist, each resulting from a deficiency in a specific enzyme.
Myasthenia Gravis (MG) is a chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles, which are responsible for breathing and moving parts of the body. It is characterized by fluctuating muscle weakness that worsens after periods of activity and improves after periods of rest. MG occurs when the normal communication between nerves and muscles is interrupted.
Multiple System Atrophy (MSA) is a rare, progressive neurodegenerative disorder that affects multiple systems in the body. It primarily involves the autonomic nervous system (which controls involuntary functions like blood pressure, heart rate, bladder control, and digestion) and movement. MSA is characterized by a combination of parkinsonism (slowed movement, rigidity, tremor), cerebellar dysfunction (problems with balance and coordination), and autonomic dysfunction. It progresses more rapidly than Parkinson's disease and has no cure.
Myopathy refers to a group of diseases that affect the muscles, leading to muscle weakness, fatigue, and sometimes pain. These conditions can be inherited or acquired and vary in severity. Myopathies interfere with muscle function at the cellular level, disrupting the normal processes required for muscle contraction and relaxation.
Macular degeneration is an eye disease that causes vision loss in the center of the visual field (the macula) due to damage to the retina. It's a leading cause of vision loss in older adults. There are two main types: dry macular degeneration, which progresses slowly, and wet macular degeneration, which can cause rapid and severe vision loss.
Madura foot, also known as mycetoma, is a chronic, progressive, destructive infectious disease that typically affects the foot, although it can occur in other parts of the body. It's characterized by tumefaction (swelling), draining sinuses, and the presence of grains (colonies of the causative organism) in the discharge. The disease is caused by true fungi (eumycetoma) or bacteria (actinomycetoma). It is more common in tropical and subtropical regions.
Medication-induced parkinsonism (MIP) is a syndrome characterized by Parkinson's disease-like symptoms that develop as a side effect of certain medications. It's typically reversible upon discontinuation of the offending drug, although symptoms can persist in some cases. It differs from Parkinson's disease, which is a progressive neurodegenerative disorder.
Milroy's disease, also known as congenital lymphedema, is a rare, inherited disorder characterized by abnormal development of the lymphatic system. This leads to swelling (lymphedema), usually in the legs and feet, that is present from birth or shortly thereafter. It is caused by mutations in the
FLT4
gene.
Mineralocorticoid excess refers to a condition characterized by abnormally high levels of mineralocorticoid hormones, primarily aldosterone, in the body. Aldosterone's main function is to regulate sodium and potassium balance, and water retention by the kidneys, thereby influencing blood pressure. Excess aldosterone leads to sodium retention, potassium loss, and increased blood volume, resulting in hypertension (high blood pressure) and other metabolic disturbances. The condition can be caused by various factors, including adrenal gland tumors, adrenal hyperplasia (enlargement), or genetic mutations.
Mononeuropathy is a type of nerve damage affecting a single peripheral nerve. This damage disrupts the nerve's ability to transmit signals, leading to specific symptoms based on the nerve's function and location. It differs from polyneuropathy, which affects multiple nerves simultaneously.
Mountain sickness, also known as acute mountain sickness (AMS), is a condition that can occur when you travel to high altitudes too quickly. The decreased air pressure and lower oxygen levels at high altitudes can cause symptoms ranging from mild headaches to life-threatening conditions like high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE).
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