Summary about Disease
Septic arthritis, also known as infectious arthritis, is a painful infection in a joint. It's caused by bacteria, viruses, or fungi entering a joint, most often through the bloodstream, but sometimes through direct injury or surgery. The infection leads to inflammation and destruction of the joint cartilage and bone. It requires prompt diagnosis and treatment to prevent permanent joint damage and systemic complications.
Symptoms
Intense joint pain, often described as throbbing
Swelling of the affected joint
Warmth and redness around the joint
Fever (often, but not always present)
Chills
Limited range of motion in the affected joint
Fatigue
General malaise
Causes
Bacterial infection: Staphylococcus aureus* is the most common cause, but other bacteria like streptococcus, pneumococcus, and gram-negative bacteria can also be responsible.
Viral infection: Viruses like HIV, hepatitis B, and parvovirus B19 can sometimes cause septic arthritis.
Fungal infection: Less common, but fungi like Candida species can cause septic arthritis, especially in immunocompromised individuals.
Direct joint contamination: Can occur due to penetrating trauma, surgery, or injection into the joint.
Spread from nearby infection: An existing infection in the bone (osteomyelitis) or soft tissue near a joint can spread into the joint space.
Risk Factors: Existing joint disease (rheumatoid arthritis, osteoarthritis), joint replacement, weakened immune system (diabetes, HIV/AIDS, cancer treatment), intravenous drug use, recent joint surgery or injection, skin infection.
Medicine Used
Antibiotics: Crucial for bacterial septic arthritis. Broad-spectrum IV antibiotics are typically started immediately after joint fluid is sampled and sent for culture. Once the specific bacteria is identified, antibiotics are tailored to the specific organism. Treatment duration is typically 2-6 weeks.
Antifungal Medications: If the cause is fungal, antifungal medications such as amphotericin B, fluconazole, or voriconazole are used.
Pain Management: Pain relievers, such as NSAIDs (nonsteroidal anti-inflammatory drugs) or opioids, may be used to manage pain.
Joint Aspiration: Repeated aspiration of the infected joint fluid may be necessary to remove pus and reduce pressure within the joint.
Is Communicable
Septic arthritis itself is not typically communicable through casual contact. However, some of the underlying infections that cause septic arthritis (e.g., certain viral infections) can be contagious. The specific contagiousness depends on the causative organism.
Precautions
Maintain good hygiene: Frequent hand washing can help prevent the spread of bacteria.
Prompt treatment of infections: Treat skin infections, urinary tract infections, and other infections promptly to prevent them from spreading to the joints.
Careful wound care: Clean and cover any open wounds to prevent infection.
Sterile Injection Techniques: Healthcare professionals should use strict sterile techniques when performing joint injections or surgeries.
Avoid IV drug use: Intravenous drug use increases the risk of septic arthritis.
Manage underlying conditions: Manage conditions like diabetes and rheumatoid arthritis to reduce the risk of infection.
How long does an outbreak last?
The duration of a septic arthritis infection depends on several factors, including:
Promptness of diagnosis and treatment: Early diagnosis and treatment lead to better outcomes.
Causative organism: Some organisms are more aggressive and difficult to treat.
Overall health of the individual: Individuals with weakened immune systems may require longer treatment courses.
Antibiotic response: The effectiveness of the antibiotics used. Typically, antibiotic treatment lasts for 2-6 weeks. Improvement in symptoms (pain, swelling, fever) should be seen within a few days of starting appropriate antibiotics. However, it can take weeks to months for full recovery and restoration of joint function.
How is it diagnosed?
Physical Examination: Examination of the affected joint, looking for signs of inflammation (redness, swelling, warmth, pain).
Joint Aspiration (Arthrocentesis): This is the most important diagnostic test. A sample of synovial fluid is removed from the joint using a needle. The fluid is then sent to the lab for:
Cell count: To look for elevated white blood cell count, indicating infection.
Gram stain and culture: To identify the causative organism (bacteria, fungus, or virus).
Crystal analysis: To rule out gout or pseudogout (crystal-induced arthritis).
Glucose level: Often decreased in septic arthritis.
Blood Tests:
White blood cell count: Usually elevated.
Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): These are markers of inflammation and are usually elevated.
Blood cultures: To look for bacteria in the bloodstream.
Imaging Studies:
X-rays: May show joint space narrowing or bone destruction in advanced cases.
Ultrasound: Can help guide joint aspiration and detect fluid collections.
MRI (Magnetic Resonance Imaging): Can show early signs of joint inflammation, bone edema, and abscess formation. Bone scans may also be used in some cases.
Timeline of Symptoms
Septic arthritis symptoms typically develop rapidly, often over a few days.
Initial Stage (First 24-48 hours):
Sudden onset of severe joint pain.
Rapid swelling and warmth around the joint.
Limited range of motion.
Fever and chills may develop.
Progressive Stage (Days 2-7):
Increasing pain and swelling.
Joint becomes increasingly tender to the touch.
Fever and chills may persist or worsen.
Significant limitation of joint movement.
Systemic symptoms like fatigue and malaise may become more prominent.
Late Stage (If untreated, after 7 days or more):
Severe joint destruction.
Risk of permanent joint damage and disability.
Spread of infection to surrounding tissues and bloodstream (sepsis).
Life-threatening complications.
Important Considerations
Prompt diagnosis and treatment are essential to prevent permanent joint damage, disability, and systemic complications.
Septic arthritis can occur in any joint, but it is most common in the knee, hip, shoulder, and ankle.
Children and older adults are at higher risk of developing septic arthritis.
Patients with prosthetic joints are at increased risk of septic arthritis, which can be more challenging to treat.
Long-term complications can include chronic pain, stiffness, decreased range of motion, and joint instability.
Follow-up care is important to monitor the effectiveness of treatment and manage any long-term complications.
Surgical intervention may be necessary in some cases to drain the infected joint or remove damaged tissue.
Rehabilitation therapy may be needed to restore joint function and strength after treatment.