Differential Diagnosis for a 6 year old with Fever, Multifocal Arthralgia, and Multiple Joint Effusions
Single Most Likely Diagnosis
- Juvenile Idiopathic Arthritis (JIA): This is the most common chronic rheumatic disease in children, characterized by joint inflammation and stiffness. The presence of fever, multifocal arthralgia, and multiple joint effusions in a 6-year-old is highly suggestive of JIA, particularly the polyarticular subtype.
Other Likely Diagnoses
- Infectious Arthritis: Bacterial, viral, or fungal infections can cause joint inflammation and effusions. The presence of fever increases the likelihood of an infectious cause.
- Lyme Arthritis: Caused by Borrelia burgdorferi, this condition can present with fever, arthralgia, and joint effusions, particularly in endemic areas.
- Post-Streptococcal Reactive Arthritis: This condition occurs after a streptococcal infection, such as strep throat, and can cause joint inflammation and pain.
Do Not Miss Diagnoses
- Septic Arthritis: A medical emergency that requires prompt diagnosis and treatment. Bacterial infection of the joint can lead to rapid destruction of cartilage and bone if not treated promptly.
- Osteomyelitis: Infection of the bone can present with joint pain and fever, and requires prompt antibiotic treatment to prevent long-term damage.
- Malignancy (e.g., Leukemia): Although rare, malignancies such as leukemia can cause joint pain, fever, and effusions, and are critical to diagnose early.
Rare Diagnoses
- Rheumatic Fever: An autoimmune complication of streptococcal infection, characterized by fever, joint pain, and inflammation.
- Sarcoidosis: A rare condition that can cause joint inflammation and fever, although it is more commonly seen in adults.
- Systemic Lupus Erythematosus (SLE): A chronic autoimmune disease that can cause joint inflammation, fever, and other systemic symptoms, although it is rare in children.