Differential Diagnosis for Low Grade Fever, Elevated CRP/ESR, and Diffuse Joint Pain
- Single Most Likely Diagnosis
- Rheumatoid Arthritis (RA): This is a common autoimmune disorder characterized by symmetric, additive, and erosive arthritis. The presence of low-grade fever, elevated CRP and ESR, and diffuse joint pain worsening over time are consistent with RA. The chronic nature of the symptoms also supports this diagnosis.
- Other Likely Diagnoses
- Osteoarthritis (OA): Although OA is more commonly associated with asymmetric joint pain and less systemic inflammation, it can present with diffuse joint pain and mild elevation in inflammatory markers, especially in advanced cases.
- Psoriatic Arthritis (PsA): This condition combines the swollen, scaly skin of psoriasis with joint pain and arthritis. The presence of back pain could suggest involvement of the spine, which is common in PsA.
- Fibromyalgia: Characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood issues. While fibromyalgia does not typically cause elevated CRP or ESR, it can be considered in the differential for diffuse joint pain.
- Do Not Miss Diagnoses
- Lyme Disease: Caused by the bacterium Borrelia burgdorferi, transmitted to humans through the bite of infected black-legged ticks. It can cause arthritis, particularly in the knees, and systemic symptoms like fever. Missing this diagnosis could lead to significant morbidity if not treated promptly.
- Endocarditis: An infection of the inner lining of the heart chambers and valves. It can present with systemic symptoms such as low-grade fever, joint pain, and elevated inflammatory markers. This condition is life-threatening and requires immediate medical attention.
- Multiple Myeloma: A type of blood cancer characterized by an overproduction of malignant plasma cells in the bone marrow. It can cause bone pain, elevated inflammatory markers, and systemic symptoms like fever. Early diagnosis is crucial for treatment and prognosis.
- Rare Diagnoses
- Relapsing Polychondritis: A rare autoimmune disorder characterized by recurrent episodes of cartilaginous inflammation. It can affect various types of cartilage, including that found in joints, ears, nose, and trachea.
- Sarcoidosis: An inflammatory disease that affects multiple organs in the body, but most commonly the lungs and lymph glands. It can cause joint pain, fever, and elevated inflammatory markers, although these are less common presentations.
- Adult-Onset Still's Disease: A rare inflammatory disorder that can cause high fevers, salmon-colored rash, and joint pain, among other symptoms. It's characterized by a distinctive pattern of fever spikes and is often diagnosed after excluding other conditions.