Differential Diagnosis for Polyarthritis without Inflammatory Markers, Negative ANA, and Rheumatoid Factor
- Single Most Likely Diagnosis
- Osteoarthritis (OA): This is the most common form of arthritis and can present with polyarticular symptoms. The absence of inflammatory markers and negative autoantibodies (ANA, rheumatoid factor) supports this diagnosis, as OA is typically non-inflammatory and seronegative.
- Other Likely Diagnoses
- Psoriatic Arthritis (PsA) without significant psoriasis: Some patients with PsA may not have obvious skin lesions at the time of diagnosis. The absence of inflammatory markers does not rule out PsA, as these can be normal in some cases.
- Crystal Arthropathies (Gout, Pseudogout): While these conditions often present with acute monoarthritis, they can occasionally cause polyarticular symptoms. The absence of inflammatory markers might be seen in early or mild cases.
- Fibromyalgia: This condition can mimic polyarthritis with widespread musculoskeletal pain but lacks true joint inflammation. It's often considered when other diagnoses are ruled out.
- Do Not Miss Diagnoses
- Lyme Arthritis: Caused by Borrelia burgdorferi, this can present with intermittent polyarthritis. It's crucial to consider this diagnosis, especially in endemic areas, as untreated Lyme disease can lead to serious complications.
- Hemochromatosis: This genetic disorder leads to iron overload and can cause arthropathy similar to OA, but it's essential to diagnose due to its potential for causing severe organ damage if left untreated.
- Whipple's Disease: A rare, systemic bacterial infection that can cause polyarthritis among other symptoms. It's critical to diagnose as it can lead to fatal outcomes if not treated.
- Rare Diagnoses
- Relapsing Polychondritis: An autoimmune disorder that affects cartilage and can cause polyarthritis, among other symptoms. It's rare but important to consider due to its potential for causing significant morbidity.
- Multicentric Reticulohistiocytosis: A rare condition characterized by the proliferation of histiocytes, leading to polyarthritis and skin lesions. It's essential to diagnose due to its potential for severe joint destruction and association with malignancies.