Differential Diagnosis for Chronic Inflammatory Arthritis
Single Most Likely Diagnosis
- Spondyloarthritis: This is a likely diagnosis due to the chronic inflammatory nature of the arthritis, which is a hallmark of spondyloarthritis. The condition often presents with axial symptoms (back pain, buttock pain) and can also involve peripheral joints.
Other Likely Diagnoses
- Crystal-induced arthritis: Conditions like gout or pseudogout can cause chronic inflammatory arthritis, especially if not properly managed. The presence of crystal deposits in the joint fluid can confirm this diagnosis.
- Early/Atypical polyarthritis: This could be an early presentation of rheumatoid arthritis or another form of polyarthritis that has not yet fully declared itself. The absence of typical symptoms or a clear diagnosis at this stage makes it a consideration.
- Indolent infection: Chronic infections, such as Lyme disease or tuberculosis, can cause chronic inflammatory arthritis. These infections may have a slow onset and can mimic other forms of arthritis.
Do Not Miss Diagnoses
- Still's disease (Adult-onset Juvenile Rheumatoid Arthritis): Although less common, Still's disease can present with high fevers, rash, and arthritis, making it critical to consider due to its potential severity and need for aggressive treatment.
- Septic arthritis: While not typically chronic, if a septic joint is not promptly diagnosed and treated, it can lead to severe joint damage and systemic infection. The initial presentation might be mistaken for chronic inflammatory arthritis.
Rare Diagnoses
- Lyme arthritis: Caused by Borrelia burgdorferi, this condition can lead to chronic arthritis, particularly in the knee, but is less common and geographically specific.
- Psoriatic arthritis: A form of spondyloarthritis associated with psoriasis, it can cause chronic inflammatory arthritis but might be considered rare depending on the population's prevalence of psoriasis.
- Reactive arthritis: Following certain infections, reactive arthritis can occur, causing chronic inflammatory symptoms. It is less common and typically follows a gastrointestinal or genitourinary infection.
Each of these diagnoses requires careful consideration of the patient's history, physical examination, laboratory tests (including inflammatory markers, autoantibodies, and potentially joint fluid analysis), and imaging studies to accurately diagnose the cause of chronic inflammatory arthritis.