Differential Diagnosis

• Single most likely diagnosis
  • Degenerative arthritis (osteoarthritis): This is considered the most likely diagnosis due to the lack of swelling on exam and decreasing inflammatory markers, which suggests that the patient's rheumatoid arthritis may be well-controlled, and the current pain could be attributed to degenerative changes.
• Other Likely diagnoses
  • Flare of rheumatoid arthritis: Despite the decreasing inflammatory markers, the patient's self-reported swelling and worsening pain could indicate a flare of her rheumatoid arthritis, which would require adjustment of her current treatment regimen.
  • Seronegative rheumatoid arthritis: Some patients with rheumatoid arthritis may not have elevated inflammatory markers, making this a possible explanation for her symptoms.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Septic arthritis: Although less likely, given the lack of swelling on exam, septic arthritis is a medical emergency that requires prompt diagnosis and treatment to prevent serious complications.
  • Malignancy (e.g., metastatic bone disease): Unusual or unexplained worsening of symptoms could be a sign of an underlying malignancy, which would be critical to diagnose and treat.
• Rare diagnoses
  • Psoriatic arthritis: This condition can cause joint pain and swelling, and although less common, it should be considered, especially if the patient has a history of psoriasis.
  • Hemochromatosis: This genetic disorder can cause degenerative arthritis, and although rare, it could be a contributing factor to the patient's symptoms.
  • Sjögren's syndrome: An autoimmune disorder that can cause joint pain and swelling, and is often associated with rheumatoid arthritis, making it a rare but possible diagnosis to consider.