Differential Diagnosis for Acute PIP Joint Pain and Swelling
Single Most Likely Diagnosis
- Gout: Given the patient's history of obesity, which is a risk factor for gout, and the presentation of acute joint pain and swelling without trauma, gout is a highly plausible diagnosis. The absence of erythema does not rule out gout, as not all gout attacks present with significant redness.
Other Likely Diagnoses
- Pseudogout (Calcium Pyrophosphate Deposition Disease, CPPD): Similar to gout, pseudogout can cause acute joint pain and swelling, particularly in the context of metabolic disorders like diabetes. The PIP joint is less commonly affected than the knee, but it's still a possible site.
- Osteoarthritis (OA) Flare: While OA is more chronic, acute flares can occur, especially in the setting of obesity, which increases the stress on joints. Diabetes can also contribute to the development of OA.
- Septic Arthritis: Although less likely without erythema or a clear source of infection, septic arthritis is a consideration, especially in diabetic patients who may have impaired immune responses.
Do Not Miss Diagnoses
- Infectious Arthritis: Despite the absence of erythema, infectious causes must be considered due to the potential for severe consequences if left untreated. Diabetic patients are at increased risk for infections, including those affecting the joints.
- Crystal Arthropathy (Gout or Pseudogout) with Atypical Presentation: It's crucial not to miss these diagnoses, even if the presentation is not typical, due to their potential for significant morbidity if not treated promptly.
Rare Diagnoses
- Rheumatoid Arthritis (RA): While RA can present with joint pain and swelling, it typically involves multiple joints and has a more gradual onset. However, it's a diagnosis to consider, especially if other symptoms or systemic signs are present.
- Psoriatic Arthritis: This condition can cause joint pain and swelling, often accompanied by skin changes of psoriasis. It's less common than other forms of arthritis but should be considered in the differential diagnosis.
- Lyme Arthritis: If the patient has been exposed to ticks, Lyme disease could be a rare cause of acute joint pain and swelling, typically affecting the knee but potentially other joints.