Differential Diagnosis for Subacute Bilateral Knee Pain
Single Most Likely Diagnosis
- Gout: Given the patient's history of chronic kidney disease (CKD) and recent congestive heart failure (CHF) exacerbation, gout is a likely diagnosis. CKD can lead to elevated uric acid levels, and diuretics used to treat CHF can further increase uric acid levels, precipitating a gout attack.
Other Likely Diagnoses
- Pseudogout (Calcium Pyrophosphate Deposition Disease): Similar to gout, pseudogout can be associated with kidney disease and can cause bilateral knee pain.
- Osteoarthritis: A common cause of bilateral knee pain, especially in a 91-year-old patient, which can be exacerbated by decreased mobility due to CHF.
- Septic Arthritis: Although less likely, the patient's age and comorbidities increase the risk of infection, making septic arthritis a consideration.
Do Not Miss Diagnoses
- Deep Vein Thrombosis (DVT): Given the patient's recent CHF exacerbation and immobility, DVT is a critical diagnosis to consider, as it can cause leg pain and swelling.
- Osteonecrosis: Although less common, osteonecrosis can occur in patients with CHF, especially if they have been treated with corticosteroids, and can cause severe knee pain.
- Infection (e.g., Cellulitis, Abscess): Infections can cause severe pain and swelling in the knees and can be life-threatening if not promptly treated.
Rare Diagnoses
- Hemochromatosis: A rare genetic disorder that can cause arthritis, including knee pain, due to iron accumulation in the joints.
- Amyloidosis: A rare condition that can cause knee pain and swelling due to the deposition of abnormal proteins in the joints.
- Sarcoidosis: A rare autoimmune disorder that can cause knee pain and swelling due to inflammation in the joints.