Differential Diagnosis for 61-year-old Male with Right Knee Pain and Redness
Single most likely diagnosis
- Gout: Acute onset of knee pain and redness is highly suggestive of gout, especially in a male patient. The knee is a common joint affected by gout, and the sudden onset of symptoms is consistent with a gouty attack.
Other Likely diagnoses
- Septic Arthritis: Bacterial infection of the joint can cause acute pain, redness, and swelling. The patient's age and the acute onset of symptoms make septic arthritis a possible diagnosis.
- Pseudogout (Calcium Pyrophosphate Deposition Disease): Similar to gout, pseudogout can cause acute knee pain and redness, although it is less common.
- Meniscal Tear or Ligament Sprain: Traumatic injury to the knee can cause pain and redness, and the patient's age increases the risk of meniscal tears.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Osteomyelitis: Infection of the bone can cause pain, redness, and swelling, and if left untreated, can lead to serious complications.
- Deep Vein Thrombosis (DVT): DVT can cause leg pain and redness, and if the clot dislodges, it can lead to a life-threatening pulmonary embolism.
- Cellulitis: Bacterial infection of the skin and soft tissues can cause redness, swelling, and pain, and if left untreated, can lead to serious complications.
Rare diagnoses
- Rheumatoid Arthritis: Although less likely, rheumatoid arthritis can cause knee pain and redness, especially if the patient has a history of autoimmune disorders.
- Hemarthrosis: Bleeding into the joint can cause pain and redness, and is more common in patients with bleeding disorders or those taking anticoagulant medications.
- Tumor or Cancer: Although rare, a tumor or cancer can cause knee pain and redness, and should be considered in the differential diagnosis, especially if the patient has a history of cancer or if the symptoms are persistent or worsening.