Differential Diagnosis for Left Knee Pain and Swelling
Single Most Likely Diagnosis
- Osteoarthritis (OA) flare-up: The patient's age, history of arthritis, and recent activity (walking on the sand) could have triggered an OA flare-up, leading to knee pain and swelling. The improvement with Tylenol arthritis and ice also supports this diagnosis.
Other Likely Diagnoses
- Meniscal tear or ligament sprain: The patient's history of frequently hitting his legs on objects and the acute onset of pain and swelling suggest a possible meniscal tear or ligament sprain.
- Bursitis: The patient's occupation and activities could have led to bursitis, which is an inflammation of the fluid-filled sacs that cushion the joints.
- Tendinitis: The patient's age and activity level could have contributed to tendinitis, which is an inflammation of the tendons.
Do Not Miss Diagnoses
- Deep vein thrombosis (DVT): Although the patient denies calf pain and has a negative Homan's sign, DVT is a potentially life-threatening condition that should not be missed. The patient's recent activity and swelling could be masking symptoms of DVT.
- Septic arthritis: The patient's age and recent activity could have led to a bacterial infection in the joint, which is a medical emergency.
- Fracture: Although the patient does not remember a specific injury, a fracture could have occurred, and it is essential to rule out this possibility.
Rare Diagnoses
- Gout or pseudogout: The patient's age and acute onset of pain and swelling could suggest a crystal arthropathy, such as gout or pseudogout.
- Hemarthrosis: The patient's history of frequent trauma to the legs could have led to bleeding into the joint, which is a rare but possible diagnosis.
- Neoplastic or inflammatory conditions: Conditions such as rheumatoid arthritis, lupus, or bone tumors could be causing the patient's symptoms, although these are less likely given the patient's presentation.