Differential Diagnosis for Knee Swelling
The patient presents with knee swelling, a lump on the bottom of the kneecap, and recent onset of redness and swelling in the leg and foot. The following differential diagnoses are considered:
- Single most likely diagnosis
- Prepatellar Bursitis: This condition is likely given the patient's history of frequent kneeling, which can cause irritation and inflammation of the prepatellar bursa. The presence of a lump, blood, and fluid after attempted drainage, and the area feeling hard and hot to the touch, are consistent with this diagnosis.
- Other Likely diagnoses
- Septic Bursitis: The patient's attempt to drain the area and the subsequent filling of the lump with blood and fluid, along with the area feeling hot to the touch, raise the possibility of a septic bursitis.
- Hemarthrosis: The presence of blood and fluid in the lump after drainage suggests the possibility of hemarthrosis, which is the accumulation of blood in the joint space.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Deep Vein Thrombosis (DVT): Although the patient does not report pain, the sudden onset of redness and swelling in the leg and foot could be indicative of a DVT, which is a potentially life-threatening condition.
- Cellulitis: The patient's symptoms of redness, swelling, and warmth in the leg and foot could also be indicative of cellulitis, a bacterial skin infection that can spread rapidly and become severe if left untreated.
- Rare diagnoses
- Synovial Chondromatosis: This is a rare condition characterized by the growth of cartilage in the joint space, which can cause swelling and a lump.
- Gout or Pseudogout: Although less likely, these conditions can cause sudden onset of joint swelling and pain, and should be considered in the differential diagnosis.