Markedly elevated intra-articular white cell count caused by gout alone

Joint pain accompanied by erythema, swelling, and decreased range of motion is concerning for septic arthritis and typically warrants joint aspiration. The synovial fluid white blood cell count plays a central role in the decision-making process regarding these patients. Traditional teaching holds that a cell count greater than 50,000 white blood cells/µL is likely caused by infection and therefore warrants either operative intervention or serial aspiration. This report describes 2 patients with extremely high synovial fluid white blood cell counts in the absence of infection. Case 1 involved a 59-year-old man who presented to the emergency department with sudden onset of atraumatic left elbow pain and was found to have a white blood cell count of 168,500 white blood cells/µL on joint aspiration and innumerable monosodium urate crystals. The patient ultimately improved with treatment with oral prednisone, avoiding operative intervention. Case 2 involved a 69-year-old man who presented to the emergency department with acute onset of atraumatic left knee pain. On arthrocentesis, the patient had a cell count of 500,000 white blood cells/µL and was therefore taken to the operating room for arthroscopic irrigation and debridement. Final analysis of the synovial fluid showed monosodium urate crystals and negative culture findings. These cases illustrate the highest synovial fluid white blood cell count reported in patients with gout and highlight the potential difficulty in differentiating between acute gout and septic arthritis in the setting of markedly elevated white blood cell count.