Diagnosis of Acute Gouty Arthritis Obscured by Anchoring Bias

A 56-year-old African American man presents to the emergency department with polyarthralgias and a fever of 103ºF. One month prior to admission, he presented with right knee pain and swelling. Blood cultures grew S. epidermidis. He was treated for presumed septic arthritis complicated by MSSE bacteremia. He was treated with meropenem and a prolonged course of daptomycin following discharge.

On the current presentation, the patient complained of fever of two days’ duration as well as left elbow and bilateral hand, knee and foot pain. He denied sick contacts, weight loss, night sweats, hemoptysis, abdominal pain, chest pain or dyspnea. His past medical history was significant for rheumatoid arthritis (RA), managed on abatacept. He had a dilated cardiomyopathy, treated with a left ventricular assist device (LVAD); atrial fibrillation, for which he was maintained on anticoagulation; a history of chronic alcohol use; and chronic kidney disease stage 2.

On physical examination, vital signs included a temperature of 103ºF, blood pressure of 122/90, heart rate of 122 beats per minute, respiratory rate of 20–33 breaths per minute and oxygen saturation of 99%. He weighed 109 kg and appeared in no acute distress, with normal mental status. Cardiopulmonary exam demonstrated normal S1 and S2, no murmurs, rubs or gallops, clear breath sounds and symmetric chest expansion. No rashes, ulcerations, lesions or nodules were noted. There was no hepatosplenomegaly or abdominal tenderness. Musculoskeletal exam revealed warmth, erythema, tenderness, swelling and limited range of motion of both hands (dorsum, right third proximal interphalangeal joint, right first interphalangeal joint and left wrist), as well as both elbows, ankles, metatarsal joints and the right knee.

Question 1

Based on the above findings and medical history, which of the following is the most likely cause of these symptoms?*

a. septic arthritis
b. rheumatoid arthritis
c. crystal arthropathy
d. osteoarthritis
e. reactive arthritis

Given the constellation of symptoms and risk factors, there is initial concern for septic arthritis, as well as an RA flare. The patient was admitted to the critical care unit, given his cardiac history, and started on broad-spectrum antibiotics, given his recent hospitalization for bacteremia.

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Labs upon admission were significant for mild leukocytosis of 12,800, lactic acid of 1.3 mg/dL, C-reactive protein of 329 mg/L with sedimentation rate >100 mm/hr, procalcitonin of 2.0 ng/mL and a serum uric acid of 6.0 mg/dL. Emergent aspiration of the right knee produced purulent fluid with a white blood count of 117,000 with a differential of 92% polys. It was at that point that septic arthritis immediately became the primary diagnosis.