A 24-year-old sexually active woman presents with fever, migratory polyarthralgia, tenosynovitis of the wrist, and two painless pustular skin lesions on the extensor surface of the forearm. Blood culture is sterile. Synovial fluid Gram stain shows no organisms. Which diagnostic approach has the highest yield for confirming the underlying infection?

• A Repeat blood cultures on chocolate agar incubated anaerobically
• B Gram stain and culture of the pustular aspirate alone
• C Serological test for rheumatoid factor and anti-CCP antibody
• D NAAT for Neisseria gonorrhoeae on urine plus pharyngeal and rectal swabs ✓

Explanation

This is disseminated gonococcal infection, the bacteraemic arthritis-dermatitis syndrome. Blood cultures are positive in under half of cases and synovial fluid cultures are often sterile at this stage, while skin lesion aspirates have very low yield. Because the mucosal source infection is frequently asymptomatic, NAAT on urine plus extragenital pharyngeal and rectal swabs gives the highest diagnostic yield and confirms gonococcaemia. Rheumatoid serology does not address the infectious diagnosis.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.