Tuberculosis of the foot mimicking Charcot arthropathy

Mycobacterium tuberculosis bone and joint infection accounts for 2% to 3% of all tuberculosis cases but is uncommon in the foot. A 32-year-old woman had foot pain and swelling, and radiographs showed midfoot bony destruction and fragmentation. She was diagnosed with Charcot arthropathy, but had no neuropathy or improvement despite total contact casting. Bone biopsy 16 months after initial presentation did not show acid-fast bacilli on smear, but M. tuberculosis was recovered on culture; concurrent chest radiographs showed patchy and nodular opacities in both upper lung zones, consistent with previous pulmonary tuberculosis. Sputum smear showed acid-fast bacilli and culture yielded M. tuberculosis. In retrospect, the patient was at increased risk for M. tuberculosis infection because of previous residence in Myanmar and India. Clinicians should consider M. tuberculosis infection in the differential diagnosis of Charcot arthropathy for patients who have exposure history and absence of risk factors for Charcot arthropathy.