Treatment paradox in musculo-skeletal tuberculosis in an immunocompetent adult male; a case report from a tertiary care hospital.

Paradoxical reactions like immune reconstitution inflammatory syndrome (IRIS) as seen with patients on retroviral treatment in HIV infection, have also been identified in HIV sero-negative patients with extra pulmonary tuberculosis especially lymph-node tuberculosis. Musculo-skeletal tuberculosis presenting as a cold abscess of the anterior chest wall is a rare entity which poses diagnostic and therapeutic challenge. A 35-year-old immunocompetent male came with complains of painless lump on right side of his chest over 9th and 10th intercostal space which gradually increased and extended upto 11th rib area. Clinically, diagnosis of cold abscess was made and anti-tubercular therapy (ATT) was started. Despite of being on ATT for 3 weeks, patient developed pain and signs of inflammation. Fluid was aspirated and sent for biochemical and microbiological investigations. The aspirated fluid was positive for acid fast bacilli by ZN stain and grew Mycobacterium tuberculosis in culture, sensitive to first line ATT. Pyogenic and fungal culture was negative. This case presented as an anterior chest wall cold abscess which deteriorated on initiation of first line ATT, thus creating a suspicion of resistance to ATT which was cleared on ATT susceptibility testing. Hence, this case underlines the possibility of treatment paradoxes seen in immunocompetent musculo-skeletal tuberculosis.