persistent marked peripheral eosinophilia due to tuberculosis: a case report

we report a case of a 68-year-old female who was a known case of diabetes mellitus and chronic liver disease and presented with complaints of dry cough and other constitutional symptoms since one month. during initial investigations, the patient was found to have peripheral blood eosinophilia. upon investigating further,the patient was found to have mediastinal lymphadenopathy and fine-needle aspiration of mediastinal lymph nodes showed features of tuberculosis. the patient was started on anti-tubercular treatment and her eosinophil counts returned to normal levels. correlation between eosinophilia and tuberculosis has not been established in classical literature. this case highlights the same association and raises awareness on this crucial finding. coexistence of eosinophilia and tuberculosis in our patient is suggested since peripheral blood eosinophilia improved with anti-tubercular treatment. the exact pathogenesis of coexistence of tuberculosis and peripheral blood eosinophilia yet remains to be deciphered, but tissue pathology is mainly associated with the discharge of toxic eosinophil products.