Disseminated Tuberculosis Driving Secondary Haemophagocytic Lymphohistiocytosis Following Adalimumab and Treatment for Latent Tuberculosis.

We describe the case of a 63-year-old man presenting with fevers, hyperferrintinaemia and pancytopaenia. He was known to have psoriatic arthritis, managed with adalimumab and methotrexate. Haemophagocytic lymphohistiocytosis (HLH) was diagnosed, and he was treated with intravenous anakinra whilst searching for an aetiology. Despite previous treatment for latent tuberculosis, he developed changes typical for miliary tuberculosis and was started on antituberculosis therapy; whole genome sequencing later demonstrated isoniazid monoresistance. This case demonstrates both the importance of recognising Mycobacterium tuberculosis as a trigger of HLH, and also the risk of latent tuberculosis treatment failure in the setting of monoresistance.