Hemophagocytic lymphohistiocytosis is a frequently fatal and likely underdiagnosed disease. It is a rare occurrence in adults and usually secondary to an insult such as viral infections, bacterial infections, autoimmune connective tissue disorders, malignancies and immunocompromised states, in contrast to its childhood counterpart, which is due to a genetic defect but may share some of same genetic etiologies. It is characterized by multisystem inflammation due to unregulated proliferation and infiltration of macrophages and CD8 T cells in the bone marrow, which leads to phagocytosis of red blood cells, platelets, lymphocytes and their precursors.
A 40-year-old Sri Lankan woman presented with a high-grade fever of 2 weeks' duration and the initial workup, including a thorough clinical examination, and all the investigations, including a septic screen, were normal. On the 18th day of hospital admission, she was found to have yellowish retinal lesions, which were confirmed as choroid tubercles by the consultant eye surgeon. Two days later she became pancytopenic and a bone marrow biopsy confirmed the diagnosis of hemophagocytic lymphohistiocytosis. She was treated with conventional category-1 antituberculous drugs and an initial 2 weeks with high-dose oral dexamethasone. All the choroid tubercles gradually disappeared and she recovered completely without any complications.
In an adult patient with hemophagocytic lymphohistiocytosis, it is pivotal to understand the underlying etiology, as it needs extensive immunosuppression. If this patient had been treated with immunosuppressants without antituberculous medications, it would have been lethal with disseminated or central nervous system tuberculosis. So, in areas where tuberculosis is endemic, if no underlying cause is found, it may be worth considering antituberculous treatment for these patients. Re-evaluation with thorough clinical examination is of utmost importance in any patient with pyrexia of unknown origin as well as in any disease with unusual manifestations.