Two Infectious Agents Causing Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune activation syndrome that should be recognized earlier for effective treatment. Adults usually have secondary HLH. An uncommon cause of secondary HLH is AIDS and simultaneous opportunistic infections. Acute human immunodeficiency virus (HIV) and opportunistic infections are also independent causes of HLH, so the presence of both should raise suspicion, especially if patients fulfill the criteria. HLH secondary to severe babesiosis is a rare entity as well. Some patients might not meet the full criteria of HLH on presentation, especially when some specific lab test results are still pending. A delay in diagnosis can happen in those cases. Here, we present two cases. The first case is of a 35-year-old homosexual male who presented with constitutional symptoms of one-week duration. He was diagnosed and started on the treatment of HIV. His fever was not resolving and further investigations led to a diagnosis of disseminated histoplasma infection. The patient fulfilled the criteria of HLH as well. Prompt therapy resulted in the improvement of clinical and laboratory parameters. The second case is of a 72-year-old female presenting with fever. A diagnosis of severe babesiosis and secondary HLH was made. Treatment of babesia resulted in the improvement of clinical and biochemical parameters.