Haemophagocytic lymphohistiocytosis triggered by Rickettsia conorii.

Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of rickettsial infections. We report a 50-y-old man from northern India who presented with fever, respiratory distress, altered sensorium and an eschar. Despite treatment with doxycycline, his condition deteriorated with multi-organ dysfunction. PCR and sequencing from the eschar confirmed Rickettsia conorii. Bone marrow examination, elevated ferritin and triglycerides, as well as an H-score of 224 confirmed HLH. The patient was treated with corticosteroids but succumbed to refractory ventricular arrhythmias. A high index of suspicion is essential in rickettsial infections that present with multi-organ dysfunction, as early recognition of HLH enables the prompt initiation of treatment of the underlying disease and adjunctive immunosuppressive therapy. [GenBank accession nos. U59728.1 and MZ779037.].