Clinical and laboratory evolution of a culture-confirmed case of human granulocytic ehrlichiosis

A 74-year-old man from suburban New York City, who was hospitalized because of chest pain and fever, was diagnosed as having human granulocytic ehrlichiosis on the eighth hospital day. Although leukocyte and platelet counts were normal on admission, they fell to abnormally low values then normalized prior to specific therapy against the human granulocytic ehrlichiosis agent. Intracytoplasmic inclusions suggestive of Ehrlichia were observed in up to six percent of granulocytes, and the human granulocytic ehrlichiosis bacterium was cultured in an HL 60 human promyelocytic cell line. The patient improved dramatically within 24 hours of doxycycline treatment, after failing to improve on various beta lactam antimicrobial agents. He was discharged from the hospital 14 days after admission. Because human granulocytic ehrlichiosis was not diagnosed until his eight hospital day, clinical and laboratory parameters prior to specific treatment were available. This case illustrates the clinical and laboratory evolution of the infection with human granulocytic ehrlichiosis agent in humans.