Acute Kidney Injury Associated With Human Granulocytic Anaplasmosis: A Case Report.

Tick-borne illnesses are a growing problem in the United States. Human granulocytic anaplasmosis (HGA), carried by the Ixodes scapularis tick, is caused by Anaplasma phagocytophilum. While the clinical manifestations of HGA may be protean, ranging from asymptomatic infection to life-threatening multiorgan failure, renal involvement is uncommon. We report a case of a 64-year-old man presenting with a febrile illness and acute nephritis in the setting of HGA infection. The patient's kidney biopsy was characterized by a membranoproliferative glomerulonephritis pattern and acute interstitial inflammation. After appropriate antibiotic treatment and high-dose steroids, the patient had a marked improvement in kidney function, although a subsequent recrudescence of nephritis required a 6-month course of additional steroids. As the prevalence of tick-borne diseases continues to spread across the United States, raising awareness of the potential for atypical presentations is important, particularly because early diagnosis and treatment can be curative and prevent further complications.