Case report: human granulocytic anaplasmosis causes acute myopericarditis with atrial fibrillation

BACKGROUND: Tick-borne illness are becoming increasingly common, in a spreading geographic area. Lyme disease is a well-known cause of cardiovascular disease, but anaplasmosis has previously had relatively little reported association with conduction and myocardial disease. CASE SUMMARY: A 65-year-old man with fever and malaise was admitted to the intensive care unit in shock. Electrocardiogram showed new atrial fibrillation and conduction abnormalities. Transthoracic echocardiogram demonstrated normal left ventricular ejection fraction but significant right ventricle dysfunction. Cardiac magnetic resonance imaging findings were consistent with myopericarditis. Workup revealed human granulocytic anaplasmosis without Lyme. He recovered with doxycycline. CONCLUSION: To our knowledge, this is one of the first reported cases of anaplasmosis causing electrical conduction and myocardial disease with haemodynamic instability in an isolated infection. Treatment with appropriate antibiotics and supportive care allowed the patient to recover to his functional baseline within a month from being discharged from the hospital. Recognition of anaplasmosis in the absence of Lyme disease as a potential cause of electrical and myocardial disease is important in the context of increasing anaplasmosis incidence across the United States.