A Case of Severe Babesiosis in a Patient with Crohnʼs Colitis on Adalimumab

Abstract

A 56-year-old male with Crohn's ileocolitis complicated by fistula on maintenance treatment with adalimumab, presented to the emergency department with 10 days of spiking fevers, chills, fatigue, abdominal pain, and anorexia after a trip to Connecticut. Physical exam revealed fever, tachycardia, hypotension and hepatosplenomegaly. At presentation, he was mildly anemic and thrombocytopenic, with leukocytes at 5400/uL, alkaline phosphatase at 140 U/L, an elevated LDH and low haptoglobin. Thick peripheral blood smear suggested babesia microti infection, which was confirmed by DNA PCR. His parasitemia level was 5.7%. He was started on oral atovaquone 750mg every 12 hours and oral azithromycin 1g every 24 hours with improvement in his parasitemia level to 1.24% by day 6, 1% by day 10, and 0% by day 14. Babesiosis is a tick-borne illness caused by intraerythrocytic protozoa. While most cases are asymptomatic, a more severe clinical disease can be seen in patients with advanced age (greater than 40 years), asplenia and depressed cellular immunity. As seen in our patient, who was immunocompromised from treatment with a TNF-alpha inhibitor (adalimumab), impaired immunity resulted in a more severe infection and prolonged hospital course. His parasitemia level did not clear until after day 10 of treatment and he had to remain on the higher dose azithromycin/atovaquone combination therapy for 3 more weeks to avoid relapsing illness. In addition, among the inflammatory bowel disease (IBD) population, the often-vague presentation of severe babesiosis can mimic a Crohn's flare - potentially delaying initiation of antimicrobial therapy and increasing risk for morbidity and mortality in these already vulnerable patients. Given the dramatic rise in cases of babesiosis in the Northeast and upper Midwest over the last decade, early consideration of babesiosis among immunocompromised IBD patients presenting with fever and poorly localized symptoms is essential. Ultimately, this case report illustrates how the severity and clinical course of a babesiosis infection varies with the immune status of a patient and highlights the importance of early consideration of babesiosis in immunocompromised IBD patients presenting with fever and non-specific symptoms.Figure 1