Case Presentation:
Patient 1. A 71-year-old woman with no significant past medical history presented to the emergency department with 3 weeks of general malaise and subjective fevers after a trip to Connecticut. Her exam was notable for hypotension, as well as pallor of the skin and conjunctiva. Laboratory evaluation revealed a hemoglobin of 7.8 g/dL, platelets of 77,000/uL, alkaline phosphatase of 14 U/L, LDH of 445 and haptoglobin <15%. Babesiosis was confirmed by thick peripheral blood smear with parasitemia level of 1.85%. She received a 10 day course of atovaquone 750mg every 12 hours and oral azithromycin 500mg the first dose and 250mg every 24 hours thereafter. By day 2 of treatment, her parasitemia had decreased to <0.75%. Follow up in the outpatient clinic revealed absence of parasitemia by day 6.
Patient 2. A 56-year-old male with Crohn’s disease on maintenance treatment with adalimumab (Humira), presented to the emergency department with 10 days of spiking fevers, chills, fatigue and abdominal pain after a trip to Connecticut. Physical exam revealed fever, tachycardia, hypotension and hepatosplenomegaly. Laboratory evaluation was notable for hemoglobin of 12.7g/dL, platelets of 79,000/uL, leukocytes of 5400/uL, alkaline phosphatase of 140 U/L, LDH of 511 U/L and haptoglobin < 6%. Thick peripheral blood smear suggested babesia microti infection, which was confirmed by DNA PCR. 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.
Discussion:
Using a classification system proposed by White, et.al, we classified our patients as having mild disease (parasitemia level <4%, normal white count and Alkaline phosphatase <125 U/L) or severe disease (parasitemia level >4%, Alkaline phosphatase >125 U/L and white blood cell counts >5 x 109/L). As per this classification system, patient 1 had a mild disease and patient 2 had severe disease. Because of her intact immune system, patient 1 responded to a typical 10 day-course of low dose azithromycin plus atovaquone and within 48 hours of treatment her parasitemia level had decreased significantly. Patient 2 on the other hand was immunocompromised due to treatment adalimumab and therefore suffered a severe infection and prolonged hospital course. His parasitemia level did not clear until after day 10 of treatment and had to remain on the higher dose azithromycin/atovaquone combination therapy for 3 more weeks to avoid relapsing illness.
Conclusions:
In the above case report, our service had two cases of babesiosis, each in patients with differing immune statuses. This afforded us the opportunity to directly compare differences in treatment and outcomes, a comparison that to the best of our knowledge, has not been reported in the existing literature. It was observed that the severity, clinical course, and treatment options of babesiosis infection varies with the immune status of a patient.