BABESIA MICROTI INFECTION WITH LOW-GRADE PARASITEMIA CAUSING ARDS IN AN IMMUNOCOMPETENT PATIENT

ABSTRACT

SESSION TITLE Unusual Critical Care SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 1015 am - 1110 am INTRODUCTION: Babesiosis can have a clinical spectrum ranging from mild illness in most cases to more severe manifestations in immunosuppressed individuals or in those with high-grade parasitemia. This patient had severe babesiosis resulting in ARDS and shock in spite of being immunocompetent and having low-grade parasitemia, making it a rare presentation. CASE PRESENTATION A 49-year-old, previously healthy woman, was admitted with high-grade fevers. Physical exam findings were normal, except for fever (103 F). Initial lab results were significant for hemolytic anemia and thrombocytopenia. Chest radiography was normal. Other microbiology studies, including COVID-19, were negative. Empiric antibiotic therapy with piperacillin-tazobactam and doxycycline was started. Peripheral smear identified rare, minute intracellular ring forms, suspicious for babesia. IV azithromycin and oral atovaquone were started. PCR was done to confirm the diagnosis and Babesia microti DNA was detected. As peripheral smear showed parasitemia of only 1% (percentage of red blood cells infected), exchange transfusion was not considered as a treatment option. Two days after admission, worsening hemodynamic and respiratory status was noted with increasing oxygen requirements. CT chest now revealed diffuse interstitial infiltrates. ARDS ensued and the patient was intubated and started on mechanical ventilation with vasopressor support. Immunodeficiency workup was normal. In view of clinical deterioration, the antimicrobials were switched from atovaquone and azithromycin to IV clindamycin and quinidine for 14 days. After a protracted ICU stay, the patient showed gradual clinical improvement, parasitemia resolved, and she was eventually discharged to a rehabilitation facility. DISCUSSION: Babesiosis is a tick-borne infectious disease endemic to the North-East and Midwest United States. Majority of the infections are self-limited. However, in immunocompromised individuals and in those with high-grade parasitemia (>10%), it manifests as a severe illness with ARDS, severe hemolysis, or shock. Diagnosis is made by identifying parasites on thin peripheral blood smears with Giemsa/Wright stains. PCR can be used for species identification and for confirming the diagnosis in cases with low-grade parasitemia (<4%). IV azithromycin plus oral atovaquone is the preferred initial regimen and IV clindamycin plus quinidine is an alternative combination that can be used in severe infection. Red blood cell exchange transfusion can be considered in patients with high-grade parasitemia or organ failure. CONCLUSIONS: Babesiosis can very rarely cause ARDS and shock in immunocompetent patients with low-grade parasitemia. Prompt diagnosis and escalation of antimicrobial regimens to clindamycin and quinidine in such cases can lead to improved clinical outcomes. Exchange transfusion can serve as a treatment option in patients with high-grade parasitemia. Reference #1 Ord RL, Lobo CA. Human babesiosis Pathogens, prevalence, diagnosis, and treatment. Current clinical microbiology reports. 2015 Dec;2(4)173-81. Reference #2 Ripoll JG, Rizvi MS, King RL, Daniels CE. Severe Babesia microti infection presenting as multiorgan failure in an immunocompetent host. Case Reports. 2018 May 30;2018bcr-2018. Reference #3 Sanchez E, Vannier E, Wormser GP, Hu LT. Diagnosis, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis a review. Jama. 2016 Apr 26;315(16)1767-77. DISCLOSURES No relevant relationships by Shankar Chhetri No relevant relationships by Vasudev Malik Daliparty No relevant relationships by Preethi Dendi No relevant relationships by samer talib