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The Best in FOAM Education

  • Ryan N Barnicle, MD, M.Ed

Bug off! A Case of Babesiosis

A 70 year old M with a past medical history of ILD presents to PCP after one week of fever (TMax: 106 F), malaise, dizziness, epigastric pain, dyspnea, myalgias, diaphoresis, chills, poor appetite. According to daughter, he found a tick on himself just before the symptoms started. He was started empirically on azithromycin, atovaquone, and doxycycline to address tickborne disease. However, his symptoms worsened and he presented to an outside hospital where he required supplemental oxygen therapy to maintain his SpO2. Blood smears showed parasite burden of 7.6%. He is transferred to your hospital for further management.

On arrival, the patient has a toxic appearance. There is tachypnea and hypoxia. He is jaundiced. Bedside US shows diffuse B lines suggesting pulmonary edema with normal cardiac function. BiPap is started and the patient is temporarily stabilized. With an established diagnosis, consults are initiated with Infectious Disease, Hematology, and the MICU. Repeat testing shows increased parasite burden to 8.2% with moderate thrombocytopenia, mild leukocytosis, mild hyponatremia, mild transaminitis, and moderate bilirubinemia. Fibrinogen and d-dimer are also elevated, but PT/PTT remains normal.

Ultimately the patient went on to be admitted to MICU due to declining respiratory status requiring intubation. He received an exchange transfusion the following morning because parasite burden peaked at 12.2%. His course has been complicated with associated with acute renal failure, septic shock, and acute respiratory distress syndrome. Despite resolution of his parasitic infection, the patient required re-transfer to MICU in the following weeks for continued hypoxic respiratory failure thought to be secondary to ventilatory associated pneumonia and interstitial lung disease flare. He remains intubated.

Take Away #1

You must think of the diagnosis of Babesosis first! Conceptually, consider it in any patient with flu-like symptoms + hemolytic anemia / jaundice / thrombocytopenia / hepatosplenomegaly. A tick exposure is not commonly recalled. Patients who are asplenic, advanced age, or immunocompromised (e.g. HIV, malignancy, corticosteroid therapy) are at greatest risk. Of course, don’t forget that Long Island risk factor.

Take Away #2

Complications can be devastating and lethal. Symptoms include:

  • Marked thrombocytopenia

  • Disseminated intravascular coagulation

  • Hemodynamic instability

  • Acute respiratory distress

  • Myocardial infarction

  • Renal failure

  • Hepatic compromise

  • Altered mental status

Consider early plasma exchange transfusion in patients who appear ill. A general indication for exchange transfusion is parasite burden > 10%.

Take Away #3

In addition to supportive critical care, the treatment must include atovaquone and azithromycin OR clindamycin and quinine. Treat for Lyme disease with doxycycline empirically.


Ryan Barnicle, MD is a current third year resident at Stony Brook Emergency Medicine.



  • Hatcher JC, Greenberg PD, Antique J, et al. Severe babesiosis in Long Island: review of 34 cases and their complications. Clin Infect Dis. 2001;32(8):1117-1125.



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