CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Clinical pathology abstracts editor: Deborah Sesok-Pizzini, MD, MBA, associate professor, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and medical director, Blood Bank and Transfusion Medicine, Children’s Hospital of Philadelphia.
Confirmed Ehrlichia ewingii infection likely acquired through platelet transfusion
Ehrlichiosis is a tick-borne disease that may be asymptomatic or result in fatal sepsis. Ehrlichiosis transmitted from transfusion of blood products has not been documented. A case report of a 9-year-old Georgia boy with a history of acute lymphoblastic leukemia is the first report of Ehrlichia ewingii infection transmitted by a platelet transfusion. The authors first describe the patient as presenting to the hospital with complaints of fever, fatigue, malaise, vomiting, diarrhea, and petechial rash. Cultures were performed and broad-spectrum antibiotics started. But despite the antibiotic therapy, the patient’s clinical status deteriorated, with worsening neutropenia, thrombocytopenia, and elevated liver enzymes. The hospital laboratory identified morulae in granulocytes on a peripheral smear on day 11 of hospitalization. The patient was started on doxycycline, and the Mayo Clinic and Centers for Disease Control and Prevention confirmed positivity for E. ewingii via real-time polymerase chain reaction testing. The family denied tick exposure or recent outdoor activity. However, the patient had a history of three transfusions of leukoreduced and irradiated platelets in one month. Trace-back investigations were conducted on all three donors. The donors reported feeling well at the time of donation, although one donor gave a history of a tick bite. The donor with tick exposure was positive for Ehrlichia species with an IgG titer of one per 512. Of interest, this was the first confirmed case of this type of Ehrlichia species to be transmitted through a blood transfusion. The authors noted that E. ewingii is a rarely reported species and that this case reinforces that it is possible for infected blood donors to be asymptomatic. Blood screening questions do not address tick exposures, and screening all donated blood products for Ehrlichia by PCR is cost-prohibitive, with no data to support its utility. The authors concluded that suspicion of a transfusion-transmitted disease should include Ehr-lichia in the differential so prompt therapy can be initiated.
Regan J, Matthias J, Green-Murphy A, et al. A confirmed Ehrlichia ewingii infection likely acquired through platelet transfusion [published online ahead of print March 19, 2013]. Clinical Infect Dis. doi:10.1093/cid/cit177.
Correspondence: Joanna Regan at jregan@cdc.gov
Transfusion strategies for acute upper gastrointestinal bleeding
Restricted transfusion strategies may be indicated in situations where hemorrhage is not too severe. Controlled trials have shown that for critically ill patients, a restrictive transfusion strategy is at least as effective as a liberal strategy. However, these trials excluded patients with gastrointestinal (GI) bleeding. The authors performed a randomized control trial in which they assessed whether a restrictive threshold for patients with acute GI bleeding was safer and more effective than a liberal strategy based on recommended guidelines. They enrolled patients in their trial from June 2003 through December 2009. The patients had upper GI bleeding defined as hematemesis, melena, or both. The patients were randomized to receive either the restrictive transfusion strategy, with a hemoglobin threshold for transfusion of 7 g/dL, or a liberal transfusion strategy, with a hemoglobin threshold for transfusion of 9 g/dL. In both groups, one unit of red blood cells was transfused. The primary outcome measure was the rate of death from any cause within the first 45 days. Secondary outcomes included the rate of further bleeding and the rate of in-hospital complications. The authors noted that 225 of the 461 patients assigned to the restrictive strategy (49 percent) did not receive transfusions as compared with 65 of 460 assigned to the liberal strategy (14 percent). Furthermore, the probability of survival at six weeks was higher in the restrictive strategy group than in the liberal strategy group. The authors concluded that the restrictive strategy significantly improved outcomes in patients with acute upper GI bleeding as compared with the liberal transfusion strategy. The outcomes included risk of further bleeding, rate of complications, need for rescue therapy, and rate of survival.
Villanueva C, Colomo A, Bosch A, et al. Transfusion strategies for acute upper gastrointestinal bleeding. N Engl J Med. 2013;368:11–21.
Correspondence: Dr. Candid Villanueva at cvillanueva@santpau.cat