A rare cause of Acquired Hemolytic Anemia in a child; Donath-Landsteiner antibody

Abstract

Abstract Introduction/Objective INTRODUCTION: The Donath-Landsteiner (DL) antibody is known to cause paroxysmal cold hemoglobinuria (PCH), a rare form of intravascular hemolytic anemia which is precipitated by an IgG biphasic hemolysin with specificity to the P blood group antigen and most commonly reported in children. The DL test is a serologic test specifically examines, the biphasic nature of the antibody activity. Methods/Case Report CASE PRESENTATION: A 4-year-old previously healthy boy presented at an academic medical center with rhinorrhea and nasal congestion. His family reported that his urine became darker almost coke colored after his symptoms started. His initial vitals; temperature of 37.1 C, heart rate of 140, blood pressure of 122/87 and O2 saturation of 96% on room air. Laboratory investigations showed a hemoglobin level of 4.2 g/dL, hematocrit level of 12.5%, platelets count of 229 K/uL, indirect bilirubin of 6.2mg/dL, haptoglobin <30 mg/dL, LDH >1800 U/L. Direct antiglobulin test was positive with complement only. Thermal Amplitude and indirect Donath-Landsteiner tests were both positive. Respiratory viral panel was positive for Rhinovirus. The antibody screen was negative, and the patient was provided supportive care including as needed RBC transfusion, warming of fluids and body. By day day 9 patient Hgb stabilized, LDH, bilirubin and haptoglobin normalized and his urine turned yellow color and was discharged in stable condition. Results (if a Case Study enter NA) NA Conclusion CONCLUSIONS PCH is classified as a cold autoimmune hemolytic anemia caused by an IgG antibody that sensitizes RBCs at cold temperatures by attaching complement to the RBCs, causing intravascular hemolysis upon rewarming. The DL test for PCH involves in vitro testing for hemolysis with the patient's serum, washed group-O cells expressing the P antigen, and fresh normal serum. To prevent autoadsorption of the antibody and hemolysis, blood should be collected in prewarmed tubes that do not contain anticoagulants and kept at 37°C during the collection procedure. A high index of suspicion especially in pediatric population should be maintained after a viral infection. The treatment is usually supportive.