A case of warm autoimmune hemolytic anemia

ABSTRACT

Introduction Warm autoimmune hemolytic anemia (AIHA) is a rare clinical disease which usually arises during or after concomitant clinical pathologies. Autoantibodies are formed against the red blood cell membrane, destroying them and causing extravascular hemolysis. Case A 68-year-old woman with medical history of anemia requiring transfusions, CAD s/p stents in 2007 and 2021, type 2 diabetes mellitus, hypertension, and COVID-19 infection nine months ago presented with chest pain and shortness of breath on exertion for two months. She described the pain as central, non-radiating chest tightness associated with dyspnea on exertion, which resolved with a few minutes of rest. She originally attributed this chest pain to her recent cardiac stent. Three weeks prior , She was treated for anemia (hemoglobin 5.4 gm/dL) with four units of packed red blood cells. Her hemoglobin increased to 7.9 gm/dL after transfusion with temporary improvement of her symptoms until this presentation. Her admit vitals were BP 154/65, HR 99, RR 20, O2 99% on room air, T 97.9°F. Physical exam was notable for generalized jaundice and scleral icterus. Laboratory results included hemoglobin of 6.5 gm/dL, MCV 106 fL, reticulocyte count 17.3%, peripheral blood smear with polychromatophils, total bilirubin 6.5 mg/dL, lactate dehydrogenase 321 U/L, and haptoglobin <30 mg/dL. Her EKG and troponin were normal. She was found to have hepatosplenomegaly on abdominal ultrasound. Further workup showed a direct antiglobulin test was positive with anti-IgG and complement C3 antibodies. This result confirmed the diagnosis of warm autoimmune hemolytic anemia. She received one unit of packed red blood cells with a subsequent hemoglobin of 6.1 gm/dL. She was then started on rituximab and prednisone with an increase in her hemoglobin to 6.9 gm/dL prior to discharge. The patient was discharged on high dose prednisone, scheduled for further rituximab infusions and given close follow-up with hematology and PCP. Atovaquone was added for pneumocystis jirovecii pneumonia prophylaxis during rituximab and prednisone treatment. Discussion Warm autoimmune hemolytic anemia is the most common type of AIHA, and its prevalence is approximately 170 per million. It can present with symptoms of chest pain, shortness of breath, and dyspnea on exertion which may at first seem to be cardiac in nature. However, further investigation with laboratory workup can reveal underlying hematologic abnormalities which can present similarly with more severe cases of AIHA. Approximately 50-60 percent of warm AIHA are associated with underlying conditions including EBV, HIV, HCV, lymphoproliferative disorders, and immunodeficiency states. It is important to consider AIHA in anemic patients with immunocompromised conditions. Cases have also been reported of new onset AIHA in association with COVID-19 infection, although there is no evidence yet of AIHA occurring several months after resolving COVID-19 infection.