Case Presentation: A 60-year-old female with hypertension and hyperlipidemia presented with 8 days of generalized weakness, fatigue, and myalgia. She reported headaches and shortness of breath but denied fever, chills or hematochezia. Vitals were stable and physical exam was unremarkable except for splenomegaly, scleral icterus, and mucosal pallor. Hemoglobin was 4.0 on admission, down from 8.4 two weeks prior. Her bilirubin, LDH, MCV, and reticulocyte count were elevated but normal iron studies, B12, and folate ruled out nutritional deficiency. Infection was also ruled out and positive direct antiglobulin test DAT test confirmed AIHA. She received two units of packed red blood cells and was started on high dose prednisone with an appropriate rise in hemoglobin to 6.4. A chest CT scan revealed several lung nodules and a thyroid nodule which further workup determined were benign. An unremarkable abdominal CT scan further ruled out malignancy or bleeding. Over the next two days her hemoglobin stabilized between 7 and 8 and high dose steroids were continued along with prophylactic antibiotics. Hematology was consulted and she was discharged for outpatient follow-up. At two weeks after discharge, no cause has been found for the AIHA but her HGB has been stable at 8-10 and she is being tapered from steroids.
Discussion: Autoimmune hemolytic anemia (AIHA) is a rare and commonly secondary to malignancies, rheumatologic conditions, and drug reactions but many cases are idiopathic. AHIA is caused by autoantibodies to host red blood cells (RBCs) and is classified as warm, cold, or mixed depending on the optimal temperature at which the antibodies bind RBCs. Most cases are warm AIHA caused by development of IgG antibodies that optimally bind RBCs at 37°C. We report a case of warm autoimmune hemolytic anemia in a patient who presented with anemia and generalized weakness. AHIA commonly presents with weakness, fatigue, shortness of breath, and splenomegaly. Laboratory findings include severe anemia, reticulocytosis, elevated LDH and bilirubin, decreased haptoglobin and the presence of schistocytes on blood smear. Since other causes of anemia can present similarly, thorough workup is important. AHIA is confirmed by a positive DAT and prompt treatment is crucial as severe cases can be fatal. Typically, 6-12 weeks of high dose prednisone is the first line treatment for AIHA and is effective in most patients. For refractory cases rituximab or other specific immunosuppressant medications are used. Since underlying malignancy, rheumatological disease or drug reactions can cause AIAH, workup for these conditions is important to treat the underlying cause of the anemia. However, as in this case, up to 50% of AIHA is idiopathic and no cause is found. Prognosis of AIHA can vary depending on the underlying cause but most patients fully recover, and recurrence is rare.
Conclusions: Here we present a case of idiopathic warm autoimmune hemolytic anemia which can be a challenging diagnosis as it can present as mild generalized weakness and fatigue. Prompt diagnosis and treatment are crucial however as severe cases of AHIA can be fatal if not promptly treated.