Immune Thrombocytopenia Purpura Secondary to COVID-19

A 73-year-old female with past medical history of essential hypertension, hyperlipidemia, seasonal allergies, and chronic back pain presented to the hospital with complaints of headaches, fevers, fatigue, generalized body aches, shortness of breath, and diarrhea. Initial complete blood count was remarkable for leukopenia with an absolute lymph count of 0.60 K/mu L and severe thrombocytopenia (platelet count < 3 K/mu L). She was tested for COVID-19 via nasopharyngeal swab polymerase chain reaction (PCR) testing and found positive. Additional labs showed an elevated D-dimer, C-reactive protein, fibrinogen, and lactate dehydrogenase. Vitamin B12 and folate levels were obtained and found to be normal. Peripheral smear showed no schistocytes or additional hematologic abnormalities apart from thrombocytopenia. The patient was transfused one unit of platelets with no improvement in platelet count. Fibrinogen count was obtained and found in normal range at 458 mg/dL. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and international normalized ratio (INR) were all found to be normal. Immune thrombocytopenia purpura (ITP) was suspected and intravenous immunoglobulin (IVIG) was administered at a dose of 1g/kg/day for two doses. By day 4, the patient had marked response to treatment with platelet recovery to 105 K/mu L and subsequently discharged by day 5 with complete resolution of symptoms and platelet count of 146 K/mu L. Twenty-eight days after discharge, she presented to hematology clinic with platelet count of 8 K/mu L. Repeat nasopharyngeal swab PCR COVID testing was negative and she was treated with WIG and pulse dexamethasone with prompt response, confirming suspicion of underlying, undiagnosed ITP prior to COVID infection.