Alemtuzumab is a humanized monoclonal antibody indicated for the treatment of adult patients with relapsing-remitting multiple sclerosis . Alemtuzumab is associated with an increased risk for autoimmune adverse events including immune thrombocytopenia (ITP). To our knowledge, adrenal insuficiency has not been described in the context of Alemtuzumab therapy. We report a case of acute adrenal insufficiency (AAI) and multiorgan failure in a patient who developed immune thrombocytopenic purpura (ITP) as a Consequence of Alemtuzumab Therapy.

A 39-year-old male with RRMS presented with acute abdominal pain, fever, encephalopathy and generalized weakness. Patient completed his second course of alemtuzumab infusions 3 months prior to admission. Patient was found to have unexplained bilateral adrenal infarcts with hemorrhagic conversion leading to adrenal insufficiency. His baseline cortisol level was 15.6 mcgs/dL and rapidly increased to 31.6 mcgs/dL after ACTH stimulation test. Subsequent complicated with multifocal pneumonia and paraneumonic bilateral pleural effusions, sepsis, portal hypertension leading to anasarca and acute renal failure. On admission his platelet count was 226 10/L but dropped as low as 36 10/L few days later. Anticardiolipin antibodies and beta2 glycoprotein were normal. No evidence of heparin-induced thrombocytopenia or secondary sources of hemorrhages. Patient received high dose corticosteroids and was started on anticoagulation with good clinical response. His platelet count increased to normal levels within 2 weeks of admission. The diagnosis of ITP was made based on lack of alternative explanations and good response to immunotherapies.

Acute adrenal Insufficiency can present as a consequence of ITP in patients receiving Alemtuzumab therapy. Our patient had good response to steroid therapy, anticoagulation and management of systemic complications. A high index of suspicion is needed to make the correct diagnosis and to initiate appropriate treatment.