Transient Acquired Amegakaryocytic Thrombocytopenia in the Setting of Severe Sepsis: A Case Report.

Acquired amegakaryocytic thrombocytopenia (AATP) is a rare disorder in which severely low platelet levels occur due to reduced or complete absence of megakaryocytes in the bone marrow. The pathophysiology of this disease is not fully understood, although anti-thyroid peroxidase antibodies (anti-TPO) binding to cellular-myeloproliferative leukemia (c-mpl) receptors is a proposed mechanism. Currently, no standard published guideline for treatment exists, but immunosuppressive therapies have been used based on the proposed mechanism and associated conditions. We present a case of a 57-year-old male who presented to the hospital with a 3-day history of progressive weakness and dysphagia. He had recently been discharged from an outside health system after evaluation for suspected gastrointestinal bleeding, although esophagogastroduodenoscopy and colonoscopy did not uncover a source of bleeding. Fifteen days later, he was admitted to our hospital for septic shock and acute renal failure with suspected lower gastrointestinal bleeding (melena on presentation). He was found to have a rapidly declining platelet count with a nadir of 0. Due to severe thrombocytopenia, filgrastim was administered. A bone marrow biopsy revealed findings consistent with amegakaryocytosis with otherwise preserved cell lines. Hematologic labs improved with the initiation of appropriate treatment for severe sepsis. After performing an extensive workup, the likely etiology of transient AATP in this case was severe sepsis-induced immune dysregulation and bone marrow suppression.

Hypercalcemia Secondary to Calcitriol Production From Dual Combination Immunotherapy in Pulmonary Metastatic Melanoma.

Nivolumab and ipilimumab are immunotherapy agents recommended for the treatment of metastatic melanoma. A rare adverse effect of these agents is hypercalcemia. The mechanism of immunotherapy-mediated hypercalcemia is thought to be due to ectopic calcitriol production from activated macrophages, similar to sarcoidosis. We present a case of a 76-year-old female with metastatic melanoma who developed severe hypercalcemia after completing a cycle of combined nivolumab and ipilimumab therapy. After other common causes of hypercalcemia in malignancy were ruled out, the decision was made to aggressively treat her hypercalcemia while inpatient and hold immunotherapy at discharge. Since holding immunotherapy, she has not had a repeat occurrence of hypercalcemia. This case stresses the importance of including immunotherapy adverse effects in the differential diagnosis for hypercalcemia in malignancy.