A MAST KNOWN CAUSE OF SHOCK

Abstract

TOPIC: Critical Care TYPE: Fellow Case Reports INTRODUCTION: The main types of shock include cardiogenic, hypovolemic, distributive, and neurogenic shock. Management of shock requires identifying and correcting the underlying cause, and supporting end-organ perfusion with fluid resuscitation and vasoactive medications. Here we present a rare cause of distributive shock. CASE PRESENTATION: A 65-year-old man presented with 2-month history of progressive weakness. Laboratory studies reviewed new thrombocytopenia to 25 x10(9)/L and acute renal failure with creatinine of 3.24 mg/dL. His bone marrow biopsy was concerning for acute mast cell leukemia, and he was started on treatment with 1 gram of methylprednisolone. About 1 hour after receiving this infusion, he developed chest pain, tachycardia and tachypnea. He was urgently transferred to the ICU. In the ICU, his condition progressed into ventricular fibrillation requiring CPR, defibrillation, and intubation. He was in refractory circulatory shock requiring high doses of norepinephrine, epinephrine, vasopressin, and stress dose steroids. Given his underlying mast cell leukemia, empirical treatment for mast cell activation syndrome was started. He received scheduled diphenhydramine, famotidine, montelukast and cromolyn. Patient was quickly weaned off vasoactive medications in the next 24 hours. Tryptase obtained at time of his hypotensive event was markedly elevated at greater than 2000 ng/mL. He had worsening renal failure requiring renal replacement therapy, and given his underlying diagnosis of mast cell leukemia, a rare hematological malignancy with limited treatment options and high mortality, the focus of his care was transitioned to concentrate solely on his comfort. DISCUSSION: Mast cell disorders include cutaneous and systemic mastocytosis, allergic diseases, and idiopathic disorders. Acute mast cell leukemia is a rare form of systemic mastocytosis characterized by at least 20% immature mast cells in bone marrow. Sudden mast cell activation leads to degranulation of mast cell and release of pre-formed mediators including histamine. It also stimulates de novo synthesis of other cytokines and chemokines. Typical symptoms include flushing, lightheadedness and abdominal cramping, but can progress to syncope and distributive shock, as seen in our patient. Treatment includes identification and avoidance of triggers, and supportive care with antihistamines (both H1 and H2 blockers) and cromolyn (mast cell stabilizer). CONCLUSIONS: It is essential for critical care clinicians to recognize mast cell activation syndrome as a potential cause of refractory shock, especially in at risk patients with systemic mastocytosis. Prompt treatment with antihistamines and cromolyn can facilitate resolution of shock. REFERENCE #1: Akin C, Valent P, Metcalfe DD. Mast cell activation syndrome: Proposed diagnostic criteria. J Allergy Clin Immunol. 2010;126(6):1099-104.e4. doi:10.1016/j.jaci.2010.08.035 REFERENCE #2: Molderings GJ, Haenisch B, Brettner S, et al. Pharmacological treatment options for mast cell activation disease. Naunyn Schmiedebergs Arch Pharmacol. 2016;389(7):671-694. doi:10.1007/s00210-016-1247-1 DISCLOSURES: No relevant relationships by Alice Gallo De Moraes, source=Web Response No relevant relationships by Zhenmei Zhang, source=Web Response