A Case of Unexplained Shock Following Steak Consumption

Abstract

SESSION TITLE: Fellow Case Report Slide: Pulmonary Critical Care Disorders: Think Twice SESSION TYPE: Affiliate Case Report Slide PRESENTED ON: Sunday, October 23, 2016 at 10:45 AM - 12:00 PM INTRODUCTION: Delayed anaphylaxis following red meat consumption is a novel phenomenon in the Southwestern United States. This presentation will illustrate a case of IgE mediated activity against the galactose-α-1,3-galactose (alpha-gal) epitope. This carbohydrate determinant is common in humans and isotope switching to alpha-gal IgE occurs following ectoparasite exposure. First described in 2009, early case reports led to identification of the Amblyomma americanum, or lone star tick, as the sensitizing exposure. We present the first reported case of anaphylaxis in New Hampshire from red meat consumption following alpha-gal sensitization. CASE PRESENTATION: Our patient is a 69 year old male who presented with an anaphylactic reaction. He has no known allergies or co-morbidities. A history revealed consumption of steak 6 hours before symptom onset of generalized urticaria, angioedema and dyspnea. Treatment included anti-histamines, steroids, and epinephrine. It was later divulged he sustained a tick bite 5 weeks prior to this admission. Further work-up identified a total IgE of 129 kU/L and an elevated alpha-gal IgE of 10 kU/L (normal ≤0.34 kU/L). His history and serologic testing allowed us to confirm a diagnosis of delayed anaphylaxis due to a red meat allergy. He made a full recovery, and received follow-up in our Allergy clinic and counseling on red meat avoidance. DISCUSSION: IgE sensitization to the oligosaccharide alpha-gal following exposure to the lone star tick is described largely in the southeastern United States. After red meat ingestion, a delayed anaphylactic reaction may occur. The diagnosis should be suspected when caring for the patient with anaphylaxis of unclear etiology, and is confirmed using an IgE specific immunoassay. Treatment in the acute setting is supportive, and long term care includes avoidance of mammalian meats and prevention of further tick exposure. CONCLUSIONS: This case demonstrates a vector-associated sensitivity leading to delayed anaphylaxis following consumption of mammalian meat. It is the first documneted occurrence in our state, supporting the described geographic spread of the lone start tick. Practitioners should maintain this condition on their differential as it becomes increasingly recognized in non-endemic regions. Reference #1: Commins, Scott P., et al. “Delayed Anaphylaxis to Alpha-gal, an Oligosaccharide in Mammalian Meat.” Allergology International 65.1 (2016): 16-20. DISCLOSURE: The following authors have nothing to disclose: Elliot Backer, James Carroll No Product/Research Disclosure Information