A Case of Unrecognized Prehospital Anaphylactic Shock

Abstract

A case of prehospital anaphylactic shock that presented atypically, without a known exposure, is discussed. Anaphylaxis is a potentially life-threatening allergic reaction that requires prompt recognition and aggressive treatment. While there is little diagnostic dilemma (specifically used in the conclusion section of this paper) in the recognition and management of "classic" presentations of anaphylaxis there is likely a need for further education of prehospital providers, as well as emergency physicians, on how to recognize atypical cases of anaphylaxis. These cases can be equally severe, with potentially fatal consequences if missed. The diagnosis and management of anaphylaxis are reviewed, as well as barriers that providers encounter in diagnosing uncommon presentations.

Cardiovascular changes during peanut-induced allergic reactions in human subjects

“…We observed a reproducible decrease in SV that was associated with increased peripheral blood flow; given the absence of significant peripheral edema during reactions, it is likely that the majority of fluid shifts occurred within the gut rather than into the cutaneous bed and thus contributed to the symptoms of abdominal discomfort reported during challenges. Significant fluid redistribution to the gut during anaphylaxis (including diffuse bowel wall edema confirmed on acute computed tomography scan) has been reported in a single case report of a patient with drug-induced anaphylaxis, 17 but this has not yet been formally investigated in food allergy. There is growing evidence that the splanchnic circulation is an important reservoir of the venous circulation (eg, in chronic heart failure), and splanchnic nerve block alters venous return and cardiac preload.…”

Delayed symptoms and orthostatic intolerance following peanut challenge

“…This suggests that some biphasic reactions may in fact be due to further allergen absorption triggered by post‐prandial gut motility, rather than representing a true “immunologically biphasic” reaction. There is evidence from animal models of food allergy that acute allergic reactions impact upon gastric motility, 24,25 and this is supported by anecdotal data from human anaphylaxis 26 . Thus, our protocol, in which participants consumed a light meal following OFC, may have resulted in an overestimation of the true rate of further symptoms after OFC.…”

Pathophysiological, Cellular, and Molecular Events of the Vascular System in Anaphylaxis

“…A recent study carried out in peanut-challenged anaphylactic patients has shown that most leakage volume takes place in the gut, contributing to the appearance of gastrointestinal symptoms ( 176 ). Furthermore, intestinal extravasation has also been determined in a drug-induced anaphylactic patient in whom a diffuse edema was observed ( 177 ).…”

“…Therefore, the venous system has additional venous valves formed by folds of the tunica intima and whose function is to prevent blood reflux (116,117,129,131). intestinal extravasation has also been determined in a druginduced anaphylactic patient in whom a diffuse edema was observed (177).…”