Alkaline ingestions cause tissue injury by liquefactive necrosis, a process that involves saponification of fats and solubilization of proteins. Cell death occurs from emulsification and disruption of cellular membranes. The hydroxide ion of the alkaline agent reacts with tissue collagen and causes it to swell and shorten. Small-vessel thrombosis and heat production occurs.
Severe injury occurs rapidly after alkaline ingestion, within minutes of contact. The most severely injured tissues are those that first contact the alkali, which is the squamous epithelial cells of the oropharynx, hypopharynx, and esophagus. The esophagus is the most commonly involved organ, with the stomach much less frequently involved after alkaline ingestions. Tissue edema occurs immediately, may persist for 48 hours, and may eventually progress sufficiently to create airway obstruction. Over time, if the injury was severe enough, granulation tissue starts to replace necrotic tissue.
Over the subsequent 2-4 weeks, any scar tissue formed initially remodels and may thicken and contract enough to form strictures. The likelihood of stricture formation primarily depends upon burn depth. Superficial burns result in strictures in fewer than 1% of cases, whereas full-thickness burns result in strictures in nearly 100% of cases. The most severe burns also may be associated with esophageal perforation.
-
Caustic ingestions. Endoscopic view of the esophagus in a patient who ingested hydrochloric acid (Lime-a-way). Note the extensive thrombosis of the esophageal submucosal vessels giving the appearance similar to chicken wire. Courtesy of Ferdinando L. Mirarchi, DO, Fred P. Harchelroad Jr, MD, Sangeeta Gulati, MD, and George J. Brodmerkel Jr, MD.
-
Caustic ingestions. Endoscopic view of the esophagus in a patient who ingested hydrochloric acid (Lime-a-way). Note the appearance of the thrombosed esophageal submucosal vessels giving the appearance of chicken wire. Courtesy of Ferdinando L. Mirarchi, DO, Fred P. Harchelroad Jr, MD, Sangeeta Gulati, MD, and George J. Brodmerkel Jr, MD.
-
Caustic ingestions. Endoscopic view of the esophagus in a patient who ingested hydrochloric acid (Lime-a-way). Note the extensive burn and thrombosis of the submucosal esophageal vessels, which gives the appearance of chicken wire. Courtesy of Ferdinando L. Mirarchi, DO, Fred P. Harchelroad Jr, MD, Sangeeta Gulati, MD, and George J. Brodmerkel Jr, MD.
-
Algorithm for the diagnosis and management of caustic ingestions. In all cases of caustic ingestion, the airway should be assessed initially and protected if necessary. If endoscopy is not rapidly available and severe injury is strongly suspected, obtain a contrast-enhanced computed tomographic (CT) study. The Usta protocol consists of methylprednisolone (1 g per 1.73 m2 of body-surface area per day, given intravenously for 3 days) plus ranitidine (4 mg per kilogram of body weight per day in children or the standard adult dose in adults, given intravenously) plus ceftriaxone (100 mg per kilogram per day in children or the standard adult dose in adults, given intravenously). NPO denotes nothing by mouth, and TPN total parenteral nutrition.
