Caustics and corrosives cause tissue injury by a chemical reaction. The vast majority of caustic chemicals are acidic or alkaline substances that damage tissue by accepting a proton (alkaline substance) or donating a proton (acidic substance) in an aqueous solution. [1]
The pH of a chemical is a measure of how easily the chemical accepts or donates a proton. This relates to the strength of the acidic or alkaline substance, and provides some, but not precise, correlation with the likelihood of injury. Substances with a pH less than 2 are considered to be strong acids; those with a pH greater than 12 are considered to be strong bases.
The severity of tissue injury from acidic and alkaline substances is determined by the duration of contact; the amount and state (liquid, solid) of the substance involved; and the substance's physical properties, such as its pH, concentration, ability to penetrate tissue, and its titratable reserve. The latter reflects the amount of tissue required to neutralize a given amount of the involved substance and is particularly useful for measuring the amount of damage that can be caused by caustics, such as phenol, that have a near-neutral pH.
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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.
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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.
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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.
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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.
