A wide variety of chemical and physical agents may cause corrosive injury. They include mineral and organic acids, alkalis, oxidizing agents, denaturants, some hydrocarbons, and agents that cause exothermic reactions. Although the mechanism and the severity of injury may vary, the consequences of mucosal damage and permanent scarring are shared by all these agents.
Button batteries are small, disk-shaped batteries used in watches, calculators, and cameras. They contain caustic metal salts such as mercuric chloride that may cause corrosive injury.
Mechanism of toxicity
Acids cause an immediate coagulation-type necrosis that creates an eschar, which tends to self-limit further damage.
In contrast, alkalis (eg, Drano) cause a liquefactive necrosis with saponification and continued penetration into deeper tissues, resulting in extensive damage.
Other agents may act by alkylating, oxidizing, reducing, or denaturing cellular proteins or by defatting surface tissues.
Button batteries cause injury by corrosive effects resulting from leakage of the corrosive metal salts, by direct impaction of the disk-shaped foreign body, and possibly by local discharge of electric current at the site of impaction.
Toxic dose. There is no specific toxic dose or level because the concentration of corrosive solutions and the potency of caustic effects vary widely. For example, whereas the acetic acid concentration in most household vinegar is 5–10%, that of “Russian vinegar” may be as high as 70%. The pH or concentration of the solution may indicate the potential for serious injury. A pH lower than 2 or higher than 12 increases the risk for injury. For alkalis, the titratable alkalinity (concentration of the base) is a better predictor of corrosive effect than is the pH. Injury is also related to the volume ingested and duration of exposure.
Inhalation of corrosive gases (eg, chlorine and ammonia) may cause upper respiratory tract injury, with stridor, hoarseness, wheezing, and noncardiogenic pulmonary edema. Pulmonary symptoms may be delayed after exposure to gases with low water solubility (eg, nitrogen dioxide and phosgene [See Gases, Irritant]).
Eye or skin exposure to corrosive agents usually results in immediate pain and redness, followed by blistering. Conjunctivitis and lacrimation are common. Serious full-thickness burns and blindness can occur.
Ingestion of corrosives can cause oral pain, dysphagia, drooling, and pain in the throat, chest, or abdomen. Esophageal or gastric perforation may occur, accompanied by severe chest or abdominal pain, signs of peritoneal irritation, or pancreatitis. Free air may be visible in the mediastinum or abdomen on radiograph. Hematemesis and shock may occur. Systemic acidosis has been reported after acid ingestion and may be caused partly by absorption of hydrogen ions. Scarring of the esophagus or stomach may result in permanent stricture formation and chronic dysphagia.
Systemic toxicity can occur after inhalation, skin exposure, or ingestion of a variety of agents (Table II–20).
Table II-20 Corrosive Agents with Systemic Effects (Selected Causes)a