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Acid Poisoning

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. 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.
 
Examples include the following:
  • Toilet bowl–cleaning products
  • Soldering flux containing zinc chloride
  • Swimming pool–cleaning products
  • Cement-cleaning products

The patient should be seen by the acid poisoning doctor. Respiratory distress is secondary to laryngeal edema. In patients with caustic ingestion, airway monitoring and control is the first priority. When airway compromise is present, a definitive airway must be established. In patients with a stable airway and no clinical or radiological sign of perforation, medical therapy should be initiated.

Acid poisoning is usually treated by acid poisoning doctor or a gastro doctor.

  • 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.

    As per the acid poisoning doctor, acid ingestions cause tissue injury by coagulation necrosis, which causes desiccation or denaturation of superficial tissue proteins, often resulting in the formation of an eschar or coagulum. This eschar may protect the underlying tissue from further damage. Unlike alkali ingestions, the stomach is the most commonly involved organ following an acid ingestion. This may due to some natural protection of the esophageal squamous epithelium. Small bowel exposure also occurs in about 20% of cases. Emesis may be induced by pyloric and antral spasm.

    The eschar sloughs in 3-4 days and granulation tissue fills the defect. Perforation may occur at this time. A gastric outlet obstruction may develop as the scar tissue contracts over a 2- to 4-week period. Acute complications include gastric and intestinal perforation and upper gastrointestinal hemorrhage.

Arrangements should be made for urgent esophagogastroduodenoscopy (EGD) to grade the degree of injury and establish long-term prognosis. In asymptomatic patients, however, EGD may be withheld in favor of observation. 

Surgical consultation is indicated for suspected perforation. Because of the risk of late complications most commonly, esophageal stricture formation arrangements for follow-up need to be made.

Adult patients with an unintentional exposure may be discharged after a 2- to 4-hour observation period if the clinician has no unique concerns regarding the ingested substance (eg, large volume, high concentration, an agent with potential for systemic toxicity) and the patient meets all the following criteria:

In patients with caustic ingestion, airway monitoring and control is the first priority. When airway compromise is present, a definitive airway must be established. In patients with a stable airway and no clinical or radiological sign of perforation, medical therapy should be initiated. Arrangements should be made for urgent esophagogastroduodenoscopy (EGD) to grade the degree of injury and establish long-term prognosis, In asymptomatic patients, however, EGD may be withheld in favor of observation. Pediatric patients who remain asymptomatic for 2 – 4 hours after an exploratory ingestion and who are tolerating a normal diet may be discharged with appropriate follow-up and return precautions.

Do not induce emesis or attempt to neutralize the substance by using a weak acid or base. This induces an exothermic reaction, which can compound the chemical injury with a thermal injury. It may also induce emesis, re-exposing tissue to the caustic agent.

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Dr. Harsh J Shah