Caustic Ingestions

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• Direct Tissue Destruction: Caustic substances (acids and alkalis) cause immediate, direct mucosal burns and local tissue necrosis upon contact with the gastrointestinal and respiratory tracts.
• Airway Compromise: Direct chemical injury to the supraglottic structures causes laryngeal edema that can begin in minutes and progress rapidly over several hours. Tracheal necrosis is one of the most frequent direct causes of death following ingestion.
• Systemic Toxicity & Shock: Severe ingestions can lead to third-spacing, massive fluid shifts, and hypovolemic shock. Widespread tissue destruction triggers a severe inflammatory cascade, leading to hemodynamic instability, fever, and profound metabolic acidosis.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Airway Stabilization: The absolute first priority is rapid airway assessment. Early intubation is mandated if there is any evidence of airway compromise (hoarseness, throat pain, drooling, or edema).
• Critical Action: Because edema and secretions can increase rapidly, preparations must be made for a difficult airway (e.g., backup video laryngoscopy, fiberoptic setup, or a surgical airway kit at the bedside).
• Resuscitation Goals: Establish large-bore IV access and resuscitate with IV crystalloid fluids to combat third-spacing, hypovolemic shock, and hemodynamic instability.
• Decontamination Limitations:
• Do NOT induce emesis or perform gastric lavage.
• Do NOT give fluids for oral dilution if the patient has difficulty swallowing.
• Medical Interventions:
• Do NOT administer corticosteroids to prevent stricture formation; evidence for their benefit is lacking and serious side effects can occur.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

• The "Can't-Miss" Co-ingestions & Mimics:
• Anaphylaxis: Can mimic the stridor, drooling, and airway edema of a caustic ingestion.
• Toxic Alcohol / Salicylate Overdose: Patients presenting with suicidal intent and severe metabolic acidosis must be evaluated for lethal co-ingestants.
• Prioritized Diagnostic Workup:
• Tox Screen: Obtain serum acetaminophen and salicylate levels in all suicidal patients to rule out occult co-ingestions.
• Labs: VBG/ABG and basic metabolic panel to assess for profound metabolic acidosis and base deficit.
• Gold Standard Diagnostics:
• Endoscopy: Traditionally the gold standard for grading esophageal injury, to be performed 12 to 24 hours after ingestion and only after the airway has been secured.
• CT Scan: The World Society of Emergency Surgery consensus conference recommends IV contrasted thoracoabdominal CT scans; recent evidence suggests CT outperforms endoscopy in predicting strictures and the need for surgical reconstruction by determining the exact depth of injury.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• Physical Exam Checklist: Look for visible burns to the face, lips, and oral cavity. Actively look for streaks of caustic burns on the face or chest, classically termed "dribble burns".
• Chest Radiograph (CXR): Obtain a CXR in patients with chest pain, dyspnea, or vomiting to specifically look for peritoneal and mediastinal air, indicating a hollow viscus perforation.
• 12-Lead ECG: While not routinely needed for most caustics, an ECG is strictly indicated following hydrofluoric acid exposure to check for QT interval prolongation caused by profound hypocalcemia.
• POCUS: Ultrasound can be utilized to evaluate and follow up on corrosive gastric injury if severe edema or perforation prevents the use of endoscopy.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• The "Lick or Sip" Rule: Do not underestimate small volumes. More than 40% of patients reporting to have "only taken a lick or sip" actually possess severe esophageal burns.
• Predictive Symptom Matrix: Oropharyngeal burns alone are poorly predictive of distal injury. However, the combination of drooling, odynophagia, dysphagia, vomiting, and stridor is highly predictive of significant distal visceral lesions.
• The Intentional Ingestion Rule: If a patient presents following an intentional caustic ingestion (suicide attempt), upper endoscopy is mandated even if their vital signs are normal, they are asymptomatic, and their oral physical exam is completely unremarkable.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• The Oral Exam Trap: Pitfall: Discharging an asymptomatic patient because they have no visible burns in their mouth. Critical Action: Recognize that oropharyngeal burns are poorly predictive of distal injury. Intentional ingestions mandate endoscopy regardless of the oral exam.
• The Dilution/Neutralization Trap: Pitfall: Attempting to neutralize the ingestion with milk, water, or weak acids/bases. Critical Action: Do not administer oral fluids, especially if the patient has difficulty swallowing, as this can provoke vomiting and cause secondary esophageal burns or lethal airway aspiration.
• The Corticosteroid Myth: Pitfall: Giving IV Solu-Medrol to prevent esophageal strictures. Critical Action: Withhold steroids; they do not prevent strictures and carry serious risks of infection and masking signs of perforation.

7. MCQ MASTERCLASS (Written Exam Tips)

• Buzzword: "Dribble burns" on the chin and chest → Exam Answer: Caustic ingestion.
• Classic Presentation: A patient presents with hoarseness, severe throat pain, and drooling after drinking a cleaning agent. → Exam Answer: Secure the airway immediately via endotracheal intubation (do not delay for imaging or endoscopy).
• Distractor Option: "Treat the patient with IV corticosteroids to prevent stricture formation." Correction: Incorrect. Steroids lack evidence of benefit and can cause harm.
• Toxin-Specific Fact: A patient ingests rust remover (hydrofluoric acid). What is the next best step? → Exam Answer: Obtain an ECG to look for prolonged QT interval (due to hypocalcemia).

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Airway Declaration: "The patient is presenting with drooling, hoarseness, and stridor after a caustic ingestion. I anticipate a rapidly deteriorating and difficult airway due to laryngeal edema. I am calling for anesthesia backup, preparing a surgical airway kit at the bedside, and proceeding with immediate intubation."
• The Diagnostic Workup: "I will not induce emesis, give activated charcoal, or attempt to neutralize the agent. I am ordering an IV contrasted thoracoabdominal CT to evaluate the depth of injury and assess for viscus perforation. I will consult Gastroenterology for an upper endoscopy to be performed at 12 to 24 hours post-ingestion."
• Addressing the Intentional Ingestion: "Because this was a suicide attempt, I am keeping the patient NPO, ordering serum acetaminophen and salicylate levels to rule out occult co-ingestions, and placing a 1:1 safety sitter."