What is the diagnostic approach to Caustic Material Swallowing (CMS) and Caustic Esophageal Stricture (CES)?

Diagnostic Approach to Caustic Material Swallowing (CMS) and Caustic Esophageal Stricture (CES)

The diagnostic approach to caustic injuries should prioritize contrast-enhanced CT as the primary evaluation tool, with endoscopy reserved for specific situations where CT cannot be used or is contraindicated. 1

Initial Assessment

• Obtain detailed information about the caustic agent ingested (type, quantity, concentration, physical form) as these factors significantly impact injury patterns and prognosis 1
• Physical form affects injury pattern: solids damage mouth/pharynx while liquids cause esophageal/gastric burns 1
• Monitor for systemic effects specific to certain corrosives: hypocalcemia (phosphoric/hydrofluoric acids), hyponatremia (strong acids/alkalis), hypokalemia, and acidosis 1

Laboratory Investigations

• Complete initial laboratory evaluation including:
  • Complete blood count (CBC), electrolytes (sodium, potassium, chlorine, magnesium, calcium)
  • Renal function (urea, creatinine), liver function tests
  • Arterial blood gas (pH and serum lactate)
  • Blood alcohol levels and β-HCG in young women 1
• Monitor laboratory values over time as initial normal values don't rule out transmural necrosis 1
• Abnormal values suggesting transmural necrosis include:
  • Severe acidosis (low pH, high lactate)
  • Deranged liver function tests
  • Leukocytosis, elevated CRP
  • Renal failure and thrombocytopenia 1

Imaging Studies

• Perform contrast-enhanced CT of neck, thorax, and abdomen 3-6 hours after ingestion 1
• CT protocol: IV injection of nonionic contrast agent (2-3 mL/s), 18-25s acquisition time, 90s scan delay 1
• CT findings are graded according to a four-stage classification:
  • Grade I: Homogenous enhancement of esophageal wall without edema
  • Grade IIa: Internal enhancement of esophageal mucosa with hypodense wall thickening ("target" appearance)
  • Grade IIb: Fine rim of external wall enhancement with non-enhancing necrotic mucosa
  • Grade III: Absence of post-contrast wall enhancement (indicates transmural necrosis) 1
• CT outperforms endoscopy in detecting transmural injuries and predicting stricture formation 1, 2
• Plain radiographs (neck, chest, abdomen) may show free air in cases of perforation 1

Role of Endoscopy

• Emergency endoscopy is indicated only when:
  1. CT is unavailable
  2. CT with contrast is contraindicated (renal failure, iodine allergy)
  3. CT suggests transmural necrosis but interpretation is uncertain
  4. In pediatric patients (to avoid radiation exposure) 1
• The Zargar endoscopic classification is commonly used but has limitations in predicting stricture formation compared to CT 1, 3
• For caustic esophageal strictures (CES), endoscopy is the main diagnostic tool in symptomatic patients 1
• Symptoms of stricture (dysphagia, regurgitation) typically appear within 4 months after ingestion 1, 3

Diagnostic Timeline and Follow-up

• Perform initial CT evaluation within 3-6 hours of ingestion 1
• For patients with non-severe injuries, monitor for stricture development, which typically occurs within 4 months 1, 3
• The median time to stricture diagnosis is approximately 12 days after ingestion (range 4-26 days) 3
• Risk factors for stricture development include:
  • Initial symptoms of dysphagia, epigastric pain, or hematemesis
  • High Zargar endoscopic grade (above IIa)
  • Ingestion of strong acids or alkalis
  • Hyperleukocytosis and low prothrombin ratio 3

Special Considerations

• In pediatric patients, endoscopy remains the upfront evaluation as severe injuries are rare and radiation exposure is a concern 1
• For suspected glass ingestion, CT has 90-100% sensitivity and 93.7-100% specificity for detecting foreign bodies 4
• Avoid endoscopy between 1-3 weeks after injury as this period carries higher procedural risks 1

Management Decision Algorithm

1. Perform contrast-enhanced CT within 3-6 hours of ingestion
2. If CT shows Grade III injury (absence of wall enhancement), consider emergency surgery 1
3. If CT shows Grade I or II injury, proceed with non-operative management with close monitoring 1
4. For patients with dysphagia developing after caustic ingestion, perform endoscopy to evaluate for stricture 1
5. For confirmed strictures, initiate endoscopic dilation 3-6 weeks after ingestion for optimal outcomes 1

The diagnostic approach to caustic injuries has evolved significantly, with CT now playing the central role in initial assessment and endoscopy being reserved for specific situations or for the management of resulting strictures.