What is the optimal timing for performing endoscopy after a caustic injury?

Timing of Endoscopy Post Caustic Injury

Emergency endoscopy should be performed within 12-48 hours after caustic ingestion when CT is unavailable, contraindicated, or in pediatric patients; however, contrast-enhanced CT performed 3-6 hours post-ingestion has largely replaced endoscopy as the primary diagnostic modality in adults due to superior ability to detect transmural necrosis and predict outcomes. 1, 2

Primary Diagnostic Approach: CT Over Endoscopy

The management paradigm has shifted away from routine emergency endoscopy toward CT-based algorithms:

• Perform contrast-enhanced CT of neck, thorax, and abdomen 3-6 hours after ingestion using a nonionic contrast agent (2 mL/kg) with 18-25 second acquisition time and 90-second scan delay 1, 3
• CT-based algorithms significantly improved patient outcomes compared to endoscopy-based management by accurately identifying transmural necrosis (Grade III injury = absence of post-contrast wall enhancement), which is an absolute indication for emergency surgery 1
• The major limitation of endoscopy is its inability to accurately predict transmural necrosis, potentially exposing patients to either futile surgery or inappropriate conservative management with increased mortality risk 1

When Emergency Endoscopy IS Indicated

Emergency endoscopy within 12-48 hours should be performed only in these specific situations:

• CT is unavailable or logistically impossible 1, 2
• CT with IV contrast is contraindicated (renal failure, iodine allergy) 1
• CT findings suggest transmural necrosis but interpretation is uncertain and confirmation is needed before proceeding to surgery 1
• Pediatric population where endoscopy remains the upfront evaluation due to severe injuries being rare and long-term radiation exposure concerns 1, 4

Optimal Timing Window for Endoscopy

When endoscopy is performed, timing matters significantly:

• Within 12-24 hours is the traditional recommendation for initial assessment to determine injury extent and guide management 5, 6
• Early endoscopy within 48 hours (versus late endoscopy >48 hours) was associated with three-fold lower risk of poor clinical outcomes, four-fold lower high-cost admissions, and five-fold lower prolonged hospitalization 7
• No significant difference in clinical outcomes between endoscopy performed within 24 hours versus 24-48 hours after admission 7

Critical Timing Caveat: The Dangerous Window

Avoid endoscopy between 1-3 weeks (specifically days 5-21) after caustic injury due to significantly higher procedural risks including perforation during the phase of maximal tissue friability. 4, 3, 8

Role of Repeat "Relook" Endoscopy

For patients who undergo initial endoscopy, consider repeat assessment:

• Day 5 endoscopy is superior to day 1 endoscopy for predicting development of esophageal strictures (specificity 83% vs 65%, PPV 60% vs 41%) and antropyloric stenosis (specificity 95% vs 61%, PPV 88% vs 54%) 9
• Day 1 endoscopy significantly overestimates injury grade; day 5 assessment provides more accurate prognostication 9
• This suggests that when endoscopy is used, a relook examination around day 5 may better guide long-term management decisions 9

Endoscopic Classification Systems

When endoscopy is performed, use standardized grading:

• Zargar endoscopic classification is most commonly employed, though its ability to predict stricture formation is controversial and outperformed by CT 1
• Grade 3b injuries on endoscopy predict higher rates of prolonged hospital stay (OR 2.44), ICU admission (OR 10.82), and gastrointestinal complications (OR 4.15) compared to grade 3a 6
• The 6-point endoscopic scale is useful for predicting immediate and long-term complications when CT is not available 6

Later Endoscopy for Stricture Management

Endoscopy becomes the primary tool in the subacute/chronic phase:

• Endoscopy is the main diagnostic tool for esophageal/gastric strictures in symptomatic patients presenting with dysphagia or regurgitation 1
• Endoscopic dilation should begin 3-6 weeks after ingestion for patients with few (<3) short (<5 cm) strictures, as most strictures develop within 4 months 1, 2
• Avoid dilation within the first 3 weeks due to increased perforation risk 2

Practical Algorithm

1. Immediate assessment (0-3 hours): Stabilize patient, obtain history of caustic agent, check labs (CBC, electrolytes, renal/liver function, ABG) 2, 3

2. 3-6 hours post-ingestion: Perform contrast-enhanced CT as primary diagnostic modality in adults 1, 3

3. If CT shows Grade III injury (no wall enhancement): Proceed directly to emergency surgery 1, 2

4. If CT unavailable/contraindicated OR pediatric patient: Perform endoscopy within 12-48 hours 1, 4

5. Days 5-21: Avoid endoscopy during this high-risk window 4, 3

6. 3-6 weeks onward: Endoscopy for stricture evaluation and dilation as needed 1, 2

7. 4-6 months: Follow-up visit for Grade II injuries to assess for late stricture development 2, 4