How soon after a first Esophagogastroduodenoscopy (EGD) showing Eosinophilic Esophagitis (EOE) is a follow-up EGD recommended?

Follow-Up EGD Timing After Initial Diagnosis of Eosinophilic Esophagitis

A follow-up esophagogastroduodenoscopy (EGD) with biopsies should be performed 8-12 weeks after initiating treatment for eosinophilic esophagitis (EOE) to assess treatment response. 1

Rationale for Follow-Up EGD Timing

The British Society of Gastroenterology (BSG) guidelines provide clear recommendations regarding the timing of follow-up EGD after initial diagnosis and treatment of EOE:

• Timeframe: 8-12 weeks after initiating therapy (dietary or pharmacological) 1
• Purpose: To assess histological response, as symptoms may not correlate with histological activity
• Evidence level: Low quality evidence, but strong recommendation with 100% agreement among experts 1

Why Endoscopic Follow-Up Is Necessary

1. Symptom-Histology Discordance:

   • Symptoms often do not correlate with histological activity 1
   • A meta-analysis found only moderate association between symptomatic and histological response, with 41% of patients reporting symptomatic improvement without histological improvement 1

2. Disease Progression Risk:

   • Untreated inflammation may lead to fibrostenotic disease and stricture formation 1
   • Diagnostic delay is associated with increased risk of strictures (17% with <2 years delay vs 71% with >20 years delay) 1

3. Treatment Optimization:

   • Allows for timely adjustment of therapy if initial treatment is ineffective 1
   • Helps prevent recurrent food bolus obstruction and emergency presentations 1

Assessment Criteria During Follow-Up EGD

1. Histological Assessment:

   • Current threshold for histological remission: <15 eosinophils per high power field (hpf) 1
   • Multiple biopsies (at least 6) from different anatomical sites in the esophagus 1

2. Endoscopic Assessment:

   • EREFS system (Edema, Rings, Exudates, Furrows, Strictures) to evaluate macroscopic features 2
   • Evaluation for fibrostenotic changes that may require dilation 1

Special Considerations

1. PPI Therapy:

   • For accurate assessment, PPIs should be withdrawn for at least 3 weeks prior to diagnostic EGD 1
   • However, if PPI is the treatment being assessed, it should be continued until the follow-up EGD

2. Treatment Response Patterns:

   • Inflammatory EOE phenotype responds better to PPI therapy than stricturing phenotype 3
   • Even on maintenance PPI therapy, 44% of patients may have histologic recurrence, with 86% of these being asymptomatic 4

3. Long-Term Monitoring:

   • After achieving remission, ongoing monitoring is needed as patients may lose response over time 1
   • For patients with low-grade esophageal eosinophilia (1-14 eos/hpf) on initial EGD, 36% may meet full EOE criteria on repeat EGD 5

Management Algorithm After Follow-Up EGD

1. If Remission Achieved (clinical and histological):

   • Consider maintenance therapy
   • Continue monitoring with periodic clinical assessment
   • Consider PPI dose reduction if appropriate (successful in 69.9% of patients) 3

2. If No Remission:

   • Change treatment approach (e.g., PPI to topical steroid)
   • Consider combination treatment modalities
   • Consider dilatation if fibrostenotic features present
   • Schedule another follow-up EGD 8-12 weeks after treatment modification 1

Common Pitfalls to Avoid

1. Relying solely on symptoms to assess treatment response (symptoms and histology often don't correlate) 1

2. Inadequate biopsy sampling (at least 6 biopsies from different anatomical sites are recommended) 1

3. Failure to follow up after food bolus obstruction (leads to recurrent episodes and unscheduled admissions) 1

4. Assuming continued remission without monitoring (44% of patients may have histologic recurrence even while on PPI maintenance therapy) 4

In conclusion, the 8-12 week timeframe for follow-up EGD represents the optimal balance between allowing sufficient time for treatment effect and ensuring timely intervention if the initial treatment is inadequate.