What are the diagnostic and treatment approaches for common gastrointestinal conditions like Gastroesophageal Reflux Disease (GERD), Irritable Bowel Syndrome (IBS), and Inflammatory Bowel Disease (IBD)?

Diagnostic and Treatment Approaches for GERD, IBS, and IBD

GERD: Diagnosis and Management

For patients with typical GERD symptoms (heartburn, regurgitation) without alarm features, initiate a 4-8 week trial of single-dose PPI therapy before pursuing objective testing, escalating to twice-daily dosing if symptoms persist. 1

Initial Assessment and Treatment Strategy

• Educate patients on GERD pathophysiology and involve them in shared decision-making regarding lifestyle modifications and pharmacotherapy 1
• Start with omeprazole 20 mg once daily taken before meals for 4-8 weeks as first-line therapy 2
• Escalate to twice-daily dosing (omeprazole 20 mg twice daily) or switch to a more potent acid suppressive agent if symptoms persist after single-dose trial 1
• Titrate to the lowest effective dose once symptom response is achieved to minimize long-term PPI exposure 1

When to Pursue Objective Testing

Perform upper endoscopy in the following scenarios 1:

• PPI non-response after adequate trial
• Presence of alarm symptoms (dysphagia, odynophagia, weight loss, anemia, gastrointestinal bleeding)
• Isolated extra-esophageal symptoms (chronic cough, laryngitis)
• Patients meeting criteria for Barrett's esophagus screening
• When long-term PPI therapy is planned to establish definitive GERD diagnosis

Use prolonged wireless pH monitoring off PPI therapy when endoscopy shows no erosive disease or Barrett's esophagus to assess esophageal acid exposure 1

Escalation for Refractory Cases

Consider anti-reflux procedures for patients with confirmed pathologic GERD 1:

• Laparoscopic fundoplication (partial fundoplication preferred in esophageal hypomotility) for non-obese patients
• Magnetic sphincter augmentation combined with crural repair when hiatal hernia is present
• Transoral incisionless fundoplication for carefully selected patients without hiatal hernia
• Roux-en-Y gastric bypass as primary intervention in obese patients or salvage option in non-obese patients

Critical prerequisite testing before invasive procedures includes confirmatory evidence of pathologic GERD, exclusion of achalasia, and assessment of esophageal peristaltic function 1

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IBS: Diagnosis and Management

Diagnose IBS based on Rome criteria without exhaustive investigation, but perform limited testing (fecal calprotectin, celiac serology) to exclude organic disease, then implement a three-domain approach addressing medical, dietary, and behavioral factors simultaneously. 1

Establishing the Diagnosis

• Apply Rome IV criteria for symptom-based diagnosis: recurrent abdominal pain at least 1 day per week in the last 3 months, associated with two or more of the following: related to defecation, change in stool frequency, change in stool form 1
• Measure fecal calprotectin as initial screening: levels <50 μg/g effectively rule out IBD 3
• Perform celiac serology (tissue transglutaminase antibody) to exclude celiac disease 1
• Obtain stool culture if diarrhea-predominant to exclude infectious causes 3

Medical Management by Subtype

For IBS with diarrhea (IBS-D) 1:

• Loperamide 4-12 mg daily as first-line anti-diarrheal
• Rifaximin 550 mg three times daily for 14 days if loperamide ineffective
• Alosetron, ramosetron, or eluxadoline as second-line options where available

For IBS with constipation (IBS-C) 1:

• Polyethylene glycol or stimulant laxatives (senna) as first-line therapy
• Linaclotide or plecanatide as second-line secretagogues with minimal systemic absorption 4

For abdominal pain 1, 4:

• Antispasmodics (dicyclomine, hyoscine, peppermint oil) for meal-related pain
• Tricyclic antidepressants (low-dose amitriptyline 10-25 mg at bedtime) as neuromodulators for chronic pain
• Avoid opiates due to risk of dependence and worsening constipation 1

Dietary Interventions

• Low FODMAP diet as first-line dietary therapy under supervision of trained dietitian, with careful attention to nutritional adequacy 1, 4
• Soluble fiber supplementation (psyllium/ispaghula 3-4g daily) for IBS-C, gradually increasing 4
• Avoid insoluble fiber (wheat bran) as it worsens bloating 4

Psychological and Behavioral Therapies

Implement early in treatment journey rather than waiting for multiple drug failures 1:

• IBS-specific cognitive behavioral therapy for anxiety related to gastrointestinal symptoms
• Gut-directed hypnotherapy for symptoms persisting beyond 12 months
• Mindfulness therapy to address brain-gut axis dysfunction 1, 4

Probiotics

• Trial probiotics for 12 weeks for global symptoms and bloating, discontinuing if no improvement 4

Critical Communication Points

• Explain IBS as a disorder of gut-brain interaction with benign but relapsing/remitting course 4
• Emphasize that gastrointestinal symptoms are real and not purely psychological 1, 4
• Set realistic expectations that complete symptom resolution is often not achievable 4

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IBD: Diagnosis and Management

Use a stepwise diagnostic approach starting with fecal calprotectin (threshold >100-250 μg/g), followed by ileocolonoscopy with biopsies from both affected and normal-appearing areas, and cross-sectional imaging (MR enterography) to assess small bowel involvement and complications. 1, 3

Initial Diagnostic Workup

Non-invasive biomarkers 3:

• Fecal calprotectin >100-250 μg/g warrants ileocolonoscopy (sensitivity 93%, specificity 96% for IBD)
• Fecal calprotectin <50 μg/g effectively rules out IBD
• Fecal lactoferrin serves as alternative biomarker with similar utility
• Exclude infection first with stool culture, as acute gastroenteritis elevates calprotectin

Baseline laboratory assessment 3:

• Complete blood count to assess for anemia (common in IBD, absent in IBS)
• CRP level (recognizing 20% of active Crohn's may have normal CRP)
• Albumin, liver profile, iron studies, renal function, vitamin B12 to establish nutritional status

Endoscopic Evaluation

Ileocolonoscopy with biopsies 1, 3:

• Multiple biopsies from each colonic segment (rectum, sigmoid, descending, transverse, ascending, cecum) and terminal ileum stored in separate vials to map inflammation distribution
• Biopsy both affected and normal-appearing areas to detect skip lesions characteristic of Crohn's disease
• Obtain 2-3 tissue levels with 5+ sections each to increase diagnostic yield 1
• Look for discontinuous "skip" lesions with normal mucosa between inflamed areas (Crohn's disease) 3
• Identify cobblestoning, strictures, fistulas highly suggestive of Crohn's disease 3
• Assess for perianal disease which strongly indicates Crohn's rather than ulcerative colitis 3

Cross-Sectional Imaging

• MR enterography (or CT enterography if MRI unavailable) should be performed in all patients at diagnosis to assess small bowel involvement (present in one-third of Crohn's patients), disease extent, and complications 3
• Imaging detects transmural inflammation, abscesses, and penetrating disease characteristic of Crohn's but absent in ulcerative colitis 3

Additional Diagnostic Considerations

• Upper endoscopy with biopsies in pediatric patients and adults with upper GI symptoms, as upper tract involvement suggests Crohn's disease 3
• Small bowel capsule endoscopy when ileocolonoscopy, gastroscopy, and cross-sectional imaging are inconclusive but clinical suspicion remains high 3

Managing Functional Symptoms in IBD Patients

A critical challenge: 39% of IBD patients have overlapping functional GI symptoms even with complete mucosal healing. 1, 5

Stepwise approach to rule out ongoing inflammation 1, 3:

1. Measure fecal calprotectin as first step
2. Perform endoscopy with biopsy if calprotectin elevated
3. Obtain cross-sectional imaging to assess for structural complications
4. Consider serial calprotectin monitoring every 3-6 months for indeterminate levels with mild symptoms 1, 5

Evaluate alternative mechanisms based on symptom patterns 1, 3:

• Small intestinal bacterial overgrowth
• Bile acid diarrhea
• Carbohydrate intolerance
• Chronic pancreatitis

Management of functional symptoms in quiescent IBD 1:

• Low FODMAP diet with attention to nutritional adequacy
• Psychological therapies (cognitive behavioral therapy, hypnotherapy, mindfulness)
• Osmotic and stimulant laxatives for chronic constipation
• Hypomotility agents or bile-acid sequestrants for chronic diarrhea
• Antispasmodics, neuropathic agents, antidepressants for functional pain while avoiding opiates
• Pelvic floor therapy for underlying defecatory disorders
• Physical exercise should be encouraged
• Do NOT offer fecal microbiota transplant for functional symptoms until further evidence available 1

Critical Pitfall to Avoid

Overtreatment of intestinal inflammation for symptoms due to functional pathophysiology increases risk of significant adverse effects while providing no symptomatic benefit. 1 The disconnect between symptoms and degree of intestinal inflammation is well-documented, making it essential to confirm active inflammation before escalating immunosuppressive therapy.