3.4 Common Gastrointestinal Complaints

Common Gastrointestinal Complaints

Gastrointestinal complaints are ubiquitous in primary care. Accurate differentiation between functional disorders and organic pathology, followed by evidence-based management, is critical to optimize patient outcomes. This section reviews gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), Helicobacter pylori eradication, and irritable bowel syndrome (IBS).

Gastroesophageal Reflux Disease (GERD)

GERD is a chronic condition characterized by the retrograde movement of gastric contents into the esophagus, leading to troublesome symptoms or mucosal damage.

Clinical Presentation and Diagnosis

The hallmark clinical symptoms of GERD are heartburn (pyrosis) (a burning retrosternal pain that propagates upward, typically worse after eating or when lying supine) and acid regurgitation. Atypical or extra-esophageal symptoms include chronic cough, wheezing, laryngitis, hoarseness, dental erosions, and non-cardiac chest pain.

In patients presenting with typical, uncomplicated symptoms, a presumptive diagnosis of GERD can be made based on clinical history alone, and a trial of empiric therapy is appropriate.

When to Perform an Endoscopy

Upper endoscopy (Esophagogastroduodenoscopy or EGD) is not indicated for typical GERD. However, it must be performed promptly in patients presenting with alarm features:

• Dysphagia (difficulty swallowing) or Odynophagia (painful swallowing).
• Unintentional weight loss.
• Persistent vomiting.
• Evidence of gastrointestinal bleeding (melena, hematemesis) or unexplained iron deficiency anemia.
• New-onset symptoms in patients over 50 years of age.
• Symptoms refractory to standard PPI therapy.

Management Guidelines

GERD management follows a stepped-care approach:

1. Lifestyle Modifications: Weight loss (for overweight patients) is the most effective lifestyle intervention. Other recommendations include elevating the head of the bed (by 6 inches), avoiding meals within 2–3 hours of bedtime, tobacco and alcohol cessation, and avoiding dietary triggers (fatty foods, chocolate, caffeine, peppermint, citrus, and carbonated beverages).
2. Pharmacotherapy:
   • Mild, Intermittent Symptoms (< 2 episodes per week): Low-dose H2-Receptor Antagonists (H2RAs) (e.g., Famotidine 10–20 mg daily or twice daily) or antacids.
   • Frequent or Severe Symptoms (≥ 2 episodes per week) or failing H2RAs: Proton Pump Inhibitors (PPIs) (e.g., Omeprazole 20 mg daily, Pantoprazole 40 mg daily) are the most effective agents. PPIs must be taken 30–60 minutes before the first meal of the day. A standard initial treatment course is 8 weeks.

Complications

Untreated or severe GERD can lead to esophageal strictures (causing progressive dysphagia) and Barrett's esophagus (metaplastic replacement of stratified squamous epithelium with simple columnar epithelium containing goblet cells). Barrett's esophagus carries a small but significant risk of progression to esophageal adenocarcinoma, requiring periodic endoscopic surveillance.

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Peptic Ulcer Disease (PUD)

Peptic ulcer disease refers to mucosal breaks (> 5 mm in size) in the stomach or duodenum that extend through the muscularis mucosae.

Etiology and Pathophysiology

The two predominant causes of PUD are:

1. Helicobacter pylori Infection: An acid-tolerant bacterium that colonizes the gastric antrum, causing chronic inflammation, mucosal damage, and increased gastrin secretion.
2. Nonsteroidal Anti-inflammatory Drugs (NSAIDs): NSAIDs inhibit cyclooxygenase-1 (COX-1), which impairs mucosal prostaglandin synthesis. Prostaglandins are critical for maintaining the gastric mucosal barrier by stimulating mucus and bicarbonate secretion and maintaining mucosal blood flow.

Clinical Presentation

• Duodenal Ulcers (DU): Pain is typically located in the epigastrium and is characteristically relieved by food or antacids, only to return 2–5 hours after a meal. Nocturnal pain that awakens the patient is common. DUs are rarely malignant.
• Gastric Ulcers (GU): Pain is often worsened by food, leading to anorexia and weight loss. GUs carry a risk of malignancy; therefore, all gastric ulcers identified on EGD must undergo biopsy, and follow-up endoscopy is required to document complete healing.

EGD is the gold standard for diagnosing PUD, allowing direct visualization, biopsy, and therapeutic intervention if active bleeding is present.

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Helicobacter pylori Eradication

Eradication of H. pylori is essential to cure PUD, prevent ulcer recurrence, and reduce the risk of gastric lymphoma (MALToma) and adenocarcinoma.

Diagnostic Testing

• Urea Breath Test (UBT) and Stool Antigen Test: Excellent non-invasive tests for active infection. Important: PPIs must be held for at least 2 weeks, and bismuth or antibiotics for 4 weeks, prior to testing to avoid false-negative results.
• Serology: Detects IgG antibodies. It cannot differentiate between active and past infections, making it useless for confirming eradication.

Eradication Regimens

Due to increasing rates of clarithromycin resistance, empiric regimens have shifted:

1. Bismuth-Based Quadruple Therapy (Preferred first-line in areas with high/unknown clarithromycin resistance, or in patients with prior macrolide exposure or penicillin allergy):
   • PPI twice daily
   • Bismuth subsalicylate (300–524 mg four times daily)
   • Metronidazole (250–500 mg four times daily)
   • Tetracycline (500 mg four times daily)
   • Duration: 10–14 days.
2. Clarithromycin Triple Therapy (Only if local clarithromycin resistance is documented to be < 15% and the patient has no prior macrolide exposure):
   • PPI twice daily
   • Clarithromycin (500 mg twice daily)
   • Amoxicillin (1 g twice daily) OR Metronidazole (500 mg twice daily if penicillin-allergic).
   • Duration: 14 days.

Eradication must always be confirmed at least 4 weeks after completing therapy using the Urea Breath Test or Stool Antigen Test (ensuring the patient has been off PPIs for at least 2 weeks).

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Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome is a common functional gastrointestinal disorder characterized by chronic, recurrent abdominal pain and altered bowel habits.

Diagnostic Criteria: The Rome IV Criteria

IBS is diagnosed clinically in the absence of organic disease. The Rome IV criteria require: Recurrent abdominal pain occurring, on average, at least 1 day per week in the last 3 months, associated with two or more of the following criteria:

1. Related to defecation.
2. Associated with a change in the frequency of stool.
3. Associated with a change in the form (appearance) of stool.

IBS Subtypes

Based on the predominant stool pattern using the Bristol Stool Scale:

• IBS-C: Constipation-predominant (> 25% hard/lumpy stools, < 25% loose/watery stools).
• IBS-D: Diarrhea-predominant (> 25% loose/watery, < 25% hard/lumpy).
• IBS-M: Mixed bowel habits (> 25% hard/lumpy AND > 25% loose/watery).

Exclusion of Organic Disease

Before establishing a diagnosis of IBS, clinicians must rule out "alarm features" that suggest organic disease (such as IBD, celiac disease, or colorectal cancer):

• Age of onset ≥ 50 years.
• Unexplained weight loss.
• Fever.
• Nocturnal diarrhea (waking up to defecate, which does not happen in IBS).
• Visible or occult blood in the stool.
• Unexplained iron deficiency anemia.
• Family history of colorectal cancer, inflammatory bowel disease (IBD), or celiac disease.

Management Strategies

• Dietary Interventions: A low-FODMAP diet (avoiding Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) reduces gas and bloating. Soluble fiber (e.g., Psyllium) is beneficial, whereas insoluble fiber should be avoided as it can worsen bloating.
• Pharmacotherapy:
  • For Pain: Antispasmodics (e.g., Dicyclomine, Hyoscyamine) or low-dose Tricyclic Antidepressants (TCAs, e.g., Amitriptyline) which prolong gut transit time (highly useful in IBS-D).
  • For IBS-D: Loperamide, Rifaximin, or Eluxadoline.
  • For IBS-C: Polyethylene glycol (PEG), Lubiprostone, or Linaclotide.