What is the appropriate workup for a patient presenting with gastrointestinal symptoms?

Appropriate Workup for Gastrointestinal Symptoms

The appropriate workup for gastrointestinal symptoms should begin with a detailed symptom history, focused physical examination, and targeted laboratory tests, followed by specific diagnostic procedures based on symptom patterns and alarm features. 1

Initial Assessment

History Taking (Critical Elements)

• Symptom characterization:

  • Duration, frequency, and pattern of symptoms
  • Relationship to meals
  • Presence of pain, its location, and character
  • Bowel habit changes (frequency, consistency using Bristol Stool Scale)
  • Presence of blood, mucus, or undigested food in stool
  • Nocturnal symptoms (highly suggestive of organic disease)
  • Weight loss (significant alarm feature)

• Alarm features requiring urgent evaluation 1:

  • Unintentional weight loss
  • Blood in stool
  • Nocturnal symptoms
  • Family history of colorectal cancer or IBD
  • Age >50 years with new-onset symptoms
  • Persistent vomiting
  • Dysphagia
  • Abdominal mass

Physical Examination

• Abdominal examination for tenderness, masses, organomegaly
• Digital rectal examination to assess for:
  • Masses
  • Rectal evacuation disorders
  • Perianal disease
  • Stool characteristics (blood, color)

First-Line Laboratory Tests 1

• Complete blood count (CBC)
• C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR)
• Liver function tests
• Serum electrolytes, creatinine, and BUN
• Thyroid function tests (if constipation is predominant)
• Celiac disease serologies (anti-tissue transglutaminase antibodies)
• Fecal calprotectin (to differentiate IBD from functional disorders)
• Stool studies:
  • Ova and parasites
  • Culture for enteric pathogens
  • Clostridium difficile toxin (if recent antibiotic use or healthcare exposure)

Diagnostic Algorithm Based on Predominant Symptoms

For Predominant Upper GI Symptoms (Nausea, Vomiting, Epigastric Pain)

1. Initial evaluation:

   • Upper GI endoscopy if:
     • Age >50 years
     • Alarm symptoms present
     • Symptoms persist despite 4-8 week PPI trial 1
   • Consider H. pylori testing
   • Consider gastric emptying study if gastroparesis suspected

2. For intractable vomiting:

   • Rule out mechanical obstruction with imaging
   • Consider metabolic disorders, CNS pathology
   • Evaluate for cyclic vomiting syndrome or cannabinoid hyperemesis 2

For Predominant Lower GI Symptoms (Diarrhea, Constipation, Lower Abdominal Pain)

1. For chronic diarrhea: 1

   • Flexible sigmoidoscopy or colonoscopy with biopsies to evaluate for:
     • Microscopic colitis
     • Inflammatory bowel disease
     • Colorectal neoplasia
   • Consider SeHCAT scan or 7α-hydroxy-4-cholesten-3-one for bile acid diarrhea
   • Screen for laxative abuse in factitious diarrhea

2. For constipation: 1

   • Colonoscopy if age >50 or alarm features present
   • Anorectal manometry and balloon expulsion test if defecatory disorder suspected
   • Colonic transit study if slow transit constipation suspected

3. For suspected IBS: 1

   • Limited diagnostic workup if Rome IV criteria met and no alarm features
   • Fecal calprotectin to exclude IBD
   • Consider colonoscopy with biopsies if diarrhea-predominant to exclude microscopic colitis

For Suspected IBD 1

1. Fecal calprotectin (values <50 μg/g suggest functional disorder)
2. Colonoscopy with ileoscopy and biopsies
3. Upper endoscopy with biopsies if upper GI symptoms present
4. Small bowel imaging (MR enterography preferred) for suspected Crohn's disease

Special Considerations

For Suspected GERD 1

• Initial 4-8 week trial of PPI therapy
• Upper endoscopy if:
  • No response to PPI
  • Alarm symptoms present
  • Symptoms >5 years (to screen for Barrett's esophagus)
• Consider pH monitoring or impedance testing for PPI-refractory symptoms

For Suspected Functional GI Disorders

• Limited testing to rule out organic causes
• Focus on symptom-based diagnosis using Rome IV criteria
• Avoid repeated testing in the absence of new symptoms or alarm features

Common Pitfalls to Avoid

1. Over-investigation of typical functional GI disorders meeting Rome criteria without alarm features
2. Under-investigation of patients with alarm features or atypical presentations
3. Misinterpreting borderline fecal calprotectin values (50-250 μg/g) without follow-up testing
4. Failure to recognize overlap between functional and organic disorders
5. Relying solely on symptoms without objective testing when alarm features are present

Remember that 76% of diagnoses are made from the medical history alone 3, but laboratory and imaging studies are essential to confirm diagnoses and increase diagnostic confidence, particularly when alarm features are present.