What is the further workup for a patient presenting with steatorrhea (greasy stools)?

Workup for Steatorrhea (Greasy Stools)

The diagnostic workup for steatorrhea should begin with laboratory tests including complete blood count, comprehensive metabolic panel, and stool tests for fat content, followed by specific testing for pancreatic insufficiency, malabsorption disorders, or liver disease based on initial findings. 1

Initial Assessment

• A thorough clinical history should focus on onset, frequency, and characteristics of greasy stools, associated symptoms (abdominal pain, weight loss, bloating), and potential risk factors (alcohol use, prior surgeries, family history of gastrointestinal disorders) 1
• Physical examination should include assessment for signs of malnutrition, abdominal tenderness, hepatomegaly, and digital rectal examination 1
• Basic laboratory tests should include complete blood count to assess for anemia, which may indicate malabsorption or chronic disease 1
• Evaluate electrolytes, liver function tests, and renal function to identify potential underlying causes 1

Stool Studies

• Quantitative fecal fat measurement (72-hour collection) remains the gold standard for confirming steatorrhea, with >7g/24h considered diagnostic 2, 3
• Acid steatocrit on random stool samples offers a simpler alternative with high sensitivity (100%) and specificity (95%) for detecting steatorrhea 3
• Qualitative microscopic examination for fat globules in stool has lower sensitivity (78%) and specificity (70%) but can be performed rapidly 3
• Stool tests for ova, parasites, and infectious causes should be performed to rule out infectious etiologies 1

Pancreatic Function Testing

• Fecal elastase-1 measurement is recommended as a non-invasive screening test for pancreatic insufficiency 1, 4
• Fecal fat concentration may help differentiate between pancreatic and non-pancreatic causes of steatorrhea, though there is significant overlap between conditions 2
• Consider direct pancreatic function tests in equivocal cases 4

Imaging Studies

• Abdominal imaging should be performed based on clinical suspicion:
  • Abdominal ultrasound to evaluate for gallstones, liver disease, or pancreatic abnormalities 1
  • CT scan or MRI of the pancreas if pancreatic disease is suspected 1
  • Small bowel imaging (CT enterography or MR enterography) if small intestinal disease is suspected 1

Endoscopic Evaluation

• Upper endoscopy with duodenal biopsies should be performed to evaluate for celiac disease, small intestinal bacterial overgrowth, or other mucosal disorders 1
• Colonoscopy may be indicated in patients with alarm symptoms (rectal bleeding, weight loss) or those over age 45 with new-onset symptoms 1
• Endoscopic ultrasound may be helpful in evaluating pancreatic disorders 1

Specialized Testing Based on Initial Findings

• For suspected celiac disease: Anti-tissue transglutaminase antibodies, anti-endomysial antibodies 1
• For suspected bacterial overgrowth: Hydrogen/methane breath testing 1
• For suspected bile acid malabsorption: SeHCAT scan (where available) or empiric trial of bile acid sequestrants 5
• For suspected liver disease: Additional liver function tests, hepatitis serology, and liver imaging 6

Common Pitfalls and Caveats

• Failure to distinguish between pancreatic and non-pancreatic causes of steatorrhea can lead to inappropriate management 2, 4
• Relying solely on qualitative stool fat testing may miss cases of steatorrhea due to lower sensitivity 3
• Not considering medication-induced causes of malabsorption (e.g., orlistat, colchicine) 1
• Overlooking liver disease as a potential cause of steatorrhea, which occurs in up to 78% of patients with various liver disorders 6
• Assuming irritable bowel syndrome without excluding steatorrhea in patients with chronic diarrhea 5

By following this systematic approach, the underlying cause of steatorrhea can be identified in most patients, allowing for targeted treatment of the specific etiology.