Characteristics of Steatorrhea
Steatorrhea is characterized by bulky, pale, malodorous, and floating stools due to excess fat content, typically defined as >7% of ingested fat present in stool or a coefficient of fat absorption <93%. 1
Clinical Presentation
- Steatorrhea is the cardinal clinical feature of exocrine pancreatic insufficiency (EPI) and presents with visible fat in the stool 1
- Stools are typically bulky, pale/light-colored, malodorous, and float due to their high fat content 1
- Associated symptoms often include flatulence, bloating, dyspepsia, urgency to pass stools, and cramping abdominal pain 1
- Weight loss is a common accompanying feature, especially in severe cases 1
- Steatorrhea may be accompanied by deficiencies in fat-soluble vitamins (A, D, E, K) even in patients with mild to moderate pancreatic insufficiency 1
Diagnostic Criteria
- Formally defined as >7% of ingested fat present in the stool or a coefficient of fat absorption <93% 1
- Visible steatorrhea usually requires moderate fat in the diet and is typically not expected unless there is severe or decompensated pancreatic exocrine insufficiency 1
- Quantitative measurement requires a diet of known fat content ingested over 5 days with stool collection during the final 3 days 1
- Fecal fat exceeding 13 g/day (47 mmol/day) is considered severe steatorrhea and is most frequently caused by pancreatic exocrine insufficiency 1
Diagnostic Testing
- Quantitative fecal fat testing is rarely needed in routine clinical practice and is burdensome to implement 1
- Fecal elastase-1 (FE-1) is the most commonly used indirect pancreatic function test due to being simple, noninvasive, and relatively inexpensive 1
- FE-1 <200 mg/g of stool is considered abnormal
- FE-1 <100 mg/g is more consistent with EPI
- FE-1 <50 mg/g is most reliable for severe EPI 1
- Stool fat measures including Sudan stain are nonspecific for EPI but can help identify the presence of fat 1
- Clinical assessment of steatorrhea by stool inspection alone is unreliable 1
Common Causes
- Pancreatic exocrine insufficiency (EPI) is the most common cause of severe steatorrhea 1
- Chronic pancreatitis
- Pancreatic carcinoma
- Pancreatic surgery
- Cystic fibrosis
- Small bowel disorders 1
- Celiac disease
- Crohn's disease
- Small bowel bacterial overgrowth
- Whipple's disease
- Tropical sprue
- Surgical causes 1
- Small bowel resections
- Bariatric surgery (especially malabsorptive procedures like BPD-DS) 1
- Bile acid malabsorption 1
- Liver disease (found in up to 78.3% of patients with various liver diseases) 2
Clinical Pearls and Pitfalls
- Steatorrhea may not be clinically apparent in milder forms of malabsorption 1
- Non-specific symptoms like bloating, excess gas, and foul-smelling or floating stools may respond to pancreatic enzyme replacement therapy (PERT), but these symptoms are non-specific and improvement may be due to placebo effect 1
- Appropriate testing (e.g., fecal elastase) is recommended before initiating therapy with PERT to avoid masking other disorders such as celiac disease 1
- Cross-sectional imaging (CT, MRI, endoscopic ultrasound) cannot directly identify EPI but can help evaluate for underlying pancreatic abnormalities 1
- Steatorrhea after bariatric surgery may lead to deficiencies in fat-soluble vitamins, zinc, copper, and magnesium 1