Steatorrhoea

• Introduction
• Definition
• Aetiology
• Clinical features
• Management

Introduction

Steatorrhoea is a condition characterised by an increase in fat content in stools leading to the production of pale, bulky, offensive and loose stools. Along with anaemia, steatorrhoea is one of the primary clinical features of malabsorption syndromes such as coeliac disease. Diagnosis relies on investigation of the fat content of stools and imaging of the gastrointestinal tract to find structural abnormalities that could interfere with the normal absorption of fat.

Definition

Steatorrhoea refers to an increase in faecal fat content caused by fat malabsorption. This results in the production of pale, foul-smelling and oily stools that are difficult to flush. There is currently no precise standardised definition of the amount of fat excretion necessary to make the diagnosis of steatorrhoea, however fat excretion of more than 6g per day is considered abnormal.

Aetiology

Fat malabsorption can result due to both digestive and absorptive disorders.
Normally dietary fat (a mixture of cholesterol and triglycerides) gets broken down partially in the stomach by a process called emulsification and then further in the duodenum (first segment of the small intestine) by certain pancreatic enzymes.
Bile (a yellow-green substance synthesised in the liver and stored in the gallbladder) also helps in the digestive and absorption process. This enters the duodenum and helps divide fat into very small globules coated with bile acids, called micelles. This aids the absorption and transport of the fats across the lining of the small intestine so the fats can enter the lymphatics.
Disruption in any of these processes can lead to malabsorption of fats which means dietary fat stays within the bowel to be later excreted in the stools in increased amounts.
Possible causes of steatorrhoea include:

• Coeliac disease (gluten-sensitive enteropathy)- when foods containing gluten are eaten, a reaction occurs that damages the lining of the small intestine. This impairs absorption of fat and other substances
• Tropical sprue is the most common cause of steatorrhoea worldwide. Tropical sprue occurs in many parts of Asia and may be seen in travellers to these areas. The exact cause of this disorder is not known but it is thought to result in damage to intestinal villi which leads to malabsorption.
• Chronic pancreatitis– This causes a reduction in the production of the pancreatic enzymes which are required for adequate fat digestion.
• Liver disease and obstruction of bile ducts (e.g. Choledocholithiasis inhibit bile entering the duodenum so lipids cannot be digested or absorbed.
• Bacterial overgrowth- This can occur spontaneously in elderly patients or in patients with diverticular disease. The abnormal bacteria can breakdown bile salts.
• Parasites- e.g. Giardiasis.
• Pancreatic carcinoma- This can cause malabsorption by inhibiting pancreatic function or b obstruction of biliary outflow.
• Short bowel syndrome- Removal of segments of bowel inhibits the capacity for absorption.
• Crohn’s disease causes damage to the ileum (final portion of the small intestine) that has important roles in absorption of bile acids and other substances.
• Cystic fibrosis– This is a genetic condition that causes abnormal secretions in various organs throughout the body. In the pancreas, mucus plugs block some of the ducts and inhibit the secretion of digestive juices by the pancreas.

Clinical features

You may notice the following symptoms if you suffer steatorrhoea:

• Foul-smelling feces.
• Bulky stool.
• Pale stools.
• Loose stools.
• Greasy stools.

Your doctor will take a thorough history regarding your symptoms and past medical history that may give the doctor a clue to the possible cause of your malabsorption. They will also perform a general examination and more specifically examine the abdomen.
When malabsorption occurs it is not uncommon for the doctor to perform several tests. These may include:

• Faecal fat determination- Stool samples are collected over three days whilst you follow a strict diet regarding fat content. The total fat content in the stool is measured and compared to normal values
• Spot stool sample- The doctor can use special stains and techniques on a single stool sample to determine the likely fat content. This is much easier than the above method but not as reliable.
• Breath test- The amount of carbon dioxide in the breath is measured after you ingest a radio-labeled fat sample. This gives an indication of fat absorption.
• Imaging such as Upper gastrointestinal endoscopy and biopsy, Barium studies and Wireless capsule enteroscopy can help identify abnormalities in the intestinal tract that may be the cause of the malabsorption.

Management

Treatment of steatorrhoea largely depends on the underlying cause. A gluten-free diet helps treat coeliac disease. Pancreatic enzyme supplements can be used in cases of pancreatic insufficiency and antibiotics are helpful if bacterial overgrowth is present. If inflammatory bowel disease is identified corticosteroids and other anti-inflammatory agents such as sulfasalazine are the treatments of choice. In addition, you may require nutritional supplements such as vitamins and minerals as absorption of these may be diminished.

References

1. Burkitt, Quick. Essential Surgery. 3rd Edition.Churchill Livingstone. 2002.
2. General Practice Notebook- Steatorrhoea. Oxbridge Solutions Ltd 2005. Available at URL: http://www.gpnotebook.co.uk/simplepage.cfm?ID=-1167392766 (last accessed: 12/07/06).
3. Kumar, Clark. Clinical Medicine. 5th Edition. Saunders. 2002.
4. Longmore, Wilkinson, Rajagopalan. Oxford Handbook of Clinical Medicine. 6th Edition. Oxford University Press. 2004.
5. Milovic V, Stein J, Caspary W, Mason J. Clinical features and diagnosis of malabsorption. UpToDate, 2006.
6. NDDIC. Celiac Disease [online]. National Institutes of Health, 2005. available at URL: http://digestive.niddk.nih.gov/ddiseases/pubs/celiac/ (last accessed: 12/07/06).
7. Yang V, Klapproth J. Malabsorption. eMedicine. Web MD, 2006. Available at URL: http://www.emedicine.com/MED/topic1384.htm

Diseases presenting with Steatorrhoea include:

• Cholecystitis
• Coeliac Disease (Gluten-Sensitive Enteropathy, Coeliac Sprue)
• Common Bile Duct Stone (Choledocholithiasis, Cholangitis, Obstructive Jaundice)
• Crohn’s Disease (Inflammatory Bowel Disease)
• Diverticular Disease (Diverticulosis; Diverticulitis)
• Gallstones
• Pancreatitis (Chronic)