Phân mỡ (Steatorrhoea)

Mô tả: Stools that are foul-smelling, soapy, bulky and oily in appearance. Quantitatively defined as stool fat >7 gd. Patients may additionally describes the faeces as difficult to flush down the toilet and very foul-smelling.

Nguyên nhân: • Typically, malabsorption syndromes including, but not limited to: More common • Thyrotoxicosis • Coeliac disease • Inflammatory bowel disease • Drugs (e.g. lipase inhibitors) • Alteration of anatomy of upper GI tract post surgery • Cirrhosis of the liver • Giardia lamblia infection Less common • Blocked bile ducts • Lymphatic obstruction • Whipple’s disease • Biliary tree disease (e.g. primary sclerosing cholangitis, primary biliary cirrhosis)

Cơ chế: An inability to break down (luminal), absorb (mucosal) or transport (post-absorptive lymphatic) fats is the principal cause of steatorrhoea. The increased fat load in the stool causes diarrhoea via an osmotic effect. Pancreatic insufficiency (luminal) When >90% of pancreatic function is lost, the normal enzymes that break down fats in the intestinal lumen (e.g. pancreatic lipase) are not produced in sufficient quantities, fats are unable to be broken down and, therefore, cannot be absorbed. Cirrhosis and biliary obstruction (luminal) In cirrhosis, insufficient bile acids are produced by the liver to break fats down. Similarly, in biliary obstruction, bile is unable to be secreted into the intestine; therefore, fats are not metabolised and, as a result, they are excreted in the stool. Coeliac disease (mucosal) Damage to the intestinal mucosa prevents the normal absorption of micelles. More fat and lipids are left in the intestine and are excreted. Lymphatic obstruction (post-absorptive) In rare congenital disorders (e.g. congenital intestinal lymphaniectasia) or after trauma, the lymphatic system may become blocked or compromised. The reassembled lipids are blocked from being transported away from the bowel and, therefore, stay in the bowel and are excreted in the stool.