Yes, liver damage can cause diarrhea. This digestive symptom arises when the liver’s function is compromised, impairing its ability to process waste and aid in nutrient breakdown. The connection between an impaired liver and loose stools involves multiple systemic and digestive mechanisms.
The Liver’s Essential Role in Digestion
One of the liver’s main digestive functions is the continuous production of bile. Bile is an alkaline fluid composed of water, cholesterol, electrolytes, and bile salts, synthesized by liver cells. This fluid is temporarily stored and concentrated in the gallbladder before being released into the small intestine after a meal.
The primary purpose of bile is the emulsification of dietary fats. Bile salts break down large fat globules into smaller droplets, increasing the surface area. This allows digestive enzymes, specifically lipases, to efficiently break down fats for absorption. Beyond fat digestion, the liver processes nutrients absorbed from the gut, converting them into usable forms or regulating blood sugar by storing and releasing glucose.
Specific Mechanisms Linking Liver Dysfunction to Diarrhea
Bile Acid Deficiency and Fat Malabsorption
When the liver is damaged, its capacity to produce and secrete adequate bile salts into the small intestine is reduced. This deficiency prevents the proper emulsification and absorption of dietary fats, a condition known as fat malabsorption or steatorrhea. Unabsorbed fats travel into the colon, drawing excess water into the bowel through osmosis, resulting in osmotic diarrhea.
The unabsorbed fatty acids in the colon irritate the lining and stimulate fluid secretion, further contributing to the diarrheal effect. This type of diarrhea is often characterized by stools that are pale, bulky, greasy, and difficult to flush, due to the high fat content.
Portal Hypertension and Gut Edema
Severe liver disease, such as cirrhosis, causes scarring that increases resistance to blood flow through the liver, leading to portal hypertension. This backup affects the entire splanchnic circulation, including the blood vessels supplying the intestines. The high pressure causes fluid to seep out of the congested intestinal capillaries, resulting in edema of the gut wall.
This swelling impairs the normal barrier function and absorption capabilities of the intestinal lining. This, combined with increased motility and poor nutrient uptake, contributes to diarrhea. Furthermore, the altered environment can promote small intestinal bacterial overgrowth (SIBO), which also contributes to diarrhea and malabsorption.
Medication Side Effects
Another common cause of diarrhea in individuals with liver disease is the treatment itself. Medications like lactulose are frequently prescribed to treat hepatic encephalopathy, a brain complication of severe liver failure. Lactulose works by drawing water into the colon and promoting laxation to clear ammonia and other toxins from the gut.
The intended therapeutic effect of lactulose is to cause frequent, loose bowel movements, which is medically induced diarrhea. Therefore, diarrhea in a person with liver disease may be a deliberate side effect of treatment rather than a direct consequence of organ dysfunction. It is important to distinguish this therapeutic effect from diarrhea caused by malabsorption or systemic complications.
Associated Symptoms and When to Seek Medical Help
Diarrhea is rarely the only symptom of liver damage; it is usually accompanied by other signs of impaired liver function. Jaundice, a yellowing of the skin and eyes, results from the buildup of bilirubin that the damaged liver cannot clear. The lack of bile reaching the intestines can cause stools to appear pale or clay-colored, while excess bilirubin makes urine unusually dark.
Other associated symptoms include fatigue, loss of appetite, and abdominal swelling, known as ascites. Easy bruising is also common because the liver produces many of the proteins needed for blood clotting. If a person experiences diarrhea along with any of these symptoms, prompt medical evaluation is needed.
Immediate medical attention is necessary if the diarrhea is accompanied by severe symptoms:
- Severe dehydration
- Persistent vomiting
- A high fever
- Any sign of bleeding, such as bloody or black, tarry stools
Signs of worsening hepatic encephalopathy, such as confusion, disorientation, or excessive sleepiness, also require emergency care. A healthcare professional can determine the underlying cause of the liver damage and the diarrhea.