Diverticulosis is the presence of small, bulging pouches called diverticula in the lining of the large intestine. This common condition often causes no symptoms and is typically associated with normal bowel habits or even constipation. Diarrhea is usually not a direct symptom of uncomplicated diverticulosis. However, it frequently occurs as a result of complications or associated functional disorders, signaling a need to investigate a change in the underlying condition.
Understanding Diverticulosis vs. Diverticulitis
Diverticulosis describes the existence of these small pouches, or diverticula, which develop when high pressure within the colon pushes the inner lining through weak spots in the muscle wall. This is a structural change, often discovered during a routine colonoscopy or other imaging. Since the muscle wall may be thickened near the diverticula, it often leads to slower movement of stool, which is why constipation is commonly linked to the condition.
The problem starts when one or more pouches become inflamed or infected, a condition called diverticulitis. Diverticulitis is an acute inflammatory process that leads to specific and sudden symptoms. This distinction is important: diverticulosis is a chronic structural finding, whereas diverticulitis is an acute disease state requiring medical attention.
When Diarrhea Occurs: The Role of Acute Inflammation
Diarrhea is a recognized symptom of acute diverticulitis, the inflammatory complication of diverticulosis. When the diverticula become inflamed, the immune response triggers inflammation in the surrounding colon tissue. This inflammation irritates the lining of the large intestine, increasing the speed of intestinal contractions, a process known as increased motility.
The large intestine’s primary role is to absorb water, but the increased speed of transit and the inflammatory environment reduce the time for absorption. As a result, the stool retains more water, leading to loose, watery stools or diarrhea. This acute diarrhea is often accompanied by severe abdominal pain, most commonly in the lower left side of the abdomen, along with fever, nausea, and an elevated white blood cell count.
Related Conditions Contributing to Diarrhea
Beyond acute inflammation, chronic conditions linked to diverticulosis can cause persistent or recurring diarrhea.
One such condition is Symptomatic Uncomplicated Diverticular Disease (SUDD). This is a chronic functional disorder where diverticula cause symptoms like abdominal pain and changes in bowel habits without overt infection. Individuals with SUDD often experience chronic or recurrent left lower quadrant pain accompanied by alternating bowel habits, including episodes of diarrhea. The symptoms of SUDD are thought to be caused by a low-grade inflammatory state, alterations in the gut microbiota, and muscle dysfunction within the colon wall.
Another related cause of chronic diarrhea is Small Intestinal Bacterial Overgrowth (SIBO), where excessive bacteria are present in the small intestine. Slow colonic transit associated with diverticulosis can create an environment that predisposes an individual to SIBO. The excess bacteria break down bile acids and carbohydrates, leading to poor absorption of fats and bacterial byproducts that trigger diarrhea. Diarrhea in this context results from malabsorption and the toxic effects of bacterial fermentation.
Managing Symptoms and Seeking Medical Care
Managing diarrhea linked to diverticular disease depends entirely on the underlying cause, underscoring the need for a correct diagnosis. For acute diverticulitis, treatment typically involves resting the bowel, dietary modification, and antibiotics to clear the infection and reduce inflammation. When experiencing an acute flare, temporary dietary changes like a low-fiber or clear liquid diet may be advised to give the colon a chance to heal. Hydration is paramount during any episode of diarrhea to replace lost fluids and electrolytes.
It is important to seek medical care immediately if the diarrhea is accompanied by certain warning signs. These symptoms may indicate a more severe complication, such as an abscess or perforation, which requires prompt medical evaluation. Warning signs include:
- Persistent and severe abdominal pain.
- A high temperature or fever.
- Significant rectal bleeding.
- Constant nausea and vomiting that prevent keeping fluids down.
- Diarrhea that lasts for more than seven days.