Crohn’s disease is a chronic condition and a type of inflammatory bowel disease (IBD) that causes inflammation and ulceration anywhere along the gastrointestinal tract, from the mouth to the anus. This persistent inflammation disrupts the normal process of digestion and absorption. The resulting changes frequently alter the appearance, frequency, and consistency of bowel movements. Monitoring these characteristics is a primary method for people to gauge their disease activity, as the stool often reflects the underlying level and location of inflammation in the digestive system.
Consistency and Frequency Changes
Diarrhea is one of the most common and noticeable changes associated with active Crohn’s disease, frequently presenting as loose, watery, or entirely liquid stools. This loose consistency often results from the inflamed intestinal lining being unable to properly absorb water before the stool reaches the rectum. During a disease flare, the frequency of bowel movements often increases significantly, with some individuals experiencing four or more passages per day, sometimes with a strong sense of urgency.
Another distinct change in consistency is the presence of steatorrhea, which is stool containing an abnormally high amount of fat. Steatorrhea typically appears pale, bulky, greasy, and is often noticeably foul-smelling, sometimes floating in the toilet water. This occurs because inflammation, particularly in the small intestine, impairs the absorption of dietary fats and other nutrients.
While diarrhea is characteristic, a subset of people with Crohn’s, especially those with strictures or blockages, may experience constipation. A stricture, a narrowing of the intestinal passage due to chronic inflammation and scarring, can partially obstruct the movement of stool. In these cases, the stool that does pass may be hard and lumpy, indicating difficulty in transit.
Identifying Blood and Mucus
The presence of blood or mucus mixed with the stool is a significant indicator of active inflammation and damage within the intestinal lining. When the inflammation and ulceration occur in the lower digestive tract, such as the colon or rectum, the blood often appears bright red, a condition known as hematochezia. This visible, fresh blood indicates bleeding that is occurring relatively close to the anus, which can also be caused by associated complications like anal fissures or hemorrhoids.
Blood originating higher up in the gastrointestinal tract, or blood that has been partially digested, may result in stool that appears very dark, tarry, and almost black. This dark appearance is called melena and signals that the blood has been chemically altered by digestive enzymes on its journey through the intestines. Mucus, which is normally present but invisible, becomes visible when inflammation prompts the intestines to produce excessive amounts to protect the lining. This excessive mucus appears as a yellowish or white, slippery, gel-like substance coating or mixed within the stool.
How Inflammation Alters Stool
The characteristic changes in stool appearance are directly linked to the pathology of Crohn’s disease, which involves transmural inflammation extending through all layers of the intestinal wall. This inflammation causes ulceration, or open sores, which disrupt the normal function of the digestive tract.
Diarrhea and Malabsorption
Inflammation compromises the primary function of absorbing water, especially in the colon, and leads to a faster transit time for waste. This combination results in frequent, loose, and watery stools. When Crohn’s affects the terminal ileum, it interferes with the reabsorption of bile salts necessary for fat breakdown. This deficiency causes fat malabsorption, resulting in steatorrhea.
Bleeding and Mucus Production
The presence of blood and mucus is a direct result of ulceration and tissue damage. As the intestinal lining breaks down, blood vessels are exposed, leading to bleeding that mixes with the stool. The inflammatory process also triggers the immune response, which contributes to the excessive release of mucus.
When to Consult a Healthcare Provider
Monitoring stool changes is an important part of managing Crohn’s disease, and certain observations require prompt medical attention. A person should contact a healthcare provider if they notice persistent changes in their stool, such as diarrhea that lasts more than seven days or a significant, unexplained increase in the frequency of bowel movements. Any consistent or significant amount of blood in the stool, whether it is bright red or tarry black, warrants a discussion with a doctor, as this often indicates an active flare-up requiring treatment adjustment.
Immediate or emergency care is necessary if stool changes are accompanied by severe symptoms like an inability to keep down liquids due to nausea and vomiting, a high fever, or constant, severe abdominal pain. The inability to pass stool or gas alongside severe pain could signal an intestinal obstruction, which is a complication of Crohn’s disease that requires urgent evaluation.