Colitis is inflammation affecting the lining of the colon (large intestine). This inflammation disrupts the colon’s normal function, and changes in bowel movements are often the first noticeable indication. Alterations in stool frequency, consistency, and content are often the first signs that colitis may be active. Understanding these specific changes can provide insight into the severity of the inflammation.
The Hallmarks of Colitis-Related Stool
The appearance of stool during a colitis flare often deviates significantly from a healthy bowel movement. The most common characteristic is diarrhea, ranging from mushy and loose to entirely watery or liquid. This rapid movement often means the stool is passed in small, frequent volumes.
A key visual feature is the presence of blood, typically appearing as bright red streaks or mixed into the diarrhea. This fresh blood, known as hematochezia, suggests bleeding from the lower gastrointestinal tract, specifically the inflamed colon or rectum. Inflammation can cause small ulcers on the lining that bleed easily when stool passes.
Alongside blood, many people observe mucus or pus in their stool. Mucus is a slick, gel-like substance that may appear whitish or yellowish. Pus, a marker of active infection or severe inflammation, may also be visible, sometimes lending a greenish tint to the output.
The urgency to pass stool is also a signature of colitis, often resulting in very little solid material being expelled. In rare instances, inflammation limited to the rectum may cause constipation where stool is hard and lumpy despite the constant feeling of needing to evacuate.
Why Inflammation Changes Stool Appearance
The underlying reason for these changes lies in the physiological impact of inflammation on the colon. Normally, the large intestine’s primary job is to absorb water and electrolytes to form solid stool. When the colon lining becomes inflamed, its ability to reabsorb water is significantly impaired.
This failure to absorb fluids leads directly to the characteristic loose and watery diarrhea seen in a colitis flare. The inflammation also irritates the intestinal walls, triggering increased muscle contractions (rapid peristalsis). This speeds up the transit time of waste, contributing to the urgency and frequency of bowel movements.
Ulceration and damage to the protective inner surface of the colon are responsible for the blood and pus observed. As inflammation worsens, open sores develop, exposing delicate blood vessels. The passage of stool over these sites causes bleeding, while the immune response generates pus and excessive mucus.
Other Key Symptoms of Colitis
Colitis involves a range of functional and systemic symptoms beyond changes in stool appearance. One particularly distressing symptom is tenesmus, the persistent and painful feeling of needing to pass a bowel movement, even when the bowels are empty. This sensation results from inflammation irritating the nerves in the rectum.
Abdominal pain and cramping are frequent companions to colitis, often felt in the lower abdomen. The intense, frequent contractions of the inflamed colon muscles cause this cramping, which can sometimes precede a bowel movement.
Many people experience profound fatigue and low energy. This systemic exhaustion can be compounded by low-grade fever, loss of appetite, and unintended weight loss. Chronic blood loss from the inflamed colon can also lead to anemia, further contributing to generalized weakness.
When to Seek Medical Help
While this article provides general information, diagnosis and treatment require professional medical attention. Specific warning signs indicate a need to contact a healthcare provider promptly. Persistent diarrhea or bloody stools lasting more than three days warrants medical consultation.
More severe signs require immediate medical evaluation or a trip to the emergency room. These include passing large amounts of blood or blood clots, experiencing severe, unrelenting abdominal pain, or showing signs of severe dehydration (such as dizziness and reduced urination). A high fever accompanied by a rapid heart rate is another sign of a serious complication needing urgent care.