A rectal ulcer is an injury to the mucosal lining of the rectum, the final section of the large intestine before the anus. This damage creates an open sore or lesion on the inner surface of the rectal wall. Although the term “ulcer” suggests a single wound, the condition can involve multiple lesions or areas of inflammation. This localized break in the tissue is often slow to heal due to the constant passage of stool.
Identifying Symptoms
The presence of a rectal ulcer often manifests through the passage of blood. This bleeding, medically termed hematochezia, is usually bright red and can range from minor streaks on the stool or toilet paper to more substantial amounts. Patients frequently report tenesmus, a persistent urge to pass stool even when the bowels are empty.
Rectal pain or discomfort is another frequent complaint, often becoming more pronounced during a bowel movement. This sensation can be accompanied by an involuntary discharge of mucus from the rectum. A person may also experience a change in bowel habits, such as chronic constipation or intermittent diarrhea.
Physical Appearance and Characteristics
Specialized medical visualization is required to see a rectal ulcer, as it occurs internally on the rectal wall. When viewed through an endoscope, an established ulcer appears as a depression in the mucosa covered by a layer of dead tissue. This covering, referred to as a slough, typically gives the ulcer a grayish, whitish, or yellowish tint.
The physical dimensions are variable, but many ulcers measure between 1 and 1.5 centimeters in diameter. Sizes can range from 0.5 centimeters up to 4 centimeters in extensive cases. The ulceration is generally shallow but may have borders that appear firmer or raised than the surrounding healthy tissue.
Ulcers are often found on the anterior (front) wall of the rectum, typically situated 3 to 10 centimeters up the rectal canal from the anal opening. The surrounding mucosal tissue may appear red and inflamed (hyperemic), or sometimes nodular and granular, occasionally mimicking a small polyp.
Common Underlying Causes
The formation of a rectal ulcer is linked to chronic mechanical stress or trauma applied to the rectal lining. The most prevalent mechanism involves excessive and prolonged straining during defecation, often a consequence of chronic constipation. This intense pressure causes the mucosal lining to stretch and become vulnerable to injury.
A primary condition associated with this injury is Solitary Rectal Ulcer Syndrome (SRUS). SRUS is believed to occur when straining causes a temporary prolapse or telescoping of the rectal tissue (intussusception) near the anal canal. This internal movement and pressure reduce blood flow to the area, leading to localized tissue damage and eventual ulceration.
Other sources of direct trauma can also initiate ulceration. These include the use of instruments or fingers inserted into the rectum, such as for the manual removal of impacted stool. Similarly, the forceful administration of enemas or suppositories can injure the delicate rectal mucosa. Any chronic physical insult or ischemia (lack of blood supply) creates an environment where an ulcer can form and persist.
Seeking Diagnosis and Medical Attention
If symptoms like unexplained rectal bleeding, persistent pain, or the feeling of incomplete stool evacuation continue, seek professional medical evaluation. Self-diagnosis is unreliable because these complaints can signal more serious conditions. A healthcare provider will typically begin with a medical history and a physical examination, which may include a digital rectal exam to check for abnormalities.
To confirm the presence of an ulcer, a procedure like flexible sigmoidoscopy is performed. This involves inserting a thin, lighted tube with a camera into the rectum to visualize the mucosal surface directly. During this examination, the physician observes the lesion and may take a small tissue sample, known as a biopsy. The biopsy is analyzed to rule out other diseases, such as inflammatory bowel disease or malignancy, providing a definitive diagnosis.