The rectum is the final section of the large intestine. Inflammation of the delicate lining of this organ is a condition known as proctitis. This inflammation can cause significant discomfort and disruption to normal bowel function. While the term describes a single anatomical problem, the underlying causes are numerous, leading to a complex picture regarding its origins.
What Is Proctitis?
Proctitis is inflammation of the rectal mucosa, affecting the last several centimeters of the large intestine. This condition frequently causes tenesmus, the persistent and urgent sensation of needing to pass a bowel movement, even when the rectum is empty. The inflamed tissue can also lead to the passage of blood or mucus, often mixed with stool.
Rectal pain and discomfort are common complaints, which may be accompanied by a feeling of fullness in the area. Inflammation may result in diarrhea, constipation, or painful bowel movements. Identifying the precise cause of the inflammation is necessary for effective management, as these symptoms overlap with many other digestive conditions.
The Autoimmune Link: Proctitis as a Manifestation of IBD
Proctitis is a term describing inflammation, but one specific type is immune-mediated. When proctitis is a chronic condition, it is most often categorized as Ulcerative Proctitis, which is the mildest and most localized form of Ulcerative Colitis. Ulcerative Colitis is a long-term inflammatory bowel disease (IBD) believed to stem from a dysfunctional immune response.
In this scenario, the body’s immune system mistakenly identifies the cells lining the rectum as a threat and launches an inflammatory attack. This immune system error leads to chronic inflammation and ulceration confined strictly to the rectal lining. Crohn’s disease, the other primary form of IBD, can also affect the rectum, though it typically involves deeper layers of the intestinal wall and can occur anywhere along the digestive tract. The confusion regarding proctitis’s autoimmune status arises because the most frequent type of chronic, recurring rectal inflammation is directly linked to these immune-driven IBD conditions.
Identifying Non-IBD Causes of Rectal Inflammation
Proctitis is not exclusively an autoimmune problem, as many external or localized triggers can cause rectal inflammation.
Infectious Proctitis
A major group of causes is infectious proctitis, which occurs when pathogens directly infect the rectal lining. Sexually transmitted infections (STIs) such as Neisseria gonorrhoeae, Chlamydia trachomatis, and the Herpes Simplex Virus are frequent culprits, particularly in individuals engaging in receptive anal intercourse.
Radiation Proctitis
Another distinct non-autoimmune cause is radiation proctitis, which develops after a patient receives radiation therapy directed at the pelvic area for cancers like prostate or cervical cancer. The high-energy radiation damages the rectal tissue, leading to inflammation and scarring, which can manifest acutely during treatment or chronically years later.
Diversion Proctitis
Diversion proctitis occurs in patients who have undergone ostomy surgery, which diverts the fecal stream away from a segment of the large intestine and rectum. The lack of fecal flow, and the subsequent shortage of nourishing short-chain fatty acids, leads to inflammation in the bypassed rectal segment.
Diagnosis and Cause-Specific Treatment
A thorough diagnostic process is required to distinguish between infectious, autoimmune, and other causes, as treatment must be tailored specifically. A physician typically performs a lower endoscopy, such as a flexible sigmoidoscopy, to visually examine the rectal lining and assess the severity and pattern of inflammation. During this procedure, a small tissue sample, known as a biopsy, is often collected to look for specific cellular changes, such as the presence of immune cells or cancerous alterations.
Stool samples are commonly collected and tested to rule out bacterial or parasitic infections, while specific blood tests can help identify signs of systemic inflammation or screen for certain infectious agents.
Treatment for IBD-related proctitis focuses on suppressing the localized immune response, often utilizing topical anti-inflammatory medications like 5-aminosalicylates (5-ASAs) or corticosteroid enemas. If the cause is infectious, the treatment is targeted, requiring specific antibiotics or antiviral medications to eradicate the pathogen. Management for radiation or diversion proctitis is often supportive, involving topical agents like sucralfate enemas or, in the case of diversion proctitis, the reintroduction of short-chain fatty acids.