Background
Proctitis is defined as inflammation of the mucosal lining of the rectum, whereas anusitis is simply inflammation of the anal canal. Inflammation in these areas can cause symptoms, such as itching, burning, rectal bleeding, pelvic pressure, and foul-smelling discharge. The distinction between proctitis and anusitis is not overly pertinent, in that the etiology and treatment of the two conditions are similar. For the purposes of this article, the term proctitis will be understood to include anusitis, though there has been a stronger correlation between diet and anusitis (which is more commonly seen in those with higher intake of citrus, alcohol, garlic, and spices).
Several different etiologies exist, including inflammatory bowel disease (IBD; eg, ulcerative colitis [UC]), infectious organisms (eg, Neisseria gonorrhoeae, Salmonella, Shigella, Clostridioides [Clostridium] difficile,Chlamydia trachomatis, cytomegalovirus [CMV], human papillomavirus [HPV]), noninfectious causes (eg, radiation, ischemia, and diversion), and other causes (eg, vasculitis, toxins, and certain medications). For convenience, the majority of proctitis cases may be grouped into three broad categories—IBD, infectious proctitis, and noninfectious proctitis—with other causes accounting for the relatively small remainder.
Proctitis can occur in both the acute setting and the chronic setting and can cause significant anorectal complaints. Treatment is generally nonsurgical; however, in certain cases, surgery is indicated.
Anatomy
It is important to recognize that most inflammatory processes of the rectum also involve the adjacent colon and the anus. The exact anatomy of the rectum and anus and the delineation of where each one begins and ends are ongoing topics of discussion, with some authorities appreciating the start of the rectum at the level of the third sacral vertebra and others considering the start of the rectum to be at the sacral promontory. Most agree that the rectum transitions to the anus where the epithelial cells change from columnar cells to squamous cells.
The World Health Organization (WHO) and the American Joint Cancer Committee (AJCC) have defined the anal canal as the distal portion of the gastrointestinal (GI) tract that corresponds to the internal anal sphincter.
In proctitis and anusitis, the anatomy does not change therapy, because a significant overlap between anorectal inflammation and rectosigmoid inflammation exists.
Pathophysiology
The pathophysiology of proctitis is dependent on the various etiologies and is not completely understood. In addition, some patients seem more susceptible to this inflammatory condition, with factors such as young age, previous abdominal surgery, hypertension, vasculopathy, and diabetes cited as possible contributing factors. The pathophysiology of proctitis in IBD is believed to be caused by an autoimmune process.
Infectious etiologies may be related to the organism itself or to a toxin produced by the organism.
Radiation proctitis is due to the radiation itself causing damage to intestinal cell DNA, which results in the cells being rendered unable to repair themselves and eventually becoming atrophic. Over time, these ischemic changes turn into fibrotic changes. Diversion proctitis is thought to be caused by a deficiency of short-chain fatty acids (SCFAs), which are the main fuel source for the cells of the colon and rectum. Ischemic proctitis may be due to mesenteric venous occlusion, aortoiliac surgery, radiotherapy, vascular intervention, atherosclerotic disease, or use of drugs (eg, cocaine).
Other causes (medications, vasculitis) all eventually cause proctitis through much the same mechanisms as the causes listed above, with damage to the lining of the rectum and anus.
Regardless, all three main categories of proctitis (ie, IBD, infectious, and noninfectious) result in an unrestrained inflammatory response, with the inflammatory cells being products that mediate cellular-tissue injury.
Etiology
Most of the potential causes of proctitis can be usefully classified into one of the following three categories:
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Proctitis due to inflammatory bowel colitides (eg, UC and Crohn disease [CD])
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Proctitis due to infection (eg, by C difficile or Salmonella); in most cases, the rectal inflammation caused by an infection is likely to cause inflammation in the colon as well
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Proctitis due to noninfectious conditions (eg, diversion, ischemia, and radiation)
A minority of cases of proctitis are attributable to other causes (eg, medication side effects, vasculitis, or toxins)
Epidemiology
The prevalence of proctitis in the general population has not been established through epidemiologic studies. However, it is possible to ascertain the incidence of proctitis through analysis of specific disease states. For example, patients with UC displayed a 31-50% frequency of proctitis upon diagnosis, depending on age at diagnosis. A study in the pediatric UC population demonstrated a significant increase in the occurrence of proctitis in female children as compared with males. [1] The frequency of chronic radiation-induced proctitis has been reported to be in the range of 2-20% and is influenced by total radiation dose, mode of delivery, and dose fractionation. [2]
Infectious proctitis is typically due to sexually transmitted disease (STD) and is more common in those with a history of anal receptive intercourse. Of these infections, gonorrhea and chlamydia were the most common STDs, followed by herpes and syphilis. Some studies have reported the incidence of gonorrheal and chlamydial proctitis among men who have sex with men (MSM) to be as high as 8.5% and 7.9%, respectively. [3]
Prognosis
In the acute setting, most bouts of proctitis have a good outcome and prognosis. More specifically, infectious proctitis, once appropriately treated, tends not to recur.
For the more chronic diseases, such as IBD, outcomes and prognoses vary. Clearly, in medically treated ulcerative colitis and proctitis, approximately 40-70% of cases do not require operation. If proctocolectomy is performed, the patient is cured of the disease. CD is another story: Because it can occur in all portions of the GI tract, even after a proctectomy, CD has a recurrence rate in the range of 45-90%.
Diversion proctitis generally has a good outcome and prognosis once the diversion is reversed.
The outcome and prognosis of radiation proctitis vary with the severity of proctitis. Outcomes range from requiring only a few medical treatments in the form of enemas to requiring surgical treatment. Complication rates for surgical treatment have been reported to be as high as 75%.
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Proctitis seen on flexible endoscopy.
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- Overview
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- Workup
- Treatment
- Medication
- Aminoglycosides
- 5-Aminosalicylic Acid Derivatives
- Antibiotics, Combos
- Antibiotics, Other
- Antiparasitic Agents
- Antivirals, HSV
- Calcineurin Inhibitors
- Cephalosporins, 3rd Generation
- Corticosteroids
- Corticosteroids, Gastrointestinal
- DMARDs, JAK Inhibitors
- Fluoroquinolones
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- Glycopeptides
- Inflammatory Bowel Disease Agents
- Nitroimidazoles
- Penicillins, Amino
- Penicillins, Natural
- Tetracyclines
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- References