Proctitis and anusitis are general terms referring to inflammation within the anal canal or rectum secondary to infectious pathogens or inflammatory causes. Sexually transmitted diseases are an increasingly common cause of proctitis with an incidence exceeding 15 million new cases annually in the United States. The differential diagnosis can be quite broad with a variety of bacteria and viruses; therefore, a systematic approach is important. The diagnosis and management of these conditions depends primarily on the underlying etiology.
The Herpes Simplex Virus (HSV) is a DNA virus that is the most prevalent STD in the United States. The majority of anogenital infections are caused by the HSV-2 serotype, accounting for approximately 80%-90% of infections. Anorectal infections typically result from autoinoculation or direct contact with infected partners. The virus travels along peripheral nerves and has a variable incubation period (days to weeks). Prodromal symptoms may consist of burning, irritation, fever, and myalgia. This typically escalates to more intense, painful proctitis, and tenesmus. The characteristic lesions are small vesicles with surrounding erythema, which eventually coalesce and rupture forming painful ulcerations. Additionally, patients may develop tender inguinal adenopathy.
Evaluation of the rectum with a proctoscope will demonstrate erythematous and friable mucosa with ulcerations and mucopurulent discharge. Tzank smear of the discharge reveals the characteristic multinucleated giants cells with intranuclear inclusion bodies. Viral cultures of the discharge from these vesicles are also highly positive in acute infections.
HSV infections are usually self-limited in the absence of superimposed bacterial infections; therefore, initial treatments, such as sitz baths and oral analgesics are aimed at controlling symptoms. There is no cure for active infections but Acyclovir, Valacyclovir, and Famciclovir will shorten the duration of symptoms and may be used for suppressive therapy in patients with frequent recurrences.
Syphilis is caused by the spirochete, Treponema pallidum, which typically has an incubation period of 2-6 weeks. This disease was once on the verge of elimination but the incidence has been increasing steadily, especially young black men.
Acute anorectal infection is characterized by a small papule (chancre) on the anal margin or within the anal canal, which eventually ulcerates and may be mistaken for a routine anal fissure. This eventually regresses spontaneously in 3-4 weeks and is followed by a secondary stage 2-10 weeks later. Secondary syphilis may consist of fever, malaise, arthralgia, a maculopapular rash on the palms and soles of the feet, tenesmus, mucoid discharge, rectal pain, and inguinal adenopathy.
There are several methods for diagnosis. Dark-field microscopy will reveal the spirochetes, which have a corkscrew-shaped appearance. Biopsy shows spirochetes on a Warthin–Starry silver stain. There are also two serologic tests, RPR and VDRL.
Treatment consists of a single dose of penicillin intramuscularly in the early phase. If identified later, three doses are given 2 weeks apart.
Gonococcal proctitis is caused by the organism, Neisseria gonorrhoeae, which is an intracellular gram-negative diplococcus. It is estimated that there are approximately 3 million people infected yearly worldwide; however, there is a large population of asymptomatic carriers. Anorectal infection results from contiguous spread from the genital area in women and from receptive anal intercourse in men.
The incubation period varies but can last up to 2 weeks. Symptoms then include pruritus, tenesmus and a thick, purulent discharge, which can be expressed from the anal crypts. Proctitis of the mid to distal rectum can be identified on proctoscopy. Standard Gram stains of the discharge are generally unreliable; however, culture on Thayer–Martin medium increases the positive yield.
The first-line treatment of anorectal gonorrhea includes a single intramuscular dose of ceftriaxone. Penicillin is no longer recommended given the high rate of resistance. Infected patients and partners should also be treated for concomitant Chlamydia infection, which is very common.
4. Chlamydial proctitis and lymphogranuloma venereum
Chlamydia trachomatis is the most common sexually transmitted infection worldwide and the most frequently reported STD in the United States. This intracellular bacteria has several serotypes that have an incubation period up to 2 weeks. Serotypes D-K are responsible for proctitis and genital infections while serotypes L1-L3 are responsible for lymphogranuloma venereum (LGV).
A large portion of patients will be asymptomatic; however, when present, symptoms of an active anorectal infection include rectal pain, tenesmus, and fever. Similar anorectal complaints are present in patients with LGV but the inguinal adenopathy is often more prominent with large matted nodes with overlying erythema.
Diagnosis of active infections can be challenging with routine culture given the intracellular location of the bacteria. Often patients with suggestive symptoms of proctitis that have a Gram stain demonstrating leukocytes without detectable gonococci are presumed to have a Chlamydia infection and treated accordingly. Cell culture is also possible using a sucrose phosphate media. Treatment consists of a single oral dose of Azithromycin or Doxycycline twice daily for 7 days. Treatment with Doxycycline is extended to 21 days for LGV. Sexual partners should be treated as well to prevent reinfection.
Condyloma acuminata, caused by the human papilloma virus, have a recognizable raised, cauliflower-like appearance and are located on the anal margin, within the anal canal, or surrounding the genitalia. This presents one of the most common STDs in the United States for which consultation with a colorectal surgeon is sought. There are more than 60 subtypes of this latent virus with types 6 and 11 producing benign exophytic lesions. Types 16 and 18 are noted to be more aggressive, often causing lesions with high-grade dysplasia that may progress to cancer if left untreated.
Patients are often asymptomatic but may present with complaints of bleeding, itching, or anal discomfort due to the growths. Once present, there is no way to eradicate the infection surgically. The goal of treatment is to remove the macroscopic burden of disease with excisional biopsies and electrocautery. Recurrences are common; therefore, surveillance of these patients is extremely important. Bichloracetic acid, trichloracetic acid, and Imiquimod are topical agents that have been used with reasonable success.
Chancroid is a rare sexually transmitted disease in the United States caused by the gram-negative bacteria, Haemophilus ducreyi. Globally, the incidence is higher in developing countries.
The infection manifests itself days after transmission with painful inguinal adenopathy and erythematous papules around the genitalia that eventually ulcerate. Diagnosis is typically made with routine culture of the fluid from the ulcers. Treatment consists of single doses of Azithromycin (orally) or Ceftriaxone (intramuscularly).
7. Inflammatory proctitis
Inflammatory proctitis refers to a general mild to moderate inflammation of the rectum that is unrelated to an underlying infection or sexually transmitted disease. Symptoms include rectal bleeding, urgency, tenesmus, and often diarrhea. Examination of the rectum is characterized by a continuous erythematous, friable mucosal surface. If applicable, cultures should be taken to elucidate any infectious etiology and biopsies should be taken to rule out Crohn disease.
This condition can be self-limited but persistent cases typically respond to short courses of steroid enemas. Additionally, mesalamine enemas are efficacious. If there is no improvement after a few weeks of treatment, the patient should be reevaluated.
Radiation proctitis is an unfortunate byproduct of pelvic irradiation that typically occurs in two phases. Acute injury occurs during or shortly after the administration of pelvic radiation. This is characterized by vascular congestion and friable mucosa. Symptoms include rectal bleeding, urgency, tenesmus, and diarrhea. The late phase of injury occurs months to years after the completion of treatment and is characterized histologically by fibrosis that can manifest clinically with strictures, fistulas to the urinary tract or vagina, and telangiectasias. Symptoms include bleeding, change in bowel habits, recurrent urinary tract infections, and vaginal discharge. Evaluation should include flexible sigmoidoscopy or colonoscopy and biopsy to make the diagnosis and rule out malignancy.
The initial treatment of acute radiation proctitis incorporates medications that manage symptoms, including bulking agents, antidiarrheals, and antispasmodics. Enemas of steroids, mesalamine, or short-chain fatty acids have been shown to improve proctitis as well. Refractory cases can be treated topical application of 4% formalin to the rectal mucosa. Radiation proctitis complicated by fistulas is best managed surgically with interposition of normal, healthy tissues.
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