In the1960s, Eric Dunlop and his associates at the Institute of Ophthalmology in London reported on the isolation of C. trachomatis by cell culture from the rectum of women who had had some association with a non-LGV C. trachomatis infection [Dunlop et al., 1969; reviewed in Munday & Taylor-Robinson, 1983]. In 13 such patients, Dunlop noted that none of these women had symptoms which were referable to the rectum, although 5 of the 13 had abnormalities of the rectal mucosa which were detectable using an operating microscope. These abnormalities were described as "follicle", "nodules", "scarring", "congestion", or a "cobblestone appearance" [Munday & Taylor-Robinson, 1983]. Polymorphonuclear leukocytes, the characteristic cellular sign of acute inflammation, were detected in only 38% of the chlamydial positive and 10% of the chlamydial negative women, suggesting that the abnormal findings were due to the presence of chlamydiae. More recently, in a study of 115 consecutive new women patients attending a department of genitourinary medicine in the UK C. trachomatis infection was found in the cervices of 15 (13%) and the rectums of 6 (5%). Rectal infection was significantly associated with rectal bleeding and microscopic evidence of proctitis, but not with diarrhoea or macroscopic proctitis [Thompson et al., 1989]. One study suggests that the presenting symptoms varies according to the serogroup of C. trachomatis, with the C complex organisms less likely to give rise to symptoms than the B complex [Boisvert et al., 1999].
Chlamydial proctitis is also a problem among homosexual men. Thus, in a study of 171 homosexual men, 96 with symptoms suggestive of proctitis and 75 without such symptoms, C. trachomatis was isolated from the rectums of 14 men. Three of these isolates were LGV organisms, which are known to cause severe granulomatous inflammation of the rectum that may be suggestive of Crohn's disease or even cancer [see: LGV introduction]. The other 11 isolates were conventional oculo-genital strains of C. trachomatis and they were obtained from eight symptomatic and three asymptomatic men. All of these men had faecal polymorphs indicative of acute inflammation plus mild abnormalities of the rectal mucosa on direct examination with a sigmoidoscope [lay reader: an optical device for examining the rectum], usually with mild non-granulomatous inflammatory changes that were seen on rectal biopsy. Thus the LGV biovar of C. trachomatis in the rectum was associated with a severe, acute, granulomatous proctitis that could mimic Crohn's disease [see: LGV Clinical] whereas the normal oculo-genital biovar of C. trachomatis is associated with mild, often asymptomatic proctitis [Quinn et al., 1981]. In adults the main route of sexual transmission and acquisition of rectal chlamydiae is likely to be unprotected anal intercourse, although in women there is the possibility of spread of cervical chlamydial infection via the perianal region to the rectum.
Up to 55 percent of homosexual men with anorectal complaints have gonorrhoea; 80 percent of the patients with syphilis are homosexuals. Chlamydia is found in 15 percent of asymptomatic homosexual men, and up to one third of homosexuals have active anorectal herpes simplex virus. In addition, a host of parasites, bacterial, viral, and protozoan are all rampant in the homosexual population [Wexner, 1990]. Evaluation of patients with symptomatic proctitis should include rectal examination by anoscopy or sigmoidoscopy, stool examination for protozoa such as Cryptosporidia and Isopora, and stool culture for enteric pathogens. Where adequate laboratory diagnostic facilties are available, treatment should be based on specific diagnosis. In the absence of these, in patients who are not HIV positive, empirical therapy for acute proctitis in persons who have recently practiced receptive anal intercourse should be directed against Neisseria gonorrhoeae and C. trachomatis. In individuals infected with human immunodeficiency virus a whole host of other infections that are not usually sexually acquired may occur [Laughon et al., 1988] and recurrent herpes simplex virus infections are common [Rompalo, 1999].
There is negligible evidence that C. trachomatis is a cause of Crohn's disease [McGarity et al., 1991]. What is less clear in the modern diagnostic age is how commonly chlamydial proctitis gets misdiagnosed as Crohn's disease or ulcerative colitis. The author is, however, aware of such cases. Where biopsies are taken for histology, rectal and sigmoidal biopsies are more likely to prove positive for C. trachomatis than biopsies of the colon ascendens, transversum, or descendens, or of the terminal ileum [Zollner et al., 1993].
In general there have been few recent studies of chlamydial proctitis using modern molecular methods of diagnosis. Modern diagnostic tests are not optimised for use with rectal samples and their performance is thus uncertain.
To study the pathogenesis of rectal infection with C. trachomatis, Quinn et al., 1986 inoculated five cynomolgus monkeys with serovar E organisms (non-LGV) and five with serovar L2 (LGV). The L2-infected animals developed a severe hemorrhagic ulcerative proctitis quite different to the mild proctitis in the non-LGV-infected monkeys. Hyperplasia of lymphoid follicles and a mucosal polymorphonuclear leukocyte and mononuclear cell infiltrate were evident in all infected monkeys. Crypt abscesses with giant cells and granuloma formation were present in two of the five LGV-infected monkeys. This experimental cynomolgus monkey infection resembled the human infection and would be useful for exploring the immunopathogenesis of chlamydial or granulomatous proctitis [Quinn et al., 1986].
A randomized antibiotic trial in 129 homosexual men who presented with acute proctitis, compared treatment with an empirical regimen (4.8 million U of aqueous penicillin G procaine intramuscularly and 1.0 g of probenecid orally, followed by 100 mg of oral doxycycline twice daily for seven days) with specific therapy for each infection as it was recognized. Therapy with the empirical regimen resulted in more rapid resolution clinical and microbiological resolution except for nearly one quarter of the patients with a herpes simplex virus infection. Empirical therapy coupled with appropriate pretreatment diagnostic testing for the initial management of acute proctitis was recommended in homosexual men with no clinical evidence of acquired immunodeficiency syndrome or AIDS-related complex [Rompalo et al., 1988].
The CDC 2002 STI Management guidelines point out that acute proctitis of recent onset among persons who have recently practiced receptive anal intercourse is usually sexually acquired. Such patients should be examined by proctoscopy and should be evaluated also for infection with HSV, N. gonorrhoeae, C. trachomatis, and T. pallidum. If an ano-rectal exudate is found on examination, or if polymorphonuclear leukocytes are found on a Gram-stained smear of ano-rectal secretions, the following therapy may be prescribed pending the results of additional laboratory tests.
If painful perianal ulcers are present or mucosal ulcers are seen on proctoscopy, presumptive therapy should include a regimen for treating genital herpes. Follow-up should be based on the specific aetiology and severity of clinical symptoms. Reinfection may be difficult to distinguish from treatment failure.
Ceftriaxone 125 mg IM
(or another agent effective against rectal and genital gonorrhoea)
Doxycycline 100 mg orally twice a day for 7 days..
Laboratory tests for the diagnosis of chlamydial infection are not licensed for use on rectal samples. Nevertheless, a pilot study of the Roche COBAS PCR and the Abbott LCx CT LCR found that Chlamydiae were detected in one or more procedures in 22 of 186 specimens. Three different procedures for processing rectal specimens for PCR were positive together with LCR in 17 of the 22 specimens [Golden et al., 2003]. Thus nucleic acid amplification based methods may be able to give valuable diagnostic information on rectal samples, but much further research is needed. Such methods may also be valuable for the evaluation of rectal specimens for sexual abuse of children, but are not yet widely accepted for medico-legal purposes [See: Sexual Abuse].
[MEW] July 2003
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CDC STI Treatment guidelines, May 2002 CDC Atlanta [For clinicians]
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