Specific Organisms and Therapeutic Regimens
Organism-specific therapeutic regimens for proctitis and proctocolitis are provided below, including those for Neisseria gonorrhoeae, Chlamydiatrachomatis, Treponema pallidum, herpes simplex virus (HSV), Shigella, Salmonella, Entamoeba histolytica, and Clostridioides (Clostridium) difficile. [1, 2, 3, 4, 5, 6, 7, 8]
Empiric treatment should be directed at the etiology that is most likely on the basis of the history.
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Travel to less developed country - Suspect enteric pathogen
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Recent antibiotics - Suspect C difficile
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Receptive anal intercourse - Suspect Neisseria, Chlamydia, syphilis, or Herpes
N gonorrhoeae
Regimens are as follows:
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Ceftriaxone 500 mg IM as a single dose; for persons >150 kg, 1 g IM as a single dose [9] or
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Gentamicin 240 mg IM as a single dose plus azithromycin 2 g PO as a single dose [9] or
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Concurrent treatment for chlamydial infection should also be given unless this infection has been excluded by microbiologic testing
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Consider culture and infectious disease consultation if cephalosporin-resistant infection is suspected [9]
C trachomatis genotype A-K (non-lymphogranuloma venereum [LGV])
Regimens are as follows:
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Doxycycline 100 mg PO q12h for 7d or
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Azithromycin 1g PO as a single dose or
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Levofloxacin 500 mg PO q24h for 3d [9]
C trachomatis genotype LGV
Regimens are as follows:
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Doxycycline 100 mg PO q12h for 21d (first line)
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Erythromycin base 500 mg q6h for 21d (second line) or
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Azithromycin 1 g PO once weekly for 3wk [9]
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Presumptive treatment should be considered for men who have sex with men (MSM) with proctitis and a positive rectal chlamydia test [10]
T pallidum
Regimens are as follows:
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Benzathine penicillin G 2.4 million units IM as a single dose (first line)
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Doxycycline 100 mg PO q12h for 14d (penicillin-allergic) [9] or
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Azithromycin 2 g PO as a single dose (penicillin-allergic) [9]
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HIV infection - Benzathine penicillin G 2.4 million units IM as a single dose for early latent syphilis
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All patients positive for primary or secondary syphilis should also be tested for HIV [9]
HSV
For patients with first-time infection, 7- to 10-day regimens are as follows [9] :
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Acyclovir 400 mg PO q8h or
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Famciclovir 250 mg PO q8h or
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Valacyclovir 1 g PO q12h or
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Acyclovir 200 mg PO 5 times daily (not recommended, because of frequency of dosing)
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Treatment can be extended if healing is incomplete at 10d
For HIV-infected patients with episodic infection, 5- to 10-day regimens are as follows [9] :
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Acyclovir 400 mg PO q8h or
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Valacyclovir 1 g PO q12h or
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Famciclovir 500 mg PO q12h
Shigella species
Regimens are as follows [11] :
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Ciprofloxacin 500 mg PO q12h for 3d or
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Levaquin 500 mg/day PO for 3d or
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Trimethoprim-sulfamethoxazole (160 mg/800 mg) 1 DS tablet PO q12h for 5d or
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Ceftriaxone 1-2 g IV q24h for 5d or
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Azithromycin 500 mg/day PO for 3d
Salmonella, severe disease, presence of vascular prosthesis, or immunocompromised
Regimens are as follows [12, 13] :
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Trimethoprim-sulfamethoxazole (160 mg/800 mg) 1 DS tablet PO q12h or
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Ciprofloxacin 500 mg PO q12h or
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Ceftriaxone 1-2 g IV q24h or
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Cefotaxime 2 g IV q8h
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Duration 3-7d (≥14d for immunocompromised patients)
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Persistent carriers should be treated for 4-6wk
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Sensitivity testing should be carried out because of a high rate of antibiotic resistance among Salmonella strains
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Severe disease in immunocompetent patients is characterized by severe diarrhea, high fever, and need for hospitalization
E histolytica
Regimens are as follows [14, 15, 16, 17] :
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Metronidazole 500-750 mg PO q8h for 5-10d or
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Tinidazole 2 g PO q24h for 2-3d, followed by an intraluminal agent for 5-10d (paromomycin, diloxanide furoate, cloquinol)
C difficile
In addition to initiating therapy as below, [18, 19, 20] discontinue other antimicrobials as soon as possible.
Mild-to-moderate disease:
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Vancomycin 125 mg PO q6h for 10d [21] or
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Fidaxomicin 200 mg PO q12h for 10d, especially if there is concern for recurrent disease [22]
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Bezlotoxumab 10 mg/kg infusion as adjunct for high-risk patients [21]
Severe disease:
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If there is no clinical improvement, add fidaxomicin 200 mg PO q12h
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Bezlotoxumab 10 mg/kg infusion as adjunct for high-risk patients [21]
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Intracolonic vancomycin by enema therapy, 500 mg in 100 mL of saline q6h
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Intracolonic vancomycin by ileostomy creation and colonic lavage
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Consider intracolonic therapy if ileus is present [21]
Additional therapeutic options:
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Fecal microbiota transplantation (FMT) [23]
Additional adjunctive agents:
Diagnostic testing
Diagnostic testing is as follows:
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Patients with acute proctitis will need anoscopy
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A Gram-stained smear of any anorectal exudate should be examined for polymorphonuclear leukocytes (PMNs)
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Patient-collected nucleic acid amplification testing (NAAT) is a preferred diagnostic test for suspected anorectal gonorrhea or chlamydial infection
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Dark-field examinations and tests to detect T pallidum directly from lesion exudate or tissue are the definitive methods for diagnosing early syphilis
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HSV diagnosis can be obtained from viral culture, polymerase chain reaction (PCR) assay, or direct fluorescent antibody (DFA) of vesicle discharge or serologic testing
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Diagnosis of enteric pathogens such as Shigella, Salmonella, Campylobacter, and Yersinia is confirmed by stool culture on selective media
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Stool microscopy can suggest intestinal amebiasis, but it is not specific for E histolytica; antigen testing, serologic examination, and PCR are all useful for specific detection of E histolytica infection
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Diagnosis of C difficile is established via a positive laboratory stool test for C difficile toxins; send stool initially for glutamate dehydrogenase (GDH) antigen test and for toxin antibody test for antibody to toxin A and B; if results are indeterminate, send stool for C difficile PCR
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Clinical criteria for C difficile infection (CDI) - Three or more unformed stools within 24 hours (in the absence of other causes) and a positive stool test or demonstration of pseudomembranous colitis [24]
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With a suspected or confirmed diagnosis, contact precautions should be instituted and strict handwashing implemented [24]
Special considerations
Special considerations include the following:
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Supportive treatment is the standard treatment for immunocompetent, healthy individuals with Salmonella, Yersinia, or Campylobacter; normally, these diseases are self-limited
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Severe cases of proctitis/proctocolitis refractory to medical treatment may call for surgical intervention (subtotal colectomy, total proctocolectomy, loop ileostomy creation, colonical lavage)
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Complications of C difficile colitis include hypotension, toxic megacolon, bowel perforation, renal failure, and sepsis
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Partner notification and simultaneous treatment are integral to the treatment of sexually transmitted causes of proctitis and proctocolitis