A 23-year-old woman comes to the office for "trouble" with her bowel movements. Despite experiencing urgency to use the bathroom, the patient frequently strains on the toilet with minimal production of stool. She describes a whitish-appearing anal discharge and itchiness but has no pain, fever, or unexpected weight loss. The patient reports several new male sexual partners in the past year. Aside from oral contraceptives, she does not take any medications. Temperature is 37.7 C (99.9 F), blood pressure is 132/65 mm Hg, pulse is 70/min, and respirations are 14/min. The abdomen is nontender and nondistended without hepatosplenomegaly. There is no palpable lymphadenopathy. External appearance of the genitalia is unremarkable. Rectal examination reveals mucopurulent anal discharge without perianal abnormalities. Which of the following is the most likely diagnosis?
Gonococcal proctitis | |
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This patient with new sexual partners has developed tenesmus (eg, straining with minimal stool production) and mucopurulent rectal discharge, a presentation concerning for gonococcal proctitis. Gonorrhea is caused by the gram-negative diplococci bacterium Neisseria gonorrhoeae and occurs most commonly in adolescents and young adults who have unprotected sexual intercourse. Rectal infection can occur through receptive anal intercourse and via proximal spread from the vagina.
Manifestations of gonococcal proctitis typically include tenesmus, mucopurulent anal discharge, and pruritus; rectal fullness, bleeding, anorectal pain, and constipation can also occur. The diagnosis is confirmed with nucleic acid amplification testing of a rectal swab. Because patients are often coinfected with Chlamydia trachomatis, they should be treated with dual antibiotic therapy (ie, ceftriaxone + doxycycline) to cover both pathogens (azithromycin has not been studied for treatment of proctitis).
(Choice A) Crohn disease (CD) causes anal fistula and perirectal abscess, which can cause mucopurulent anal discharge; however, both conditions are typically visible on examination. In addition, because the rectum is typically spared, CD usually does not cause tenesmus. Typical manifestations of CD include abdominal pain, weight loss, and diarrhea, possibly with hematochezia.
(Choices B and D) Cryptosporidium parvum and giardiasis both cause profuse watery diarrhea, although steatorrhea is sometimes seen in giardiasis. Tenesmus and mucopurulent anal discharge are not consistent with either infection.
(Choice C) Escherichia coli O157:H7 produces Shiga toxin, which leads to hematochezia and sometimes hemolytic uremic syndrome (eg, renal failure, hemolytic anemia, thrombocytopenia). Abdominal pain is typical, and tenesmus and mucopurulent anal discharge are unexpected.
Educational objective:
Gonococcal proctitis typically occurs in adolescents or young adults practicing unprotected sexual intercourse. Rectal infection can occur via receptive anal intercourse or proximal spread from the vagina. Manifestations include tenesmus, mucopurulent anal discharge, and pruritus; rectal fullness, bleeding, anorectal pain, and constipation may also occur.