Authors M. STRUYVE (1), W. MEERSSEMAN (2), W. VAN MOERKERCKE (3) / [1] UZ Leuven Gasthuisberg, Leuven, Belgium, Gastroenterology and Hepatology, [2] UZ Leuven Gasthuisberg, Leuven, Belgium, Internal Medicine, [3] AZ Groeninge, Kortrijk, Belgium, Gastroenterology and Hepatology
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Methods -
Results A 36-year-old man was seen at the outpatient clinic after referral by his general practitioner to exclude underlying perianal abscess since the patient was complaining about mushy stools mixed with blood and mucus during the last four days. At the same time, he mainly suffered from a perianal discomfort, abdominal pain and a fever (38.9 degrees Celsius). He had no prior important medical history. Familial history revealed a sister with severe Crohn’s disease. Further systemic history didn’t reveal any important issues. A physical examination showed a mild abdominal tenderness in the right lower quadrant of the abdomen. Anal inspection showed no signs of an abscess or fistula. Adenopathies could not be clinically discovered. Laboratory analyses demonstrated a normal white blood cell count (8.69 x10*9/l) with a normal differentiation, but an elevated C-reactive protein level (40 mg/l [0.0 – 5.0]) was seen. The remainder of the blood analysis was satisfying. We performed a stool analysis that could not identify any pathogens. Analysis of fecal calprotectin turned out to be highly positive (814 microgram / g feces, whereas a normal range is below 50). The patient was admitted the same day in the hospital for a semi-urgent diagnostic work-up. We performed a magnetic resonance imaging of the lower abdomen and pelvis for the purpose of excluding hidden abscesses and fistulae, also because this was the reason of patient referral by the general practitioner since the patient had a sister with severe Crohn’s disease with perianal manifestations. The images showed an edematous rectal abdominal wall with inflammatory infiltration of the mesorectal adipose tissue and the presence of enlarged lymphatic nodules. An ileocolonoscopy was performed the day after. There was a normal appearing mucosa of the terminal ileum and colon, except for the inspection of the rectal mucosa, which showed multiple atypical mucosal ulcerations with adjacent edematous mucosa. Multiple biopsies were taken as well of the ileum, the colon as the rectum. The anatomopathological findings of the terminal ileum and colon were normal. Those of the rectum showed a mild chronic inflammatory reaction suggestive of an infectious colitis with also an excess of plasma cells in the inflammatory infiltrate. There was no evidence for underlying inflammatory bowel disease. Taking into account that the rectal ulcers had atypical characteristics, we asked for sexual behavior. Because the patient admitted having unprotected anal intercourse, we performed testing for sexually transmitted disease (STD). The analyses of Chlamydia trachomatis and Neisseria gonorrhoeae on a rectal swab and on an urine sample (to exclude urethritis as a co-infection) were negative. We also performed a more general diagnostic work-up for other STD by screening for hepatitis B, hepatitis C and HIV by serologic tests. These results turned out to be negative. Laboratory analyses demonstrated a positive Treponema pallidum hemagglutination assay (TPHA) (index 15.8, positive when > 1.1) and a positive Venereal Disease Research Laboratory test (VDRL). We established the diagnosis of an early primary syphilis infection of the anorectum, also described as a syphilitic proctitis, and treated the patient and his sexual partner with one intramuscular injection of 2.4 million units of benzathine penicillin G. An endoscopic reassessment was performed six weeks after initiation of the treatment. This showed a proper endoscopic healing with remaining small stellate scars. Control of serologic tests after treatment showed a negativation of the VDRL test while the TPHA test remained positive.
Rectal ulcerations are an uncommon presentation of a primary syphilis infection or primary syphilitic proctitis. It is difficult to diagnose because of its often asymptomatic or atypical clinical presentation. It is important to consider sexually transmitted diseases in all patients presenting with rectal symptoms. A history of anal sexual intercourse should be made, especially in men having sex with men (MSM). Moreover, the possibility of a primary syphilis infection of the rectum should be considered. Endoscopic findings might be diverse, whereas a typical chancre can present as an anorectal ulcer associated with regional lymphadenopathy. It is important to consider other causes of anorectal ulcers, like other STD, IBD or even malignant causes. The diagnosis of anorectal syphilis is based on the combination of the clinical presentation, serology tests, endoscopic findings and biopsies. The cornerstone of the treatment is based on an intramuscularly administration of a long-acting preparation of penicillin (benzathine penicillin G).
