A 55-year-old man presented to the author's department with a 1-day history of abdominal pain and bloody diarrhea. Four months previously, chronic gastritis due to Helicobacter pylori was diagnosed at a medical check-up. After failure of eradication by rabeprazole-amoxicillin-clarithromycin triple therapy (first-line therapy), he was started on rabeprazole-amoxicillin-metronidazole triple therapy (second-line therapy) 5 days earlier. Vital signs were normal, and his abdomen was soft. Although laboratory evaluation showed a normal leukocyte count and a C-reactive protein of 0.5 mg/dL (range <0.3), computed tomography revealed thickening of the intestinal wall from the transverse colon to splenic flexure (Fig. 1). Colonoscopy confirmed hemorrhagic and edematous mucosa (Fig. 2). A histological evaluation of specimens obtained by biopsy showed no specific findings. Antibiotic-associated hemorrhagic colitis (AAHC) was diagnosed by a positive stool culture for Klebsiella oxytoca as well as the abovementioned findings; thus, eradication therapy was discontinued. His symptoms resolved within 2 days.
FIG. 1. Computed tomography of the transverse colon showing thickening of the intestinal wall.
FIG. 2. Colonoscopy revealing hemorrhagic and edematous mucosa.
AAHC is a rare but important complication of antibiotic therapy. The etiology remains unclear; however, several mechanisms, including allergic reaction, mucosal ischemia, and microbial substitution by antibiotic-induced overgrowth of K. oxytoca, have been proposed.1 Symptoms include diarrhea, abdominal tenderness, and ultimately bloody diarrhea occurring within 1 week of antibiotic use; furthermore, symptoms typically disappear within 3 days after cessation of antibiotic therapy.2 Since AAHC is mainly present in the right or transverse colon, sigmoidoscopy alone would miss many cases.1
H. pylori infection is associated with peptic ulcers and gastric cancer. The International Agency for Research on Cancer recommends population screening for H. pylori and its eradication to reduce the incidence of gastric cancer.3 Additionally, the incidence rate of AAHC induced by H. pylori eradication therapy was reported to be <1% [first-line therapy 0.35–0.6% vs. second-line therapy 0.96%] in Japan.4
In the present case, the important clinical messages are as follows:
(1) Physicians should be cautious of AAHC in patients taking antibiotics.
(2) Despite no adverse events associated with first-line therapy for H. pylori eradication, second-line therapy can cause AAHC.
(3) Colonoscopy is required for the diagnosis of AAHC.
Footnotes
CONFLICT OF INTEREST STATEMENT: None declared.
References
- 1.Högenauer C, Langner C, Beubler E, Lippe IT, Schicho R, Gorkiewicz G, et al. Klebsiella oxytoca as a causative organism of antibiotic-associated hemorrhagic colitis. N Engl J Med. 2006;355:2418–2426. doi: 10.1056/NEJMoa054765. [DOI] [PubMed] [Google Scholar]
- 2.Moulis H, Vender RJ. Antibiotic-associated hemorrhagic colitis. J Clin Gastroenterol. 1994;18:227–231. doi: 10.1097/00004836-199404000-00012. [DOI] [PubMed] [Google Scholar]
- 3.Herrero R, Park JY, Forman D. The fight against gastric cancer - the IARC Working Group report. Best Pract Res Clin Gastroenterol. 2014;28:1107–1114. doi: 10.1016/j.bpg.2014.10.003. [DOI] [PubMed] [Google Scholar]
- 4.Hamada Y, Tanaka K, Yamada R, Takei Y. Hemorrhagic colitis induced by second-line Helicobacter pylori eradication. Intern Med. 2020;59:301–302. doi: 10.2169/internalmedicine.3565-19. [DOI] [PMC free article] [PubMed] [Google Scholar]