Clinical and Pathological Characteristics of Amoxicillin Associated Hemorrhagic Colitis

Background and objective: Amoxicillin is an antibiotic with various benefits for patients. However, adverse reactionssometimes occur, and the clinical misdiagnosis rate is highbecause some clinicians have limited knowledge regarding this drug. Combined with literature review, this study explores the clinical pathological features of hemorrhagiccolitis caused by amoxicillin to improveits diagnosis and treatment. Methods: “Amoxicillin”, “hemorrhagiccolitis”, “antibioticassociated colitis (AAC) ”, “antibioticassociated hemorrhagic colitis (AAHC) ”were used as the index words to retrieve Pubmed, EMbase, Wanfang Database and Chinese national knowledge infrastructure (CNKI). Related articles were then selected and combined with thepatient information obtained from our department to complete the clinical pathological files.To summarize the clinicopathological data, diagnosis, treatmentof the disease.Results: A total of 19 articles were included in the study. Patients may have abdominal pain, bloody stools or blood in the stool, but generally no anemia.The laboratory tests for hemoglobin (HGB) and erythrocyte sedimentation rate (ESR) are normal, andC-reactive protein (CRP) is often elevated. Abdominal ultrasound and computed tomography (CT) findings revealed that the intestinal wall wasthickened and presented edema, and some partsexhibited peritoneal effusion.Upper gastrointestinal endoscopy usually has no bleeding changes. A colonoscope was used to reveal the mucosal erosion, mainly found on the right hemicolon and this finding was consistent with acute colitis. The pathology is consistent with acute hemorrhagic colitis.The symptoms were relieved after drug withdrawal and principally with supportive treatment. The patient’s gastrointestinal symptoms usually did not recur.Conclusion: Patients with acute colitis caused by amoxicillingenerally experienced abdominal cramps and bloody stools, but treatment response was good, and follow-up monitoring revealed norecurrence. The history of antibiotic therpy and early total colonoscopy examination are important to establish the correct diagnosis. Klebsiella oxytoca (K. oxytoca) were cultured in fourteen cases, which is described as a causative organism for AAHC.