Comp Clin Pathol (2009) 18:473–475 DOI 10.1007/s00580-009-0826-7 BRIEF COMMUNICATION Rectal prolapse secondary to antibiotic-associated colitis in a dog Mehdi Marjani & Masoud Selk Ghaffari & Farhad Moosakhani Received: 15 December 2008 / Accepted: 9 February 2009 / Published online: 4 March 2009 # Springer-Verlag London Limited 2009 Abstract Many animals with rectal prolapse have an antecedent history of dyschezia and tenesmus associated with colonic inflammatory disease. However, it seems that there are no reports of rectal prolapse concurrent with antibiotic-associated colitis in the veterinary literature. A 3month-old male cross-bred dog presented with a history of recurrent episodes of rectal prolapse following the administration of oral cephalexin. The rectal prolapse was corrected surgically. Based on the dog's recent history of antibiotic use, the sudden onset of bloody diarrhoea, tenesmus and subsequent rectal prolapse, antibioticassociated diarrhoea was considered as the primary cause of rectal prolapse in this case. Clostridium perfringens were isolated from a bacteriological stool culture. The dog was treated with amoxicillin for three consecutive weeks. There were no detectable signs of diarrhoea or a recurrence of rectal prolapse during the 2-month follow-up period. Keywords Rectal prolapse . Dog . Antibiotic-associated colitis Introduction Rectal prolapse is uncommon in dogs. Clinically, a rectal prolapse appears as a pink to red rosette-like structure protruding from the anus (Simpson 1996). A prolapse may be described as either partial or complete, depending on whether it involves just the mucosa, or all layers of the M. Marjani (*) : M. Selk Ghaffari : F. Moosakhani Department of Clinical Studies, School of Veterinary Medicine, Islamic Azad University-Karaj Branch, Karaj, Iran e-mail: mzmarjani@gmail.com rectal wall (Pratschke 2005). Many animals with a rectal prolapse have an antecedent history of dyschezia and tenesmus associated with anorectal or colonic inflammatory disease (Barrand 1999). Also the condition is wellrecognised in patients with colitis; however, it seems that there are no reports of rectal prolapse concurrent with antibiotic-associated colitis in the veterinary literature. The present report describes a young dog exhibiting rectal prolapse as a consequence of antibiotic-associated colitis. Case report A 3-month-old male cross-bred dog presented with recurrent episodes of rectal prolapse. A careful examination of the clinical history indicated that the dog had received oral cephalexin for the treatment of suspected pneumonia by the referring veterinarian. One the third day of treatment with cephalexin, the animal had severe diarrhoea characterised by tenesmus and multiple painful attempts during defecation. Six days after the onset of diarrhoea, a rectal prolapse occurred. Although the rectal prolapse was corrected surgically, it re-occurred 2 days later. The case was referred for further investigation. At the initial presentation the dog was alert and responsive. There were no other abnormalities at the perineal region except for the presence of the rectal prolapse (see Fig. 1). For a differential diagnosis of rectal prolapse from prolapsed ileocolic intussusception, several unsuccessful attempts were made to insert a lubricated thermometer between the prolapsed tissue and the anus. Abdominal radiography was unremarkable. A warm sterile saline solution was applied to lavage the exposed mucosa and the prolapse was gently reduced following the application of a lubricant to its surface. A purse-string suture was placed in the anus under routine surgery. 474 Fig. 1 Photograph shows rectal prolapse during the admission To determine the primary cause of the rectal prolapse, the following diagnostic tests were performed. Faecal analysis was negative for the detection of intestinal parasites and parvovirus antigen. Two swabs were obtained from the faecal sample and submitted to the laboratory for cytological evaluation and microbiological studies. Numerous spores containing bacillus were evident on cytological smears (see Fig. 2). For microbiological examination, a faecal sample was inoculated on both blood and MacConkey agars. The plates were incubated aerobically and anaerobically for 72 h at 37°C. On the basis of colony, cellular morphology and biochemical properties, the isolates were identified as clostridium perfringens and Escherichia coli. Sensitivities were determined by a modified disc diffusion method and isolates were fully susceptible to amoxicillin. Due to the occurrence of diarrhoea after antibiotic therapy, a presumptive diagnosis of antibiotic-associated diarrhoea was made. Amoxicillin (20 mg/kg) was administrated for the management diarrhoea and tenesmus to prevent recurrence of rectal prolapse. Three days after treatment with Amoxicillin, there was an improvement in the enteritis. To achieve optimal results, the treatment with Amoxicillin was continued for three consecutive weeks. Sutures were removed 6 days after surgical correction for the prolapse. A telephone conversation with the owner revealed that there was no detectable signs of diarrhoea or a recurrence of a rectal prolapse during the 2-month follow-up period. Comp Clin Pathol (2009) 18:473–475 cause ecological disturbances in the normal intestinal microflora. Suppression of the normal microflora may lead to reduced colonisation resistance with subsequent overgrowth by pre-existing, naturally resistant microorganisms (Greb et al. 2003). In this presented case, antibioticassociated diarrhoea appeared 3 days after the administration of cephalexin. In hamsters, the condition develops 4 to 10 days after antibiotic therapy. There is no clear information with regards to the duration of antibiotic therapy and development of diarrhoea in dogs in the veterinary literature and textbooks. This may be due to the rare incidence of severe colonic disease in dogs and cats in comparison with humans and small mammals, such as hamsters (Goodman 2002; Jergens and Willard 2000). The two most commonly implicated antibiotics are cephalosporins and penicillins since these drugs are commonly used for prophylaxis against bacterial infections in veterinary practise (Madison et al. 2002; Ahmad et al. 1993). In our case, faecal cytological observation of multiple spore-forming rods and the results from faecal bacterial culture indicated that C. perfringens was the causative organism of the diarrhoea. Although Clostridium difficile is the most common cause of antibiotic-associated colitis, other bacteria can also cause this condition. For instance Streptococcus pyogenes, Pseudomonas aeruginosa and Candida albicans have been isolated in a dog with severe colitis after the administration of antibiotics (Willard et al. 1998). In light of the dog's recent history of antibiotic use, the sudden onset of bloody diarrhoea, tenesmus and subsequent rectal prolapse, antibiotic-associated diarrhoea was considered as a primary cause of the rectal prolapse. In animals with rectal prolapse, effective therapy and prognosis depends on eliminating the primary cause (Slatter 2003). It seems that the recurrence of the rectal prolapse after its correction by the primary veterinarian was directly related to a misunderstanding of Discussion Antibiotic-associated diarrhoea is well-recognised in humans, dogs and small mammals (Hrapkiewicz et al. 1998; Jergens and Willard 2000; Ellert-Zygadlowska et al. 1995). Oral and parenteral administration of antibiotics can Fig. 2 Photomicrograph shows multiple spore forming rods (arrows) Comp Clin Pathol (2009) 18:473–475 the primary underlying cause and management which focused only on the correction of the rectal prolapse. In conclusion, in cases with rectal prolapse the predisposing factors should be carefully evaluated in affected patients. Furthermore, non-selective bacterial culture of faecal samples should be considered for dogs with severe large-bowel diarrhoea associated with antibiotic treatment. References Ahmad SH, Kumar P, Fakhir S, Ahmad KN, Rattan A, Channa RS, Bajaj G (1993) Antibiotic associated colitis. 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