Although laboratory rabbits are commonly used as models of appendicitis in man, spontaneous appendicitis was only described ante-mortem in one pet rabbit with an acute abdomen. The aim of this article is to describe two spontaneous cases of appendicitis in pet rabbits, to describe therapeutic appendectomy, and to discuss the microbial flora of the inflamed appendix. A 5-month-old intact female and a 16-month-old, neutered male were presented to the veterinary clinic with restlessness, anorexia, and reduced faecal output. The main clinical findings were restlessness, severe discomfort on abdominal palpation, a mid-abdominal palpable tubulous mass and an elevated rectal temperature. Blood analyses showed lymphocytosis, monocytosis, and hyperglycaemia. Radiography was inconclusive. Abdominal ultrasound revealed a presence of a tubular structure with wall thicknesses of 4.2 and 3.7 mm in the two rabbits, respectively. The tubular structure had a rounded, closed end, and a multilayered wall, suggestive of appendicitis. Due to metabolic acidosis and poor prognosis, the first rabbit was euthanized. In the 16-month-old rabbit, appendectomy was performed. Recovery was uneventful, and 4 h after surgery, the rabbit started to become normally active. Postoperative care consisted of fluid therapy, multimodal analgesia, supportive care and prokinetics. Follow-up examinations at 10 days, 1 month, and at 11 months after the surgery did not show any abnormal clinical or laboratory findings. Histopathological examination of appendices from both rabbits showed gangrenous appendicitis. Aerobic cultivation showed the presence of pure culture of Klebsiella variicola sensitive to enrofloxacin, marbofloxacin, tetracycline, cefuroxime, trimethoprim sulphonamide, neomycin, and gentamicin. Restlessness associated with anorexia, abdominal pain, palpable abdominal mass, hyperglycaemia, lymphocytosis, and elevated rectal temperature may be indicative of inflammation within the gastrointestinal tract. Abdominal ultrasound is recommended in rabbits with showing these clinical signs because radiography can be inconclusive. Appendicitis is a life-threatening condition, which should be included into the list of differential diagnoses; for the rabbit, an acute abdomen and gastrointestinal stasis syndrome and must be treated immediately. K. variicola may be associated with appendicitis in rabbits as a causative agent or in association with appendix intraluminal dysmicrobia.

Department of Pathological Morphology Faculty of Veterinary Medicine Veterinary University Brno Czechia

Department of Pharmacology and Pharmacy Faculty of Veterinary Medicine University of Veterinary Sciences Brno Brno Czechia

Jekl and Hauptman Veterinary Clinic Brno Czechia

Zobrazit více v PubMed

Dasso JF, Obiakor H, Bach H, Anderson AO, Mage RG. A morphological and immunohistological study of the human and rabbit appendix for comparison with the avian bursa. Dev Comp Immunol. (2000) 24:797–814. 10.1016/S0145-305X(00)00033-1 PubMed DOI

Besoluk K, Eken E, Sur E. A morphological and morphometrical study on the sacculus rotundus and ileum of the Angora rabbit. Vet Med. (2006) 51:60–55. 10.17221/5519-VETMED DOI

Stan F. Anatomical particularities of the cecum in rabbits and chinchillas. Bulletin UASVM Vet Med. (2014) 71:406–12. 10.15835/buasvmcn-vm:10587 DOI

Jeklova E, Leva L, Faldyna M. Lymphoid organ development in rabbits: major lymphocyte subsets. Dev Comp Immunol. (2007) 31:632–44. 10.1016/j.dci.2006.10.002 PubMed DOI

Nicoletti A, Di Girolamo N, Zeyen U, Selleri P, Masi M, Fonti P. Ultrasound morphology of cecal appendix in pet rabbits. J Ultrasound. (2018) 21:287–91. 10.1007/s40477-018-0316-3 PubMed DOI PMC

Dachman AH, Nichols JB, Patrick DH, Lichtenstein JE. Natural history of the obstructed rabbit appendix: observations with radiography, sonography, and CT. Am J Roentgenol. (1987) 148:281–4. 10.2214/ajr.148.2.281 PubMed DOI

Liu S, Pei F, Wang X, Li D, Zhao L, Song Y, et al. . The immune impact of mimic endoscopic retrograde appendicitis therapy and appendectomy on rabbits of acute appendicitis. Oncotarget. (2017) 8:66528–39. 10.18632/oncotarget.16236 PubMed DOI PMC

Fujiwara H, Uchida K, Takahashi M. Occurrence of granulomatous appendicitis in rabbits. Exp Anim. (1987) 36:277–80. 10.1538/expanim1978.36.3_277 PubMed DOI

Longo M, Thierry F, Eatwell K, Schwarz T, Pozo Jd, et al. . Ultrasound and computed tomography of sacculitis and appendicitis in a rabbit. Imaging diagnosis. Vet Radiol Ultrasound. (2018) 59:1–5. 10.1111/vru.12602 PubMed DOI

Prebble JL, Shaw DJ, Meredith AL. Bodyweight and body condition score in rabbits on four different feeding regimes. J Small Anim Pract. (2015) 56:207–12. 10.1111/jsap.12301 PubMed DOI

Leineweber C, Müller E, Marschang RE. Blood reference intervals for rabbits (Oryctolagus cuniculus) from routine diagnostic samples. Tierarztl Prax Ausg Kleintiere Heimtiere. (2018) 46:393–8. 10.1055/s-0038-1677403 PubMed DOI

Brandão J, Graham G, Quesenberry KE. Basic approach to veterinary care of rabbits. In: Quesenberry KE, Orcutt CJ, Mans C, Carpenter JW. editors. Ferrets, Rabbits, Rodents: Clinical Medicine Surgery. St. Louis, MO: Elsevier Saunders; (2021). p. 150–61.

Rodrigues C, Passet V, Rakotondrasoa A, Brisse S. Identification of Klebsiella pneumoniae, Klebsiella quasipneumoniae, Klebsiella variicola and related phylogroups by MALDI-TOF mass spectrometry. Front Microbiol. (2018) 9:3000. 10.3389/fmicb.2018.03000 PubMed DOI PMC

Bhangu A, Søreide K, Di Saverio S, Assarsson JH, Drake FT. Acute appendicitis: modern understanding of pathogenesis, diagnosis, and management. Lancet. (2015) 386:1278–87. 10.1016/S0140-6736(15)00275-5 PubMed DOI

Wangensteen OH, Buirge RE, Dennis C, Ritchie WP. Studies in the etiology of acute appendicitis: the significance of the structure and function of the vermiform appendix in the genesis of appendicitis. Ann Surg. (1937) 106:910–42. 10.1097/00000658-193711000-00007 PubMed DOI PMC

Chen CY, Chen YC, Pu HN, Tsai CH, Chen WT, Lin CH. Bacteriology of acute appendicitis and its implication for the use of prophylactic antibiotics. Surg Infect. (2013) 13:383–90. 10.1089/sur.2011.135 PubMed DOI

Hattori T, Yuasa N, Ikegami S, Nishiyama H, Takeuchi E, Miyake H, et al. . Culture-based bacterial evaluation of the appendix lumen in patients with and without acute appendicitis. J Infect Chemother. (2019) 25:708–13. 10.1016/j.jiac.2019.03.021 PubMed DOI

Barrios-Camacho H, Aguilar-Vera A, Beltran-Rojel M, Aguilar-Vera E, Duran-Bedolla J, Rodriguez-Medina N, et al. . Molecular epidemiology of Klebsiella variicola obtained from different sources. Sci Rep. (2019) 9:10610. 10.1038/s41598-019-46998-9 PubMed DOI PMC

Rodriguez-Medina N, Barrios-Camacho H, Duran-Bedolla J, Garza-Ramos U. Klebsiella variicola: an emerging pathogen in humans.Emerg Microbes Infect. (2019) 8:973–88. 10.1080/22221751.2019.1634981 PubMed DOI PMC

Brisse S, van Duijkeren E. Identification and antimicrobial susceptibility of 100 Klebsiella animal clinical isolates. Vet Microbiol. (2005) 105:307–12. 10.1016/j.vetmic.2004.11.010 PubMed DOI

Coletti M, Passamonti F, Del Rossi E, Franciosini MP, Setta B. Klebsiella pneumoniae infection in Italian rabbits. Vet Rec. (2001) 149:626–7. 10.1136/vr.149.20.626 PubMed DOI

Német Z, Szenci O, Horváth A, Makrai L, Kis T, Tóth B, et al. . Outbreak of Klebsiella oxytoca enterocolitis on a rabbit farm in Hungary. Vet Rec. (2011) 168:243. 10.1136/vr.c6350 PubMed DOI

Velasco-Galilea M, Piles M, Viñas M, Rafel O, González-Rodríguez O, Guivernau M, et al. . Rabbit microbiota changes throughout the intestinal tract. Front Microbiol. (2018) 9:2144. 10.3389/fmicb.2018.02144 PubMed DOI PMC

Fontana L, Bonura E, Lyski Z, Messer W. The brief case: Klebsiella variicola-identifying the misidentified. J Clin Microbiol. (2019) 57:e00826–18. 10.1128/JCM.00826-18 PubMed DOI PMC

Chen S, Quesenberry KE. Rabbits. In: Birchard SJ, Sherding RG. editors. Saunders Manual of Small Animal Practice. St. Luis, MO: Saunders; (2006). p. 1858–80.

Pokharel S, Shrestha P, Adhikari B. Antimicrobial use in food animals and human health: time to implement ‘One Health' approach. Antimicrob Resist Infect Control. (2020) 9:181. 10.1186/s13756-020-00847-x PubMed DOI PMC

Paul-Murphy J. Critical care of the rabbit. Vet Clin North Am Exotic Anim Pract. (2007) 10:437–61. 10.1016/j.cvex.2007.03.002 PubMed DOI

Gladden JN, Lennox AM. Emergency critical care of small mammals. In: Quesenberry KE, Orcutt CJ, Mans C, Carpenter JW. editors. Ferrets, Rabbits, Rodents: Clinical Medicine Surgery. St. Louis, MO: Elsevier Saunders; (2021). p. 595–608.

Huynh M, Vilmouth S, Gonzales MS, Calvo Carrasco D, Di Girolamo N, Forbes NA. Retrospective cohort study of gastrointestinal stasis in pet rabbits. Vet Rec. (2014) 175:225. 10.1136/vr.102460 PubMed DOI

Oglesbee BL, Lord B. Gastrointestinal diseases of rabbits. In: Quesenberry KE, Orcutt CJ, Mans C, Carpenter JW. editors. Ferrets, Rabbits, Rodents: Clinical Medicine Surgery. St. Louis, MO: Elsevier Saunders; (2021). p. 174–87.

Harcourt-Brown FM. Gastric dilation and intestinal obstruction in 76 rabbits. Vet Rec. (2007) 161:409–414. 10.1136/vr.161.12.409 PubMed DOI

Melillo A. Rabbit clinical pathology. J Exot Pet Med. (2007) 16:135–45. 10.1053/j.jepm.2007.06.002 PubMed DOI PMC

Harcourt-Brown FM, Harcourt-Brown SF. Clinical value of blood glucose measurement in pet rabbits. Vet Rec. (2012) 170:674. 10.1136/vr.100321 PubMed DOI

Bonvehi C, Ardiaca M, Barrera S, Cuesta M, Montesinos A. Prevalence and types of hyponatraemia, its relationship with hyperglycaemia and mortality in ill pet rabbits. Vet Rec. (2014) 174:554. 10.1136/vr.102054 PubMed DOI

Becker C, Kharbanda A. Acute appendicitis in pediatric patients: an evidence-based review. Pediatr Emerg Med Pract. (2019) 16:1–20. PubMed

Simşek G, Sevinç B, Ünlü Y, Hasirci I, Kurku H, Karahan Ö. Effect of medical treatment on histological findings in rabbits with acute appendicitis. Ulus Travma Acil Cerrahi Derg. (2016) 22:516–20. 10.5505/tjtes.2016.79825 PubMed DOI

Souza LC, Ortega MR, Achar E, Simionato Netto D, Ribeiro Junior MA. Application of high frequency bipolar electrocoagulation LigaSure™ in appendix vermiformis of rabbits with or without acute inflammatory process. Acta Cir Bras. (2012) 27:322–9. 10.1590/S0102-86502012000500008 PubMed DOI