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Edited by Holly Boyden
Sweet Bun, a three-year-old dwarf lop rabbit, presented after hours to North Shore Veterinary, Specialist and Emergency Hospital with a history of gradual onset lethargy and anorexia over the previous 24 hours.
On presentation, Sweet Bun was ambulatory but quiet, and was noted to have skin tenting and a painful, tense abdomen.
Sweet Bun’s PCV/TP was 52/72, indicating haemoconcentration. He also had mild hyperglycaemia of 10.1 mmol/L (3.9-8.3), and mildly elevated ALT at 235 IU/L (20-100). Abdominal lateral and VD radiographs showed a moderately enlarged, gas-filled stomach.
The tentative diagnosis by the after-hours veterinarian was GI stasis or obstruction.
Sweet Bun was started on Plasmalyte 148 IV fluids, with a 10ml/kg bolus and then maintenance rates thereafter. He was prescribed ranitidine 4mg/kg PO as a prokinetic and buprenorphine 0.03mg/kg SC q8 hours for analgesia—and was given free access to grass hay and greens.
The following morning, Sweet Bun was referred in-house to Dr Joanne Sheen of the exotics veterinary specialist team for reassessment. Sweet Bun had been stable overnight but remained lethargic with a painful cranial abdomen.
Recheck of Sweet Bun’s PCV/TP after rehydration indicated that he was actually mildly anaemic, with values of 29/58. His ALT had further increased to 928.
Due to his poor clinical response to treatment, anaemia and elevated liver parameters, liver lobe torsion (LLT) was suspected. Sweet Bun’s owners were offered advanced imaging for further investigation (with the option of surgery if LLT was confirmed), versus ongoing medical management if costs were a concern. Sweet Bun’s owners consented to a CT, and surgery if required.
The CT imaging study showed reduced attenuation of the caudate liver lobe, with the lobe position cranial to the gastric pylorus—findings consistent with LLT.
Sweet Bun underwent GA for surgical treatment of LLT. Upon exposure of the peritoneal cavity, a moderate haemoabdomen was discovered. Examination of the liver revealed a torsed caudate process of the caudate liver lobe. Without derotation of the torsion, two surgical haemoclips were placed at the hilus of the process to ligate the vascular pedicle (and prevent release of any toxins, free radicals or microemboli) prior to liver lobectomy. The abdominal muscular layer was closed with 3/0 Biosyn using a Ford interlocking suture pattern, followed by a bupivacaine <1mg/kg splash block. The subcutaneous and intradermal closure was then achieved with 3/0-4/0 Biosyn using simple continuous suture patterns.
Post-operatively, Sweet Bun received analgesia with buprenorphine 0.03mg/kg SC q8 hours, and broad-spectrum antibiotic coverage with procaine penicillin 30mg/kg q24 hours SC and metronidazole 20mg/kg q12 hours PO. Ranitidine 4mg/kg q12 hours PO was continued for gastrointestinal prokinetic action, with the addition of cisapride 0.5mg/kg q12 hours PO. Plasmalyte 148 IV fluids were continued at 1.5 x maintenance.
Sweet Bun recovered uneventfully for two days in hospital prior to discharge. His PCV remained stable at 24, and his ALT decreased slightly to 866. He was discharged home on ongoing procaine penicillin injections, as well as metronidazole, ranitidine, and cisapride PO. Analgesia was continued with meloxicam 0.3mg/kg PO q24 hours. SAMe 100mg PO q24 hours was added to the regime for liver support.
One week later, Sweet Bun was rechecked. His owners reported him to be bright, eating normal amounts, and becoming sassy with his medications! Recheck of his blood tests showed a significantly improved PCV of 34, and ALT of 137. He was prescribed one more week of penicillin and metronidazole. Dr Sheen plans to recheck Sweet Bun after a further month.
LLT is becoming increasingly recognised in pet rabbits. The North Shore exotics specialist team report up to two cases weekly on a regular basis. LLT is thought to have been previously underdiagnosed due to its clinical similarity to GI stasis. It frequently causes non-specific clinical signs, such as anorexia, lethargy and reduced faecal output. Common physical examination findings include abdominal pain, dehydration, lethargy and hypothermia.
Definitive diagnosis of LLT prior to surgery generally requires advanced imaging such as CT, or at least high-quality abdominal ultrasonography by an experienced operator (utilising color flow Doppler to demonstrate lack of blood flow to the affected lobe).
Abdominal radiographs of LLT cases frequently demonstrate only non-specific increased stomach and intestinal gas patterns (as often seen with GI stasis). However, radiography is still useful for ruling out GI obstruction or any underlying triggers for GI stasis such as urolithiasis.
GP vets can consider the following simple in-house diagnostics to help screen unwell rabbits for LLT:
PCV—rabbits with LLT frequently show mild to moderate anaemia.
Hepatic enzyme analysis—acute LLT consistently causes moderate to marked elevations in ALT (which is not affected by patient restraint as AST can be).
Blood glucose—rabbits with LLT will commonly show a mild-moderate hyperglycaemia consistent with stress. This is in comparison to the severe hyperglycaemia seen in rabbits with GI obstruction (mean BG of 24mmol/L).
In the early stages, medical management with IVFT, analgesia and nutritional support may allow reversal of the torsion. If owners are financially limited, this can be offered as a treatment option, although it is important to note that survival rate has been reported as <50%.
In rabbits who are poorly responsive to medical treatment or significantly compromised, liver lobectomy is recommended. This is reported to have an excellent long-term prognosis, provided necessary resuscitative measures are performed prior, including blood transfusion if the rabbit is clinically anaemic. Post-operatively, rabbits should be supported with IVFT, adequate analgesia, prophylactic broad-spectrum antibiotics, prokinetics, and supportive feeding if required.
Dr Joanne Sheen
Dr Joanne Sheen graduated from the University of Edinburgh in 2004. She holds a Certificate in Zoological Medicine from the Royal College of Veterinary Surgeons in the UK, and in 2017, became a Diplomate in the American Board of Veterinary Practitioners in Exotic Companion Mammal Practice. She is currently only one of two veterinarians in Australia that hold this qualification.
Dr Sheen has been involved in exotic animal medicine in various capacities since 2005 both in Australia and internationally, ranging from a first opinion and referral exotic animal veterinarian in the private sector, and in industry, to an expert witness for a number of organisations.
Dr Sheen’s professional interests are in hepatic diseases of rabbits and mycobacteriosis in exotic mammals.
She is currently the senior associate exotic animal veterinarian at Sydney Exotics and Rabbit Vets, Australia.