Saturday, August 24, 2013

Skink caesarian

video

WARNING: This video does depict surgery (the successful delivery of baby skinks). (It isn't very gory or bloody, and its 27 seconds long but probably won't play on a smartphone so you might need to rely on ye olde school desktoppe).

One of my favourite articles written in recent history is one I wrote about a caesarian in a pink-tongued skink. I must confess I never knew about this species until I met Jane whilst hanging out with one of my favourite veterinarians, Dr Robert Johnson, at South Penrith Veterinary Clinic.

Below is an extract of an article featured in The Veterinarian Magazine, in the monthly clinical zoo column. 

Jane presented with a mass protruding from a wound on her flank. I assumed it was a kidney. Nope. Twas a gravid uterus. Jane is anaesthetised here and intubated with a catheter functioning as an endotracheal tube. The tape is holding the tube in place.
Jane Doe, a female pink-tongued skink (Cyclodomorphus gerrardii) presented to Dr Robert Johnson following a dog attack in a suburban back yard. For the uninitiated, pink tongued skinks are extremely similar in appearance to Eastern Blue-Tongue lizards, distinguished by a more slender body, a narrower tail, striking cross-band markings and of course a pink – as opposed to blue – tongue, hence the name. They’re just a lot less common.

They typically inhabit forests and woodlands, sheltering below leaf litter, under rocks and other crevices. Populations occur in the Blue Mountains in New South Wales, around the NSW central coast and along the Eastern coastal ranges to Cairns in Far North Queensland.

“We have a unique population in Springwood,” Johnson says. “When we had the old surgery in Springwood we had a couple living under the building, but they often hang around in rooves. Unlike bluetongues, they are very good climbers.”

Their culinary preference for snails and slugs ensures that suburban gardens are the ideal haunt for these critters – just as long as these are free of dogs and cats. Pink tongue skinks will use their climbing skills to escape predation, but not always fast enough to avoid injury.

Such was the case with Jane, who had been enjoying a meal of slugs in a lush suburban garden when she was suddenly disturbed by a curious dog. The dog picked her up in its mouth, biting into her flank. She was prised from the offending jaws immediately by the dog’s owner but the damage had been done – the bite had penetrated her coelomic cavity, and what appeared to be a solid, kidney shaped organ herniated through the defect.

Jane was rushed to the clinic, where Johnson examined her. Close inspection of the hernia revealed a thin sac containing a silver and black striped mass. It wriggled. The mass, it turned out, was a live young pink tongued skink. Jane was pregnant. After a gestation period of just over 100 days, pink tongue skinks are known to produce large litters of 20-30 young (although there are reports of litters containing as many as 67 offspring).

If these were to survive, Jane would require an emergency caesarean. Johnson premedicated her with a combination of morphine (2mg/kg) and midazolam (1mg/kg) via intramuscular injection.

“If it is a small volume you can give it in the front leg, otherwise in the epaxial muscles or subcutaneously.”

Induction can be challenging as venous access in skinks is not always easy.
“Skinks tend to required higher doses of alfaxalone when compared with a lot of other reptiles,” Johnson said. “If we don’t premedicate them they may need up to 20mg/kg IV, but in this case after premedication I gave 10mg/kg via the ventral tail vein, and then left her for ten minutes.”

Intubation is difficult because of the large, slippery and in this case pink tongue obscuring view of the epiglottis which is just caudal to the main body of the tongue. Johnson routinely applies lignocaine and uses an intravenous catheter (with the stylette removed) as an endotrachael tube. In this case, he chose an 18 gauge catheter. Jane was maintained on isoflurane in oxygen using intermittent positive pressure ventilation.

“You can hook them up to a ventilator but we used a trusty veterinary student called Katrina,” Johnson said.

Typically he performs midline caesareans, but in this case the dog had already created a defect.

“We opportunistically used the incision that the perpetrator had inflicted and went for it,” Johnson said.

The wound was cleaned, prepped and extended to facilitate a flank caesarean.
Exploration of the coelomic cavity revealed ruptured oviducts, with several injured and deceased young floating freely. However, the majority (27 out of 30) remained in utero, and were delivered via multiple incisions.

Jane's babies in situ. They are coiled so neatly in that uterus. Note the way their little tails are folded over their bodies.
“We don’t tend to suture the oviducts in skinks and pythons as it does not affect their reproductive ability in my opinion,” he said. “The oviduct is so thin and fragile that you would have to use 7.0 or 8.0 suture material, but you need to get in and out, flush out the coelomic cavity and save the life of the patient.”

The neonates in the "creche" (a lined, heated Tupperware container). The yellow-red bits at the placentas which the babies eat as they wake up. 
And her offspring of course. The neonates were placed together in a Tupperware container placed on a heating pad. Gradually they came to life, slowly animating their limbs and tails. All were attached to large yellow-red placentas, approximately the size of their head. Once mobile, each neonatal skink tucked ravenously into its placenta.

Eating the placenta. Gross but also a vital source of energy. And hey, they don't know any different at this age!
The wound was closed routinely with nylon skin sutures. As her young reanimated in their tiny crèche, Jane recovered slowly from an anaesthetic. Post-operatively she was kept in a warmed vivarium and given enrofloxacin every two days for antimicrobial coverage, after all the flank wound was the result of a contaminated bite. For analgesia she was given meloxicam (0.2mg/kg SC) every second day for around ten days, after which she was released back into the wild.

“We let the babies go virtually the next day,” Johnson said. “At least those which were lively. They have so many babies because there is a high attrition rate – from marauding kookaburras to red bellied black snakes and anything else that wants to eat a juicy neonatal reptile.”

Mum didn’t exactly pine for her offspring.
“There is very little maternal behaviour exhibited by any reptile with the exception of crocodiles which are closer to a bird than a gecko,” Johnson said. “They have a four-chambered heart, they almost have a diaphragm (two membranes, a part pulmonary and post-hepatic membrane that act as a diaphragm) and they guard their nests like birds. But pink tongued skinks are born live so the mother needn’t worry about incubating eggs.”

Can you believe this single creature produced this many offspring?
After being born live and dining out on a placenta, these kids are on their own in the big, bad world. Interestingly, egg laying is more typical in reptiles that live in warmer climates.
“Elapids like tiger snakes tend to have live bearing young because it’s just not warm enough for eggs to incubate in their usual habitat. But pythons and bearded dragons can lay eggs because they live in a warmer climate.”

Johnson was mindful to hospitalise Jane in a temperature controlled environment until she had recovered her appetite and appeared livelier, but tries to avoid keeping reptiles in hospital for too long.

“We released her with sutures still in place as you have to weigh up the potential stress and risk of infection in hospital against the risks of being released. The sutures should not be a major problem as skinks shed their skin in part, not whole. We need to try to avoid keeping free ranging wild animals in captivity for too long.”

By the time of release, 15 out of 30 of Jane’s offspring were thriving.
Johnson will be presenting at the World Veterinary Congress in Prague this year. For further information or to register visit www.worldvet.org

Acknowledgement:

Herpetologist and veterinary anatomist Dr Glenn Shea provided information about the distribution of pink tongued skinks.

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