Can you see my heart beating? A snake with a very big problem!

Snake transport box

I received an unusual phone call recently from the owner of an 18 month old False Water Cobra (Hydrodynastes gigas), a South American rear-fanged, mildly venomous species of snake (http://www.reptilesmagazine.com/Snake-Species/False-Water-Cobra/). The owner had noticed shortly after acquiring the snake that it had what was described as a wound on it’s underside through which you could see it’s insides! Naturally, I was quite worried so asked for the snake to be brought in for examination, and in the meantime they emailed me some photos and reassurance that the snake was acting perfectly normally, eating and defaecating fine and didn’t seem in any way bothered by the strange ‘wound’.

False Water Cobra Hospital Vivarium on AdmissionFalse Water Cobra Hospital Vivarium on Admission 1

Having examined the animal, it appeared that she had a defect in the body wall on her ventral surface or belly with a large hole visible in the ventral muscles. Bizarrely, this defect was at the level of the heart about a third of her length down her body. The only tissue separating her visibly beating heart from the outside world was a thin membranous layer of body cavity lining and some connective tissue which was quite transparent. I have seen some similar lesions in reptiles at the umbilicus or site where the blood vessels carry nutrients into the growing embryo from the egg or from maternal tissues in the case of live bearing species. Sometimes when these animals hatch or are born the hole in the body wall fails to close completely and an umbilical hernia or body wall defect is left behind. However, I have never seen or even heard of such a defect high up on the body overlying the heart! I concluded that this must be a congenital problem that the snake was born with, perhaps a fluke genetic mutation or a developmental insult during incubation of the egg which disrupted the normal growth of the embryo resulting in a physical abnormality at birth. Having spoken to a few reptile enthusiasts in the UK who keep this species of snake, it turns out there have been a few reported with the exact same defect in the exact same place, so it looks likely this is a genetic problem, most likely caused by inbreeding in certain lines due to relatively low genetic diversity in the UK population.

Snake membranous hernia before surgery

The risk of leaving the snake in this condition was that during the course of her life she may snag this fragile membrane protecting her heart and eviscerate herself or worse still puncture her heart. Although this risk was small, it would be safer to carry out a surgery now than always wonder and worry if she might do some damage and seriously injure herself, when pulling off her shed skin for example. I admitted her and set her up in our reptile ward in a heated vivarium to bring her body temperature up to preferred range. Once her temperature was correct I injected her with a combination of sedative drugs into the muscle in her back. I say I injected her, but actually I restrained her with a thick pair of gloves whilst my nurse Justyna gave her the injection. She was very feisty, strong, and objected to restraint, trying to bite the gloves. Obviously considering her potential to give a painful bite and possible envenomation we took great care at this stage. Rear fanged snakes are different to other venomous species in that they have modified salivary glands and teeth at the back of their mouth, with which they chew their prey in order to inject and subdue it. Therefore it would be difficult to get a dangerous bite  from a rear fanged species unless you allowed the snake to chew on you. Front fanged species can deliver a dry or wet bite from the front of the mouth with a rapid strike and minimal contact so are far more dangerous to work with and handle. After her injection we left her back in her hospital vivarium in the correct temperature to allow her to metabolise the drugs efficiently. Ectothermic or ‘cold-blooded’ animals such as reptiles rely on external temperature to control their biological functions and metabolic rate, so it is vital when treating ill specimens and indeed when undertaking anaesthesia and surgery to maintain their body temperature in the correct range so everything runs smoothly and drug dosages work effectively. After about a 20-30 minute induction period, now nice and relaxed after her sedation we removed her and placed her into an anaesthetic gas chamber so she fell further asleep and we could position and prepare her for surgery. She was maintained under anaesthesia by using a gas mask delivering a safe gaseous drug called Sevoflurane. Normally for a prolonged surgical procedure in a snake I would intubate the animal with a solid plastic or rubber tube placed into the windpipe or trachea for better control and access to her airway should she stop breathing for instance, but in the case of venomous species I prefer not to mess around in the mouth due to the risk of accidental envenomation. A correct sized mask with her head taped inside in place and sealing the entrance provides the next best option and is safer for all involved.

Snake anaesthesia preparing for surgery

 

Here’s a video link showing the heart visibly beating underneath the membranous layer of the abdominal wall defect:

Once Justyna prepped her with a surgical scrub and insulating layers to maintain her body temperature lying belly up on a surgical heat mat, I was ready to begin. I carefully dissected away the thin membrane covering her heart from the scales on either side of the deficit. I had to be extremely careful as this layer of tissue was so thin and the heart was literally beating against it directly underneath. Tiny blades and scissors were required, and I cut in time between the beats to avoid cutting at the moment the heart filled to maximum capacity with blood. Myself, Justyna and the veterinary student who is seeing practice with us this week to learn more about exotic pet medicine were all holding our breaths at times. Credit to the student Conor for taking the photographs while I operated by the way. Justyna found this anaesthetic very easy to monitor throughout as we were literally watching the heart beating throughout so she could record heart rate and strength with the naked eye for a change! Often we use sensitive probes to monitor heart rate through the body wall but not needed in this case.

And here is a video during the surgery when I had carefully dissected away the thin tissue revealing the heart beating underneath before I began to suture the defect closed:

Once the tissue had been separated away from the half sized scales lining either side of the lesion I set about suturing the hole back together, bringing the soft tissue of the internal body wall and the edges of the scales together to meet in the middle and form a tight seal which would heal and protect the heart and blood vessels underneath. I was quite happy with a neat and tidy job at the end. She was given a long acting pain medication and anti-inflammatory by injection, and a reversal drug for the sedatives given earlier and placed back in a clean dry cage with paper substrate to recover. We turned up the heat temporarily to boost her metabolic rate and aid her clearance of the anaesthetic drugs, and within 20 minutes she was groggy but wandering around her cage getting her bearings again. It always surprises me how tough these animals are. Reptiles have been around for millions of years and they really are quite resilient and remarkable in what they can withstand. Many of my clients fret and worry about anaesthetic risk in particular if their pet reptile needs a surgery for example. Although the general risk is higher than in dogs and cats I find them to be remarkably sturdy anaesthetic patients for the most part, so the risk is still quite low as long as you seek out an experienced and knowledgeable reptile vet.

Snake repair after closure

 

In terms of aftercare, she just needs to be kept clean and dry. No antibiotics were prescribed as it was a sterile op and good hygiene practices should prevent infection from here. Being a semi-aquatic species that likes to bathe in water, I’ve specified that she is not allowed a water dish in which she could submerge as the wound could act as an entry point for water and bacteria or other contamination into the body cavity if she submerged in the coming week or so. I will keep her in overnight and send her home tomorrow. So far she is making an excellent recovery. The sutures I placed are dissolvable over time and should slough off the next time she sheds her skin or possibly after that, so I just need to recheck her in a week to make sure the wound looks good, is healing well and is free of infection. Problem solved!

Snake in recovery

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Frog Enucleation: Eye Removal Surgery

Eye surgery

Eye surgery

Splat the albino horned frog (sometimes called Pacman frogs because of their large mouth and appetite!) somehow injured his eye, presumably by jumping into one of the furnishings in his vivarium. Unfortunately, the eyeball itself was ruptured and could not be saved so it had to be removed, or enucleated. Here he is in an anaesthetic bath containing dissolved anaesthetic drugs that he is absorbing through his skin.

2 Once anaesthetised, I also injected some local anaesthetic around the eye socket and behind the eye itself. He had earlier been given pain relief and antibiotic injections to ensure he was comfortable and to prevent infection. I carefully dissected out the eye from the underlying ocular muscles lining the eye socket. 3

Once the eye had been removed, I placed collagen implant into the socket and packed it well to prevent bleeding and allow the remaining space to fill in with new tissue as it heals. At this point we started to rinse Splat in order to start the process of recovery from his anaesthetic.

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Here he is after the surgery having closed the eyelids with dissolvable suture material. Now it was time to recover him and wake him from his operation.

5

We placed him in clean, de-chlorinated water and irrigated him regularly whilst keeping him warm in order to dilute the anaesthetic residue in his skin and keep him maximally hydrated so that he could recover and wake from anaesthesia. He recovered well, and went home the next day having been given another pain relief injection and oral antibiotic drops for the owner to administer. Here’s hoping he will be fighting fit in no time!

The snake that became unstuck!

Crystal the Royal python got in a rather sticky situation, when she managed to tangle herself in some loose duct tape that was being used temporarily in her vivarium when her owners were installing new lights. Unfortunately in her bid to untangle herself she managed to rip the delicate thin skin on her neck and caused a full thickness laceration exposing the underlying muscle. Her owners were panicked and rushed her down to see me, travelling nearly 3 hours in traffic to get to the surgery. Luckily it was my turn to work the Saturday clinic that day and my afternoon wasn’t as busy as usual so we managed to see her quickly and fix her up before more damage was done.

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Snakes and sticky tape do not mix

Here she is being given some anaesthetic gas and oxygen, after initially being given sedative drugs via intramuscular injection. At this point we couldn’t see the true extent of her injury, but knew it was bad. I was confident however that we would stitch her up and have her reasonably back to normal in no time. I took the opportunity while she was going under anaesthetic to administer pain relief and antibiotic injections to make her comfortable and prevent infection setting in.

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Snake laceration wound

Once she was fully anaesthetised I used surgical spirit to dilute the solvent on the tape and peel it off bit by bit, taking great care not to allow any spirit to contact her delicate tissues underlying her scales or to cause further tears. After removing the tape the area was cleaned and disinfected and prepped for surgery, reducing contamination and minimising the risks of post-operative infection. She was kept on a warm heat pad throughout the procedure to enable her cold-blooded body to maintain it’s metabolism and process the anaesthetic and other drugs effectively. Reptile patients are unique in that all bodily functions rely on external heat from immune function, to heart rate and even breathing rate. Therefore it is vital that they are warmed throughout surgery and maintained in thermostatically controlled conditions whilst hospitalised and in recovery.

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Suturing snake wound

I carefully sutured her skin back together taking care not to cause too much tension and not to invert the scale edges so that the wound could knit back together efficiently and heal quickly. Good surgical technique at this stage was critical to obtain a cosmetic and functional wound that would repair over the coming weeks without causing future problems with shedding skin for example.

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A vet’s work is never done, even on a Saturday evening

Here I am hard at work on a Saturday afternoon whilst all my colleagues (apart from my nurse Sharon assisting on anaesthetic duties) were out in the back car park starting our end of summer barbecue, beers and wine in hand. Now there’s dedication, eh?!

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Python in recovery hospital cage

After she was stitched back together I reversed her sedative drugs with another injection and set her up in a warm hospital cage on a heat pad to recover from her ordeal. By this point her meds ensured she would awake pain free within a couple of hours. Things are definitely slower in my reptilian patients compared with dogs and cats.

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Snake wound sutured post-op

This was the finished handiwork post-operatively. I am happy to say she went home very alert and happy on the Monday morning to her relieved owners and will come back to visit me to remove her sutures in 4-6 weeks.

Case Study: Follicular stasis & secondary impaction in a Uromastyx lizard

Uromastyx 1

This Uromastyx lizard presented to me almost two weeks ago for constipation, having not defaecated in several days which was highly unusual for her. She was extremely bright and well, with a good appetite and no other changes in behaviour. There was no obvious mass or obstruction on abdominal palpation which may have indicated a blockage, foreign body or tumour although her abdomen was quite distended. After discussion with the owner it was decided to trial conservative treatment by giving her a liquid paraffin enema and feeding her more at home on her food. Unfortunately as she was so stubborn and strong I failed to convince her to open her mouth to pass a stomach tube to give liquid paraffin directly. Strong little lizard!

She came back several days later having still not passed any significant amount of faeces, so I decided to perform an X-ray to visualise her internal abdomen and find out what was wrong. The X-ray revealed that she was impacted with opaque white, gritty sand material visibly transversing the mid abdomen in her intestine. I was also quite suspicious of the large greyish spherical masses occupying her abdomen as they looked like they may have been ovarian follicles.

Uromastyx 2

I hospitalised her to allow me to pass liquid paraffin directly each day with the aid of some anaesthetic gas so I could open her mouth without causing undue stress or damage, and repeated the X-ray two days later. She had by now stopped eating and although she was still very lively we needed to know whether the impaction was resolving with medical management or would we need to be more aggressive with treatment. She had produced some small amounts of faeces whilst hospitalised so I knew it was a partial obstruction most likely rather than a complete blockage. I tested her faeces for parasites as sometimes intestinal worms can cause sluggish gut transit and impaction issues but she was negative for any parasites. The clinical picture didn’t fit very well though in that the impaction had not moved or progressed. It was in the same location and if anything appeared denser and more compact. More importantly, the abdomen itself was now less inflamed so gave a clearer view of the suspected follicles. It was decided to perform an exploratory surgery to spay her to treat the follicular issue as well as trying to sort out the impaction.

Upon opening her abdomen and carefully inspecting the contents, it was obvious what had happened. She had produced lots of large mature ovarian follicles in preparation for breeding. This condition is known as pre-ovulatory egg binding or follicular stasis, and is life threatening if left untreated. In this case one of the large follicles had looped over a length of intestine, pulling on it therefore causing compression. Food material and some loose ingested substrate which normally would have passed out in the faeces then accumulated upstream of the rogue follicle that was weighing down the intestine. I managed to pass the offending follicle back through the intestinal loop it had become entangled in and proceeded to remove both ovaries and follicle masses. There were 14 in total and they were proportionally the largest ones I’ve ever removed from a lizard. After the pressure was off the intestine I could massage and break up the impacted material and ‘milk’ it down the intestine. I decided not to open the intestine at this stage as was confident she would now be able to pass the offending material. There would have been a huge infection risk of opening the intestine in any case. Here are the offending follicles attached to each ovary which I removed:

Uromastyx 3

I reversed her sedative drugs and took her off the anaesthetic gas to recover, after giving her some warm subcutaneous fluids to replace blood and fluid loss during the surgery. She recovered remarkably well, and was kept in overnight for post-operative monitoring. She was discharged the next day with instructions to house her in a sterile vivarium with paper substrate while her wound is healing. When she came back for post-op check the other day she was full of energy and very bright. Her owners were a little taken aback to see the size and number of follicles that had to be removed! Here she is in recovery and later happily posing with her bounty at the post-op check:

Uromastyx 4

Uromastyx 5

Hopefully she will have no further reproductive problems now her ovaries have been removed. I say ‘hopefully’ as when spaying lizards there is always a small chance some ovarian cells could be left behind and regenerate. The anatomy means that it can be tricky to place ligatures between the ovaries and surrounding structures without causing damage or catching some ovarian tissue in the ligature itself. On one side of the abdomen the ovary lies in close proximity to a large vein and on the other the adrenal gland. So it is a technically challenging operation, but one that brings great satisfaction when it results in a successful outcome.

Monitor Spay

Monitor Spay

This was a case of follicular stasis I treated in an Argus Monitor last year, which required surgery to remove the ovaries and overgrown follicles. I’ll be writing alot more on reproductive problems down the line, as they are extremely common in captive reptiles, but in the meantime here’s a great article on this condition outlining the disease process, diagnosis and treatments commonly encountered:

http://veterinarymedicine.dvm360.com/vetmed/article/articleDetail.jsp?id=564425