staging.vettimes.com

Tag: Toxicology

Rat bait’s sneaky trick: bleeding into the dorsal tracheal membrane
Most of us are familiar with anticoagulant rodenticide toxicosis and the range of clinical signs it can present with, but there is one potentially fatal manifestation of coagulation pathology that is perhaps not as widely known…

Dogs with severe clotting problems will occasionally bleed into the dorsal tracheal membrane. This causes collapse of the thoracic trachea and can lead to severe respiratory distress.

Presenting signs

These cases can present with none of the other signs of bleeding normally associated with coagulopathies, so rat bait poisoning may not come to mind as a differential diagnosis if you are not aware of this syndrome.

The typical case will present as an otherwise healthy dog that develops acute respiratory problems. Early signs can be as mild as a persistent cough, but it can quickly escalate into a life-threatening respiratory crisis.

Severe cases will have an obvious stridor on both inspiration and expiration, cyanotic mucous membranes, and patients may be very distressed.

It will look very much like:
- a dog that is choking from a tracheal foreign body
- an old dog with tracheal collapse
- the end stages of laryngeal paralysis – except the stridor will come from much lower in the respiratory tract than it does in laryngeal paralysis
So, what do you do?

On initial presentation you would approach it as any respiratory distress case: oxygen, oxygen, oxygen, calm and stress-free handling, and light sedation (butorphanol, for example).

Once it is safe to do so, you should take chest rads to look for what you’ll probably suspect is a tracheal foreign body, and you’ll get an image like the one above (although it may not be this severe). Then you’ll remember this article, have an “aha!” moment and run a clotting profile (but if it’s as bad as this case, you’ll obviously first save the animal’s life by passing an ET tube).

Once a clotting problem is confirmed you’ll need to stop the bleeding with standard therapy for anticoagulant rodenticide toxicity: plasma and vitamin K.

Severe cases

In a severe case you may need to keep the dog intubated for several hours, until the clotting times have normalised, before cautiously attempting to extubate.

If the patient is unable to stay well oxygenated without an ET tube (mucous membrane colour, pulse oximetry, blood gas), consider placing a long oxygen catheter past the narrowing – either via a tracheostomy or a nasal O₂ catheter.

If these cases are quickly recognised for what they are, and an open airway can be maintained, the prognosis should be good. These are potentially very satisfying cases with great potential for you to be a total hero.
February 19, 2024
Catharsis, enemas and colonic irrigation for acute oral poisoning
Great news for those who hate enemas: you may not have to do any of these ever again. This is the consensus by both the American Academy of Clinical Toxicology, and the European Association of Poisons Centres and Clinical Toxicologists.

The theory behind these procedures is legitimate – reducing systemic exposure of a toxicant by accelerating gastrointestinal tract (GIT) expulsion. But this is assuming the toxicant is absorbed very slowly, undergoes substantial enterohepatic cycling, or undergoes slow reabsorption in the lower GIT – all of which are uncommon characteristics of the types of toxicants veterinary patients are exposed to.

In fact, most toxicants of veterinary interests are generally rapidly absorbed in the upper GIT and absorption are not affected by catharsis.

Lack of evidence

No clinical evidence exists to support the use of a cathartic alone, or in combination with activated charcoal, to reduce the bioavailability of drugs or to improve the clinical outcome of poisoned patients. In fact, some evidence shows systemic exposure is increased following oral dosing of sorbitol, with activated charcoal, in canine paracetamol poisoning cases.

Similarly, no evidence exists that enemas and/or colonic irrigation improve clinical outcome in the treatment of oral poisoning.

The risks can be quite high with these procedures, with patients at risk of:
- haemorrhage (in the case of anticoagulant vitamin K antagonist rodenticides, for example)
- electrolyte destabilisation
- bowel perforation
- rectal prolapse
- phosphate toxicities (cats)
The risks simply do not outweigh the benefit (or lack thereof). In fact, repeated dosing with combination preparations containing sorbitol and activated charcoal is not recommended.

This may be the most exciting news in veterinary medicine!
March 28, 2022
Emesis: a thing of the past?
Until I started researching this Tip of The Week, I did not know the medical profession has abandoned the routine use of emesis in oral poisoning.

This is based on multiple medical literatures that have proven emesis induction does not influence the clinical severity of poisoning, the length of hospitalisation and the clinical outcome or mortality.

Although the rationale for inducing emesis is obvious, it is not necessarily evidence based. It is also dependent on satisfying a few large assumptions, all of which are untrue:
- Emesis is a very effective way of removing gastric contents.
- No separation exists of poison from its vehicle while inside the acidic environment of the stomach.
- Poison is not absorbed through the stomach wall.
Ineffective method

Snail bait ingestions: this patient ate 500g of snail bait containing metaldehyde.

Emesis induction is an ineffective way of clearing stomach contents. A review of the effectiveness of induced emesis, with both human and canine participants, showed at 30 minutes post-ingestion of non-absorbable markers, the recovery rate averaged between 17.5% and 52.1%, but never exceeded 62%.

In fasted puppies, this was even lower at 2% to 31%, despite inducing emesis immediately after marker administration. These have been confirmed by the presence of poisonous materials in the stomach of dead patients, despite effective emesis induction until clear fluid was brought up.

The clinical outcome only improves if the systemic exposure of a toxicant is reduced by more than half. However, considering animals rarely practice restraint, the ingested amount is unlikely to be exactly the lethal dose and no more. Therefore, even reducing the ingested toxic dose by 62% is unlikely to make a clinical difference.

Furthermore, most patients rarely present within 30 minutes of ingesting a toxicant, thus further reducing its efficiency.

The absorption conundrum

Some may argue the retrieval of metaldehyde or anticoagulant rodenticide granules from vomitus is indicative of reducing the toxicant dose. This could be true, but only if emesis was induced immediately after ingesting the poison.

The poison itself is colourless and has a different absorption characteristic to the coloured vehicle (granule); therefore, the presence of granule only serves to confirm ingestion, but is of no indication whether the poison has already been absorbed.

Contraindications

Many well-recognised absolute contraindications also exist to inducing vomiting:
- Ingestion of oils, which includes waxes that melt to oil in the internal body environment, as this poses a high risk of lipoid and bacterial pneumonia. This is of significant veterinary significance, as wax is routinely used in rodenticide baits.
- Ingestion of hydrocarbons and other volatile substances, or caustic or corrosive substances.
- When the mental status is altered – for example, hyperexcitable or depressed mental state.
- Where the patient is at risk of seizures (seizures can be induced by emesis).
- Increased intracranial pressure.
- Risk of intracranial or cerebral haemorrhage – for example, thrombocytopenia or abnormal clotting parameters.
Other less severe, yet important, reasons include:
- delays administration of more effective treatment, such as activated charcoal, antidote or other treatments
- risk of aspiration pneumonia
- hypochloraemia in recurrent emetic patients
- significant CNS and respiratory depression from apomorphine
- rare, but reported, complications such as cerebral haemorrhage, oesophageal tear/ rupture, hiatal hernia, gastric rupture, pneumothorax and pneumomediastinum
- legal implications – for example, if the product information clearly states emesis should not be induced
A place for everything

Emesis induction is not a benign procedure. It still has its place in certain circumstances, but its use in the routine management of oral poisonings may need to be reconsidered – especially if it means delaying administration of a more effective treatment, such as activated charcoal.

So, after all this, how do I tackle this information? It is a bit hard to swallow. My clinical experience is emesis is generally safe, especially in canine patients using apomorphine. So, I still feel some merit exists in reducing the amount of toxicant in the stomach if you have a chance – and in some situations, you don’t know until you try.

Emesis after ingestion of a toxic dose of chocolate can be incredibly rewarding, even six hours after ingestion, leading to patients not developing clinical signs at all.

Overall, I am biased by my personal successes with emesis, so still feel a time and place exist for emesis induction. But I now stop and question my decision to induce emesis, whereas I did not hesitate before.
- Some drugs listed are used under the cascade.
December 6, 2021
Supporting new grads: are you up to the job?
As I discussed in my previous blog post, if you are a boss, partner or practice manager, it’s important to consider whether your practice is suitable for a new graduate, before taking one on.

Perhaps you’re considering taking on a new grad for the first time, or maybe you’ve employed them before, but are struggling to attract candidates for your job vacancies – or it might be your new grads are leaving you after a short spell of employment.

If any of these apply, or you’re simply looking for inspiration on what you could do to offer support to new grads, I’d like to offer some suggestions from the new grads themselves.

Friendly face of support

Every new graduate looks for “support” in his or her first (or, in my case, second) vet role, but what exactly does that look like?

By far the most important aspect of support is communication – we’re all different, and the key to a great working relationship with a new grad is asking him or her the kind of support wanted or needed, and discussing how you can provide that.

This should also be considered a fluid, flexible conversation that continues through the first few months of employment – the rate at which a new grad gains confidence and experience will vary due to individual personalities, but will also greatly depend on caseload.

Being patient, friendly and answering questions are all important when dealing with a new grad. Image © .shock / Adobe Stock

Never assume

If your practice doesn’t see many cats, your new grad’s first cat spay might not happen for several months, and you can’t just assume having performed a lot of other surgeries, he or she will be fine to just get stuck in, when he or she may never have used a flank approach before.

On the contrary, some new grads can be dangerously over-confident, and that’s where your clinical and character judgement will be vital in ensuring the safety of their patients.

It can be a very delicate balancing act between pushing a new grad to improve, and not letting him or her charge in all guns blazing without the right skills.

Suggestions

The answer is not straightforward – no “one size fits all” new graduate induction plan exists – but a number of areas can be considered to help your new grad settle in.

I’m not suggesting you action all of them, or even that they’d all be suitable for every new grad or practice – they’re just ideas to think about.
- Provide a booklet with practice protocols – for example:
  - vaccine protocol
  - neutering advice (ages)
  - treatment protocols for common ailments (as a starting point)
  - what should be included in estimates for operations
- Order uniform or name badges and have them ready for the first day. It may seem trivial, but it symbolises being part of the team. Being asked 10 times a day who you are, or “are you new here?” gradually chips away at what little confidence you have as a new grad.
  Ordering a name badge for your new grad can help him or her feel part of the team. Image © kegfire / Adobe Stock
- Have him or her spend a morning on reception to learn how to book appointments and other tasks, to get used to the computer system.
- Put a nurse or receptionist in consults with the new grad to help him or her navigate charging for consults, saving notes, making up estimates and so on.
- Have the new grad observe some consults or accompany other vets on call-outs to help him or her grasp how the practice runs and to introduce some of your regular clients.
- Allow the new grad to pick up consults from a general list at his or her own pace.
- Book out double appointments for the new grad initially, then shorten these as he or she gets more confident – and, therefore, faster.
- Always have a more experienced vet available (in the prep room, perhaps) to answer those quick questions while the new grad is consulting. He or she need not be twiddling his or her thumbs, but, if performing procedures, ensure your new grad knows he or she can pop in and ask without feeling like an inconvenience.
- Decide on a maximum length of time for a consulting block and allow breaks for the new grad to catch up or have five minutes to gather his or her thoughts.
- Assign a formal buddy or mentor within the practice (not the boss) for him or her to go to as a first port of call for any problems – clinical or non-clinical.
- Provide regular constructive feedback – we don’t know if we’re doing okay unless you tell us!
- Have formal scheduled progress review meetings to let the new grad discuss any issues in a fair manner (the boss informally asking “how are you doing?” in front of half the staff will not always elicit an honest response).
- Have a working list of procedures or cases your new grad wants to gain experience in so all staff know to try to involve him or her if they get one in. Similarly, have a list of procedures he or she is happy to do alone (and an expected timescale) so reception staff don’t book in three bitch spays on day one.
- Supervision for operations – ask your new grad whether he or she wants someone scrubbed in, either in the same room or just within shouting distance, for different procedures.
- Have goals for the new grad to work towards without pressurising him or her.
- Show the new grad respect. Don’t undermine him or her in front of clients, even if he or she is in the wrong – better ways of addressing it exist without shattering the new grad’s confidence and credibility.
  Assigning your new grad a buddy or mentor can help as a first port of call for any problems he or she may encounter. Image © michaeljung / Adobe Stock
- Take on board any suggestions the new grad may have in practice discussions – he or she will have the most up-to-date knowledge, and it can be a huge confidence boost to have your ideas taken up.
- Try not to put your new grad to the bottom of the pile for holidays. In fact, some bosses almost force new grads to book a holiday after two months because they know they’ll need it.
- Give the new grad a Christmas at home (or at least the choice of doing so). Nobody wants to work at Christmas, but is it advisable to have a stressed out new grad – who will likely still need backup in December – on call for the busiest “my dog’s eaten the Christmas pud” poisoning fest of the year? He or she will have likely moved a long way from home and will be particularly lonely at this time of year.
- Have formal second on-call in place for as long as the new grad needs. Don’t assume he or she will be fine after six months – this will vary greatly depending on caseload.
Making a difference

From discussing our varying inductions and levels of support with my university friends, by far the most important thing is just being patient and friendly – even when it’s crazily busy.

Taking 30 seconds to answer a question will make a huge difference for the new grad, rather than letting us spend ages unable to find the answer in an ancient textbook.

If you take an interest in your new grad’s learning and development, rather than just employing us for cheap labour, you’re already heading in the right direction and your efforts to welcome us into the profession will be greatly appreciated.
February 27, 2018
RCVS council election manifesto: Thomas Lonsdale

THOMAS LONSDALE

BVetMed, MRCVS

PO Box 6096, Windsor Delivery Centre, NSW 2756, Australia.

T +61 2 4577 7061

M +61 437 2928 00

E tom@rawmeatybones.com

PROPOSERS: Roger Meacock, Andrew Stephens

1980s – woke from vet-school induced stupor to realisation junk pet-food industry relies on bogus science and negligent vet “profession”.

1991 – Blew whistle on junk pet food cult.

1993 – Preventive dentistry PGCVS.

1994 – Feeding versus nutrition, Aust Vet Practice.

1994 – Cybernetic hypothesis, J Vet Dent (postulates ecological theory of health and disease as extension of Gaia Hypothesis).

1994-7 – Junk pet food cult brought four disciplinary actions before New South Wales vet board.

1995 – Periodontal disease and leucopaenia, JSAP.

2001 – Raw Meaty Bones: Promote Health published.

2004 – Nominated for ACVSc award.

2014 – Most supportive vet award; FOI research: junk pet food grease in seven Australian vet schools.

2015 – Science death experiment.

Manifesto

Pompous, arrogant, mouthing incantations, the vet high priests worship at the altar of bogus science. Founded on fallacy, they oversee the junk food poisoning of pets, betrayal of consumers and brainwashing of vet students.

They must be stopped.

Morgan Spurlock embarked on a risky experiment. For 30 days he ate junk food at every meal. He gained 11kg, his liver turned to fat, cholesterol shot up and he doubled his risk of heart failure. Fortunately for Spurlock, he escaped addiction to junk food, followed his doctor’s orders and stopped the experiment.

The medical profession tells us carbohydrate-laden junk food injures health; that periodontal inflammation and obesity are precursors of systemic disease and early death. By contrast, the junk pet food industry controls the veterinary agenda. Vet schools deliver industry-funded propaganda on diabetes, periodontal disease and obesity – while simultaneously ensuring pious mumbo-jumbo obscures the despicable, lamentable truth.

Vet “experts” jet about the world spruiking the latest concoctions; extolling the alleged benefits of elaborate treatments instead of declaring that junk food contaminates all aspects of vet science, teaching and practice. According to them, natural food, as determined by evolution, is dangerous while their paymaster’s industrial junk represents the pinnacle of excellence.

For 20 consecutive RCVS elections, I’ve called for our “self-regulating” profession to act with integrity and honour. Alas, the high priests refuse even to consider. Time, then, for the courts to decide. I recommend legal proceedings against the RCVS, junk food companies, veterinary schools and individuals in respect to animal cruelty, breach of contract, theft and fraud.

Please vote in support; instruct your lawyers and brief the media. Pets, pet owners and the wider community need our help. Thank you.

March 24, 2016
Festive threats to four-legged family members

Now well into December, and getting ever closer to Christmas, there will be an abundance of “goodies” around the house that are not so good for the four-legged family members.

Jordan advises colleagues to ensure clients keep an eye on their pets during the festivities. Image: © Freeimages/s22k.

Most owners are aware of the dangers of chocolate and so are likely to rush down to the vet on Boxing Day when their Labrador has broken into the tin of Heroes – but what other festive dangers are there that owners are not so clued up on?

Pudding

The festive favourite Christmas pudding, while enjoyable for us, can be lethal for pets. It is the raisins, currants and sultanas that may lurk within that are poisonous.

While the mechanism of toxicity is poorly understood, we know it can cause acute kidney failure in dogs.

The treatment protocol for poisoning by raisins, etc, is similar to general suspected poisoning with an unknown agent: give an emetic (to make the animal vomit), an adsorbent (for example, activated charcoal) and supportive care (IV fluids) to protect the kidneys for a few days.

Antifreeze

Ethylene glycol, more commonly known as antifreeze, is extremely toxic to pets, with consumption of tiny amounts resulting in crystal formation in the kidneys, and so acute renal failure. Antifreeze smells and tastes sweet, so pets are often attracted to it. For this reason, it is best for owners to ensure it is kept in a secure container, well away from pets.

Early symptoms include neurological signs, such as wobbliness, twitching, seizures and depression. As the poisoning progresses, the animal will have cardiac and respiratory signs, such as increased heart and respiratory rate. It’s vitally important owners look out for these signs if their pets have had any possible access to antifreeze (for example, if they’ve got into the garage or if a cat has been missing for a few days and potentially been locked in someone’s shed).

The antidote for ethylene glycol poisoning is ethanol, because it replaces ethylene glycol as a substrate for the enzyme that breaks it down into toxic products. More specifically, lab-grade ethanol is best.

Sweetener

Xylitol is a sugar-free sweeter that is used in chewing gum, cakes and sweets, particularly diabetic foods. Xylitol causes insulin release in the body, resulting in hypoglycaemia and, later, liver damage.

Symptoms include vomiting and signs of hypoglycaemia: lethargy, weakness, collapse and, if it progresses, seizures and coma. Unlike ethylene glycol, there isn’t a specific antidote, but supportive care, including fluids and liver protectants, is vital. The prognosis for xylitol toxicity is good if the animal’s hypoglycaemia is corrected quickly, so it is essential for owners that suspect this to contact their vet immediately. If you’re trying to determine whether xylitol is in a product, it is often listed as a food additive, code E967.

Decorations?

And don’t forget the potential foreign body too – if the cat has been playing with the tinsel and managed to swallow some or the dog has ingested a few tasty looking baubles.

Enjoy the festive season, but advise owners to keep an eye on their pets this Christmas.

December 15, 2015