The Autumn Edition of Toxic Times

Toxic Times A u e tu su mn 2014 Is

Welcome to the Autumn edition of Toxic Times

With the days of summer slipping from our horses are considered, whilst the dangers of memory, this edition of Toxic Times looks at the sycamores to horses is also examined, with a dangers of antifreeze exposure, which could be timely reminder from The Blue Cross highlighting more of a concern when motorists are checking the risks. and topping up levels of antifreeze, leaving spillages of the product in garages, streets There are 4 remaining CPD dates for this year, or gutters. and if you would like to reserve a place or receive more information, contact [email protected] We’ll also be discussing the year-round issue of ingestion of rodenticides, which is often, although Please feel free to let us know your concerns not always, an acute rather than chronic exposure. or areas that you would like covered; we really enjoy meeting you at CPD and other events Switching to the natural world, the problems and your comments and ideas are always associated with acorn ingestion in dogs and greatly appreciated.

VPIS, Mary Sheridan House, Guy’s Hospital, 13 St Thomas Street, London SE1 9RY Tel: +44(0) 20 7188 0200 • Fax: +44(0) 20 7188 0700 • Email: [email protected] • Web: www.vpisuk.co.uk If you do not wish to receive future issues of the VPIS Newsletter please email ‘Unsubscribe’ to [email protected] Rodenticide ingestion: a commonly seen issue

We receive numerous calls regarding anticoagulant rodenticides, with difenacoum and bromadiolone featuring each year in our Top 10 most frequent enquiries. Most UK rodenticides contain these compounds, usually, but not always, at concentrations of 0.005%.

Concern would arise weakness, inappetence, anorexia and where there is the anaemia are commonly seen clinical possibility of chronic effects. There may also be lameness exposure, small as a result of swelling around the joints, amounts eaten over and pulmonary haemorrhage would be a number of days, or indicated by coughing, dyspnoea with where a professional moist rales and blood-tinged froth product has been around the mouth. used by a pest control company. This scenario If exposure is thought to be either large or is potentially a problem chronic, repeated clotting tests for the first on farms where dogs few days post exposure can help determine may have repeated the likelihood of clinical signs developing, access to rat bait. and whether intervention with oral Vitamin K may be necessary. In this situation, the compounds can disrupt Unless prothrombin time is found to be the clotting cascade, elevated, asymptomatic animals should Often the owner of the animal does not which may result in haemorrhage and not be given prophylactic Vitamin K whilst know the name of the product, or the coagulopathy. The visible effects may be coagulation tests are being conducted. packaging has been discarded (or eaten!), delayed for several days, and although but small, acute exposures to the products bleeding from the mouth, nose, gums and Animals who are severely poisoned, which are available to the general public bowel are characteristic clinical effects, possibly late presenting or non-witnessed from shops such as B&Q or Sainsburys external bleeding is not always present. exposures may require fresh plasma or Homebase are unlikely to cause problems. Lethargy, pale mucous membranes, blood transfusions, but these cases or rare.

Antivenom from Biomed

Availability of adder antivenom is always an issue for veterinary practices, some times of the year being more frustrating than others.

We would love to hear about your experiences with the Polish adder antivenom from Biomed. You can let us know about cases where you have used it by email or by completing our online case reporting tool (available on our website, see ‘Report a case’). We are always keen to receive follow up information on poisoning cases, even those where you have not needed to contact us. Oak/Acorns (Quercus species) Ingestion in dogs and horses

Ingestion of acorns by dogs is a common occurrence during the autumn months, and over the years the VPIS has received more than 182 enquiries about dogs ingesting acorns in their usual enthusiastic way.

Quercus species contain the toxin If the animal is showing any of the clinical severe bloody diarrhoea. In severe or tannic acid; however it may not be the signs, or less commonly, melaena and extreme cases convulsions, coma and only substance responsible for the toxic hyperthermia, the renal and liver function respiratory distress may be present. Renal effects observed in animals, which are should be monitored. failure with elevated urea and creatinine, mainly gastrointestinal and renal. Tannic polyuria, haemoglobinuria, proteinuria, acid may lead to increased vascular Acorn ingestion by horses, especially glycosuria, hyperphosphataemia, permeability and subsequent fluid loss, of large amounts or in a chronic situation, hypocalcaemia and hypochloraemia may which can result in oedema and fluid is potentially more serious. The VPIS has also be seen. The urine specific gravity accumulation, although this is mainly only had 6 cases reported to us over the will be low and may contain granular and seen in ruminants and horses. years, although this of course is not a hyaline casts. Hyperglycaemia, raised liver complete reflection of the incidence. In enzymes and disseminated intravascular Following an acute ingestion, vomiting horses, the onset of effects may not occur coagulation (DIC) can also be seen. and diarrhoea are likely to be seen, until several days after ingestion. In severe both of which may be bloody. Lethargy, cases death may occur within 24-72 In some cases, there have been reports abdominal tenderness and inappetence hours following the onset of effects; less of stomach rupture. can also be seen and there is also the severely poisoned animals may survive for possibility of gastrointestinal obstruction weeks or months before death occurs. Again, treatment will be symptomatic and if large amounts have been ingested. supportive. Insertion of a stomach tube Where a small quantity has been ingested, will allow release of excess stomach gas, There have been reports of renal and liver the animal may be constipated and and the administration of a laxative and damage following substantial or chronic depressed and the faeces may be grey water may be of benefit. The renal function ingestion, a scenario more commonly and contain acorn husks. and fluid balance should be monitored. seen in horses, cattle, sheep or goats. The ingestion of larger quantities could The use of spasmolytics and steroid For most small animal cases, treatment is result in mouth ulcers, dullness, abdominal therapy has also been suggested, and essentially supportive; as vomiting usually pain, depression, hypothermia, sweating, restricting food, other than small amounts occurs, emetics are often unnecessary, weakness, inability to walk, incoordination, of hay may be beneficial. and the emphasis should be on rehydration. red or brown urine, constipation then Ethylene glycol - A timely reminder The super-organised amongst us may Cats who present late after exposure and are already unwell, where ingestion has not been witnessed, may have a poor be thinking of checking or topping up prognosis. Once renal damage has occurred the outcome the car’s antifreeze in readiness for is likely to be very poor and at this stage antidotal treatment the colder months ahead. is of limited or no benefit.

Most motor vehicle antifreezes contain ethylene glycol, and it Ethanol is a specific antidote for ethylene glycol poisoning, is also found in some screenwashes and de-icers. It is very toxic as it is the preferred substrate for alcohol dehydrogenase. to domestic animals, particularly cats. The long-standing myth This means that the metabolism of ethylene glycol is blocked that it’s sweet tasting and is perhaps palatable is unsupported, by the administration of ethanol and is excreted as the parent as it tastes acrid-not that the VPIS would endorse confirming this compound with very little toxic metabolites formed. yourself! Cats, of course, lack the functional protein to even taste sweet substances. Many products have bittering agents added, Ethanol should be given as soon as possible after ingestion. which may be why it rarely causes serious effects in children; what There is no point in giving ethanol to block ethylene glycol is not clear is if and why cats and dogs are actually attracted to metabolism if it has already been metabolised. Ethanol should antifreeze or apparently not deterred by the bittering agents used. not be given to an animal in renal failure as it is unlikely to be effective, will not be eliminated and may be detrimental as Most antifreeze is more or less pure ethylene glycol; even the ethanol of course has its own toxic effects. “ready-to-use” radiator top-up fluids are around 50%. Most car engines will have around 50% antifreeze in their cooling system. Fomepizole (4-Methylpyrazole or 4-MP) is another direct inhibitor It follows that both the neat product and run off or drained of alcohol dehydrogenase; this antidote is often used in human antifreeze is a danger. poisoning as it has few adverse effects and a slower elimination. Clinical reports suggest that fomepizole is successful in treating Whatever the taste, only a few millilitres could cause serious ethylene glycol toxicity in dogs and cats. However fomepizole is toxicity and death in cats. The often quoted lethal dose in cats not widely available, even for human poisonings, and is also very is around 1g (or 1ml) / kg; effectively therefore any amount. expensive. In addition cats require 6 times the dose used in dogs Cats are more susceptible to ethylene glycol than dogs and and humans. signs progress more rapidly. The reasons are not clear; toxic metabolites may be eliminated more slowly, or metabolites may While the severity of poisoning from ethylene glycol cannot be metabolised more rapidly to other more toxic metabolites. be underestimated, and the case fatality rate is high, especially For dogs it might be somewhat more and we recommend in cats, aggressive early treatment can be successful. intervention for more than 2ml/kg of undiluted product.

Ethylene glycol itself is not the major toxicant. The parent compound is metabolised by alcohol dehydrogenase to form Ethanol treatment glycoaldehyde which is then metabolised to glycolic acid, responsible for the acidosis seen with these poisonings. Ethanol is available as medicinal, pharmaceutical Oxalate, a metabolite of glycolic acid, causes renal damage and grade injectable material and is preferred. However hypocalcaemia by binding to calcium to form calcium oxalate. it is not widely held by veterinary practices. Calcium oxalate crystals appear in the urine of poisoned animals – a useful diagnostic aid as the crystals may be visible on standing Vodka however is widely available, if not actually in urine samples, although the absence of these crystals does held by veterinary practices. not rule out ethylene glycol poisoning. The aldehydes produced through metabolism may inhibit oxidative phosphorylation Oral use: it is possible to give ethanol orally, however and respiration. the disadvantage is that animals are often already unwell and even dilute vodka may induce vomiting. Cats presenting with a history of potential antifreeze exposure, or where there may have been an ‘outbreak’ of such poisonings A constant rate infusion would be preferred (to achieve locally, may have central nervous system signs (due early on to more consistent ethanol levels which are high enough unmetabolised ethylene glycol), including depression, vomiting, to block metabolism of ethylene glycol, but not so ataxia, tachycardia and weakness. They may also have polyuria, high as to cause toxicity) and if there is no IV ethanol polydipsia dehydration, tachypnoea, acidosis and hypothermia. available then IV vodka has been recommended. The treatment of ethylene glycol is aimed at blocking the formation of these toxic metabolites and therefore the longer the delay between ingestion and initiation of treatment the less favourable the prognosis. Sycamore Poisoning in Horses

In their blog, posted on 01 May A recent study in the Journal of Veterinary Other Acer species and other animals 2014, The Blue Cross urged Internal Medicine by Unger at al., has The VPIS has received numerous calls horse owners to stay vigilant confirmed the presence of hypoglycin A regarding dogs ingesting the seeds of in Acer pseudoplatanus, and preventing sycamore, and although clinical effects and keep their pets away from horses from grazing in fields or on land included abdominal tenderness, drooling, sycamore trees following the containing sycamore trees during late hypersalivation, pain, vomiting and tragic death of a pony from autumn and early spring might be an hyperthermia, all animals recovered atypical myopathy. effective way of reducing the incidence with supportive care. of atypical myopathy. Although there were no sycamore trees The related species Acer rubrum close to the pony’s field, he died after Additional advice from The Blue Cross (red maple) and Acer saccharum (sugar eating sycamore seeds that had been includes maple) have been shown to cause scattered by floodwater. haemolysis and methaemaglobinaemia • Feed forage, such as hay in parched in equines. This is as a result of the toxin, Atypical myopathy is a fatal muscle fields, off of floor in haynets or feed racks thought to be gallic acid, oxidising red blood cells. Interestingly, ruminants do disease thought to be caused by the • Do not over stock chronic ingestion of hypoglycin A, not appear to be susceptible to toxicity • Limit turnout. Ideally stable horses a toxin contained in sycamore (Acer from red maple ingestion. over night pseudoplatanus) seeds. • Section off areas around poisonous With red maple toxicity, non-specific signs The disease is present in the UK and trees and collect and dispose of leaves occur within 24-48 hours. Haematological Northern Europe, and an equivalent safely away from horses changes can occur within 24 hours with erythrocyte destruction products present condition in the USA, referred to as • Remove young sapling plants Seasonal Pasture Myopathy (SPM), has in the urine from the second day. Death been linked to hypoglycin A found in the • Be careful of streams running through occurs in 4 to 7 days (Divers et al., 1982). box elder tree or ashleaf maple (Acer paddocks as this is thought to be more Recovery can take 2 to 3 weeks. negundo), which is commonly planted in prevalent in moist places the UK. The leaves of the box elder are • Be vigilant of the potential signs of this Clinical signs are those of tissue hypoxia, non-typical to the Acer family, bearing a disease and act quickly if your horse anaemia and methaemoglobinaemia. greater resemblance to the leaves of ash becomes poorly. In some cases death can occur within or elder, and thus there is the potential for 24 hours from methaemoglobin-induced • Ensure you check your horse regularly non or misidentification of this plant. hypoxia. In animals which survive longer at least twice daily there is anorexia, lethargy, dehydration, depression, tachycardia, tachypnoea, Young horses appear to be more yellow or brown mucous membranes, susceptible, as are those being grazed jaundice, brown discolouration of blood, on parched land. and red or dark discolouration of urine (often the presenting sign). The clinical effects of the disease may include depression, muscle weakness, Symptomatic animals will require intensive colic-like symptoms and dark red urine, supportive care for several days. The VPIS and a prompt diagnosis is more likely can give full information on treatment to lead to a positive outcome. options and prognosis.

ABOVE: BOX TREE ELDER (ACER NEGUNDO) LEFT: SYCAMORE (ACER PSEUDOPLATANUS) Meet the Team

What is your most memorable VPIS Favourite music? telephone enquiry? Canto Della Terra (Andrea Bocelli), Sous Two bouncy and happy Labrador dogs Les Ciels De Paris (Andre Rieu), Espana found by their owner suspiciously quieter Cani (Andre Rieu), Samba de Arerê than usual. It turned out that they had (Arlindo Cruz). shared between them a bottle of wine, and nobody knew how on earth they Where is the most managed to open it. unusual place you have ever visited? Do you have a pet/pets? I have not yet visited that Despite being allergic to furry pets, I love many unusual places animals, specially cats and dogs. I had in the world. However, a poodle cross back home in Brazil but I found El she died a few years ago. Golfo quite Name: Andreia Amaral De Sousa. unusual. It Job Title: Information Scientist. What do you like to do in your is located in free time? Timanfaya How long have you worked for VPIS? When I’m at home, I just relax and National Park, Since November 2013. do whatever I feel like, which could be in Lanzarote, anything such as singing, cooking or even and it has What do you most like about your job? spending the day taking care of myself volcanic To know that the service we provide helps and doing the things I don’t do when I’m landscapes a great deal to save the lives of many busy. I also like to travel and explore new and a green lake. poisoned animals. And, of course, the places, cultures and the cuisines from priceless learning experience. around the world. Favourite quote: “He who conquers others is strong; What do you most dislike about the job? Favourite food? he who conquers himself is mighty” Working very early in the morning. Back to my roots: Brazilian food! (Lao Tzu).

VPIS Subscription 2014 CPD COURSES and Payment Options ‘Getting to Grips with Animal Poisonings’ Upcoming CPD event: 3rd September – Bristol There are two different options available to use (still accepting bookings!) our service based upon your specific needs. The aim of the course is to introduce to and remind vets and vet Pay-As-You-Go nurses of the common and not-so-common poisons they are likely You buy case credits online and top them up when needed, to come across in small animal practice. The course is centered with several credit bundles to choose from. Furthermore, if you on case histories, and the lessons and principles that can be opt for an Auto Top Up, you will get a discounted price per credit. drawn from these. For further details, visit www.vpisuk.co.uk

Dates Locations VPIS Annual Contract Subscription 3rd September . . . . . Bristol As a busy practice, you may require our 24-hour emergency service 1st October ...... London several times a year. With the contract option you only pay once a year 10th November . . . . . Manchester (based on your previous and expected usage), which saves you the 2nd December . . . . . Cambridge hassle of remembering to top up when your case credits are running low. Furthermore, a combination of online CPD and class-based CPD Online CPD Courses courses are included in your subscription (depending on the contract VPIS also offers a series of 10 online CPD modules covering the level), thus saving you money compared to buying the credits and the most common poisonings in veterinary medicine. Each module is CPD elements separately. worth 1-hour of CPD and contains real-life case studies and self- assessment tests. These can be accessed through the Vetacademy To request an annual contract subscription, fill out the online form website http://bit.ly/1dytLzx on our website here: http://bit.ly/1dyuO2y Alternatively, you can email us at: [email protected]