What happens to a dog with hyperthermia

Published on 24 August 2020 at 19:51

Last month Professor Steve Dean kindly allowed DogsandBlogs to publish his 2018 article on hot dogs and this month I promised to publish his second article on what happens to an over-heated dog and how to effectively trear.  It does not make very pleasant reading BUT I felt it necessary information for those dog owners who consider it ok to leave their dogs in such situations.  I would also like to add that most people think over heated dogs are only found in vehicles on hot summer days, but this is not true.  Dogs can over heat when locked in conservatories or south facing rooms as well as when being over walked on hot days, so be warned and please "think dog!".


Professor Dean wrote:

Writing about dogs suffering hyperthermia on hot days seems to have ensured spring has been further delayed. Hopefully the message about dogs overheating even in winter, if the localised environment is challenging, was understood. In the past several dogs have suffered from hyperthermia at large indoor dog shows where ambient temperature and humidity were high. Just to get yet another the point across, this is a problem for all types of dogs.


Anyway perhaps it would be worth considering what you can do about the risk because, when it occurs, this is one of the few life threatening emergencies which requires prompt action. So the first important step is to recognise the signs at an early stage.


Signs and symptoms 


Hyperthermia is a condition that is capable of escalating quite rapidly in a poorly ventilated car, on a hot summer day. A dog can be in a serious life threatening condition in less than 30 minutes if no action is taken.


Dogs will pant in any hot conditions. This is quite normal and although this is not a sign of hyperthermia it is the first sign that your dog is finding the environment too warm. There is no need to be concerned about hyperthermia at this point but it is the right time to take some preventive action to allow your dog to keep cool.


Things to consider include moving your doing into shade, ideally where there is a breeze, offering cool water to drink and reducing or stopping exercise. Allow dogs rest time to cool down if they are being quite active, let their normal physiology work.


Ensure adequate access to fresh air by removing anything covering any cage or other enclosure. Access to shade and a breeze are two important factors in keeping cool. Muscle contractions during movement add to internal heat production and this includes the act of panting. Nevertheless, normal panting will reduce body temperature quite quickly and the dog should cease to pant in around 10 minutes or so. Providing plenty of opportunity to drink replaces the water lost during panting, this is also an important point to consider.


Wet towels placed over a dog’s back or ‘special’ jackets intended to reduce the radiant heat from direct sunlight have been the fashion for some time. However neither are likely to have a great effect on canine thermoregulation and neither will offer meaningful positive effect in reducing the risk of hyperthermia. On the upside they probably do not increase the risk either so the message is simply do not rely on these as your preventative measure.


Always be watchful for a dog that is focused on panting. These dogs often have their ears drawn back, are less responsive to your voice and have an anxious look to their expression. This situation often escalates quite quickly to harsh sounding, rapid panting which is a signal of significant hyperthermia.


If the tongue is hanging out of the mouth, the mucous saliva is thick or frothy or the tongue appears to be tinged blue and engorged vessels can be seen this is a serious sign that urgent attention is needed. Such symptoms are rapidly followed by increasingly harsh sounding throat sounds and a dog may well lose consciousness at this point. This should be considered a very serious situation  demanding immediate action.


First aid

During the early stages, moving a dog from a hot environment such as a car can be effective if the ambient air is cooler and humidity is not high. A drink of water can help but dogs might not want to drink at this point as they are entirely focused on their breathing.


Water intake is helpful for restoring the water lost during panting rather than its internal cooling effect. Modern practice suggests it is unnecessary to add any electrolytes to the water to aid rehydration as panting is chiefly water loss and added electrolytes may put further stress on the system. 


Rapid cooling

The best treatment for a dog suffering hyperthermia is rapid cooling and the best method is either immersion in water or thoroughly wetting a dog’s coat with running water from a hosepipe. Ice packs are a poor alternative remedy, although they will help to keep a dog cool if they lie upon them.


A dog’s coat is a very effective insulator keeping heat in as well as out. In cold weather a coat prevents heat loss and in hot weather it prevents radiant heat reaching the skin. Wetting the coat reduces the dry coats insulating effect dramatically and allows cooling through the skin assuming there is either running water or the dog is immersed in cool water.


Immersion or soaking the coat in running water, draws heat out of the body quite rapidly, thus reducing core body temperature. If you reach the point where the dog is shivering you have gone just too far so simply stop the therapy.


However, monitor what is happening. Rapid cooling can be dangerous however left untreated with a body temperature continuing to rise, irreparable damage to the brain or other vital organs may be the result of acute hyperthermia. So given the situation, even if the cooling therapy seems to work, a veterinary check-up soon afterwards would be a sensible thing to do.


…. and after treatment


If a dog has suffered acute hyperthermia it requires a little care for a few days. Feed lightly, keep exercise to quite moderate levels and allow the dog to rest. The normal physiology needs time to recover and stressed organs need an opportunity to heal.


A reminder

Nearly all the dogs that suffer from hyperthermia do so because of human error. This may be one, or a combination of three common mistakes a) their environment lacked adequate ventilation and became hot and/or humid b) they are exercised too much in hot conditions without adequate rest periods (c) there is insufficient supervision resulting in the early signs being missed and prompt action was thus not taken. So think about your dog in hot weather and do not be slow to act to keep them cool.

Contact me with comment, argument and ideas for articles by writing care of Our Dogs or by email to stevedean@tyrianborder.com

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