CVMA | Documents | Identifying Pain Can Prevent Further Suffering in Pets

Identifying Pain Can Prevent Further Suffering in Pets

October 23, 2012

While most people know what pain is, few understand it, especially pain in animals.

There are many misconceptions about pain and animals. For example, because a pet is not moaning or crying out does not mean it is free of pain. Most animals (unlike humans) are quite long-suffering and less vocal about their pain. From a survival point of view, it is more to their advantage to suffer quietly so as not to draw the attention of predators to themselves. Similarly, because a cat is purring does not mean that it is content. On the contrary, cats may purr if upset, afraid or in pain. It is also wrong to assume that pets do not feel pain the same way we do. Based on physiological and neurological studies, it has been shown that animals feel pain in very much the same way that we do. 

For these and other reasons, the veterinarian and the pet owner must look carefully to determine whether or not an animal is in pain. There are certain indications or signs that one can look for. For example, certain behavioural responses may suggest pain. Vocalization (crying out, whimpering, growling, etc.) can be an indication of existing pain. Commonly a pet will retreat from the family or try to hide and be left alone. The pet may appear uncomfortable, which manifests itself in the form of pacing, restlessness, and repeatedly assuming different positions (e.g., arched back, forelegs held out from chest wall, in a prayer position). Often, an animal in pain will pant excessively. Some may growl or snap if handled, while others may simply grunt or try to get away. There may be a reluctance to move. Frequently, there may be a decrease or lack of appetite, listlessness or lethargy, and decreased personal hygiene (especially in cats). 

Body language can be very important. For example, if there is localized pain, the animal may lick or bite at the area that is painful. If it has a broken leg or paw, it will try to hide the leg by tucking it underneath itself. These animals will also limp or not bear any weight on the affected limb. If there is abdominal pain, some dogs will stretch out and assume a praying position (called a "posture of relief"). There are also clinical signs that veterinarians look for that tell them that an animal is in pain. Dilated pupils, increased heart and respiratory rate and increased blood pressure indicate the presence of pain. Sometimes signs are not well correlated with pain since like people, cats and dogs have different thresholds for pain tolerance. Some are much more stoic than others.

Analgesics (i.e., painkillers) are used frequently and routinely in veterinary medicine, not only for the comfort of the patient, but to simplify handling of the pet as well. Studies have also shown that patients recover more rapidly if pain is controlled or alleviated. 

The greatest benefit arises when medication is given pre-emptively, that is, before the pain occurs. This prevents a firing-up of the pain receptors, and allows us to control pain using lower doses of medication more effectively. 

Pet owners should learn to recognize the signs of pain in their pets. However, painkillers should never be administered without first consulting a veterinarian. Many painkillers (e.g., ibuprofen, naproxen, acetaminophen, ASA) can be extremely toxic and need to be administered with extreme caution to dogs. Cats are very sensitive to human NSAIDs and these should never be given at home without prescription since human doses are deadly for cats.

Human medications generally contain much more medicine per tablet than is safe, so it is important that these medications be kept out of reach of pets at home. Bottles should not only be securely closed, but also kept in locked cupboards since pets have been known to chew the lids off of bottles left within their reach, resulting in poisoning.