Because pain is often a response to actual or potential tissue damage, it has a protective role. For example, if a muscle strain or pull causes pain in a limb, not putting weight on that limb can help prevent further injury.

Signs of Pain in Pets
You can play a central role in relieving your pet's pain by learning to recognize some common indicators of pain and discomfort. Physical Signs Change in heart rate Heavy breathing Enlarged pupils Slowed reflexes Behavioral Signs Reduced appetite Reluctance to lie down Unusual restlessness or anxiety Withdrawn behavior Mood or personality changes Licking, biting, or rubbing the site of pain Irritability
Modified with permission from Colorado State University Animal Cancer Center web site, “How will I know if my pet is in pain?

The most common types of pain can be categorized as acute, chronic, cancer, and neuropathic.

Acute pain is the normal, predictable, noticeable response to an undesirable stimulus (such as twisting, crushing, or burning) or tissue injury (such as bruises, wounds, and surgical incisions). People describe acute pain as sharp, throbbing, aching, or burning. Acute pain generally improves within the first 3 days after the event that caused it, but sometimes it can last for weeks or months.

Chronic pain persists for longer than the expected time frame for healing, or it can be associated with progressive noncancerous disease, such as osteoarthritis.

Cancer pain is the result of primary tumor growth, a spreading cancerous disease, or the toxic effects of chemotherapy or radiation.

Neuropathic pain results from damage to a nerve or some other part of the central nervous system. This type of pain is frequently not diagnosed in veterinary medicine, mainly because animals cannot communicate a problem such as a tingling sensation.

Last full review/revision July 2011 by Peter W. Hellyer, DVM, MS, DACVA