“Pain is perfect misery,
The worse of all evils,
Overturns all patients.”
John Milton, Paradise Lost
Trauma to body tissues results in the release of chemicals that induce inflammation and stimulate pain receptive nerve endings called nociceptors. These pain impulses are transmitted initially to the spinal cord then to the thalamus and brain stem and finally to the sensory cerebral cortex. Chronic pain may result in neuronal windup or amplification of the pain signals which may persist even after the original pain inducing insult has resolved.
Unlike humans our pets’ response to pain is general withdrawal, they do occasional “cry” but mainly look sad and avoid interaction. In hospital there is the presumption of pain with most pain relief being pre emptive (before it occurs) as it has been shown to be more effective. We pain score using subjective and objective assessments and take a “treat first” approach if suspected. At home, pets in pain become quiet, withdrawn and refuse to move or go for walks. Owners often notice that their pets lie down a lot and have difficulty climbing stairs or getting into cars.
Aside from the moral and ethical considerations there is irrefutable evidence that, whilst the physiological responses to pain are initially beneficial, prolonged pain is acutely detrimental to patients and the human/animal bond.
Multimodal pain relief is a strategy whereby doctors target pain relief at the various sites of transmission by using a combination of drugs and techniques. This allows for lower dosages of each single drug and a “tailoring” of therapy to suit each individual. We have “rescued” many patients with severe spinal pain that were likely under the effects of neuronal wind up. These dogs become “sensitised” and even innocuous bumps, handling and movement are perceived as excruciatingly painful. We firstly “reset” the nervous system with an infusion given over 24-36 hours and then use medication to target different points along the pain “pathway” . The use of these drug combinations can give owners back their pets and gives pets back their quality of life.