Posted on 09-17-2012
Pain may be gain in the gym or training for an Ironman, but not when our pets are injured or having surgery. Pain is a natural warning that something is wrong and needs to be fixed. Once we receive that warning and diagnose the problem, we need to control the pain so our pets can heal. Uncontrolled pain can cause stress, anxiety, increased cortisol (a hormone that decreases healing), increased blood pressure, decreased appetite, and decreased sleep. All of those things can delay or inhibit healing and the only thing we gain is an unhappy pet!
Pain is caused by a cascade of nerve signals and chemicals in the body. Once the cascade is started, it actually builds on itself (a condition called "wind up") and the same injury can feel more painful as time passes if the pain is not controlled. Blocking the pain chemically with medications can stop or reverse "wind up" and get the pain under control. Of course, correcting the cause of the pain, when possible, is important too.
Just like a forest fire, pain is easier to prevent than it is to treat. When we can't prevent it, it is easier to control when caught as early as possible and then kept under control. We don't put out forest fires by spraying water on them only now and then. We fight them until they are under control, then we put them out. Same thing with pain in our pets, especially during surgery. If we can prevent the pain response with medication BEFORE the surgery, we can use much less medication over all and have a much happier pet along the way.
For example, before knee surgery we give pets epidural anesthesia. We block the pain signals before they even get to the neurons in the spine. By blocking the pain before it happens we avoid wind up, we can use less general anesthesia (making it much safer for the pet), and we can transition to oral pain medications before the epidural wears off after the procedure, making the transition before the pet starts to feel the pain.
For other surgeries we use local anesthetics or regional nerve blocks in addition to general anesthesia. Like the epidural, these block the pain signals before they reach the neurons, actively controlling the pain response before it starts.
Lastly, sometimes we get mixed signals about pain. Limping, for example, can certainly be a sign of pain but it can also be due to instability. If your pet has a torn cruciate ligament in his knee, the joint will undergo an abnormal shift during weight bearing. This triggers a spinal reflex that causes the muscles of the leg to relax abruptly. Even if there is no pain response the pet limps or bears only a little weight on the leg because of the instability. Make no mistake, tearing a cruciate ligament hurts initially (I remember when I tore mine!). But after the inflammation subsides and the swelling goes down we are still left with an unstable joint and a limp until we get it fixed.
That is a very brief summary about the really complex topic of pain. Next time we'll talk about the CO2 laser and some of the ways we use it in surgery. As always, we hope your pet never needs surgery, but if they do we're here to help.
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