If you've been noticing your cat shake, periodically or steadily, one of several underlying conditions might be to blame. Generally, a cat will shake or vibrate as his muscles react to a good stretch. This is normal behavior, especially after a healthy nap. If your cat shakes while awake, as if cold, there are other symptoms and signs to look for when determining a possible problem.
Generalized Cat Tremors
Tremors are an involuntary and rhythmic shaking of the limbs, head or body. The location of the tremors, if localized, would be the first step in indicating a potential cause. Generalized tremors where the entire body is shaking could indicate a few things, the most common of which would be poisoning. Whether your cat goes outside or stays indoors, check to see if there are any toxic substances that may have been accessible. Anti-freeze, chemicals of any sort, and some plants may be particularly harmful to your cat. If you have recently made a change to your cat's diet, administered medication, or applied any type of flea and tick product, this may be causing your cat to shake. Some cats have been reported to be violently allergic to certain types of flea and tick medication.
Toxic food substances or medication may be causing a reaction as well. If generalized tremors are accompanied by problems using the litter box, an intestinal blockage due to disease or ingestion of a foreign substance may be to blame. Other causes of full-body shaking may include neurological disorders or hypomyelination, a condition that generally affects kittens and most often resolves itself without treatment.
Localized Cat Tremors - The Head Region
Shaking of the head can indicate many things, some serious and some easily treatable. If your cat is shaking its head back and forth, possibly accompanied by scratching at the head or ears, the first thing would be to check for ear mites, or a flea infestation. Deeper trembling of the head area would indicate a more serious problem. If it's possible that your cat may have been hit by a car, engaged in a fight with another cat, or fallen from a high location, head trauma may be responsible for the tremors. Ongoing head tremors may indicate a genetic disease, however shaking that has begun suddenly and is not associated with trauma may point to encephalitis, brain abnormalities, epileptic seizures or vestibular disorders, which affect a cat's balance.
Localized Cat Tremors - The Pelvic Region
Often, trembling or shaking of a particular limb can indicate severe pain or weakness of that area. Check for localized trauma to the limb, or bunches or lumps that may be signs of a tumor. Shaking of the entire hind end may point to metabolic diseases like kidney failure or low blood sugar. Neuromuscular diseases and tumors or other conditions affecting the spine area and vertebra may also lead to shaking. Spinal pressure or muscular conditions may cause problems with walking or movement as well.