Your cat needs to undergo a thorough physical examination from your vet immediately. It sounds like your cat is experiencing seizures, which is a sudden firing of nerves in the brain, leading to involuntary contractions of the muscles. Symptoms often include defecating, urinating, scratching and teeth gnashing. The underlying causes of seizures are extremely varied, but include low blood sugar, liver disease, poisoning and head trauma.

If your cat undergoes a seizure more than once in 24 hours, or if any episode lasts for longer than a few minutes, you must treat the incident as a medical emergency. During a seizure you should concentrate on timing the episode and observing the actual characteristics of the seizure in order to assist the vet in his diagnosis.