Attacks of Sleep and Weakness in Cats
Narcolepsy and cataplexy, disorders that affect the way an animal is able to physically operate, are rare but well studied disorders of the nervous system. Narcolepsy is symptomized by excessive daytime sleepiness, lack of energy, and brief losses of consciousness. The episodes are typically brief and go away by themselves. Cataplexy is characterized by sudden muscle weakness and paralysis without loss of consciousness. A cat that is affected by cataplexy will remain alert and capable of following movement with its eyes throughout the episode. Cataplexy is similar to narcolepsy in that the episodes are spontaneous, brief, and reversible. Individuals may be affected with one, or both of these disorders.
Symptoms and Types
A cat that has either of these conditions will not always have any secondary or underlying conditions related to it. A physical exam will usually show normal physical and neurologic responses with no obvious abnormalities. This is not a fatal disease, but it is one that requires attention and awareness. Narcoleptic and cataplectic episodes can last from several seconds up to 30 minutes, and often will take place when the cat is eating, playing, excited, or is engaging in sexual activity. Cataplexy in particular is characterized by episodes that occur during moments of heightened emotion. During a narcoleptic episode, the affected cat will collapse onto its side or stomach, its muscles will slacken, and all physical movement briefly ceases. It is just as if the cat has suddenly fallen into a deep sleep. Closed eye movement continues, as with the stage of REM sleep. During a cataplectic episode, the cat is aware and conscious of what is going on around it, its eyes remain open and under the cat's control, but it is otherwise paralyzed. The cat typically will come out of the episode in response to external stimuli, such as when it hears a loud sound or is petted.
Some of the usual symptoms of narcolepsy and cataplexy are:
- Rapid onset of episodes, with no apparent warning of imminent collapse
- Sudden loss of consciousness
- Paralysis of limbs, head, and torso
- Episodes last from several seconds up to 30 minutes
- Eye movement, muscular twitching, and whimpering during episodes
- Episodes usually end when stimulated by petting, loud noises, etc.
Generally, narcolepsy and cataplexy are categorized as idiopathic, since there has been no connection to an underlying cause. Some of the suspected causes that are still being studied are disorders of the immune system, and disorders of the nerves.
Your veterinarian will perform a thorough physical exam on your cat, including a blood chemical profile, a complete blood count, a urinalysis, and an electrolyte panel to rule out any underlying diseases. You will need to give a thorough history of your cat's health, the onset of symptoms, and possible incidents that might have precipitated this condition. If it is possible to visually record a narcoleptic or cataplectic attack, it will help you and your veterinarian in finding a pattern to the episodes, if there is a pattern. If there is an activity that appears to consistently bring about episodes, your veterinarian will attempt to simulate the activity so that an episode can be observed first-hand. A food-elicited cataplexy test may also be performed, since many animals with cataplexy have attacks while eating.