Attacks of Sleep and Weakness in Dogs
Narcolepsy and cataplexy are disorders of the nervous system. Narcolepsy occurs when an animal suffers from excessive daytime sleepiness, lack of energy, or brief losses of consciousness. The episodes are brief and go away by themselves. Cataplexy is characterized by sudden muscle paralysis without loss of consciousness. The animal remains alert and can follow movement with its eyes throughout the episode. Cataplexy is similar to narcolepsy in that the episodes are spontaneous, brief, and reversible. These disorders are relatively common in dogs.
Symptoms and Types
A dog that has either of these conditions will not always have any secondary or underlying conditions related to it. A physical exam will typically 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, often occurring when the dog is eating, playing, excited, or is engaged in sexual activity. Moments of heightened emotion play a role in both conditions and in the onset of an episode.
During a narcoleptic episode, the affected dog will collapse onto its side or stomach, its muscles slacken, and all physical movement briefly ceases. It is just as if the dog has suddenly fallen into a deep sleep. Closed eye movement continues, as if the dog were in the stage of REM sleep. During a cataplectic episode, the dog is in a paralyzed state, although its eyes remain open, and it has control over its eye movement. The dog remains aware and conscious of what is going on around it during this type of episode. Typically, the dog will come out of an episode in response to other external stimuli, such as when it hears loud sounds, or when it 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.
- Hereditary in Labrador retrievers, poodles, dachshunds, and Doberman pinschers
- Possible immune system involvement
- Nerve disorder
- Idiopathic (unknown)
Your veterinarian will perform a thorough physical exam, 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 dog'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 may help you and your veterinarian to find a predictable pattern leading up to the episodes. 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.