How to Diagnose and Treat Narcolepsy
In Part One of my ‘Two Part Primer on Narcolepsy,’ we discussed the causes of narcolepsy, the hormones that are involved in the evolution of the disease, classes and types of narcolepsy, and cataplexy. For this second part in the series, we’ll explore what you need to know about how doctors diagnose narcolepsy, as well your options for treatment.
How is the diagnosis of Narcolepsy made?
First, it’s important to identify and recognize symptoms that point to a diagnosis of narcolepsy. ‘Sleepiness’ alone is not a direct indicator of a possible narcolepsy diagnosis. Due to increasingly hectic lifestyles found in our society, the most common cause of being sleepy is actually insufficient sleep.
The signs of narcolepsy are the triad of symptoms that also accompany the specific type of sleepiness these individuals experience:
Sleep attacks – You suddenly are unable to keep your eyes open at inopportune times, like when you’re actively talking to someone. This is different from feeling sleepy and yawning because of lack of sleep.
Sleep paralysis — You are in bed and have the sensation of being unable to move. This can occur when waking up from sleep or when you are in between periods of sleep. It is a very dramatic feeling and quite frightening. Patients clearly articulate this phenomenon.
Hypnagogic hallucinations – You see some kind of strange vision when just waking up or just before going to sleep. It’s actually the intrusions of dreams into waking hours. They can be perceived as very real and are also quite frightening.
How do you confirm a definitive diagnosis of narcolepsy in the presence of this triad of symptoms?
To be fair, some of the symptoms such as sleep paralysis and hallucinations can also occur when you have had insomnia for more than 24 hours and are incredibly sleep deprived. So even these three signs by themselves, may not confirm the diagnosis.
One symptom that is unique to narcolepsy is the patient experiencing and describing an episode of cataplexy. Sudden paralysis during waking hours as a response to an emotional stimulus, such as laughter, strongly supports the diagnosis. However, the test that truly confirms the diagnosis is the Multiple Sleep Latency Test (MSLT).
What is the Multiple Sleep Latency Test?
The MSLT is a disorder diagnostic test used to measure the time elapsed from the start of a daytime nap to the very first signs of sleep (sleep latency). It is based on the notion that the sleepier people are, the faster they will fall asleep.
The doctor will start the test by making sure you have a full night’s sleep (minimum 6 hours of deep, uninterrupted sleep). The following day a series of five scheduled naps are taken by the patient. You can read more about the MSLT test. Expect it to take most of the day, with results taking a few to several days. The results reflect how long it took to fall asleep each time and whether you entered REM or not. People with narcolepsy have two or more REM experiences during the five naps. It’s not normal to have REM during short, 20 minutes naps.
What other diagnosis does the MSLT data reveal?
Other conditions like idiopathic hypersomnia can cause an abnormal MSLT. These individuals never experience REM during any of the nap trials. Narcolepsy, as discussed, will have patients achieving REM at least twice during the MSLT.
Are there any other tests for narcolepsy?
When the results of the MSLT are inconclusive and there is a high clinical probability of narcolepsy, the doctor may decide to do a lumbar puncture to measure orexin levels in the cerebrospinal fluid. There is even a test to identify the presence of a gene associated with narcolepsy, HLA DQB10602.
How can a person manage the disease?
Lifestyle adjustment is a crucial element to managing narcolepsy. A starting step is to structure the day for maximal functional ability. It may be feasible to take precautions to avoid injury when the cataplexy attacks are predictable.** Short daytime naps** are actually refreshing for someone with narcolepsy, so adding them daily may help. In the condition idiopathic hypersomnia, naps don’t really help.
Are there any medications that can help?
The most commonly prescribed medication is Provigyl (Modafinil). Its mechanism of action is similar to amphetamines, but without the addictive potential. This medication is used to help keep you awake with narcolepsy. There is a newer generation of the drug, Nuvigil, which is longer-acting and can be taken once a day. In the event that you don’t respond to these drugs, or they no longer provide relief, your doctor may prescribe dextroamphetamine or Ritalin, which is also used for attention deficit syndrome.
(Side effects of these drugs include: fever, sore throat, nausea and vomiting, bruising and feeling a tingling sensation).
These medications treat the sleepiness of narcolepsy, but do they treat cataplexy?
The FDA approved drug to treat cataplexy is called sodium oxybate, or brand name Xyrem. Great care must be taken when using this drug because it is highly sedative. It’s chemically related to gamma hydroxybutyric acid, and is in some cases recognized for its use as the “date rape drug,” GHB or roofies. For this reason a doctor has to have a special prescriber license.
This medication is also short-acting, so it is typically taken before going to sleep and may require a second dose during the night, if you wake up.
(Side effects of the drug that you should be aware of and alert your physician: hallucinations, severe confusion, shallow breathing and sleep walking).
Narcolepsy is an extremely complex and fascinating disease. It’s not easily diagnosed and managing this disease is often challenging. I expect to see an increase in cases in years to come, as we encounter newer and complicated infections and sports that have risk of head trauma and lasting impairment.