Narcolepsy

What is narcolepsy?

One of the most common causes of severe excessive sleepiness.

There are three basic reasons that a person could be too sleepy:

  • INADEQUATE OR POOR QUALITY SLEEP. Best example: patients with sleep apnea. Their alertness will be restored once their sleep-related breathing problems are controlled.
  • IMPAIRED BRAIN MECHANISMS THAT NORMALLY SHOULD KEEP ONE AWAKE. In such cases, even if sleep were perfect, the individual would still be too sleepy.
  • A COMBINATION OF BOTH OF THE ABOVE. For example, some people develop narcolepsy in late childhood or their teen years–and then, with increased age and weight, also develop sleep apnea: making an already bad situation worse.
  • CRUCIAL POINT! If a patient with both sleep apnea and narcolepsy is treated at a facility that focuses only on sleep apnea and if the diagnosis of narcolepsy is missed, the results can be disastrous.

Treatment of sleep apnea in individuals with both problems will make them “better but not better enough”. The fact that management of sleep apnea will protect them against cardiac complications and stroke will be small consolation should they subsequently fall asleep at the wheel anyway, from their still untreated narcolepsy, with serious injury or death of self or others.

There is no law against having more than one sleep disorder or more than one cause of a single basic symptom such as sleepiness. It is important to ensure thoroughness of the care that you receive.

Narcolepsy involves both “brain sleepiness” as explained above, and disturbances related to REM sleep (a tendency for REM sleep to occur too rapidly after sleep onset and for its component parts to intrude into wakefulness). Resulting possible symptoms:

  • Dreaming in brief naps
  • Dream fragments occurring either prior to falling asleep or persisting after awakening (hypnagogic and hypnopompic hallucinations)
  • Sleep paralysis (inability to move or call out when first dozing off or when awakening).
  • Cataplexy (attacks of sudden loss of muscle strength triggered by emotions, particularly laughter)

Only cataplexy is diagnostic of narcolepsy, and not all narcoleptics suffer from cataplexy.

Who develops narcolepsy?

Narcolepsy can occur in people of both sexes. Symptoms–particularly sleepiness–usually begin in late childhood, the teen years or the early twenties. Narcolepsy can begin after age 30: but such is relatively uncommon. In contrast, while sleep apnea can develop in childhood, it more often becomes a significant and progressive problem later in life.

Two valuable clues to the possible diagnosis of narcolepsy in a sleepy person:

  • Indications of cataplexy
  • Onset of sleepiness early in life, particularly if no severe snoring was noted then. For example, falling asleep more frequently in school than one’s classmates, taking naps after school, and in some cases, hyperactive behavior (which in children, can be a manifestation of impaired alertness)

What causes narcolepsy?

The cause in the vast majority of cases has been found to be a specific problem with the chemical “neurotransmitters” that regulate communications between different groups of nerve cells in the brain. Brain cells in the lateral hypothalamus that produce a neurotransmitter called hypocretin or orexin are lost.

Why does this loss of nerve cells (neurons) occur? An explanation is being sought. We have know for some years that narcolepsy is strongly associated with specific HLA types (see below), a phenomenon that has been noted in many autoimmune disorders (conditions in which the body mounts an immune defense against its own tissues. However, it has not been shown with any certainty that narcolepsy is an autoimmune disorder and that autoimmune mechanisms are responsible for the loss of hypocretin (orexin)-containing nerve cell bodies.

Only rare cases have been reported of narcolepsy arising as the consequence of such structural causes as brain tumors, brain infections and head injuries. CT/MRI scans of the brain are normal in the vast majority of cases.

Narcolepsy can “run in families” such that some individuals appear genetically predisposed to develop it. However, it is not a genetic disorder per se in humans. Some breeds of dogs do develop narcolepsy on a genetic basis.

The onset of narcolepsy sometimes follows stressful events, but such does not indicate that it is a psychological disorder.

Is narcolepsy a rare condition?

Not at all! It is roughly as common as MS (multiple sclerosis) in the United States.

How is narcolepsy diagnosed?

A careful history, followed by specific sleep center studies (both an overnight sleep monitoring and a multiple sleep latency test).
An introvertible history of cataplexy is far more diagnostic of narcolepsy than a multiple sleep latency test, since both false negative and false positive MSLTs occur frequently.

Can narcolepsy be diagnosed by a “blood test”?

No! Such is a common misimpression that resulted from the discovery that most (but not quite all) narcoleptics share particular HLA types (genetically determined markers on white blood cells that are used to determine tissue compatibility–for example, to assess one’s ability to donate a kidney to a possible recipient without high likelihood that the transplanted kidney will be rejected). HLA types are evaluated with a blood test. There are two reasons why these tests cannot be used to diagnose narcolepsy:

  • First, some definite narcoleptics who even have cataplexy will come out negative on these tests.
  • Second, an even greater problem is that up to 25% of the general population will show the same HLA typing that has been associated with narcolepsy!

How is narcolepsy treated?

It is best managed with a combination of medications and common sense! Treatment must be tailored to the needs of the individual patient, and medications alone are not the answer. One must also eliminate aggravating factors that would make the symptoms worse and the prescribed medications less effective.

For example: one does not manage diabetes by giving insulin and then informing the patient that since they now have medicine, they can do whatever they please…such as eating entire pies and cakes and drinking a case of beer every day! It would be illogical to use such a “medications only” approach for any illness–including narcolepsy.

The physician treating the patient with narcolepsy should be experienced in its management and also take the time needed to educate the patient about the condition and factors that can make it worse–empowering the patient and enabling him or her to “outsmart” the disorder as much as possible.

Medications that can be helpful include stimulants and wakefulness promoting agents, sodium oxybate (Xyrem) which is ingested at night, and antidepressants. All have their own advantages and potential side effects, and they must be selected carefully for each individual patient, based upon his or her symptoms, other medications and medical history.

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