There are a variety of sleep problems that occur in MS. Some are directly related to MS and some would likely occur even without MS. The following is a list of some of the more common problems.
Bladder dysfunction – You really cannot get a good night’s sleep if you have to get up 3 or 4 times because of urinary urgency. In addition to the usual bladder management methods (see section on bladder), vasopressin (Desmopressin®) is sometimes used to minimize urine production during the night. Patients should restrict fluid intake for 1-2 hours before bed and it is taken at bedtime. This has a disadvantage as you must get rid of the fluid in the morning to prevent edema. This may result in considerable urinary frequency in the morning but it is usually easier to deal with than the lack of sleep.
Sleep apnea – This is particularly common in overweight and obese people, with or without MS. If you wake up gasping for breath or your partner notices that you stop breathing followed by a sudden deep breath while sleeping, you should suspect sleep apnea. Usually if sleep apnea is suspected, a sleep specialist is consulted and formal testing with polysomnography is done. Polysomnography is a test in which the person sleeps with electrodes that monitor EEG, respiration and heart rate and can tell the physician a lot about how well you sleep. It is often treated with use of a CPAP machine during sleep. CPAP stands for continuous positive airway pressure and prevents the airway from closing and shutting off the airway in people with sleep apnea.
Narcolepsy – There appears to be an increased risk of narcolepsy in MS. In narcolepsy the individual falls asleep almost anytime. There are a number of distinctive features in narcolepsy in addition to falling asleep. These include cataplexy (a sudden weakness that occurs when surprised that can actually cause you to fall), hypnogogic and hypnopompic hallucinations (Hypnagogic or hypnopompic hallucinations are visual, tactile, auditory, or other sensory events, usually brief but occasionally prolonged, that occur at the transition from wakefulness to sleep (hypnagogic) or from sleep to wakefulness (hypnopompic). These can be so real that it is difficult to determine if it really happened or was a dream. Sleep paralysis where you wake up unable to move for a few minutes can also occur.
Restless Leg Syndrome – This is a condition in which there is a persistent urge to move the legs at night, sometimes causing the person to get up and walk around. It is common in MS. It can be caused by anemia (low red blood cell count) particular in women. When caused by anemia, treatment of the anemia may help. MS can cause it in the absence of anemia. There are several treatments that help. These include dopamine agonists such as ropinirole (Requip®) and pramipexole (Mirapex®). Benzodiazepines, particular clonazepam (Klonopin®) may be helpful in some instances.
Napping – napping during the day can interfere with sleep at night. This is not a common problem in those who are still working but can interfere with sleep at night, particularly if it is frequent during the day. Stimulants such as modafinil (Provigil®) and armodafinil (Nuvigil®) may be helpful for excessive daytime sleepiness.
In regards to narcolepsy, the symptoms of MS and the symptoms of narcolepsy disorder may be similar. For a person with diagnosed MS, the symptoms may actually be a nerve fiber fatigue encounter.
What do you suggest to recognize a nerve fiber fatigue encounter?
What happens in MS can be an acquired narcolepsy but it can also involve demyelination or fiber loss in the ascending reticular activating system which is located in the pontine tegmentum and is required to maintain wakefulness. It probably differs from standard narcolepsy in being much more closely related to fatigue and usually does not involve the narcolepsy concomitants of sleep paralysis, hypnogogic hallucinations and cataplexy (sudden weakness when startled)..
Nerve fiber fatigue is most often noticed with Uhthoff’s phenomenon which refers to transient visual loss during exercise in an eye that has previously been affected by optic neuritis. It is noticed in walking when the legs give out and simply won’t respond until rested. It can be seen as a rapid increase in weakness in any extremity with exercise. Nerve conduction in a demyelinated fiber is extremely sensitive to an increase in body temperature. Anyone with MS should never get into a hot tub without someone else present as people have died because they became to weak to get out of the hot tub and developed hyperthermia.
Typical nerve fiber fatigue events are loss of vision in bright light, loss of strength in a limb during exercise of that limb. Probably the most commonly observed is walking. As the spinal cord is increasingly affected, the legs just stop working and the person may be able to walk a certain distance such as a block and the legs simply quit working. Heat increases nerve fiber fatigue which is why getting over heated causes weakness.