Eyes wide open: Update on sleep disorders
Getting a good night's sleep is vital to our mental, physical, and emotional health. However, each patient's sleep needs are individual, generally ranging from six to nine hours per 24-hour cycle. Most people need approximately 7.5 to eight hours of sleep. Many factors determine the number of hours of sleep required, including age, genetics, medical and psychiatric health, prescription and OTC medications being used, alcohol intake, prior acute and chronic sleep loss, and circadian rhythm and time of day, as well as sleep hygiene. In the absence of sleep disorders, the amount of sleep needed is that which permits the individual to awaken refreshed and feel alert throughout the day without nodding off unintentionally.
Age has a profound effect on sleep. The ability to attain deep and efficient sleep decreases as we age, although sleep need may not decrease. Age may cause numerous sleep changes, including an earlier and dampened circadian rhythm, longer time to fall asleep, frequent awakenings, loss of the ability to attain delta/deep sleep, and early-morning awakenings.
Q. Could the patient's sleep difficulties be simple fatigue?
A. Differentiating sleepiness from fatigue can sometimes be difficult clinically. It is helpful to know if the patient nods off inappropriately in inactive situations, such as watching television or reading; in active situations, such as social conversation or at work; or in dangerous situations, such as driving. The Epworth Sleepiness Scale is a simple office questionnaire used to identify situational somnolence.
The patient can monitor the quantity and timing of sleep by completing a two-week, 24-hour sleep log or diary. Documentation includes the patient's bedtime, time to fall asleep from lights out, time and length of nocturnal awakenings, time of awakening on weekdays versus weekends, and unintentional as well as intentional naps. Sleepy patients may be asked to complete sleep logs while increasing the total sleep time by one-half to one hour over a two-week period.
Q. Are naps good or bad?
A. The benefits of napping vary from patient to patient. Ideally, an individual has one consolidated nocturnal sleep of sufficient quality and quantity to allow awakening refreshed and staying alert throughout the course of the day. In such a person, a nap may decrease the usual evening sleepiness that precedes and initiates normal sleep onset. Thus, increasing the nocturnal sleep by going to bed earlier or rising later is preferable to a nap in an otherwise normal, partially sleep-deprived individual.
Patients with insomnia may have more difficulty falling asleep if they have taken a nap because there is less of a sleepiness load, or less sleep pressure, at night. Sleep pressure is thought to be an important influence in increasing the amount of delta/deep sleep during the initial portion of sleep.
Naps may be ideal to supplement sleep time in those who are unable to get enough sleep, for example, shift workers or new mothers, or in patients whose sleep quality is poor, such as those with chronic pain or the elderly. The benefits of napping can be determined clinically by a two-week trial of napping while completing a sleep log.
Q. Is a sleep study part of the initial workup?
A. The first step is a detailed medical, psychiatric, and sleep history, as well as a physical exam. A detailed sleep history includes questions concerning the quality and description of nighttime sleep, the quantity of sleep over the 24-hour cycle, the timing of sleep, and the assessment of daytime alertness/daytime sleepiness. A sleep history also includes sleep hygiene habits and lists the amount and timing of ingestion of caffeine, alcohol, and OTC and prescription medications. Patients with such sleep disorders as sleep apnea or narcolepsy require sleep studies.
If a history and two-week sleep log indicate inadequate sleep time, a trial of increased sleep time may be considered before referral to a specialist. It is important to remember that disturbances in circadian physiology and sleep can exacerbate many medical illnesses, such as nocturnal asthma, ulcer disease and nocturnal reflux, nocturnal epilepsy, and sleep-related dysrhythmias.
Q. What disorders cause daytime sleepiness?
A. Sleep apnea and narcolepsy are two disorders to consider in those who report daytime sleepiness. Sleep history symptoms suggesting sleep apnea syndrome may include a description of habitual snoring, the presence of witnessed breathing pauses or gasping, nocturnal diaphoresis, nocturia, unexplained nocturnal awakenings, restless or unrefreshing sleep, dull morning headaches, impotence, and daytime sleepiness. Daytime symptoms may also include decreased energy, concentration, motivation, and memory. The risk for sleep apnea in women increases during and following menopause. Physical examination of a patient with sleep apnea may reveal hypertension; obesity; nasal or oropharyngeal obstruction; retromicrognathia; macroglossia; neck circumference >16.5 inches in men; hypothyroidism; and numerous other associated cardiopulmonary conditions, such as heart failure.
Narcolepsy is another disorder that causes complaints of sleepiness in patients. Clinical symptoms include sleep attacks, cataplexy (sudden muscle tone loss while awake, following such emotional reactions as laughter or anger), sleep paralysis (a frightening inability to move while falling asleep or awakening, lasting several seconds), or hypnagogic hallucinations (a brief frightening awareness of a hallucination while falling asleep or awakening). Narcolepsy is uncommon and frequently misdiagnosed because many patients have numerous concurrent problems, ranging from diabetes to depression.
Those suspected of having sleep apnea syndrome or narcolepsy and any patient who has dangerous sleepiness despite having increased total sleep time should undergo sleep studies or be referred to a sleep specialist. Clinicians ordering sleep studies should be familiar with the diagnosis and treatments of various sleep disorders. Generally, it may be cost-effective to refer patients with unexplained sleepiness, especially sleepy patients without apnea symptoms, directly to a sleep specialist, who may order daytime sleep studies in addition to nocturnal polysomnography.