- 发布时间：2008-08-29 来源：飞华健康网医生组 46人关注
Charles E. Henley
Insomnia is more than just being unable to fall asleep. It is a subjective condition of insufficient or nonrestorative sleep despite an adequate opportunity to sleep. The Institute of Medicine and most current studies place the prevalence of insomnia at 30% to 40% in the general adult population. Although the need for sleep does not necessarily decrease with age, the incidence of sleep disturbances appears to increase with age, particularly among women. Actually, the elderly are more prone to sleep maintenance problems, whereas younger people tend to have trouble falling asleep.
Insomnia represents a symptom of an underlying problem and is not in itself a disease entity. Sleep and alertness are regulated by a complex interaction between the body's internal biologic clocks, the reticular activating system, and various influences such as light or anxiety that can interfere with the normal sleep cycles. The approach to diagnosis should recognize the potential for various causes and use history and special studies to determine the cause of the insomnia.
A. Types of insomnia.
Although more than one classification system for insomnia exists, a consensus seems to support dividing insomnia into transient (lasting a few days), short-term (lasting weeks), and long-term or chronic (lasting many weeks to months or years). The Association for the Psychophysiological Study of Sleep has classified insomnia as:
1. Psychophysiologic, which covers the transient and short-term problems associated with situational factors such as concern about an ill family member.
2. Psychiatric, especially depression, which has a very high concordance with insomnia, and which also covers other affective disorders and psychosis.
3. Drugs and alcohol, especially chronic alcoholism, and the use of central nervous system stimulants such as caffeine, nicotine, or other drugs.
4. Sleep-related movements syndromes. These syndromes comprise a special category related to behavioral or motor problems. Periodic limb movements and restless leg syndrome are the most frequent diagnoses.
5. Sleep-induced respiratory problems (e.g., obstructive sleep apnea). With this condition, the patients usually have no trouble falling asleep initially, but have multiple arousals and awakenings during the night.
6. Medical and environmental causes such as repeated rapid eye movement (REM) interruptions from outside noise.
7. Unknown causes--the patient may just be a short sleeper.
B. Special concerns.
Potentially, the most serious problem associated with insomnia is related to obstructive sleep apnea. If left untreated, it is associated with oxygen desaturation, hypercapnia, and hypopnea, which can lead to significant cardiovascular problems (e.g., systemic and pulmonary hyper tension, cor pulmonale, and right ventricular failure).
A. Characteristics of insomnia.
Insomnia cannot be diagnosed by the amount of time a person sleeps. Rather, it is distinguished by the daytime consequences of unsatisfactory sleep. A pertinent history for insomnia would include:
1. A history of restlessness, irritability, daytime somnolence, and impaired work or social functioning, which can lead to situational stress. This may be a transient problem, but it can lead to difficulties with initiation of sleep and early awakenings.
2. Use of caffeine or other stimulants, especially over-the-counter medications (e.g., decongestants) that may contain ephedrine or phenylpropanolamine. Late evening exercise can also be a stimulant. Alcohol may help induce sleep, but it interferes with REM sleep and leads to nonrestorative sleep and early awakenings.
3. Affect changes, sadness, hopelessness, and vegetative signs such as weight loss should suggest depression, the most common psychiatric disorder associated with insomnia (Chapter 3.3). This is especially true if the insomnia persists for weeks. Anxiety disorders cause difficulty with getting to sleep, whereas patients with depression may fall asleep more readily but have early awakening.
4. Medical problems such as peptic ulcer disease and heart failure have been implicated in insomnia (Chapters 7.5 and 9.6). A history of frequent nocturnal urinations can also disrupt sleep and may indicate benign prostate hyperplasia or other prostate problems. Hyperthyroidism can cause irritability and insomnia, as can thyroid replacement therapy for hypothyroidism. Other problems such as asthma, angina, back pain, and sinusitis can also cause sleep disorders.
5. Loud snoring, daytime somnolence, forgetfulness, difficulty concentrating, and a history from the bed partner of periods of discontinuation of breathing during sleep of 10 seconds or more should suggest a more thorough evaluation for obstructive sleep apnea. Daytime napping, associated findings of gastrointestinal reflux disease, and hypertension are also suggestive associations for sleep apnea.
6. The bed partner is also a good person to ask about leg movements during sleep. This could be suggestive of a periodic limb movement disorder. A similar syndrome, restless legs, is associated with a history of unpleasant sensations in the legs and a persistent desire to move them. Both conditions cause a delay in sleep onset and nocturnal awakenings.
7. Sleep phase disturbances caused by jet lag or shift work can be characterized by early awakening or by awakening later in the day.
III. Physical examination.
The physical examination for insomnia is more a search for other underlying disease states than for any specific signs for insomnia, although hypertension, obesity, and thick neck suggest consideration of sleep apnea.
The diagnosis of unexplained insomnia may involve testing in a sleep laboratory using polysomnography. This provides the opportunity to monitor such parameters as the electroencephalogram (EEG),'breathing, oxygen saturation, and body movements during sleep. Polysomnography can determine the disturbances in chronobiologic rhythms and loss of normal sleep-awake patterns associated with circadian rhythm disorders. The EEG results from the sleep laboratory will demonstrate a patient's ability to progress through the five cycles of normal sleep and where in the process any disturbances may be located. For instance, a short REM sleep latency period from initiation of sleep to actual REM sleep, along with increased REM sleep, and reduced total sleep time with frequent awakenings are all associated with depression.
V. Diagnostic assessment.
The key to diagnosing insomnia and other sleep disorders is history and sleep laboratory monitoring. Short-term problems related to difficulty with initiating sleep may be situational or environmental. Long-term problems with sleep_, lasting weeks to months, may be more psychophysiologic such as with chronic anxiety or depression. A thorough history of personalor job-related issues, caffeine, alcohol and other drug use, related medical problems, abnormal leg and body movements at night, problems with daytime napping and somnolence as well as night time snoring, and apnea spells will all direct the practitioner to the cause of most problems. A good sleep study often confirms the diagnosis and leads to specific interventions.