History
The diagnosis of circadian rhythm disorders is primarily based on a thorough history. Differentiation of transient disorders from chronic disorders and primary disorders from secondary disorders influences the direction of evaluation and treatment plans.
As with all medical and psychiatric histories, the nature of the complaint is the first order of business. In cases of sleeplessness, distinguishing individuals with difficulty initiating sleep from those with difficulty maintaining sleep, those with significant daytime impairment, and those with nonrestorative sleep is important.
Duration of symptoms
Transient changes can be seen with air flights of long duration, jet lag, transient stresses (eg, illnesses), and short-term sleep schedule disruptions (eg, shift work). Chronic circadian changes can be seen with advanced sleep-phase syndrome (ASPS), delayed sleep-phase syndrome (DSPS), and irregular sleep-wake cycles.
Pattern of the sleep-wake cycle
This is an important part of the history in patients with circadian rhythm disturbances. The pattern of the sleep-wake cycle allows diagnosis within the chronic subtypes. DSPS is characterized by a persistent inability (ie, >6mo) to fall asleep and awaken at socially accepted times. Once asleep, these patients are able to maintain their sleep and have normal total sleep times.
DSPS is most frequently identified in adolescents, college students, and night workers. Differential diagnosis includes lifestyle preference, inadequate sleep hygiene, primary insomnia, jet lag, and psychophysiologic insomnia. Teenagers with DSPS are at increased risk for behavioral problems and depression.
Advanced sleep-phase syndrome
ASPS is characterized by persistent, early evening sleep onset (between 6:00 pm and 9:00 pm), with an early morning wake-up time, generally between 3:00 and 5:00 am. The sleep schedule is usually stable. ASPS occurs much less frequently than DSPS and is seen most commonly in the elderly and in persons who are depressed. It needs to be differentiated from exogenous depression and from excessive daytime sleepiness (EDS), which is associated with other sleep disorders (eg, obstructive sleep apnea [OSA]).
Irregular sleep-wake cycle
An irregular sleep-wake schedule features multiple sleep episodes without evidence of recognizable ultradian or circadian features of sleep and wakefulness. As with APSD and DPSD, total sleep time is normal. Daily sleep logs demonstrate irregularity not only of sleep but also of daytime activities, including eating. Body temperature also randomly fluctuates. The principal complaints are excessive daytime sleepiness and/or insomnia.
Shift workers
For shift workers, the need to adjust the biologic clock is coupled with the social pressure of more noise and disturbance during the day, leading to difficulties in sleeping. This is most difficult for workers who must switch their schedule and rotate between morning, evening, and night shifts. For those who consistently work the same shift, only environmental issues affect sleep quality once their biologic clock adjusts to the new time.
Total sleep time
In ASPS and DSPS delays, total sleep time is normal. Shift workers, even those who work a consistent night shift, tend to have shorter sleep times.
Peak alertness
Patients with DSPS have their peak alertness in late evening and night, whereas patients with ASPS have their peak alertness in the early morning. Patients with irregular sleep-wake cycles demonstrate no consistent pattern of alertness.
Recent travel
Jet lag is a form of transient circadian rhythm disturbance. It results from an inability to synchronize one's normal rhythm to rapidly changing time shifts of environmental cues.
Although many of the symptoms have been associated with high-altitude flight in general, the distinguishing factor seems to be the length of symptoms. Symptoms related to flight generally last less than 24 hours, whereas those of jet lag may persist for days. The duration of the flight is the primary determinant of the intensity and duration of the jet lag. In general, jet lag is most likely to be experienced if 3 or more time zones are crossed. The likelihood of sleep disturbance during travel across time zones increases with aging. [7]
Daytime sleepiness
Daytime sleepiness is seen in all circadian rhythm disorders, although the severity may vary from individual to individual and from day to day. Assess for the presence of consequences of daytime sleepiness, which include poor concentration, impaired performance (including a decrease in cognitive skills), and poor psychomotor coordination. Headaches may also be present. The presence of early morning headaches should suggest further investigation for obstructive sleep apnea (OSA).
For children and adolescents, early school hours are associated with shorter total sleep time and increased daytime sleepiness. This is more prominent in teenagers.
Psychological assessment
Psychophysiological insomnia, depressive disorders, and other psychiatric disorders may present with symptom profiles similar to those of circadian rhythm disorders. Assess patients for these disorders.
Cognition
Assess impact on complex cognitive tasks such as selective attention and executive function as these will impact on risks for both work and school performance.
Patient attempts at treatment
Perform a careful inquiry concerning the patient’s use of commonly employed sleep aids, including alcohol, herbal preparations, and over-the-counter (OTC) sleep aids. Residual sleepiness can be seen with some of these preparations, as well as with prescription hypnotics and some of the allergy preparations. Johnson et al reported that 13% of the general population had used alcohol as a short-term sleep aid during the previous year. [8]
Medication history
Obtain a careful medication history regarding the timing of administration of drugs. For example, beta-adrenergic drugs, typically used in the treatment of asthma, can delay sleep because of their stimulant effect. Amphetamines, caffeine, selective serotonin reuptake inhibitor (SSRI) antidepressants, steroids, nicotine, theophylline, and clonidine can also affect sleep.
Snoring
Chronic loud snoring with or without witnessed apnea should direct the physician to evaluate the patient for risk factors for upper airway resistance syndrome and OSA.
Other medical problems
The 2 most commonly seen medical diseases that affect sleep and daytime function are congestive heart failure and chronic obstructive pulmonary disease. Chronic pain syndromes and thyroid disease also affect sleep and daytime function. Hyperthyroidism is associated with sleep disruption, whereas hypothyroidism is associated with daytime sleepiness and fatigue.
Environmental cues and sleep hygiene
This is particularly important to assess in shift workers. The intensity of light, level of noise, and environmental temperature can influence sleep. Exercise and stimulant intake prior to bedtime are frequent lapses in good sleep hygiene and can be easily addressed.
Finally, inquire about any history of motor vehicle accidents or other accidents occurring as a result of decreased alertness/excessive sleepiness.
Physical Examination
The physical examination complements the history in patients with insomnia. Focus the physical examination on identifying risk factors for other conditions that may precipitate, exacerbate, or mimic insomnia. These may include depression, obstructive sleep apnea (OSA), and neurodegenerative disease. The exam can include the following evaluations:
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Affect - Assess general affect and sense of well-being in patients presenting with insomnia as a primary sleep complaint
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Body mass index - Patients with obesity who have increased body mass indices are at increased risk for OSA
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Craniofacial morphology - The head and neck examination is important in assessing risk for OSA; patients with large tonsils, narrow oropharyngeal spaces, and large necks are at risk for OSA
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Chest - Barrel chest (ie, increased anteroposterior diameter) is associated with chronic lung disease; crackles, murmurs, and cardiac enlargement evidenced by displaced point of maximum impulse (PMI) suggest congestive heart failure
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Digital clubbing - Clubbing may be associated with chronic lung disease or congenital heart disease, or it may be familial; this finding suggests a need for further medical evaluation
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Neurologic examination - Alzheimer disease and other neurodegenerative diseases frequently are associated with irregular sleep-wake cycles
