What type of sleep study should be ordered for a patient with a history (hx) of sleep apnea and a history (hx) of narcolepsy?

From the Guidelines

For a patient with a history of both sleep apnea and narcolepsy, a comprehensive overnight polysomnography (PSG) followed by a Multiple Sleep Latency Test (MSLT) the next day is the most appropriate sleep study to order. This recommendation is based on the guidelines provided by the American Academy of Sleep Medicine, which states that portable monitoring (PM) is not appropriate for the diagnostic evaluation of patients suspected of having other sleep disorders, including narcolepsy 1. The overnight PSG will monitor various physiological activities to assess the sleep apnea, while the MSLT will evaluate for narcolepsy by measuring sleep latency and REM sleep onset.

Key aspects of this approach include:

• Evaluating the type and severity of sleep apnea using PSG
• Assessing narcolepsy using MSLT, which measures how quickly the patient falls asleep and enters REM sleep
• Treating sleep apnea adequately before making a definitive narcolepsy diagnosis, as untreated sleep apnea can mimic some narcolepsy symptoms
• Using in-laboratory PSG instead of PM, as PM does not include data necessary to reach diagnostic criteria for narcolepsy or other sleep disorders 1

The combination of PSG and MSLT provides a comprehensive evaluation of both sleep apnea and narcolepsy, allowing for accurate diagnosis and effective treatment of these distinct sleep disorders. By prioritizing this approach, clinicians can ensure the best possible outcomes in terms of morbidity, mortality, and quality of life for patients with complex sleep disorders.

From the FDA Drug Label

The criteria for narcolepsy include either: 1) recurrent daytime naps or lapses into sleep that occur almost daily for at least three months, plus sudden bilateral loss of postural muscle tone in association with intense emotion (cataplexy); or 2) a complaint of excessive sleepiness or sudden muscle weakness with associated features: sleep paralysis, hypnagogic hallucinations, automatic behaviors, disrupted major sleep episode; and polysomnography demonstrating one of the following: sleep latency less than 10 minutes or rapid eye movement (REM) sleep latency less than 20 minutes The criteria for OSA include either: 1) excessive sleepiness or insomnia, plus frequent episodes of impaired breathing during sleep, and associated features such as loud snoring, morning headaches and dry mouth upon awakening; or 2) excessive sleepiness or insomnia and polysomnography demonstrating one of the following: more than five obstructive apneas, each greater than 10 seconds in duration, per hour of sleep and one or more of the following: frequent arousals from sleep associated with the apneas, bradytachycardia, and arterial oxygen desaturation in association with the apneas

Sleep Study Recommendation:

• For a patient with a history of sleep apnea and narcolepsy, a polysomnography (PSG) study should be ordered to assess both sleep apnea and narcolepsy.
• The PSG study can help diagnose and assess the severity of sleep apnea by measuring the number of apneas and hypopneas per hour of sleep.
• Additionally, the PSG study can help diagnose narcolepsy by measuring sleep latency and REM sleep latency.
• The Multiple Sleep Latency Test (MSLT) can also be considered to assess excessive daytime sleepiness, which is a common symptom of both sleep apnea and narcolepsy 2.

From the Research

Sleep Study Recommendations

To determine the appropriate sleep study for a patient with a history of sleep apnea and narcolepsy, the following points should be considered:

• The patient's history of sleep apnea and narcolepsy suggests the need for a comprehensive sleep evaluation.
• The multiple sleep latency test (MSLT) is a standard test for assessing objective sleepiness and diagnosing narcolepsy, as noted in 3 and 4.
• Nocturnal polysomnography (PSG) is essential for diagnosing sleep apnea and should be performed the night before the MSLT, as stated in 3.
• The MSLT and PSG can provide valuable information on the patient's sleep patterns, sleep latency, and REM latency, which can help differentiate between narcolepsy type 1 and type 2, as discussed in 5.

Key Considerations

Some key points to consider when ordering a sleep study for this patient:

• The presence of sleep apnea may interfere with the diagnosis of narcolepsy, as noted in 6.
• The MSLT and PSG should be performed in accordance with established protocols to ensure accurate results, as emphasized in 7.
• The patient's demographic characteristics, such as body mass index, and prevalence of sleep paralysis, should be taken into account when interpreting the results, as mentioned in 5.

Recommended Sleep Study

Based on the patient's history and the available evidence, the recommended sleep study would include:

• Nocturnal polysomnography (PSG) to diagnose sleep apnea and assess sleep patterns.
• Multiple sleep latency test (MSLT) to assess objective sleepiness and diagnose narcolepsy, as supported by 3, 4, and 7.