Approach to sleep disorders: Clinical sciences

Sleep disorders are conditions that interfere with sleep or the transition between sleep-wake cycles. These disorders can affect different aspects of sleep, including sleep initiation, maintenance, or duration, and cause significant distress in daily activities.

Some conditions are associated with abnormal motor or verbal activity during sleep, which include the REM parasomnias and non-REM parasomnias; while others are characterized by difficulties in sleep initiation or maintenance, or excessive sleepiness. These include restless legs syndrome, delayed sleep-wake disorders, and chronic insomnia, as well as narcolepsy with cataplexy and sleep apnea.

Now, if a patient presents with chief concerns suggestive of a sleep disorder, you should first obtain a focused history and physical examination.

Your patient will typically report poor sleep quality, meaning difficulty falling asleep, interrupted sleep, or waking up too early. Family or friends might also report that the patient has abnormal movements or vocalizations during sleep. The physical exam may or may not be normal. In this case, you should think of a sleep disorder, so be sure to assess for abnormal verbal or motor activity during sleep.

Here’s a clinical pearl to keep in mind! Sleep disturbances can also be secondary to other medical conditions, such as hyperthyroidism and congestive heart failure, so be sure to keep a wide differential in mind!

So, if abnormal verbal or motor activity is present during sleep. Assess if the patient has a detailed recall of recurrent dreams. If yes, diagnose REM-related parasomnia, which is typically seen in older adults and conditions like REM sleep behavior disorder and nightmare disorder.

Here are some high-yield facts to keep in mind! Remember that there are different stages of sleep, with REM being the last stage. REM sleep is characterized by dreams, rapid eye movements, and muscle atonia. The longest periods of REM sleep occur during the last third of the night, so REM-related parasomnias generally happen later in the night.

During REM-related parasomnias, the patient’s eyes are closed, and they have no awareness of their surroundings.

Once you diagnose REM-related parasomnia, further evaluate the history and physical exam findings to assess the underlying cause. First, let’s focus on REM sleep behavior disorder, which is characterized by frequent, unpleasant dreams. The patient’s family member or partner will usually report that the patient has abnormal activity during the dreams, such as kicking, punching, or screaming. These behaviors can occasionally cause physical harm to the patient or their partner.

Next, the physical exam could be normal, or you might find signs of parkinsonism, which include bradykinesia, rigidity, or tremors. With these findings, consider REM sleep behavior disorder, so be sure to obtain video polysomnography, which is a sleep study with video.

If the polysomnogram shows episodes of complex motor behaviors or vocalizations during REM sleep without muscle atonia, diagnose REM sleep behavior disorder.

Here's a clinical pearl to keep in mind! There is a strong association between REM sleep behavior disorder and Parkinson disease and certain Parkinson-plus syndromes, specifically dementia with Lewy bodies and multiple system atrophy.

Next up is nightmare disorder. In this case, the patient will report frequent, unpleasant dreams that revolve around physical harm or threats to security or survival. After being awakened from these episodes, the patient is fully alert and aware. Keep in mind that these dreams or the resulting sleep disturbance cause significant distress and impair the patient’s functioning at work or school. Finally, if the physical exam is normal, you can diagnose...nightmare disorders.

Alright, now let’s go back and discuss patients who do not have detailed recall of recurrent dreams.

In this case, diagnose a non-REM-related parasomnia, which occurs more commonly in younger patients and conditions like sleepwalking and sleep terrors.

Here’s another high-yield fact! Remember that there is more non-REM sleep in the first third of the night, so episodes due to non-REM-related parasomnias tend to occur early in the night. Unlike in REM-related disorders, episodes are not related to dreams, and there is an abnormal level of arousal during events, with eyes usually opened. In this case, your patients will have limited or no recall of the episodes.

In sleepwalking, a family member or partner will report that the patient has recurrent episodes of getting out of bed and walking. Sometimes, the patient will perform additional tasks like eating or toileting. Additionally, the physical exam will be normal. At this point, diagnose sleepwalking.

On the flip side, sleep terrors are associated with recurrent episodes of fear, possibly with screams. In this case, the patient is confused after being awakened. The physical exam between episodes is normal, but during episodes, there are signs of autonomic hyperactivity, such as tachycardia, tachypnea, diaphoresis, and dilated pupils. In this case, diagnose sleep terrors.

Now, switching gears and moving on to individuals with no abnormal verbal or motor activity during sleep.