Approach to sleep disorders: Clinical sciences

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Introduction 0:00–0:50

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.

Focused H&P 0:50–1:43

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 prol 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.

REM-related parasomnia 1:43–2:36

If yes, diagnose REM-related parasomnia, which is typically seen in older adults. 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.

REM sleep behavior disorder 2:36–3:59

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's 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.

Nightmare disorder 3:59–4:32

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. All right, now, let's go back and discuss patients who do not have detailed recall of recurrent dreams.

Non-REM parasomnia 4:32–5:19

In this case, diagnose a non-REM related parasomnia, which occurs more commonly in younger patients. Here's another high yield fact.
Remember that there is more non-REM sleep in the 1st 3rd 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. Once you diagnose non-REM related parasomnia, further evaluate the history and physical exam findings to assess the underlying cause.

Sleepwalking 5:19–5:38

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.

Sleep terrors 5:38–6:06

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, tachypnia, diaphoresis, and dilated pupils.

Restless legs syndrome 6:06–7:27

In this case, diagnose sleep terrors. Now, switching gears and moving on to individuals with no abnormal verbal or motor activity during sleep.
In these patients, your next step is to ask if they have difficulties with sleep initiation, or in other words, if they have trouble falling asleep.
If present, think of restless legs syndrome, delayed sleep-wake phase disorder, and chronic insomnia disorder. In restless legs syndrome, the patient will report an urge to move their legs, which is often associated with an uncomfortable sensation, particularly during rest at night.
The sensations improve when moving their legs. The same phenomenon may occur in the arms as well.
History might also reveal iron deficiency, pregnancy, and chronic renal failure. Also, there might be a family history of similar symptoms.
Finally, if the physical exam is normal, you can diagnose restless legs syndrome. Now here's a clinical pearl to keep in mind.
Most patients with restless legs syndrome also have periodic limb movements during sleep, which are repetitive stereotyped movements, usually of the legs.

Delayed sleep-wake phase disorder 7:27–8:50

These episodes can affect sleep maintenance and contribute to poor sleep. Next, let's talk about delayed sleep-wake phase disorder, which is a certain type of circadian rhythm sleep-wake disorder typically seen in adolescents and young adults.
In this case, the patient will report consistently going to bed late and waking up late, which can affect their daily activities such as school or work.
If their schedule is flexible, meaning they don't have to wake up early, the patient would get enough sleep. These findings in combination with a normal physical exam are suggestive of delayed sleep-wake phase disorder.
Here are a few more high yield facts. Other circadian rhythm sleep-wake disorders include advanced sleep-wake phase disorder, shift work disorder, and jet lag disorder.
In advanced sleep-wake phase disorder, patients go to sleep and wake up earlier than normal, which is common in older patients.
Shift work disorder occurs when the patient's work schedules overlap with the usual sleep time, affecting normal sleep and wake times or causing excessive sleepiness during the day.
Finally, jet lag disorder, which occurs when traveling across different time zones, is characterized by insomnia or excessive daytime sleepiness with decreased total sleep duration.

Chronic insomnia 8:50–9:24

Next up is chronic insomnia. These individuals report difficulty falling asleep or staying asleep or waking up too early despite having adequate sleep times.
Also, they might feel tired and sleepy all the time, experience mood changes, and have impaired attention, concentration, and memory.
In extreme cases, this can impact their daily functioning, causing disturbance at social events or work. Finally, if the physical exam is normal, you can diagnose chronic insomnia disorder.

Narcolepsy with cataplexy 9:24–11:11

Next, let's go over conditions where people have no difficulties with sleep initiation. In narcolepsy with cataplexy, the patient will report unexpectedly falling asleep during the day, particularly during quiet activities like meetings or classes.
Sometimes they might even fall asleep while performing various activities like eating or drinking. Additionally, patients will report episodes of sudden weakness triggered by strong emotions such as laughter.
In some cases, history might reveal hallucinations at sleep onset known as hypnagogic hallucinations or upon wakening, known as hypnopompic hallucinations.
Lastly, the patient might report episodes of feeling paralyzed upon awakening, also known as sleep paralysis. The physical exam between episodes of weakness will be normal.
However, during these episodes, the exam will reveal bilateral focal or diffuse decreased tone and weakness, as well as a loss of deep tendon reflexes in affected regions.
With these findings, consider narcolepsy with cataplexy as a cause. Be sure to obtain a multiple sleep latency test.
Also, consider obtaining a CSF sample to check the concentration of hypocretin 1, which is a peptide produced in the hypothalamus that helps regulate sleep.
If the multiple sleep latency test shows that the patient takes 8 minutes or less to fall asleep, and 2 or more REM periods at sleep onset, with low hypocretin 1 levels, you can diagnose narcolepsy with cataplexy.

Sleep apnea11:11–12:44

Finally, let's go over sleep apnea. In this case, the patient typically reports waking up gasping for air or experiencing shortness of breath during sleep.
Additionally, history will reveal excessive daytime sleepiness. In some cases, their bed partner might notice that the patient stops breathing during sleep or that they are frequently snoring.
In some cases, history might reveal conditions like hypertension, atrial fibrillation, congestive heart failure, or a recent stroke.
On examination, you might notice increased neck circumference, central obesity, or enlarged structures in the oropharynx, such as the tonsils, uvula, and tongue.
With these findings, consider sleep apnea as the cause. Be sure to obtain sleep polysomnography.
If the apnea hypopnea index is at least 5, diagnose sleep apnea. In other words, your patient should have at least 5 episodes of apnea or hypopnea per hour to confirm the diagnosis.
Now, here's a high yield fact to keep in mind. There are two types of sleep apnea.
The first one is obstructive sleep apnea, which is caused by anatomical obstruction to airflow, while the second one is central sleep apnea, which occurs due to a lack of respiratory drive, due to structural brain lesions or sedating medications.

Review 12:44–13:43

Alright, as a quick recap, sleep disorders are conditions that interfere with sleep or the transition between sleep-wake cycles.
Once you identify a sleep disorder, your first step is to assess for abnormal verbal or motor activity during sleep. If present, think of REM-related parasomnias, like REM sleep behavior disorder and nightmare disorder, and non-REM related parasomnias like sleepwalking and sleep terrors.
On the flip side, if there is no abnormal verbal or motor activity during sleep, assess for difficulty with sleep initiation.
If present, consider restless legs syndrome, delayed sleep-wake phase disorder, and chronic insomnia. However, if absent, you should think of narcolepsy with cataplexy and sleep apnea.