Sleep Medicine & Neuromuscular Disorder Flashcards
What is the most powerful zeitgeber entraining the sleep–wake rhythm?
Light
What structure in the brain acts as the master circadian rhythm generator in mammals, and where is it located?
Suprachiasmatic nucleus; anterior hypothalamus
Stimulants such as amphetamines and modafinil promote wakefulness by…?
increasing excitatory neurotransmitters (norepinephrine, dopamine, and hypocretin).
Caffeine increases wakefulness by..?
blocking the receptors of adenosine, a CNS neurotransmitter.
Which neurotransmitter is responsible for rapid eye movement sleep generation?
Acetylcholine
When is melatonin secreted? What is its function?
Secreted at night; promotes sleep by causing drowsiness and lowering body temperature (think of melatonin as the darkness signal.)
A 19-year-old woman sleeps from 3 am until 11 am daily. She starts college in 1 month and has 7 am classes. What circadian rhythm sleep disorder does she have? When would you give her melatonin?
She has a delayed sleep phase disorder; should receive melatonin early in the night to help her fall asleep earlier.
A 76-year-old man sleeps from 7 pm until 4 am once a day. He wants to join his local Bingo group that meets at 8 pm, and he would like to stay up longer at night. What circadian rhythm sleep disorder does he have, and when would you give him melatonin to treat it?
He has advanced sleep phase disorder, and he should receive melatonin in the early morning, after being cautioned that melatonin can cause drowsiness
Ghrelin stimulates appetite, and leptin inhibits appetite.
Ghrelin = Grow
Leptin = Lean
What is/are the effect(s) of REM sleep compared to NREM sleep on the autonomic nervous system?
A transient increase in sympathetic activity during phasic REM sleep
How are hormones ghrelin and leptin affected by sleep deprivation?
Ghrelin increases, and leptin decreases
What characteristic EEG waveforms define sleep stage N2?
K-complex and sleep spindles
What are two defining characteristics of narcolepsy on PSG with MSLT?
Decreased SOL and ≥ two SOREMPs on MSLT
Sleep apnea is uncommon as the sole etiology for significant pulmonary hypertension; when present, other etiologies should be considered.
Increased risk for cardiovascular disease in the context of OSA is tied more to degree of oxygen desaturation than to AHI.
Which patients should not undergo a portable home sleep study?
Patients with cardiovascular disease, stroke, COPD, and hypoventilation syndromes
What is the best historic predictor of OSA?
Witnessed apneas— daytime sleepiness is the most common symptom
What is the #1 reason for residual daytime sleepiness in patients who are on CPAP therapy for SDB?
CPAP noncompliance
Nocturia associated with OSA improves with CPAP use.
Which outcome is the most likely to improve with use of CPAP in OSA?
Daytime sleepiness
A 74-year-old man with heart failure (LVEF 20%) and atrial fibrillation is referred for frequent nocturnal desaturations noted during a recent hospitalization. What type of SDB would you be concerned about?
Cheyne-Stokes respiration
Would a patient with Cheyne-Stokes respiration be hypercapnic, hypocapnic, or eucapnic on a daytime arterial blood gas?
Typically hypocapnic
What is the first step in the management of CSRs in the setting of heart failure?
Optimize heart failure (i.e., ACE inhibitors)
What is the most important determinant of sleep- related hypoxemia in COPD?
Hypoventilation
The hallmark of narcolepsy is daytime sleepiness. If a patient is not sleepy, the diagnosis of narcolepsy is highly unlikely.
Mnemonic
Sleep hallucinations—GO to sleep. POp awake.
HypnaGOgic HypnoPOmpic
Mnemonic
Clinical features of narcolepsy—Some Patients Can Fall Hard
Sleepiness
Paralysis
Cataplexy Fragmentation of sleep Hallucinations
An MSLT is suggestive of narcolepsy if the mean sleep latency is < 8 minutes and if there are at least two SOREMPs.
What clinical feature is virtually pathognomonic for narcolepsy?
Cataplexy
Clinical features of RLS—
URGE
Urge to move legs Rest precipitates
symptoms
Getting up and moving
alleviates symptoms Evening and nighttime
worsening of symptoms
What is the treatment of choice for Idiopathic Hypersomnia?
Orexin (hypocretin)
Decreased levels of which neurotransmitter is implicated in narcolepsy?
Modafinil or armodafinil
Although RLS and periodic limb movement disorder are similar, they are two different conditions. RLS is a clinical diagnosis and does not require a PSG. However, if a PSG is performed, PLMs usually are found.
RLS is related to low CNS iron stores, which disrupt dopamine synthesis. Dopamine agonists relieve RLS.
Parasomnias typically occur during NREM sleep and thus are more often present during the first half of the night.
Patients with RBD are at high risk of developing which condition?
Parkinson disease
What inhibits melatonin production?
Light
A 32-year-old woman reports sleeping only 3 hours per night for many years. She reports good sleep quality, denying any daytime impairment, sleepiness, or distress. Does this patient have insomnia?
No because the patient is not experiencing impairment or distress as a result of the short sleep duration.
The gold standard treatment of insomnia of long duration is CBT.
Nocturnal NIPPV is the cornerstone of respiratory management in patients with neuromuscular disorders.
Features that distinguish GBS from other neuromuscular disorders include neuropathic pain, autonomic dysfunction, and diminished deep tendon reflexes on physical exam.
What are the only disease- modifying treatment options for GBS?
Plasmapheresis or IVIG
Signs of upper and lower motor neuron involvement are very characteristic of ALS. Spasticity, atrophy, and fasciculations will help distinguish ALS from other neuromuscular disorders.
Classically, the muscle weakness of myasthenia gravis worsens as the day progresses.
Lambert–Eaton syndrome is strongly associated with small cell lung cancer.
In contrast to myasthenia gravis, repetitive nerve stimulation results in increased amplitude of action potentials at Lambert Eaton
Symptoms of organophosphate poisoning?
Mnemonic
SLUDGE—
Salivation Lacrimation Urination Defecation GI upset Emesis
PFT findings in severe kyphoscoliosis are?
low TLC and VC, with preserved RV.
This results in an increased RV:TLC ratio.
