A 50-year-old man with severe obstructive sleep apnea (AHI 65 events/hour) and CPAP intolerance despite multiple mask trials undergoes maxillomandibular advancement surgery. Three months post-operatively, he continues to report excessive daytime sleepiness and his bed partner reports persistent snoring. Post-operative polysomnography shows AHI of 28 events/hour. He has a BMI of 38 kg/m² (unchanged from pre-surgery) and crowded posterior pharynx. Evaluate the next management strategy.
Q2
A 70-year-old man with newly diagnosed Parkinson disease and REM sleep behavior disorder is being considered for treatment. His neurologist is concerned about medication interactions and disease progression. He also has mild cognitive impairment, orthostatic hypotension, and a history of visual hallucinations. Evaluate the optimal therapeutic approach considering his complex medical profile.
Q3
A 25-year-old medical resident presents with excessive daytime sleepiness and difficulty maintaining wakefulness during lectures. Polysomnography shows normal sleep architecture with a sleep latency of 8 minutes. Multiple Sleep Latency Test (MSLT) shows a mean sleep latency of 4 minutes with 1 sleep-onset REM period (SOREMP). She works rotating shifts, sleeps 4-5 hours on workdays, and has no cataplexy. Evaluation of this clinical scenario suggests which diagnosis best accounts for all findings?
Q4
A 40-year-old woman presents with chronic insomnia, taking zolpidem 10 mg nightly for 2 years. Despite medication, she reports difficulty falling asleep, frequent awakenings, and spends significant time in bed worrying about sleep. She naps for 2-3 hours in the afternoon and has an irregular sleep schedule. Her bedroom has a television that she watches until falling asleep. Analysis of perpetuating factors suggests which intervention addresses the core maintaining mechanism of her insomnia?
Q5
A 55-year-old obese man with treatment-resistant hypertension, type 2 diabetes, and atrial fibrillation undergoes polysomnography which reveals an apnea-hypopnea index (AHI) of 45 events/hour with oxygen desaturations to 78%. He is started on CPAP therapy but returns 3 months later with improved sleep but persistent hypertension despite four antihypertensive medications. Analysis of the relationship between his conditions suggests which mechanism best explains the treatment resistance?
Q6
A 32-year-old pregnant woman in her third trimester presents with uncomfortable sensations in her legs described as 'crawling' and 'creeping' that worsen in the evening and at night. The sensations are relieved by movement. Laboratory studies show hemoglobin of 9.2 g/dL, MCV of 72 fL, and ferritin of 8 ng/mL. Analysis of her clinical presentation suggests which pathophysiological mechanism is most likely contributing to her symptoms?
Q7
A 12-year-old boy is brought to the clinic by his parents who report that he has episodes 1-2 hours after falling asleep where he suddenly sits up in bed screaming with his eyes open, appears terrified and confused, and does not respond to their attempts to comfort him. The episodes last 5-10 minutes, and he has no memory of them in the morning. Application of which management strategy would be most appropriate?
Q8
A 65-year-old man with Parkinson disease presents after his wife witnessed him punching and kicking violently during sleep while appearing to act out his dreams. He has no recollection of these events. His current medications include carbidopa-levodopa and pramipexole. Which characteristic polysomnographic finding would confirm the suspected diagnosis?
Q9
A 28-year-old woman presents with a 6-month history of sudden episodes of muscle weakness triggered by laughter or excitement, causing her to drop objects or collapse. She also reports excessive daytime sleepiness, vivid dream-like experiences when falling asleep, and occasional brief paralysis upon awakening. Which neurotransmitter deficiency is most directly responsible for her symptoms?
Q10
A 45-year-old man presents to the clinic complaining of excessive daytime sleepiness and his wife reports loud snoring with witnessed breathing pauses during sleep. He has a BMI of 34 kg/m² and a neck circumference of 44 cm. Physical examination reveals a crowded oropharynx with a Mallampati score of IV. Which of the following is the most appropriate next step in management?
Sleep disorders US Medical PG Practice Questions and MCQs
Question 1: A 50-year-old man with severe obstructive sleep apnea (AHI 65 events/hour) and CPAP intolerance despite multiple mask trials undergoes maxillomandibular advancement surgery. Three months post-operatively, he continues to report excessive daytime sleepiness and his bed partner reports persistent snoring. Post-operative polysomnography shows AHI of 28 events/hour. He has a BMI of 38 kg/m² (unchanged from pre-surgery) and crowded posterior pharynx. Evaluate the next management strategy.
A. Hypoglossal nerve stimulation therapy evaluation
B. Repeat maxillomandibular advancement with greater advancement distance
C. Observe for another 3 months as surgical swelling may still be resolving
D. Revisit CPAP therapy with auto-adjusting pressure settings (Correct Answer)
E. Proceed directly to tracheostomy for definitive airway management
Explanation: ***Revisit CPAP therapy with auto-adjusting pressure settings***
- **Maxillomandibular advancement (MMA)** significantly reduced the **Apnea-Hypopnea Index (AHI)** from 65 to 28; while not curative, this anatomical change may lower the **positive airway pressure (PAP)** requirements, potentially improving **patient tolerance**.
- **Auto-CPAP** is the most appropriate next step to determine if the post-surgical airway allows for successful treatment at manageable pressures, especially before considering more invasive options.
*Hypoglossal nerve stimulation therapy evaluation*
- This patient's **BMI of 38 kg/m²** currently exceeds the standard FDA-approved threshold of **35 kg/m²** for **hypoglossal nerve stimulation**.
- Evaluation requires a **Drug-Induced Sleep Endoscopy (DISE)** to check for **concentric palatal collapse**, but primary medical optimization remains the priority.
*Repeat maxillomandibular advancement with greater advancement distance*
- **Revision MMA** carries significantly higher surgical risks, including **nerve injury** and **non-union**, and is generally not indicated when initial surgery was technically successful.
- The persistent **AHI of 28** is more likely due to the patient's **persistent obesity** and soft tissue volume rather than inadequate bony advancement.
*Observe for another 3 months as surgical swelling may still be resolving*
- Three months is typically sufficient for the resolution of **post-operative edema** impacting the airway, and active treatment is needed for **moderate OSA** (AHI 28) and **daytime sleepiness**.
- Delaying management puts the patient at continued risk for **cardiovascular complications** and accidents associated with **excessive sleepiness**.
*Proceed directly to tracheostomy for definitive airway management*
- **Tracheostomy** is the most invasive surgical intervention and is reserved for **life-threatening OSA** where all other medical and surgical options have failed.
- It represents a significant **quality-of-life burden** and should not be considered until less invasive modalities like post-surgical **PAP therapy** are re-attempted.
Question 2: A 70-year-old man with newly diagnosed Parkinson disease and REM sleep behavior disorder is being considered for treatment. His neurologist is concerned about medication interactions and disease progression. He also has mild cognitive impairment, orthostatic hypotension, and a history of visual hallucinations. Evaluate the optimal therapeutic approach considering his complex medical profile.
A. Quetiapine for both hallucinations and RBD symptoms
B. Clonazepam 0.5 mg at bedtime with close monitoring for falls
C. Rivastigmine to address cognitive impairment and sleep disturbance
D. Melatonin 3-12 mg at bedtime as first-line therapy (Correct Answer)
E. Pramipexole dose adjustment to suppress REM sleep
Explanation: ***Melatonin 3-12 mg at bedtime as first-line therapy***
- **Melatonin** is the preferred first-line treatment for **REM sleep behavior disorder (RBD)** in elderly patients with neurodegeneration due to its excellent safety profile.
- It effectively reduces **dream enactment** with a lower risk of side effects like **excessive sedation** or motor instability compared to other agents.
*Quetiapine for both hallucinations and RBD symptoms*
- While **Quetiapine** is used to manage **visual hallucinations** in Parkinson's, it is not an established or effective therapy for managing **RBD symptoms**.
- It may worsen **orthostatic hypotension** and daytime somnolence, complicating the patient's existing clinical state.
*Clonazepam 0.5 mg at bedtime with close monitoring for falls*
- **Clonazepam** is highly effective for RBD but is generally avoided in patients with **mild cognitive impairment** and **orthostatic hypotension** due to the high risk of **confusion** and **falls**.
- It can also exacerbate **obstructive sleep apnea** or cause significant **morning-after sedation** in the elderly.
*Rivastigmine to address cognitive impairment and sleep disturbance*
- **Rivastigmine**, a cholinesterase inhibitor, is used for **Parkinson disease dementia** but is not the primary treatment for **REM sleep behavior disorder**.
- Although it may help cognitive symptoms, it does not reliably suppress the physical **dream enactment** characteristic of RBD.
*Pramipexole dose adjustment to suppress REM sleep*
- **Dopamine agonists** like **Pramipexole** are known to potentially **worsen RBD** and can significantly increase the frequency of **visual hallucinations**.
- Increasing the dose in this patient would likely exacerbate his **psychosis** and **orthostatic hypotension**.
Question 3: A 25-year-old medical resident presents with excessive daytime sleepiness and difficulty maintaining wakefulness during lectures. Polysomnography shows normal sleep architecture with a sleep latency of 8 minutes. Multiple Sleep Latency Test (MSLT) shows a mean sleep latency of 4 minutes with 1 sleep-onset REM period (SOREMP). She works rotating shifts, sleeps 4-5 hours on workdays, and has no cataplexy. Evaluation of this clinical scenario suggests which diagnosis best accounts for all findings?
A. Idiopathic hypersomnia with long sleep time
B. Narcolepsy type 1 requiring CSF hypocretin measurement
C. Shift work sleep disorder with circadian misalignment
D. Narcolepsy type 2 based on objective sleepiness and one SOREMP
E. Insufficient sleep syndrome related to work schedule (Correct Answer)
Explanation: ***Insufficient sleep syndrome related to work schedule***
- The patient reports sleeping only **4-5 hours** on workdays, which represents chronic **sleep restriction** compared to the physiological requirement of 7-9 hours.
- **Chronic sleep deprivation** can lead to a shortened mean sleep latency of <8 minutes and single **SOREMPs** on MSLT, making it the most plausible explanation for the findings in a medical resident.
*Idiopathic hypersomnia with long sleep time*
- This condition is characterized by a mean sleep latency of <8 minutes but typically involves **prolonged sleep episodes** (more than 10-11 hours) with significant **sleep drunkenness**.
- The diagnosis requires ruling out **insufficient sleep**, and this patient’s restricted 4-5 hour sleep window directly contradicts the "long sleep time" criteria.
*Narcolepsy type 1 requiring CSF hypocretin measurement*
- **Narcolepsy Type 1** requires the presence of **cataplexy** or low **CSF hypocretin-1** levels, neither of which is suggested by the patient's history.
- The MSLT results in this case only showed **one SOREMP**, whereas Narcolepsy Type 1 diagnosis usually requires **two or more SOREMPs** (or one SOREMP during polysomnography and one during MSLT).
*Shift work sleep disorder with circadian misalignment*
- While the patient works rotating shifts, this disorder specifically involves insomnia or sleepiness that is temporally linked to the **work schedule** causing **circadian misalignment**.
- The primary issue here is the **quantity of sleep** (4-5 hours) rather than the timing of sleep relative to her internal clock, pointing more specifically to insufficient sleep syndrome.
*Narcolepsy type 2 based on objective sleepiness and one SOREMP*
- Diagnostic criteria for **Narcolepsy Type 2** require a mean sleep latency of ≤8 minutes and **two or more SOREMPs**; this patient only had one SOREMP.
- A diagnosis of Narcolepsy Type 2 cannot be made until **insufficient sleep syndrome** is ruled out by ensuring adequate sleep hygiene for at least two weeks prior to testing.
Question 4: A 40-year-old woman presents with chronic insomnia, taking zolpidem 10 mg nightly for 2 years. Despite medication, she reports difficulty falling asleep, frequent awakenings, and spends significant time in bed worrying about sleep. She naps for 2-3 hours in the afternoon and has an irregular sleep schedule. Her bedroom has a television that she watches until falling asleep. Analysis of perpetuating factors suggests which intervention addresses the core maintaining mechanism of her insomnia?
A. Polysomnography to identify underlying sleep architecture abnormalities
B. Switching to a longer-acting benzodiazepine receptor agonist
C. Gradual tapering of zolpidem with substitution of melatonin
D. Cognitive behavioral therapy for insomnia (CBT-I) with sleep restriction (Correct Answer)
E. Adding a sedating antidepressant to the current regimen
Explanation: ***Cognitive behavioral therapy for insomnia (CBT-I) with sleep restriction***
- This patient exhibits **maladaptive behaviors** such as excessive time in bed, afternoon napping, and conditioned arousal (watching TV in bed) that perpetuate chronic insomnia.
- **CBT-I** is the first-line treatment as it uses **sleep restriction** and **stimulus control** to consolidate sleep and address the underlying cognitive distortions regarding sleep.
*Polysomnography to identify underlying sleep architecture abnormalities*
- **Polysomnography** is generally not indicated for the diagnosis of chronic insomnia unless a breathing disorder or **periodic limb movement disorder** is suspected.
- It does not address the **perpetuating behavioral factors** such as napping and irregular schedules identified in this patient.
*Switching to a longer-acting benzodiazepine receptor agonist*
- Switching to long-acting agents increases the risk of **daytime sedation**, falls, and cognitive impairment without addressing behavioral causes.
- This does not target the **conditioned arousal** or poor sleep hygiene that are maintaining the patient's insomnia.
*Gradual tapering of zolpidem with substitution of melatonin*
- While tapering is often necessary, **melatonin** has limited efficacy for chronic insomnia and does not address the core behavioral issues like excessive time in bed.
- It fails to provide the **cognitive restructuring** needed to manage the patient's anxiety about falling asleep.
*Adding a sedating antidepressant to the current regimen*
- Adding more medication leads to **polypharmacy** and fails to treat the root cause, which is behavioral and cognitive in nature.
- Sedating antidepressants do not improve **sleep efficiency** or consolidate the sleep cycle as effectively as behavioral interventions.
Question 5: A 55-year-old obese man with treatment-resistant hypertension, type 2 diabetes, and atrial fibrillation undergoes polysomnography which reveals an apnea-hypopnea index (AHI) of 45 events/hour with oxygen desaturations to 78%. He is started on CPAP therapy but returns 3 months later with improved sleep but persistent hypertension despite four antihypertensive medications. Analysis of the relationship between his conditions suggests which mechanism best explains the treatment resistance?
A. Poor CPAP adherence with inadequate resolution of nocturnal hypoxemia (Correct Answer)
B. CPAP therapy requires 6-12 months to impact blood pressure
C. Concurrent primary hyperaldosteronism is the cause of both conditions
D. Intermittent hypoxia has caused irreversible sympathetic nervous system activation
E. Aldosterone excess from obstructive sleep apnea persists despite CPAP
Explanation: ***Poor CPAP adherence with inadequate resolution of nocturnal hypoxemia***
- The most common reason for **persistent hypertension** despite starting **CPAP** is inadequate device adherence, as clinically significant BP reduction requires at least 4-6 hours of use per night.
- Ongoing **nocturnal hypoxemia** due to poor adherence continues to drive **sympathetic nervous system** overactivity, preventing the stabilization of blood pressure levels.
*CPAP therapy requires 6-12 months to impact blood pressure*
- Significant physiological improvements in **hemodynamics** and reductions in **blood pressure** are typically observed within weeks to 3 months of effective, consistent **CPAP** use.
- Waiting 6-12 months for an initial response is inconsistent with clinical guidelines for assessing **treatment-resistant hypertension**.
*Concurrent primary hyperaldosteronism is the cause of both conditions*
- While **primary hyperaldosteronism** is a cause of resistant hypertension, it does not cause **obstructive sleep apnea (OSA)** directly; rather, **OSA** can cause secondary elevations in **aldosterone**.
- There is no clinical evidence in the stem, such as **hypokalemia**, to specifically prioritize this diagnosis over treatment non-adherence.
*Intermittent hypoxia has caused irreversible sympathetic nervous system activation*
- Although chronic **OSA** causes neural remodeling, the **sympathetic activation** is largely reversible or at least modifiable with high-quality, continuous treatment.
- Labeling the activation as **irreversible** at this stage is medically incorrect, as blood pressure usually improves once **apneic events** are consistently eliminated.
*Aldosterone excess from obstructive sleep apnea persists despite CPAP*
- Effectively treated **OSA** typically leads to a reduction in **aldosterone levels** because it removes the stimulus of intermittent hypoxia and **RAAS activation**.
- If **CPAP** therapy is effective and adherent, any remaining **aldosterone excess** would likely be due to a primary adrenal pathology rather than the **OSA** itself.
Question 6: A 32-year-old pregnant woman in her third trimester presents with uncomfortable sensations in her legs described as 'crawling' and 'creeping' that worsen in the evening and at night. The sensations are relieved by movement. Laboratory studies show hemoglobin of 9.2 g/dL, MCV of 72 fL, and ferritin of 8 ng/mL. Analysis of her clinical presentation suggests which pathophysiological mechanism is most likely contributing to her symptoms?
A. Autoimmune destruction of hypocretin-producing neurons
B. Iron deficiency affecting dopamine synthesis and receptor function (Correct Answer)
C. Excessive accumulation of adenosine in the basal ganglia
D. Decreased dopaminergic neurotransmission in the substantia nigra
E. Impaired GABA-mediated inhibition in motor pathways
Explanation: ***Iron deficiency affecting dopamine synthesis and receptor function***
- The patient presents with classic **Restless Legs Syndrome (RLS)** symptoms, and her labs confirm **iron-deficiency anemia** (low hemoglobin, low MCV, and ferritin <15 ng/mL).
- **Iron** is a vital cofactor for **tyrosine hydroxylase**, the rate-limiting enzyme in **dopamine synthesis**; iron deficiency leads to brain dopamine dysregulation in the basal ganglia.
*Autoimmune destruction of hypocretin-producing neurons*
- This mechanism explains the pathophysiology of **Narcolepsy Type 1**, which presents with excessive daytime sleepiness and cataplexy.
- It is not associated with the creeping limb sensations or **iron deficiency** seen in RLS.
*Excessive accumulation of adenosine in the basal ganglia*
- **Adenosine** typically promotes sleep, and **adenosine receptor antagonism** (e.g., via caffeine) is actually a common trigger that worsens RLS.
- There is no evidence that excessive adenosine accumulation contributes to the crawling sensations associated with pregnancy or iron loss.
*Decreased dopaminergic neurotransmission in the substantia nigra*
- This description refers to the pathology of **Parkinson's Disease**, characterized by tremors, bradykinesia, and rigidity.
- While RLS involves **dopamine dysfunction**, it is functionally different from the structural neuronal loss and motor deficits found in the **substantia nigra pars compacta**.
*Impaired GABA-mediated inhibition in motor pathways*
- Impaired **GABAergic** signaling is often linked to conditions like **Stiff Person Syndrome** or certain types of spasticity.
- RLS is primarily driven by the **dopaminergic system** and iron levels rather than a primary deficit in GABA-mediated inhibition.
Question 7: A 12-year-old boy is brought to the clinic by his parents who report that he has episodes 1-2 hours after falling asleep where he suddenly sits up in bed screaming with his eyes open, appears terrified and confused, and does not respond to their attempts to comfort him. The episodes last 5-10 minutes, and he has no memory of them in the morning. Application of which management strategy would be most appropriate?
A. Behavioral therapy focusing on nightmare rescripting
B. Low-dose selective serotonin reuptake inhibitor (SSRI)
C. Polysomnography to rule out nocturnal seizures
D. Starting a dopamine agonist before bedtime
E. Scheduled awakening 15 minutes before typical episode onset (Correct Answer)
Explanation: ***Scheduled awakening 15 minutes before typical episode onset***
- This patient presents with **sleep terrors**, a **NREM parasomnia** occurring during **slow-wave sleep (N3)**; the treatment of choice is disrupting the sleep cycle to prevent the transition into the terror.
- Management focuses on **reassurance** and **scheduled awakenings**, as most children naturally outgrow this condition without long-term sequelae.
*Behavioral therapy focusing on nightmare rescripting*
- This approach is used for **nightmares**, which occur during **REM sleep**, typically in the latter half of the night, and involve **vivid dream recall**.
- Sleep terrors involve **amnesia** of the event and occur in the first third of the night, making dream-focused therapy ineffective.
*Low-dose selective serotonin reuptake inhibitor (SSRI)*
- SSRIs are not the standard pharmacological treatment for sleep terrors; if medication is truly necessary for severe cases, **benzodiazepines** (which reduce N3 sleep) are preferred.
- Pharmacotherapy is generally avoided in children unless the episodes pose a **safety risk** or are extremely frequent.
*Polysomnography to rule out nocturnal seizures*
- **Polysomnography** is generally unnecessary for classic sleep terrors unless the presentation is atypical or **nocturnal epilepsy** is strongly suspected.
- The clinical history of **autonomic arousal**, timing in the first third of the night, and **lack of memory** are diagnostic of sleep terrors.
*Starting a dopamine agonist before bedtime*
- **Dopamine agonists** are indicated for **Restless Legs Syndrome** or **Periodic Limb Movement Disorder**, not for NREM parasomnias.
- These medications do not address the **deep sleep arousal** mechanism that causes sleep terrors.
Question 8: A 65-year-old man with Parkinson disease presents after his wife witnessed him punching and kicking violently during sleep while appearing to act out his dreams. He has no recollection of these events. His current medications include carbidopa-levodopa and pramipexole. Which characteristic polysomnographic finding would confirm the suspected diagnosis?
A. Sleep-onset REM periods with decreased REM latency
B. Loss of REM sleep muscle atonia (Correct Answer)
C. Increased periodic limb movements during NREM sleep
D. Excessive slow-wave activity during stage N3 sleep
E. Absent sleep spindles and K-complexes
Explanation: ***Loss of REM sleep muscle atonia***
- The gold standard for diagnosing **REM Sleep Behavior Disorder (RBD)** on polysomnography is demonstrating **REM sleep without atonia (RSWA)**, where the normal paralysis of REM sleep is absent.
- This condition is highly indicative of underlying **alpha-synucleinopathies** such as **Parkinson disease**, Lewy body dementia, or multiple system atrophy.
*Sleep-onset REM periods with decreased REM latency*
- This finding is a classic hallmark of **narcolepsy**, where patients transition directly from wakefulness to REM sleep within minutes.
- While patients with narcolepsy may have comorbid RBD, this specific finding does not explain the **dream enactment behavior** seen here.
*Increased periodic limb movements during NREM sleep*
- These are repetitive, stereotyped movements typical of **Periodic Limb Movement Disorder (PLMD)**, occurring primarily during **non-REM (NREM)** sleep.
- Though common in patients with Parkinson's, they do not involve the complex, purposeful **violent dream enactment** characteristic of RBD.
*Excessive slow-wave activity during stage N3 sleep*
- Excessive activity or incomplete arousals during **stage N3** are associated with **NREM parasomnias** like sleepwalking or sleep terrors.
- Unlike RBD, NREM parasomnias usually occur in the **first third** of the night and patients typically have **amnesia** for the event but are not acting out distinct dreams.
*Absent sleep spindles and K-complexes*
- Sleep spindles and **K-complexes** are the physiologic markers of **Stage N2 sleep**; their absence would indicate a severe disruption of normal sleep architecture.
- This finding is not diagnostic of RBD and is more likely seen in advanced neurodegenerative states or specific **thalamic lesions**.
Question 9: A 28-year-old woman presents with a 6-month history of sudden episodes of muscle weakness triggered by laughter or excitement, causing her to drop objects or collapse. She also reports excessive daytime sleepiness, vivid dream-like experiences when falling asleep, and occasional brief paralysis upon awakening. Which neurotransmitter deficiency is most directly responsible for her symptoms?
A. Gamma-aminobutyric acid (GABA)
B. Serotonin
C. Hypocretin (orexin) (Correct Answer)
D. Acetylcholine
E. Dopamine
Explanation: ***Hypocretin (orexin)***
- This patient presents with the classic tetrad of **Narcolepsy Type 1**, including **excessive daytime sleepiness**, **cataplexy** (muscle weakness triggered by emotion), **hypnagogic hallucinations**, and **sleep paralysis**.
- The underlying pathophysiology is the autoimmune destruction of **hypocretin-producing neurons** in the **lateral hypothalamus**, leading to low CSF levels of **Hypocretin-1 (Orexin-A)**.
*Gamma-aminobutyric acid (GABA)*
- **GABA** is the primary inhibitory neurotransmitter in the brain, but its deficiency is associated with **anxiety** and **seizure disorders**, not narcolepsy.
- While GABA-modulating drugs like **sodium oxybate** are used for treatment, a deficiency is not the primary cause of cataplexy.
*Serotonin*
- **Serotonin** is involved in mood regulation and sleep-wake cycles, but its deficiency is primarily linked to **Major Depressive Disorder**.
- Although **SSRIs** are used to manage cataplexy by suppressing REM sleep, they do not address the core neurotransmitter defect in narcolepsy.
*Acetylcholine*
- **Acetylcholine** levels are typically increased during **REM sleep**, but a deficiency does not cause the clinical manifestations of narcolepsy.
- It plays a more prominent role in **Alzheimer’s disease** (cognitive decline) and **Myasthenia Gravis** (neuromuscular junction).
*Dopamine*
- **Dopamine** deficiency is the hallmark of **Parkinson's disease**, characterized by motor symptoms such as bradykinesia and resting tremors.
- Medications that increase dopamine are used as **stimulants** for alertness in narcolepsy, but its lack is not the direct cause of cataplexy.
Question 10: A 45-year-old man presents to the clinic complaining of excessive daytime sleepiness and his wife reports loud snoring with witnessed breathing pauses during sleep. He has a BMI of 34 kg/m² and a neck circumference of 44 cm. Physical examination reveals a crowded oropharynx with a Mallampati score of IV. Which of the following is the most appropriate next step in management?
A. Recommend weight loss and follow-up in 3 months
B. Refer for polysomnography (Correct Answer)
C. Start continuous positive airway pressure (CPAP) therapy
D. Prescribe a benzodiazepine for sleep quality
E. Prescribe modafinil for daytime sleepiness
Explanation: ***Refer for polysomnography***
- The patient presents with classic signs of **Obstructive Sleep Apnea (OSA)**, including **daytime sleepiness**, **snoring**, and **witnessed apneas**, which require diagnostic confirmation.
- **Polysomnography** is the gold standard for diagnosing OSA, providing the **Apnea-Hypopnea Index (AHI)** needed to determine severity and guide treatment.
*Recommend weight loss and follow-up in 3 months*
- While **obesity (BMI 34 kg/m²)** is a major risk factor and **weight loss** is a recommended lifestyle modification, it should not delay the primary diagnostic workup.
- Delaying diagnosis for three months ignores the immediate cardiovascular risks and the **daytime impairment** associated with untreated OSA.
*Start continuous positive airway pressure (CPAP) therapy*
- **CPAP** is the first-line treatment for moderate to severe OSA, but it should generally be initiated after a definitive **diagnosis** is made via sleep study.
- Objective data from a sleep study is necessary to determine the appropriate **pressure settings** and confirm that the apnea is obstructive rather than central.
*Prescribe a benzodiazepine for sleep quality*
- **Benzodiazepines** are contraindicated in patients with suspected OSA because they promote **muscle relaxation** in the oropharynx, potentially worsening airway collapse.
- These medications can suppress the **arousal response** to hypoxia, making apneic episodes longer and more dangerous.
*Prescribe modafinil for daytime sleepiness*
- **Modafinil** is a wake-promoting agent that may be used as an adjunct in OSA, but only after the underlying **airway obstruction** has been addressed with CPAP.
- Prescribing stimulants without treating the **nocturnal hypoxia** masks the symptoms while leaving the patient at risk for long-term complications like **hypertension**.
