Sleep disorders US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Sleep disorders. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Sleep disorders US Medical PG Question 1: A 45-year-old obese man presents to his primary care provider for an annual physical. The patient states that he has noticed increased sleepiness during the day at work over the past 6 months in addition to difficulty concentrating and worsening memory. He denies recent weight loss, and is not sure if he snores because he sleeps by himself. His past medical history is significant for hypertension and type II diabetes. Vital signs are T 98.6 F, HR 75 bpm, BP 140/90 mm Hg, RR 18/min. Physical exam reveals a 350 pound man. Jugular venous distension is difficult to evaluate due to excess tissue in the neck. There is no peripheral edema. Lung exam is normal. Routine CBC shows WBC count of 5000 cells/ml, platelet count of 350,000/mcL, hemoglobin of 18 gm/dL, and hematocrit of 54%. What is the most likely cause of his abnormal lab results?
- A. JAK2 mutation
- B. Malignancy
- C. Cor pulmonale
- D. Sleep apnea (Correct Answer)
- E. Diuretic overuse
Sleep disorders Explanation: ***Sleep apnea***
- The patient's **obesity**, daytime sleepiness, difficulty concentrating, and high hemoglobin/hematocrit are highly suggestive of **sleep apnea**. The chronic nocturnal hypoxia from sleep apnea triggers increased erythropoietin production, leading to **secondary polycythemia** [2].
- While the patient isn't sure if he snores, the combination of his symptoms and elevated red blood cell parameters in an obese individual makes sleep apnea the most likely cause [2].
*JAK2 mutation*
- A **JAK2 V617F mutation** is characteristic of **polycythemia vera**, a myeloproliferative neoplasm, which typically presents with very high hemoglobin and hematocrit and can be associated with symptoms like fatigue and pruritus [1]. However, **secondary polycythemia** due to sleep apnea is a more common cause of elevated red cell counts in an obese patient with these symptoms.
- Unlike **secondary polycythemia**, which primarily affects red blood cell production, polycythemia vera often involves increases in all three blood cell lines (panmyelosis), though these are not seen here.
*Malignancy*
- While some **malignancies** can cause paraneoplastic syndromes leading to polycythemia (e.g., renal cell carcinoma producing erythropoietin), this is typically less common than sleep apnea as a cause of secondary polycythemia in an obese patient with these symptoms.
- The patient's general signs and symptoms are more consistent with the chronic issues related to sleep-disordered breathing rather than a specific malignancy.
*Cor pulmonale*
- **Cor pulmonale** refers to right-sided heart failure due to chronic lung disease or pulmonary hypertension [3]. While chronic hypoxia from severe lung disease can cause **secondary polycythemia**, the patient has a normal lung exam and no peripheral edema or overt signs of right heart failure.
- Although sleep apnea can eventually lead to pulmonary hypertension and cor pulmonale, the primary cause of the polycythemia and presenting symptoms in this case is the hypoxia of sleep apnea itself, rather than advanced cor pulmonale.
*Diuretic overuse*
- **Diuretic overuse** can cause hemoconcentration and apparent increases in hemoglobin and hematocrit due to fluid loss, but it would typically be accompanied by other signs of dehydration or electrolyte abnormalities, and would not explain the patient's severe daytime sleepiness and cognitive issues.
- The patient denies recent weight loss and has an elevated blood pressure, making severe dehydration from diuretic overuse less likely.
Sleep disorders US Medical PG Question 2: A 63-year-old man presents to his primary care physician complaining of excessive daytime sleepiness. He explains that this problem has worsened slowly over the past few years but is now interfering with his ability to play with his grandchildren. He worked previously as an overnight train conductor, but he has been retired for the past 3 years. He sleeps approximately 8-9 hours per night and believes his sleep quality is good; however, his wife notes that he often snores loudly during sleep. He has never experienced muscle weakness or hallucinations. He has also been experiencing headaches in the morning and endorses a depressed mood. His physical exam is most notable for his large body habitus, with a BMI of 34. What is the best description of the underlying mechanism for this patient's excessive daytime sleepiness?
- A. Poor oropharyngeal tone (Correct Answer)
- B. Circadian rhythm sleep-wake disorder
- C. Deficiency of the neuropeptides, orexin-A and orexin-B
- D. Insufficient sleep duration
- E. Psychiatric disorder
Sleep disorders Explanation: ***Poor oropharyngeal tone***
- This patient's symptoms, including **excessive daytime sleepiness**, loud **snoring**, **morning headaches**, **obesity (BMI 34)**, and depressed mood, are all highly suggestive of **obstructive sleep apnea (OSA)**.
- In OSA, poor oropharyngeal tone, often exacerbated by obesity, leads to the collapse of the upper airway during sleep, causing interrupted breathing and subsequent sleep fragmentation, which manifests as daytime sleepiness.
*Circadian rhythm sleep-wake disorder*
- This disorder typically involves a **misalignment between endogenous sleep-wake rhythms** and external environmental cues, often seen in shift workers or with jet lag.
- While the patient previously worked as an overnight conductor, he has been retired for 3 years, and his symptoms are more aligned with chronic airway obstruction rather than a desynchronized internal clock.
*Deficiency of the neuropeptides, orexin-A and orexin-B*
- A deficiency in **orexin (hypocretin)** is the underlying mechanism for **narcolepsy type 1**, characterized by excessive daytime sleepiness, cataplexy (sudden loss of muscle tone triggered by strong emotions), and sleep paralysis/hypnagogic hallucinations.
- This patient specifically denies muscle weakness or hallucinations, which makes narcolepsy less likely.
*Insufficient sleep duration*
- While insufficient sleep duration can cause excessive daytime sleepiness, the patient reports sleeping approximately **8-9 hours per night**, which is generally considered an adequate duration for adults.
- The loud snoring and other symptoms point towards a **qualitative problem with sleep**, despite seemingly adequate hours.
*Psychiatric disorder*
- While **depressed mood** is present, it is often a **consequence or comorbidity of chronic sleep deprivation** and fragmented sleep rather than the primary cause of the patient's excessive daytime sleepiness and loud snoring.
- Depression alone does not explain the physical signs like snoring and morning headaches without an underlying sleep disorder.
Sleep disorders US Medical PG Question 3: A mother brings her 7-year-old son to the pediatrician because she is worried about his sleep. She reports that the child has repeatedly woken up in the middle of the night screaming and thrashing. Although she tries to reassure the child, he does not respond to her or acknowledge her presence. Soon after she arrives, he stops screaming and appears confused and lethargic before falling back asleep. When asked about these events, the child reports that he cannot recall ever waking up or having any bad dreams. These events typically occur within four hours of the child going to sleep. The child’s past medical history is notable for asthma and type I diabetes mellitus. He uses albuterol and long-acting insulin. There have been no recent changes in this patient’s medication regimen. His family history is notable for obesity and obstructive sleep apnea in his father. Physical examination reveals a healthy male at the 40th and 45th percentiles for height and weight, respectively. Which of the following EEG waveforms is most strongly associated with this patient’s condition?
- A. Delta waves (Correct Answer)
- B. Theta waves
- C. Sleep spindles
- D. Beta waves
- E. Alpha waves
Sleep disorders Explanation: ***Delta waves***
- The child's symptoms (screaming, thrashing, unresponsiveness during waking, confusion afterward, and no recall) are characteristic of **sleep terror (pavor nocturnus)**, which is a **non-REM parasomnia**.
- Sleep terrors typically occur during **slow-wave sleep (NREM stage 3/4 sleep)**, which is predominantly characterized by the presence of **delta waves** on an EEG.
*Theta waves*
- **Theta waves** are characteristic of **NREM stage 1 and 2 sleep**, which are lighter stages of sleep.
- Sleep terrors are arousal disorders that originate from the deep stages of non-REM sleep, not the lighter stages where theta waves are prominent.
*Sleep spindles*
- **Sleep spindles** and **K-complexes** are characteristic EEG findings of **NREM stage 2 sleep**.
- While stage 2 is part of NREM sleep, sleep terrors are specifically associated with the deeper NREM stage 3/4, which is dominated by delta waves, not sleep spindles.
*Beta waves*
- **Beta waves** are high-frequency, low-amplitude waves associated with **awake, alert, and active mental states**.
- Their presence indicates wakefulness or active mental engagement and is not associated with any stage of sleep.
*Alpha waves*
- **Alpha waves** are characteristic of a state of **relaxed wakefulness**, often with closed eyes, and are a precursor to sleep onset.
- They are not associated with the deep sleep stages where sleep terrors occur.
Sleep disorders US Medical PG Question 4: A 21-year-old man presents to the clinic complaining of feeling tired during the day. He is concerned as his grades in school have worsened and he does not want to lose his scholarship. Upon further questioning, the patient describes frequently experiencing a dreamlike state before falling asleep and after waking up. He also has frequent nighttime awakenings where he finds himself unable to move. He denies snoring. The patient does not drink alcohol or abuse any other drugs. The patient's BMI is 21 kg/m2, and his vital signs are all within normal limits. What is this patient's diagnosis?
- A. Obstructive sleep apnea (OSA)
- B. Insomnia
- C. Alcohol withdrawal
- D. Delayed sleep phase syndrome (DSPS)
- E. Narcolepsy (Correct Answer)
Sleep disorders Explanation: ***Narcolepsy***
- The patient's symptoms of **excessive daytime sleepiness**, **hypnagogic/hypnopompic hallucinations** (dreamlike state before falling asleep and after waking up), and **sleep paralysis** (unable to move during nighttime awakenings) are the **classic tetrad of narcolepsy** (cataplexy is the 4th feature, not present here).
- The absence of snoring, normal BMI, and lack of alcohol/drug use rule out other common causes of sleep disturbances, supporting the diagnosis of narcolepsy.
- Narcolepsy is a **chronic sleep-wake disorder** caused by hypothalamic hypocretin (orexin) deficiency.
*Obstructive sleep apnea (OSA)*
- While OSA also causes **daytime sleepiness**, a key feature is **snoring**, which this patient denies.
- OSA is often associated with obesity, but this patient has a **normal BMI of 21 kg/m²**.
- OSA would not explain the hypnagogic hallucinations or sleep paralysis.
*Insomnia*
- Insomnia primarily involves difficulty initiating or maintaining sleep, leading to **insufficient sleep quantity or quality**.
- This patient's symptoms are more specific, including episodes of sleep paralysis and vivid dreamlike states, rather than just general difficulty sleeping.
- The hallmark features of narcolepsy distinguish this from simple insomnia.
*Alcohol withdrawal*
- Alcohol withdrawal can cause **sleep disturbances**, but it is typically accompanied by other symptoms like tremors, anxiety, autonomic hyperactivity, and potentially seizures, none of which are present.
- The patient **explicitly denies drinking alcohol**, making this diagnosis highly unlikely.
*Delayed sleep phase syndrome (DSPS)*
- DSPS is a **circadian rhythm disorder** characterized by a delayed sleep-wake cycle, where individuals fall asleep and wake up later than desired.
- While it can cause daytime fatigue if individuals are forced to wake up early, it does **not** involve the specific symptoms of hypnagogic/hypnopompic hallucinations or sleep paralysis seen in this patient.
- DSPS is primarily a timing issue, not a neurological sleep disorder.
Sleep disorders US Medical PG Question 5: A 55-year-old man presents to the physician for the evaluation of excessive daytime sleepiness over the past six months. Despite sleeping 8–9 hours a night and taking a nap during the day, he feels drowsy and is afraid to drive. His wife complains of loud snoring and gasping during the night. His blood pressure is 155/95 mm Hg. BMI is 37 kg/m2. Oropharyngeal examination shows a small orifice and an enlarged tongue and uvula. The soft palate is low-lying. The examination of the nasal cavity shows no septal deviation or polyps. Examination of the lungs and heart shows no abnormalities. Polysomnography shows an apnea-hypopnea index of 20 episodes/h. The patient is educated about weight loss, exercise, and regular sleep hours and duration. Which of the following is the most appropriate next step in management?
- A. Continuous positive airway pressure (Correct Answer)
- B. Upper airway neurostimulation
- C. Supplemental oxygen
- D. Oral appliances
- E. Upper airway surgery
Sleep disorders Explanation: ***Continuous positive airway pressure***
- This patient presents with symptoms and polysomnography findings consistent with **moderate to severe obstructive sleep apnea (OSA)** (apnea-hypopnea index of 20 episodes/h). **CPAP is the first-line treatment** for such cases.
- CPAP works by **delivering pressurized air** via a mask, creating a pneumatic splint that prevents the collapse of the upper airway during sleep, thereby reducing apneas and hypopneas.
*Upper airway neurostimulation*
- This therapy involves stimulating the **hypoglossal nerve** to activate upper airway muscles, improving airway patency.
- However, it is generally considered a **second-line treatment** for patients with moderate to severe OSA who **cannot tolerate or fail CPAP therapy**.
*Supplemental oxygen*
- While oxygen therapy can reduce nocturnal desaturation, it **does not address the underlying airway obstruction** that causes apneas and hypopneas.
- It might even **worsen apnea by blunting the ventilatory drive**, making it an inappropriate primary treatment for OSA.
*Oral appliances*
- **Mandibular advancement devices (MADs)** can be effective for **mild to moderate OSA**, or for patients with severe OSA who cannot tolerate CPAP.
- They work by repositioning the jaw and tongue forward to enlarge the pharyngeal space, but CPAP is generally more effective for the severity described.
*Upper airway surgery*
- Various surgical procedures, such as **uvulopalatopharyngoplasty (UPPP)**, aim to remove excess tissue in the pharynx to enlarge the airway.
- Surgery is typically reserved for patients who **fail or cannot tolerate CPAP and oral appliances** and are carefully selected based on anatomical considerations.
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