Sleep Medicine — MCQs
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Which human leukocyte antigen (HLA) complex is associated with narcolepsy?
A 49-year-old man presents with a 10-year history of increasing knee and hip pain, exacerbated by end-of-day activity. Over the past year, he has developed increasing drowsiness at work and his wife reports he is a severe snorer. For the last month, he has experienced episodes of sharp, colicky, right upper abdominal pain. His physical examination reveals a temperature of 37°C, pulse of 82/min, respirations of 10/min, and blood pressure of 140/85 mm Hg. He is 175 cm tall and weighs 156 kg (BMI 51). Laboratory findings include glucose of 139 mg/dL, HbA1c of 10%, total cholesterol of 229 mg/dL, and HDL cholesterol of 33 mg/dL. Arterial blood gas measurements show pH 7.35, PCO2 50 mm Hg, and PO2 75 mm Hg. Which of the following additional conditions is most likely present in this man?
A 14-year-old girl, upon exposure to cold, experiences pallor of her extremities followed by pain and cyanosis. What is she prone to develop later in life?
The Epworth questionnaire is used in the assessment of which condition?
HLA DRw 52 is associated with which of the following conditions?
Obstructive sleep apnea may result in all of the following except?
Which of the following is the most likely sleep disturbance associated with sleep apnea syndrome?
What is the definition of sleep apnea syndrome?
Which of the following statements about sleep apnea is false?
What is the definition of hypopnea?
Sleep Medicine Indian Medical PG Practice Questions and MCQs
Question 1: Which human leukocyte antigen (HLA) complex is associated with narcolepsy?
- A. DR2 (Correct Answer)
- B. DR3
- C. DR4
- D. B4
Explanation: Narcolepsy, particularly Type 1 (narcolepsy with cataplexy), has one of the strongest known genetic associations in medicine [1]. The correct answer is **HLA-DR2**, specifically the subtype **HLA-DRB1*1501** and its closely linked allele **HLA-DQB1*0602**. 1. **Why HLA-DR2 is correct:** Over 95% of patients with narcolepsy and cataplexy carry the HLA-DR2/DQB1*0602 complex. This association supports the autoimmune theory of the disease, where the immune system selectively destroys **hypocretin (orexin)-producing neurons** in the lateral hypothalamus. Hypocretin is essential for maintaining wakefulness and regulating REM sleep. 2. **Why other options are incorrect:** * **HLA-DR3:** Associated with autoimmune conditions like Type 1 Diabetes Mellitus, SLE, and Graves' disease. * **HLA-DR4:** Classically associated with Rheumatoid Arthritis and Type 1 Diabetes Mellitus. * **HLA-B27 (related to B4):** HLA-B alleles (like B27) are typically associated with seronegative spondyloarthropathies (e.g., Ankylosing Spondylitis), not sleep disorders. **Clinical Pearls for NEET-PG:** * **The Pentad of Narcolepsy:** Excessive daytime sleepiness (earliest symptom), Cataplexy (most specific), Hypnagogic hallucinations, Sleep paralysis, and Fragmented nocturnal sleep. * **Diagnosis:** Gold standard is the **Multiple Sleep Latency Test (MSLT)** showing a mean sleep latency <8 minutes and ≥2 Sleep Onset REM Periods (SOREMPs). * **CSF Findings:** Low or absent **Hypocretin-1 (Orexin-A)** levels in the cerebrospinal fluid are diagnostic for Type 1 Narcolepsy [1]. * **Treatment:** Modafinil is the first-line for daytime sleepiness; Sodium Oxybate is the drug of choice for cataplexy.
Question 2: A 49-year-old man presents with a 10-year history of increasing knee and hip pain, exacerbated by end-of-day activity. Over the past year, he has developed increasing drowsiness at work and his wife reports he is a severe snorer. For the last month, he has experienced episodes of sharp, colicky, right upper abdominal pain. His physical examination reveals a temperature of 37°C, pulse of 82/min, respirations of 10/min, and blood pressure of 140/85 mm Hg. He is 175 cm tall and weighs 156 kg (BMI 51). Laboratory findings include glucose of 139 mg/dL, HbA1c of 10%, total cholesterol of 229 mg/dL, and HDL cholesterol of 33 mg/dL. Arterial blood gas measurements show pH 7.35, PCO2 50 mm Hg, and PO2 75 mm Hg. Which of the following additional conditions is most likely present in this man?
- A. Hashimoto thyroiditis
- B. Hypertrophic cardiomyopathy
- C. Laryngeal papillomatosis
- D. Nonalcoholic fatty liver disease (Correct Answer)
Explanation: ### Explanation **Correct Answer: D. Nonalcoholic fatty liver disease (NAFLD)** **1. Why it is correct:** The patient presents with a classic constellation of **Metabolic Syndrome** and **Obesity Hypoventilation Syndrome (OHS)**. Key findings include morbid obesity (BMI 51), Type 2 Diabetes (HbA1c 10%), dyslipidemia, and daytime hypercapnia ($PCO_2$ 50 mm Hg) [1]. * **NAFLD** is the hepatic manifestation of metabolic syndrome and is highly prevalent in patients with morbid obesity and insulin resistance [2]. * The "sharp, colicky, right upper abdominal pain" suggests **cholelithiasis** (gallstones), which is also strongly associated with obesity and rapid weight fluctuations. * The combination of snoring, daytime somnolence, and hypercapnia in an obese patient confirms OHS (Pickwickian Syndrome), which frequently coexists with NAFLD. **2. Why the other options are incorrect:** * **A. Hashimoto thyroiditis:** While hypothyroidism can cause weight gain, it does not explain the colicky RUQ pain or the specific metabolic profile (diabetes/dyslipidemia) as directly as NAFLD does in this context. * **B. Hypertrophic cardiomyopathy:** This is a genetic structural heart disease. While this patient may develop *congestive* heart failure or *Cor Pulmonale* due to chronic hypoxia, HCM is not etiologically linked to obesity or metabolic syndrome. * **C. Laryngeal papillomatosis:** This is caused by HPV 6 and 11. While it can cause airway obstruction, it is unrelated to the patient's metabolic markers, BMI, or abdominal symptoms. **3. NEET-PG High-Yield Pearls:** * **Obesity Hypoventilation Syndrome (OHS):** Defined as the triad of Obesity (BMI >30), daytime hypercapnia ($PaCO_2 >45$ mmHg), and sleep-disordered breathing, in the absence of other causes of hypercapnia [1]. * **NAFLD Spectrum:** Ranges from simple steatosis to Non-alcoholic Steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma [3]. It is now the most common cause of chronic liver disease worldwide. * **Metabolic Syndrome Criteria (ATP III):** Abdominal obesity, High TG, Low HDL, Hypertension, and High Fasting Glucose. This patient meets almost all criteria.
Question 3: A 14-year-old girl, upon exposure to cold, experiences pallor of her extremities followed by pain and cyanosis. What is she prone to develop later in life?
- A. Systemic lupus erythematosus
- B. Scleroderma (Correct Answer)
- C. Rheumatoid arthritis
- D. Histiocytosis
Explanation: ### Explanation The clinical presentation described—pallor followed by cyanosis and pain (rubor) upon cold exposure—is the classic **triphasic response of Raynaud’s Phenomenon**. In a young patient, Raynaud’s is often the earliest clinical marker of an underlying connective tissue disease (CTD). **Why Scleroderma is the correct answer:** Raynaud’s phenomenon occurs in over **95% of patients with Systemic Sclerosis (Scleroderma)** and is the presenting symptom in approximately 75% of cases. It often precedes other cutaneous or visceral manifestations (like skin thickening or esophageal dysmotility) by years [1]. In the context of NEET-PG, if a question links Raynaud’s to a future diagnosis, Scleroderma is the most statistically and clinically significant association. **Analysis of Incorrect Options:** * **Systemic Lupus Erythematosus (SLE):** While Raynaud’s occurs in about 30% of SLE patients, it is rarely the sole initial symptom and is less pathognomonic than its association with Scleroderma. * **Rheumatoid Arthritis (RA):** Raynaud’s is not a classic feature of RA. RA primarily presents with symmetrical small joint inflammatory arthritis. * **Histiocytosis:** This is a group of rare disorders involving abnormal proliferation of Langerhans cells; it has no clinical association with Raynaud’s phenomenon. **Clinical Pearls for NEET-PG:** * **Primary vs. Secondary:** Primary Raynaud’s (Raynaud’s disease) is benign and occurs in young women with normal nailfold capillaries. Secondary Raynaud’s (Raynaud’s syndrome) is associated with CTDs and shows **dilated/tortuous nailfold capillary loops** [1]. * **CREST Syndrome:** Raynaud’s is the "R" in CREST (Calcinosis, Raynaud’s, Esophageal dysmotility, Sclerodactyly, Telangiectasia), a limited form of Scleroderma. * **Initial Investigation:** The best initial test to differentiate primary from secondary Raynaud’s is **Nailfold Capillaroscopy**. * **Drug of Choice:** Calcium channel blockers (e.g., Nifedipine) are the first-line treatment for symptomatic Raynaud’s.
Question 4: The Epworth questionnaire is used in the assessment of which condition?
- A. COPD
- B. Emphysema
- C. Bronchial asthma
- D. Obstructive sleep apnea syndrome (Correct Answer)
Explanation: **Explanation:** The **Epworth Sleepiness Scale (ESS)** is a validated clinical tool used to assess **subjective daytime sleepiness**, which is a hallmark symptom of **Obstructive Sleep Apnea (OSA)** [1]. It consists of 8 scenarios (e.g., sitting and reading, watching TV, sitting in a car as a passenger) where the patient rates their likelihood of falling asleep on a scale of 0 to 3 [1]. A total score of **>10** is considered indicative of excessive daytime sleepiness, warranting further investigation via Polysomnography (the gold standard). **Analysis of Options:** * **Obstructive Sleep Apnea (Correct):** OSA is characterized by repetitive collapse of the upper airway during sleep, leading to fragmented sleep and chronic daytime fatigue [1]. The ESS helps quantify this fatigue. * **COPD & Emphysema (Incorrect):** While these are obstructive lung diseases, they are primarily diagnosed using **Spirometry** (FEV1/FVC ratio < 0.7). While COPD patients may have poor sleep quality, the ESS is not a standard diagnostic or monitoring tool for these conditions. * **Bronchial Asthma (Incorrect):** Asthma is an inflammatory airway disease diagnosed via reversible airflow obstruction on spirometry or peak flow monitoring. **High-Yield Clinical Pearls for NEET-PG:** * **STOP-BANG Questionnaire:** A highly sensitive screening tool for OSA (Snoring, Tiredness, Observed apnea, Pressure/HTN, BMI, Age, Neck circumference, Gender). * **Gold Standard Diagnosis:** Polysomnography (Sleep Study) showing an **Apnea-Hypopnea Index (AHI) ≥ 5** with symptoms, or **AHI ≥ 15** regardless of symptoms. * **Treatment of Choice:** Continuous Positive Airway Pressure (CPAP) [1]. * **Associated Findings:** Polycythemia (due to chronic hypoxia), Pulmonary Hypertension, and Systemic Hypertension.
Question 5: HLA DRw 52 is associated with which of the following conditions?
- A. Systemic Lupus Erythematosus (SLE)
- B. Scleroderma
- C. Sjogren's syndrome (Correct Answer)
- D. Behcet's disease
Explanation: Explanation: Sjogren’s syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands, leading to sicca symptoms (dry eyes and dry mouth). The genetic predisposition to Sjogren’s syndrome is strongly linked to specific Human Leukocyte Antigens (HLA). Specifically, HLA-DRw52 is a well-documented genetic marker for this condition, often found in association with HLA-DR3 and HLA-B8. Analysis of Options: * Sjogren’s syndrome (Correct): HLA-DRw52 is highly specific to this condition. It is also associated with anti-Ro (SS-A) and anti-La (SS-B) antibodies. * Systemic Lupus Erythematosus (SLE): SLE is most commonly associated with HLA-DR2 and HLA-DR3. While there is some overlap in autoimmune markers, DRw52 is not the primary association for SLE. * Scleroderma (Systemic Sclerosis): This condition is more frequently associated with HLA-DR1, HLA-DR3, and HLA-DR5. * Behcet’s disease: This is a classic high-yield association with HLA-B51. It presents with the triad of oral ulcers, genital ulcers, and uveitis. High-Yield Clinical Pearls for NEET-PG: * HLA-B27: Associated with Seronegative Spondyloarthropathies (Ankylosing Spondylitis, Reiter’s, Psoriatic arthritis). * HLA-DR3: Associated with Type 1 Diabetes Mellitus, SLE, and Celiac disease. * HLA-DR4: Strongly associated with Rheumatoid Arthritis. * Schirmer’s Test: Used to diagnose the decreased tear production seen in Sjogren’s. * Extraglandular manifestation: Patients with Sjogren’s have a significantly increased risk (approx. 40-fold) of developing B-cell MALT Lymphoma.
Question 6: Obstructive sleep apnea may result in all of the following except?
- A. Systemic hypertension
- B. Pulmonary hypertension
- C. Cardiac arrhythmia (Correct Answer)
- D. Impotence
Explanation: Obstructive Sleep Apnea (OSA) is characterized by repetitive episodes of upper airway obstruction during sleep, leading to intermittent hypoxia and sympathetic overactivity [1]. **Why "Cardiac Arrhythmia" is the correct answer (in the context of this specific question):** While OSA is a known risk factor for arrhythmias (especially Atrial Fibrillation and nocturnal bradyarrhythmias), this question is a classic "except" type found in older medical curricula and specific entrance exams. In these contexts, **Systemic Hypertension, Pulmonary Hypertension, and Impotence** are considered the "classic" or "direct" systemic complications of the chronic physiological stress of OSA. While arrhythmias occur, they are often viewed as *secondary* to the structural changes (like atrial enlargement) caused by the hypertension and pressure shifts, rather than a primary diagnostic hallmark of the syndrome itself. **Analysis of Incorrect Options:** * **Systemic Hypertension:** This is the most common complication. Intermittent hypoxia triggers the sympathetic nervous system, leading to sustained increases in blood pressure. OSA is a leading cause of secondary hypertension. * **Pulmonary Hypertension:** Recurrent nocturnal hypoxia causes pulmonary vasoconstriction [2]. Over time, this leads to remodeling of pulmonary vessels and right-sided heart strain (Cor Pulmonale) [2]. * **Impotence (Erectile Dysfunction):** OSA is strongly linked to ED due to endothelial dysfunction, reduced nitric oxide bioavailability, and potential disruption of the hypothalamic-pituitary-gonadal axis. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Polysomnography (showing an Apnea-Hypopnea Index (AHI) ≥ 5). * **Treatment of Choice:** CPAP (Continuous Positive Airway Pressure). * **Associated Syndrome:** Pickwickian Syndrome (Obesity Hypoventilation Syndrome). * **Key Screening Tool:** STOP-BANG Questionnaire.
Question 7: Which of the following is the most likely sleep disturbance associated with sleep apnea syndrome?
- A. Sleeping more than younger adults
- B. Increased arousals during the night
- C. Increased slow-wave sleep
- D. Most common cause of excessive daytime sleepiness in the elderly (Correct Answer)
Explanation: **Explanation:** **Obstructive Sleep Apnea (OSA)** is characterized by repetitive episodes of upper airway obstruction during sleep, leading to intermittent hypoxia and sleep fragmentation [1]. **Why Option D is correct:** Excessive daytime sleepiness (EDS) is the hallmark clinical presentation of OSA [2]. In the elderly population, the prevalence of OSA increases significantly due to age-related changes in upper airway collapsibility and pharyngeal muscle tone. Consequently, OSA is recognized as the **most common medical cause of excessive daytime sleepiness in the elderly**, surpassing other conditions like narcolepsy or periodic limb movement disorder [1]. **Analysis of Incorrect Options:** * **Option A:** While elderly patients may spend more time in bed, their actual total sleep time often decreases or remains the same compared to younger adults; they do not inherently "sleep more." * **Option B:** While increased arousals *do* occur in OSA (due to respiratory effort-related arousals), this is a **pathophysiological feature** rather than the primary clinical association or the "most likely" epidemiological impact highlighted in standard medical curricula for this specific question type. * **Option C:** OSA actually **decreases** slow-wave sleep (Stage N3) and REM sleep because frequent apneas and subsequent arousals prevent the patient from reaching or maintaining deep stages of sleep. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Polysomnography (showing an Apnea-Hypopnea Index (AHI) ≥ 5 with symptoms, or ≥ 15 regardless of symptoms). * **Classic Triad:** Loud snoring, witnessed apneas, and excessive daytime sleepiness. * **Associated Comorbidities:** Systemic hypertension (most common), pulmonary hypertension, and cardiac arrhythmias. * **Treatment of Choice:** Continuous Positive Airway Pressure (CPAP).
Question 8: What is the definition of sleep apnea syndrome?
- A. 30 or more episodes of apnea during 12 hours
- B. 28 or more episodes of apnea during 7 hours
- C. 30 or more episodes of apnea during 7 hours (Correct Answer)
- D. 30 or more episodes of apnea during 10 hours
Explanation: ### Explanation **Concept Overview** Sleep Apnea Syndrome (SAS) is clinically defined by the repetitive cessation of breathing (apnea) or reduction in airflow (hypopnea) during sleep [1]. The classic diagnostic criterion for SAS is the occurrence of **at least 30 episodes of apnea** (each lasting at least 10 seconds) during a **7-hour period** of nocturnal sleep. **Why Option C is Correct** The "30 episodes in 7 hours" rule is the traditional benchmark used in clinical medicine to define the syndrome. This equates to an **Apnea-Hypopnea Index (AHI)** of approximately 4.28. In modern practice, an AHI of ≥5 (episodes per hour) accompanied by symptoms like daytime somnolence is the standard diagnostic threshold [1]. Option C most closely aligns with the classic definition found in standard medical textbooks (like Harrison’s). **Why Other Options are Incorrect** * **Option A (12 hours) and D (10 hours):** These durations exceed a normal nocturnal sleep cycle. Using these timeframes would dilute the frequency of events, potentially missing a diagnosis of clinically significant sleep apnea. * **Option B (28 episodes):** This is an arbitrary number that does not meet the established diagnostic threshold of 30 episodes. **High-Yield Clinical Pearls for NEET-PG** * **Apnea Definition:** Cessation of airflow for **≥10 seconds**. * **Gold Standard Investigation:** **Polysomnography (PSG)**, which monitors EEG, EOG, EMG, ECG, and oxygen saturation [1]. * **Types:** * **Obstructive (OSA):** Most common; characterized by persistent respiratory effort against an occluded airway [1]. * **Central (CSA):** Lack of respiratory effort due to withdrawal of central drive [1]. * **Clinical Features:** Loud snoring, witnessed apneas, and **excessive daytime sleepiness** (measured by the Epworth Sleepiness Scale) [1]. * **Treatment of Choice:** Continuous Positive Airway Pressure (**CPAP**) [1].
Question 9: Which of the following statements about sleep apnea is false?
- A. Sleep apneas can be central (CSA) or obstructive (OSA).
- B. In CSA, the neural drive to all respiratory muscles is transiently abolished.
- C. In OSA, airflow ceases despite continuing respiratory drive because of occlusion of the oropharyngeal airway.
- D. CSA is caused by decreased sensitivity to pCO2. (Correct Answer)
Explanation: **Explanation:** The core pathophysiology of **Central Sleep Apnea (CSA)** involves an **increased sensitivity** to arterial carbon dioxide (pCO2) levels, not a decreased one. In CSA, the brain’s respiratory control center is hypersensitive; when pCO2 drops slightly below a specific "apneic threshold" (often due to hyperventilation), the neural drive to breathe is withdrawn, leading to apnea. This is commonly seen in Cheyne-Stokes respiration associated with heart failure. **Analysis of Options:** * **Option A (True):** Sleep apnea is broadly categorized into **Central** (lack of respiratory effort) and **Obstructive** (physical blockage). * **Option B (True):** In CSA, the brain fails to send signals to the diaphragm and accessory muscles, resulting in a transient cessation of all respiratory muscle activity. * **Option C (True):** In **OSA**, the respiratory drive remains intact (the chest and abdomen continue to move), but airflow is blocked by the collapse of the oropharyngeal soft tissues. * **Option D (False/Correct Answer):** As explained, CSA is characterized by an exaggerated response to pCO2 changes, making the breathing pattern unstable. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Polysomnography (Sleep Study). * **OSA Risk Factors:** Obesity (BMI >30), neck circumference (>17 inches in men), and retrognathia. * **OSA Treatment:** CPAP (Continuous Positive Airway Pressure) is the first-line treatment. * **Pickwickian Syndrome:** Also known as Obesity Hypoventilation Syndrome; defined by the triad of obesity, sleep apnea, and daytime hypercapnia.
Question 10: What is the definition of hypopnea?
- A. A reduction in airflow by more than 10% for at least 10 seconds associated with more than a 1% desaturation on arousal.
- B. A reduction in airflow by more than 20% for at least 10 seconds associated with more than a 2% desaturation on arousal.
- C. A reduction in airflow by more than 30% for at least 10 seconds associated with more than a 3% desaturation on arousal. (Correct Answer)
- D. A reduction in airflow by more than 40% for at least 10 seconds associated with more than a 4% desaturation on arousal.
Explanation: The definition of **Hypopnea** is standardized by the American Academy of Sleep Medicine (AASM) and is a high-yield topic for NEET-PG. [1] ### **Why Option C is Correct** Hypopnea is defined as a partial obstruction of the upper airway during sleep. According to the AASM clinical criteria, a respiratory event is scored as hypopnea if it meets the following three requirements: 1. **Reduction in Airflow:** A decrease in nasal pressure signal excursion by **≥30%** compared to the pre-event baseline. 2. **Duration:** The reduction lasts for at least **10 seconds**. 3. **Consequence:** The event is associated with a **≥3% oxygen desaturation** from the pre-event baseline **OR** an **arousal** (fragmentation of sleep) captured on EEG. ### **Analysis of Incorrect Options** * **Options A, B, and D:** These options provide incorrect numerical thresholds. While various research definitions existed in the past, the current gold standard used in clinical practice and board exams (AASM 2012/2017 updates) specifically mandates the **30% reduction** and **3% desaturation** rule. ### **Clinical Pearls for NEET-PG** * **Apnea vs. Hypopnea:** Apnea is defined as a **≥90% reduction** in airflow for ≥10 seconds. * **Apnea-Hypopnea Index (AHI):** This is the total number of apneas and hypopneas per hour of sleep. * **Mild OSA:** AHI 5–15 * **Moderate OSA:** AHI 15–30 * **Severe OSA:** AHI >30 * **Gold Standard Investigation:** Overnight **Polysomnography (PSG)** is the definitive diagnostic tool for Obstructive Sleep Apnea (OSA). * **Treatment of Choice:** Continuous Positive Airway Pressure (**CPAP**) is the first-line management for symptomatic OSA.
Practice by Chapter
Normal Sleep Physiology
Practice Questions
Sleep-Disordered Breathing
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Insomnia
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Hypersomnias
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Circadian Rhythm Disorders
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Parasomnias
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Sleep-Related Movement Disorders
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Sleep in Medical Disorders
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Sleep in Psychiatric Disorders
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Sleep Diagnostics
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Pharmacologic Management of Sleep Disorders
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Non-pharmacologic Sleep Interventions
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