Sleep Medicine — MCQs
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A 40-year-old man presents with daytime sleepiness and impaired concentration and memory. On examination his BMI is 41 kg/m2, BP is 160/100 mm Hg. His awake ABG analysis is given: PaO2=66 mm Hg, PaCO2=50 mm Hg, HCO3=28 mEq/L. What is the most likely diagnosis?
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?
The sleep apnea syndrome is defined as -
What is the minimum diagnostic threshold for obstructive sleep apnoea according to current guidelines?
Muller's manoeuvre is used to
A 42-year-old obese male presented with disturbed sleep and daytime somnolence. All of the following are correct except?
Which of the following statements about obstructive sleep apnea is false?
A patient presents with snoring and excessive daytime sleepiness. What is the initial investigation of choice?
What AHI range indicates MILD obstructive sleep apnea?
The Apnea-Hypopnea Index (AHI) is specifically used for diagnosing and assessing the severity of which condition?
Sleep Medicine Indian Medical PG Practice Questions and MCQs
Question 21: A 40-year-old man presents with daytime sleepiness and impaired concentration and memory. On examination his BMI is 41 kg/m2, BP is 160/100 mm Hg. His awake ABG analysis is given: PaO2=66 mm Hg, PaCO2=50 mm Hg, HCO3=28 mEq/L. What is the most likely diagnosis?
- A. Obstructive sleep apnea (Correct Answer)
- B. Narcolepsy
- C. Obesity hypoventilation syndrome
- D. Central sleep apnea
Explanation: ***Obstructive Sleep Apnea (Correct Answer)*** - Classic triad: **morbid obesity (BMI 41 kg/m²)**, **excessive daytime somnolence**, and **systemic hypertension (160/100 mmHg)** — hallmarks of OSA - **ABG findings** (PaO2=66 mmHg, PaCO2=50 mmHg, HCO3=28 mEq/L) indicate **chronic nocturnal hypoxemia and hypercapnia** with compensatory **metabolic alkalosis** from repeated apneic episodes - **Cognitive impairment** (impaired concentration and memory) results from **sleep fragmentation** and intermittent nocturnal hypoxia - Obesity promotes **pharyngeal fat deposition** → upper airway narrowing and collapse during sleep → recurrent obstructive events *Narcolepsy* - Causes excessive daytime sleepiness but is **not associated with obesity, hypertension, or ABG abnormalities** - Hallmarks include **cataplexy**, sleep paralysis, and hypnagogic/hypnopompic hallucinations — none present here - Caused by **orexin (hypocretin) deficiency**; associated with **HLA-DQB1*06:02**; ABG is normal *Obesity Hypoventilation Syndrome (OHS / Pickwickian Syndrome)* - Defined as **awake PaCO2 >45 mmHg + BMI >30 kg/m²** with exclusion of other causes of hypoventilation - OHS frequently coexists as an **overlap with and consequence of severe OSA** rather than being the primary diagnosis - In this setting, **OSA is the most prevalent and primary diagnosis**; OHS is specifically considered when awake hypoventilation persists despite adequate OSA treatment *Central Sleep Apnea* - Results from **failure of central respiratory drive** (brainstem), not upper airway obstruction - Associated with **congestive heart failure, opioid use, high-altitude exposure, or neurological disease** — none present here - Not characteristically associated with morbid obesity; clinical and ABG picture here favors an **obstructive** rather than central pattern
Question 22: 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
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.
Question 23: The sleep apnea syndrome is defined as -
- A. Apnea-Hypopnea Index (AHI) ≥ 5/hour (Correct Answer)
- B. Apnea-Hypopnea Index (AHI) ≥ 10/hour
- C. Apnea-Hypopnea Index (AHI) ≥ 30/hour
- D. Apnea-Hypopnea Index (AHI) ≥ 15/hour
Explanation: ***Apnea-Hypopnea Index (AHI) ≥ 5/hour*** - The definition of **sleep apnea syndrome** generally requires an **AHI of 5 or more events per hour**, often accompanied by symptoms like excessive daytime sleepiness or cardiovascular complications [1]. - This threshold identifies individuals with clinically significant sleep-disordered breathing that warrants further evaluation and potential treatment [1]. *Apnea-Hypopnea Index (AHI) ≥ 10/hour* - While an AHI of 10/hour indicates sleep apnea, it is a higher severity criterion and does not represent the **minimum threshold** for defining the syndrome [1]. - Patients with an AHI between 5 and 10 also have sleep apnea and can experience significant symptoms. *Apnea-Hypopnea Index (AHI) ≥ 30/hour* - An AHI of 30/hour or more signifies **severe sleep apnea**, which requires aggressive management. - This is far above the **general diagnostic threshold** for sleep apnea syndrome. *Apnea-Hypopnea Index (AHI) ≥ 15/hour* - An AHI of 15/hour is typically classified as **moderate sleep apnea**. - This value is higher than the **lowest AHI threshold** used to define the presence of sleep apnea syndrome.
Question 24: What is the minimum diagnostic threshold for obstructive sleep apnoea according to current guidelines?
- A. AHI <5 events per hour
- B. AHI 15-30 events per hour
- C. AHI >30 events per hour (Correct Answer)
- D. AHI 5-15 events per hour
Explanation: AHI >30 events per hour - An Apnoea-Hypopnoea Index (AHI) greater than 30 events per hour indicates severe obstructive sleep apnea (OSA), which is definitively above the minimum diagnostic threshold [1]. - While an AHI of 5 or more is generally considered diagnostic for OSA, an AHI >30 signifies severe disease and often leads to more pronounced symptoms and health risks [1]. *AHI <5 events per hour* - An AHI score of less than 5 events per hour is typically considered normal or within the non-pathological range for sleep-disordered breathing [1]. - Individuals with an AHI below this threshold usually do not meet the diagnostic criteria for any form of sleep apnea. *AHI 15-30 events per hour* - This range indicates moderate obstructive sleep apnea. While it is diagnostic for OSA, it is not the minimum threshold [1]. - Patients in this category often experience significant symptoms and may require treatment, but it is not the lowest AHI at which a diagnosis can be made. *AHI 5-15 events per hour* - This AHI range is considered mild obstructive sleep apnea. An AHI of 5 or more, accompanied by relevant symptoms, is generally the minimum diagnostic threshold for OSA [1]. - However, the question asks for the minimum diagnostic threshold, and while 5 events per hour is a minimum, "AHI >30 events per hour" indicates a clear and severe diagnostic case.
Question 25: Muller's manoeuvre is used to
- A. To remove foreign body from ear
- B. To find degree of obstruction in sleep disordered breathing (Correct Answer)
- C. To remove laryngeal foreign body
- D. To find out opening of mouth
Explanation: ***To find degree of obstruction in sleep disordered breathing*** - **Muller's manoeuvre** is a diagnostic technique where the patient attempts to inspire forcefully against a **closed mouth and nostrils** while an endoscope observes the upper airway. - This maneuver helps to simulate the negative intraluminal pressure that occurs during sleep, making it useful in identifying the **site and severity of airway obstruction** in patients with sleep-disordered breathing. *To remove foreign body from ear* - Removing foreign bodies from the ear typically involves **irrigation**, specialized instruments (e.g., alligator forceps), or suction, not a breathing maneuver. - This option is unrelated to the physiological assessment of airway obstruction. *To remove laryngeal foreign body* - The primary methods for removing laryngeal foreign bodies are the **Heimlich maneuver** (abdominal thrusts) or direct laryngoscopy and removal. - Muller's manoeuvre is a diagnostic procedure, not a therapeutic one for foreign body extraction. *To find out opening of mouth* - Measuring the **opening of the mouth** is typically done with a ruler or specific instruments to assess jaw mobility (e.g., for temporomandibular joint disorders or trismus). - This is a simple measurement and does not involve the complex physiological assessment of the upper airway that Muller's manoeuvre provides.
Question 26: A 42-year-old obese male presented with disturbed sleep and daytime somnolence. All of the following are correct except?
- A. Apnea with hypoxia
- B. Pharyngeal muscle contraction increases OSA (Correct Answer)
- C. Apnea with awakening
- D. Apnea with fall in saturation
Explanation: ***Pharyngeal muscle contraction increases OSA*** - Obstructive sleep apnea (OSA) is caused by the collapse of the upper airway due to the **relaxation** and consequent loss of tone in the **pharyngeal muscles** during sleep, not by their contraction [1]. - While muscle contraction normally helps maintain airway patency, **reduced muscle activity** allows the airway to narrow or collapse. *Apnea with hypoxia* - **Apnea**, defined as a cessation of breathing for at least 10 seconds, often leads to periods of **hypoxia** (decreased blood oxygen levels) due to insufficient gas exchange [1]. - This **recurrent hypoxia** is a hallmark of OSA and contributes to its cardiovascular and neurological consequences. *Apnea with awakening* - Following an apneic episode, the body's protective reflex often causes a brief **arousal or awakening** from sleep to restore airway patency and ventilation [2]. - These frequent **micro-awakenings** are a primary reason for the disturbed sleep and subsequent daytime somnolence experienced by patients with OSA [2]. *Apnea with fall in saturation* - During an apneic event, the lack of airflow into the lungs results in a **decrease in oxygen saturation (SpO2)**, which is a key diagnostic criterion for OSA severity [2]. - This **desaturation** is directly linked to the duration and frequency of apneic episodes.
Question 27: Which of the following statements about obstructive sleep apnea is false?
- A. Apnea is associated with high respiratory effort
- B. Apnea is associated with fall in SpO2
- C. Apnea is associated with sudden awakening
- D. Contraction of pharyngeal muscles can worsen obstruction (Correct Answer)
Explanation: ***Contraction of pharyngeal muscles can worsen obstruction*** - In **obstructive sleep apnea (OSA)**, the pharyngeal muscles are normally responsible for maintaining airway patency [1]. - A *contraction* of these muscles would *open* the airway, whereas *relaxation* or *loss of tone* leads to collapse and obstruction. *Apnea is associated with high respiratory effort* - During an **apneic episode** in OSA, the airway is *obstructed*, leading to continued but **unsuccessful inspiratory efforts** against a closed airway. - This results in a significant increase in **respiratory effort** as the diaphragm and accessory muscles try to overcome the obstruction. *Apnea is associated with fall in SpO2* - The cessation of airflow during **apnea** prevents **gas exchange**, leading to a progressive decrease in **oxygen saturation (SpO2)**. - This **hypoxia** is a hallmark physiological consequence of apneic events and often triggers arousal from sleep [2]. *Apnea is associated with sudden awakening* - The combination of **hypoxia** and **hypercapnia** (increased CO2), along with the increased respiratory effort, stimulates the central nervous system [2]. - This stimulation causes a **brief arousal or awakening** from sleep, often accompanied by gasping or snorting, to re-establish airway patency.
Question 28: A patient presents with snoring and excessive daytime sleepiness. What is the initial investigation of choice?
- A. Laryngoscopy
- B. Polysomnography (Correct Answer)
- C. MRI of the neck
- D. Echocardiography
Explanation: ***Polysomnography*** - This is the **gold standard** for diagnosing **sleep apnea**, which is characterized by snoring and excessive daytime sleepiness. - It records multiple physiological parameters during sleep, including **brain activity, oxygen levels, heart rate, and breathing patterns**. *Laryngoscopy* - This procedure examines the larynx and vocal cords; it is commonly used for evaluating **hoarseness or throat pain**, not primary sleep disorders. - While it can identify structural abnormalities in the upper airway, it doesn't assess the **physiological impact** of these abnormalities during sleep. *MRI of the neck* - This imaging technique provides detailed anatomical views of soft tissues in the neck, which can identify **structural airway obstruction** in specific cases. - However, it does not assess the dynamic physiological changes occurring during sleep that lead to conditions like **obstructive sleep apnea**. *Echocardiography* - This test is used to evaluate the **heart's structure and function**, primarily for cardiac issues like heart failure or valvular disease. - While sleep apnea can have cardiovascular consequences, **echocardiography** is not an initial diagnostic tool for the sleep disorder itself.
Question 29: What AHI range indicates MILD obstructive sleep apnea?
- A. 5 - 15 (Correct Answer)
- B. 15 - 30
- C. >30
- D. <5
Explanation: **5 - 15** - An **Apnea-Hypopnea Index (AHI)** between **5 and 15** events per hour signifies **mild obstructive sleep apnea (OSA)** [1]. - This classification helps guide treatment decisions, as mild OSA may respond to lifestyle modifications or oral appliances [1]. *<5* - An AHI of **less than 5** events per hour is generally considered **normal** or indicative of no significant sleep apnea [1]. - While some individuals may have mild symptoms with an AHI below 5, it typically does not meet the diagnostic criteria for OSA [1]. *15 - 30* - An AHI in this range indicates **moderate obstructive sleep apnea**. - Patients with moderate OSA often experience more pronounced symptoms and typically require intervention such as **Continuous Positive Airway Pressure (CPAP)** therapy. *>30* - An AHI **greater than 30** events per hour is classified as **severe obstructive sleep apnea**. - This level of severity is associated with significant health risks and almost always necessitates immediate and effective treatment like **CPAP**.
Question 30: The Apnea-Hypopnea Index (AHI) is specifically used for diagnosing and assessing the severity of which condition?
- A. Emphysema
- B. Asthma
- C. Hyaline membrane disease
- D. Obstructive sleep apnea (OSA) (Correct Answer)
Explanation: ***Obstructive sleep apnea (OSA)*** - The **Apnea-Hypopnea Index (AHI)** quantifies the average number of apneas and hypopneas per hour of sleep, which is the primary metric for diagnosing and determining the severity of OSA [1]. - An apnea is a complete cessation of airflow, while a hypopnea is a significant reduction in airflow, both leading to **oxygen desaturation** and sleep disruption [1]. *Emphysema* - Emphysema is a form of **Chronic Obstructive Pulmonary Disease (COPD)** characterized by destruction of the alveoli, leading to reduced gas exchange. - Its diagnosis and severity assessment rely on **spirometry** (e.g., FEV1/FVC ratio) and imaging, not AHI [2]. *Asthma* - Asthma is a chronic inflammatory airway disease characterized by **reversible airway obstruction** and bronchial hyperresponsiveness [2]. - Its diagnosis involves **pulmonary function tests** like spirometry, often with bronchodilator challenge, and clinical symptoms, but not AHI [2]. *Hyaline membrane disease* - **Hyaline membrane disease** (also known as Infant Respiratory Distress Syndrome) is a respiratory disorder primarily affecting premature infants due to insufficient surfactant production. - Diagnosis is based on **clinical presentation** at birth, chest X-rays, and arterial blood gas analysis, not AHI.
Practice by Chapter
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