Sleep-Disordered Breathing — MCQs

10 questions

Severe Obstructive sleep apnea is defined as AHI of greater than

Which of the following laboratory findings is most consistent with hypoxia due to acute respiratory distress syndrome (ARDS)?

Modafinil is approved by FDA for treatment of all except:

A 42-year-old obese male presented with disturbed sleep and daytime somnolence. All of the following are correct except?

Which of the following is the most effective diagnostic test to differentiate between central and peripheral cyanosis in a patient with hypoxia?

Laser uvulopalatoplasty is indicated for which of the following conditions?

A patient presented with 2 days history of fever. On examination there was a swelling in the neck and one side tonsil was pushed to midline. What is the most likely diagnosis:-

All of the following criteria are required for diagnosis of obesity hypoventilation syndrome except -

Which is incorrect about the instrument shown?

Q10Medium

All of the following are true regarding Zenker's diverticulum EXCEPT?

Sleep-Disordered Breathing Indian Medical PG Practice Questions and MCQs

Question 1: Severe Obstructive sleep apnea is defined as AHI of greater than

A. 15 events/hour
B. 30 events/hour (Correct Answer)
C. 25 events/hour
D. 20 events/hour

Explanation: ***30 events/hour*** - A **severe form of obstructive sleep apnea (OSA)** is diagnosed when the Apnea-Hypopnea Index (AHI) is greater than or equal to **30 events per hour** [1]. - The AHI represents the average number of **apnea and hypopnea events** per hour of sleep [1]. *15 events/hour* - An AHI of **15 to 30 events/hour** typically defines **moderate sleep apnea**, not severe. - This level indicates a significant number of sleep disturbances, but less than what is categorized as severe. *25 events/hour* - An AHI of **25 events/hour** falls within the **moderate range** of OSA severity (15-30 events/hour). - It does not meet the criteria for severe OSA, which requires a higher AHI. *20 events/hour* - An AHI of **20 events/hour** also falls into the **moderate category** of OSA. - This value is above the threshold for mild OSA (5-15 events/hour) but below the threshold for severe OSA.

Question 2: Which of the following laboratory findings is most consistent with hypoxia due to acute respiratory distress syndrome (ARDS)?

A. Increased PaCO2 with decreased pH
B. Increased A-a gradient (Correct Answer)
C. Decreased PaO2 with normal PaCO2
D. Normal A-a gradient

Explanation: ***Increased A-a gradient*** - In ARDS, the **lung pathology** (e.g., alveolar edema, collapse, or consolidation) impairs gas exchange, leading to a significant **mismatch between ventilation and perfusion**. - This mismatch results in a larger-than-normal difference between the alveolar oxygen partial pressure (PAO2) and the arterial oxygen partial pressure (PaO2), which is measured as an **increased A-a gradient**. *Increased PaCO2 with decreased pH* - This finding describes **respiratory acidosis**, which would typically occur in severe **hypoventilation** or end-stage ARDS with respiratory failure. - In initial or moderate ARDS, patients often compensate with **hyperventilation** due to hypoxia, leading to decreased or normal PaCO2. *Decreased PaO2 with normal PaCO2* - While a decreased PaO2 is characteristic of hypoxia in ARDS, a **normal PaCO2** in the presence of significant hypoxemia still implies an impairment in gas exchange that would manifest as an increased A-a gradient. - This specific combination (decreased PaO2, normal PaCO2) is not as specific as the A-a gradient for identifying the underlying cause of hypoxia due to shunt or V/Q mismatch. *Normal A-a gradient* - A normal A-a gradient suggests that **gas exchange in the lungs is efficient**, and any hypoxia is likely due to **hypoventilation** or **low inspired oxygen**. - This finding would rule out significant intrinsic lung disease, such as ARDS, as the primary cause of hypoxia.

Question 3: Modafinil is approved by FDA for treatment of all except:

A. Narcolepsy
B. Shift work sleep disorder (SWSD)
C. Obstructive sleep apnea syndrome (OSAS)
D. Lethargy in depression (Correct Answer)

Explanation: ***Lethargy in depression*** - Modafinil is **not FDA-approved** for treating lethargy or fatigue specifically in the context of depression. Its primary indications are for disorders of excessive daytime sleepiness. - While it may be used off-label in some cases for depression-related fatigue, it lacks formal FDA approval and specific efficacy data for this indication. *Narcolepsy* - Modafinil is **FDA-approved** as a wakefulness-promoting agent for the treatment of excessive daytime sleepiness associated with **narcolepsy**. - It helps reduce the frequency and severity of sleep attacks by promoting wakefulness through effects on **dopamine**, **norepinephrine**, and **histamine** systems in the brain. *Shift work sleep disorder (SWSD)* - Modafinil is **FDA-approved** to improve wakefulness in patients with excessive sleepiness associated with **shift work sleep disorder**. - It helps individuals working non-traditional hours (night shifts, rotating shifts) maintain alertness during their work periods. *Obstructive sleep apnea syndrome (OSAS)* - Modafinil is **FDA-approved** as an **adjunctive treatment** for residual excessive daytime sleepiness in patients with **obstructive sleep apnea/hypopnea syndrome (OSAHS)** who are receiving adequate treatment with CPAP. - It addresses persistent sleepiness that remains even after appropriate primary airway management.

Question 4: 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 5: Which of the following is the most effective diagnostic test to differentiate between central and peripheral cyanosis in a patient with hypoxia?

A. Arterial blood gas analysis (Correct Answer)
B. Pulse oximetry
C. Chest X-ray
D. Electrocardiogram

Explanation: ***Arterial blood gas analysis*** - An **arterial blood gas (ABG)** can definitively measure the **partial pressure of oxygen (PaO2)** and **oxygen saturation (SaO2)**, which are crucial for differentiating the physiological causes of hypoxia leading to central versus peripheral cyanosis [2]. - In **central cyanosis**, both PaO2 and SaO2 are low, indicating inadequate oxygenation of arterial blood, whereas in **peripheral cyanosis**, SaO2 might be relatively normal in arterial blood, but tissue extraction of oxygen is increased. *Pulse oximetry* - **Pulse oximetry** measures **peripheral oxygen saturation (SpO2)**, which estimates arterial oxygen saturation [1]. - While useful for detecting hypoxemia, it doesn't provide information on PaO2, nor can it reliably differentiate between true arterial desaturation (central cyanosis) and local circulatory issues leading to increased oxygen extraction (peripheral cyanosis), especially in conditions like **shock** or **vasoconstriction** where peripheral perfusion is compromised. *Chest X-ray* - A **chest X-ray** is a structural imaging test used to evaluate the lungs and heart for abnormalities that might cause hypoxemia [2]. - While it can identify potential causes of hypoxia (e.g., **pneumonia**, **pulmonary edema**), it does not directly measure oxygen levels or differentiate between central and peripheral cyanosis. *Electrocardiogram* - An **electrocardiogram (ECG)** measures the **electrical activity of the heart** and is used to diagnose cardiac arrhythmias, ischemia, or structural heart abnormalities [3]. - While cardiac issues can lead to hypoxia and cyanosis, an ECG doesn't directly assess oxygenation status or differentiate between central and peripheral cyanosis.

Question 6: Laser uvulopalatoplasty is indicated for which of the following conditions?

A. Obstructive sleep apnea (Correct Answer)
B. Pharyngotonsillitis
C. Cleft palate
D. Stammering

Explanation: ***Obstructive sleep apnea*** - **Laser uvulopalatoplasty (LUP)** is a surgical procedure that reshapes the **uvula** and **soft palate** to enlarge the airway in patients with **obstructive sleep apnea (OSA)**. - OSA is characterized by repetitive episodes of upper airway obstruction during sleep, leading to snoring, daytime sleepiness, and other health issues. *Pharyngotonsillitis* - This condition involves inflammation of the **pharynx** and **tonsils**, usually caused by bacterial or viral infections. - Treatment typically involves antibiotics for bacterial infections or symptomatic relief for viral infections, not surgical reshaping of the palate. *Cleft palate* - **Cleft palate** is a congenital birth defect where the roof of the mouth does not fully close during fetal development. - The primary treatment involves **surgical repair** to close the opening, which is a different procedure from LUP and focuses on reconstructing normal anatomy. *Stammering* - **Stammering** is a **speech disorder** characterized by disruptions in fluency, such as repetitions, prolongations, or blocks in speech. - It is managed through **speech therapy** and behavioral interventions, and is unrelated to airway obstruction or surgical procedures on the palate.

Question 7: A patient presented with 2 days history of fever. On examination there was a swelling in the neck and one side tonsil was pushed to midline. What is the most likely diagnosis:-

A. Retropharyngeal abscess
B. Parapharyngeal abscess
C. Tonsillitis
D. Quinsy (Correct Answer)

Explanation: ***Quinsy (Peritonsillar abscess)*** - **Quinsy** is a **peritonsillar abscess** that presents with fever, severe throat pain, and the pathognomonic sign of **unilateral tonsil pushed toward the midline**. - The abscess forms in the **peritonsillar space** (between the tonsillar capsule and superior constrictor muscle), causing **medial displacement of the tonsil** and **bulging of the soft palate**. - Patients typically have **trismus, dysphagia, "hot potato voice"** and may have visible neck swelling. - This clinical presentation exactly matches the description: tonsil pushed to midline is the **classic finding for peritonsillar abscess**. *Parapharyngeal abscess* - A **parapharyngeal abscess** involves the deep parapharyngeal space lateral to the pharynx. - While it can cause neck swelling and fever, it typically causes **fullness and induration of the lateral pharyngeal wall** rather than prominent medial displacement of the tonsil itself. - The **tonsil is usually NOT pushed to the midline** in parapharyngeal abscess; instead, there is lateral pharyngeal wall bulging. - Often presents with more prominent external neck swelling below the angle of mandible. *Retropharyngeal abscess* - A **retropharyngeal abscess** occurs in the retropharyngeal space behind the posterior pharyngeal wall. - Presents with **posterior pharyngeal wall bulge**, neck stiffness, and dysphagia. - Does **NOT cause medial displacement of the tonsil** as the abscess is posterior, not lateral to the tonsil. *Tonsillitis* - **Acute tonsillitis** causes bilateral tonsillar inflammation with erythema and exudates. - While both tonsils may be enlarged, there is **no unilateral medial displacement** of one tonsil. - Less likely to cause significant neck swelling compared to deep space infections.

Question 8: All of the following criteria are required for diagnosis of obesity hypoventilation syndrome except -

A. PaCO2 > 45 mmHg
B. BMI 30 kg/m2
C. Hypertension (Correct Answer)
D. Sleep disorder breathing

Explanation: ***Hypertension*** - While **hypertension** is a common comorbidity in patients with **obesity hypoventilation syndrome (OHS)**, it is _not_ a diagnostic criterion. - OHS is defined by specific respiratory and obesity-related parameters, not the presence of associated cardiovascular conditions. *BMI $\geq$ 30 kg/m$^2$* - A **body mass index (BMI)** of **30 kg/m$^2$** or greater is a fundamental criterion for diagnosing OHS, as the syndrome is directly linked to obesity. - Severe obesity leads to mechanical compression of the lungs and chest wall, contributing to hypoventilation. *PaCO$_{2}$ > 45 mmHg* - A **daytime arterial partial pressure of carbon dioxide (PaCO$_{2}$)** greater than **45 mmHg** is a key diagnostic criterion, indicating chronic alveolar hypoventilation. - This persistent hypercapnia is present even when other causes like obstructive lung disease have been excluded. *Sleep-disordered breathing* - **Sleep-disordered breathing**, most commonly **obstructive sleep apnea (OSA)**, is almost universally present in OHS patients and is a required diagnostic criterion [1]. - The combination of severe obesity and OSA often leads to the development of chronic hypoventilation [1].

Question 9: Which is incorrect about the instrument shown?

A. Boyle Davis gag
B. Uses a draffin bipod stand (Correct Answer)
C. Used in uvulopalatopharyngoplasty
D. Used to perform procedures on the tongue

Explanation: ***Uses a draffin bipod stand*** - The image shows a **Boyle-Davis mouth gag** being used, which is typically self-retaining and **does not require an additional stand** such as a Draffin bipod. - The Draffin bipod stand is primarily used with a **Draffin mouth gag** or similar instruments to provide stability and hands-free retraction. *Boyle Davis gag* - The instrument shown suspending the tongue and keeping the mouth open is indeed a **Boyle-Davis self-retaining mouth gag**, commonly used in tonsillectomies and other oral cavity procedures. - Its design includes a central part that keeps the jaws apart and a tongue blade to depress the tongue. *Used in uvulopalatopharyngoplasty* - The Boyle-Davis mouth gag provides excellent exposure of the **oropharynx**, making it suitable for procedures like **uvulopalatopharyngoplasty (UPPP)**, which aims to improve breathing by reshaping the soft palate and uvula. - It allows for clear visualization and access to the surgical area in the back of the throat. *Used to perform procedures on the tongue* - While its primary function is to retract the tongue and keep the mouth open, it also provides good access for procedures directly on the tongue, such as **tongue base reduction** or biopsy. - The tongue blade component directly depresses the tongue, facilitating its manipulation for surgical access.

Question 10: All of the following are true regarding Zenker's diverticulum EXCEPT?

A. It is a false diverticulum
B. It occurs in children (Correct Answer)
C. It is a posterior pharyngeal pulsion diverticulum
D. The most common site for the diverticulum is Killian's dehiscence

Explanation: **Explanation:** Zenker’s diverticulum is a **pulsion diverticulum** caused by the herniation of the pharyngeal mucosa through a site of weakness in the muscular wall. 1. **Why Option B is the correct answer (False statement):** Zenker’s diverticulum is a disease of the **elderly**, typically occurring in the 7th or 8th decade of life. It is almost never seen in children because it is an acquired condition resulting from long-term incoordination of the cricopharyngeal muscle and increased intraluminal pressure. 2. **Why Option A is wrong (True statement):** It is a **false diverticulum** because it consists only of the mucosa and submucosa. A "true" diverticulum would involve all layers of the visceral wall, including the muscularis. 3. **Why Option C is wrong (True statement):** It is a **pulsion diverticulum** (pushed out by pressure) and it occurs **posteriorly** in the midline of the pharynx. 4. **Why Option D is wrong (True statement):** The anatomical site of herniation is **Killian’s dehiscence**, a triangular area of weakness between the thyropharyngeus and cricopharyngeus parts of the inferior constrictor muscle. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Regurgitation of undigested food, halitosis (foul breath due to stagnant food), dysphagia, and a gurgling sound in the neck (Boyce’s sign). * **Diagnosis:** The investigation of choice is a **Barium Swallow**, which shows a pouch behind the esophagus. * **Management:** Endoscopic Dohlman’s procedure (stapling the party wall) or open diverticulectomy with cricopharyngeal myotomy. * **Complication:** Aspiration pneumonia is the most common serious complication.

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