USMLE Step 2 Quiz
Practice Sleep Related Breathing Disorders in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
Question 1 / 20
0 of 20 answered
A 63-year-old woman with heart failure (LVEF 28%) has polysomnography showing central sleep apnea with Cheyne–Stokes respiration, AHI 32/hour, and oxygen nadir 85%. She asks whether adaptive servo-ventilation (ASV) is appropriate. She is stable on medical therapy but remains symptomatic at night.
In this patient, which of the following is the most appropriate next step in managing this patient’s sleep apnea?
This quiz focuses on Sleep Related Breathing Disorders, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 63-year-old woman with heart failure (LVEF 28%) has polysomnography showing central sleep apnea with Cheyne–Stokes respiration, AHI 32/hour, and oxygen nadir 85%. She asks whether adaptive servo-ventilation (ASV) is appropriate. She is stable on medical therapy but remains symptomatic at night.
In this patient, which of the following is the most appropriate next step in managing this patient’s sleep apnea?
Explanation: This question tests understanding of sleep-related breathing disorders, specifically focusing on diagnosis and management of obstructive and central sleep apnea. The concept involves recognizing the signs and symptoms of sleep apnea, interpreting sleep study results, and applying appropriate management strategies based on clinical guidelines. In this vignette, the patient presents with central apnea and Cheyne-Stokes in heart failure with low LVEF, which are indicative of central sleep apnea. Choice A is correct because it aligns with clinical guidelines for managing CSA in low EF heart failure, which involves avoiding ASV due to increased mortality risk from trials like SERVE-HF. Choice B is incorrect because it starts ASV, which is contraindicated here, a common error when not recalling specific trial outcomes. To help students: Emphasize the importance of differentiating between obstructive and central sleep apnea, understanding risk factors like heart failure, and applying evidence-based treatment plans. Encourage practice with sleep study interpretations to improve diagnostic accuracy.
A 47-year-old woman presents with a chief complaint of persistent fatigue and morning headaches. Her Epworth Sleepiness Scale score is 13. She has a BMI of 27 kg/m². Her husband mentions that she has started to snore more loudly over the past two years. Physical examination is unremarkable.
What is the most appropriate next step to confirm the suspected diagnosis?
Explanation: This patient's symptoms of fatigue, morning headaches, daytime sleepiness (indicated by the Epworth score >10), and snoring are highly suggestive of obstructive sleep apnea, even in a non-obese woman. The gold standard for diagnosis is an in-laboratory polysomnography (sleep study), which measures various physiologic parameters during sleep, including respiratory effort, airflow, and oxygen saturation, to confirm the diagnosis and assess its severity. While hypothyroidism and depression can cause fatigue, the combination of symptoms makes OSA the primary concern that requires definitive testing.
A 62-year-old man with a BMI of 31 kg/m² undergoes a sleep study for snoring and mild daytime fatigue. The polysomnography report shows an apnea-hypopnea index (AHI) of 12 events/hour with oxygen desaturations to 90%. He feels his symptoms are manageable and is hesitant to start CPAP therapy.
What is the most appropriate initial management recommendation for this patient?
Explanation: This patient has mild obstructive sleep apnea, defined by an AHI between 5 and 15 events/hour. For patients with mild OSA and minimal symptoms, the most appropriate initial management is conservative measures, including lifestyle modifications. These include weight loss, regular exercise, avoiding alcohol and sedatives before bed, and considering positional therapy. CPAP is typically reserved for moderate-to-severe OSA or for mild OSA with significant symptoms or comorbidities.
A 55-year-old man with moderate obstructive sleep apnea (AHI of 25 events/hour) was prescribed CPAP. After several weeks of trying different masks and pressure settings, he reports being unable to tolerate the therapy due to severe claustrophobia and pressure sensation. He remains symptomatic with significant daytime sleepiness.
Which of the following is the most appropriate alternative treatment for this patient?
Explanation: For patients with mild to moderate OSA who are unable to tolerate or are refractory to CPAP, an oral appliance, such as a mandibular advancement device, is a recommended second-line therapy. These devices work by advancing the mandible and tongue forward, which increases the caliber of the upper airway. Supplemental oxygen does not treat the obstructive events. Modafinil treats residual sleepiness but not the underlying apnea. Tracheostomy is a definitive treatment but is highly invasive and reserved for life-threatening cases where other therapies have failed.
A 60-year-old man with a history of heart failure undergoes polysomnography. The study demonstrates recurrent 30-second episodes of breathing cessation. During these episodes, simultaneous monitoring of chest wall and abdominal movement shows a complete absence of respiratory effort. These apneas are followed by a brief arousal.
These findings are most characteristic of which of the following conditions?
Explanation: The key finding that distinguishes central sleep apnea (CSA) from obstructive sleep apnea (OSA) is the absence of respiratory effort during the apneic event. In OSA, the patient continues to make an effort to breathe against a collapsed airway. In CSA, the brain fails to send appropriate signals to the respiratory muscles, leading to a cessation of both airflow and respiratory effort. CSA is commonly associated with conditions like heart failure and stroke.
A 49-year-old commercial truck driver is diagnosed with severe obstructive sleep apnea (AHI of 52 events/hour) after his wife urged him to get evaluated for loud snoring and gasping at night. He admits to feeling very sleepy during long drives and has had two near-miss accidents in the past six months.
In addition to initiating CPAP therapy, which of the following is the most critical recommendation for this patient?
Explanation: Patients with untreated, symptomatic obstructive sleep apnea, particularly those in safety-sensitive occupations like commercial driving, are at a significantly increased risk of motor vehicle accidents. The most important recommendation for patient and public safety is to advise the patient to refrain from driving professionally until their treatment (e.g., CPAP) is optimized and their daytime sleepiness has resolved. This is often a legal and regulatory requirement. Other measures are insufficient to mitigate the high risk of falling asleep at the wheel.
A patient's overnight polysomnography report is finalized. The key finding is an apnea-hypopnea index (AHI) of 22 events/hour, associated with oxygen desaturations to 88%. The patient reports moderate daytime sleepiness.
Based on the American Academy of Sleep Medicine criteria, how should this patient's condition be classified?
Explanation: The severity of obstructive sleep apnea is classified based on the apnea-hypopnea index (AHI), which is the number of apnea and hypopnea events per hour of sleep. The standard classification is: Mild (AHI 5-15), Moderate (AHI 15-30), and Severe (AHI >30). An AHI of 22 events/hour falls into the moderate category.
A 19-year-old man with a normal BMI (23 kg/m²) presents with severe daytime sleepiness, poor school performance, and morning headaches. His roommate reports extremely loud snoring. On physical examination, his tonsils are noted to be massively enlarged, nearly touching in the midline (grade 4+).
Which of the following is the most appropriate definitive management for this patient's condition?
Explanation: In this young, non-obese patient, the clear etiology of his obstructive sleep apnea symptoms is massive tonsillar hypertrophy, which is a significant anatomical obstruction. In such cases, tonsillectomy is often a curative, first-line treatment. While CPAP could be used, surgery addresses the underlying cause and may obviate the need for lifelong therapy. Oral appliances and conservative measures are less likely to be effective given the degree of physical obstruction.
A 62-year-old woman with well-controlled moderate obstructive sleep apnea on CPAP for the past two years presents for follow-up. She was recently started on a new medication for generalized anxiety disorder. She reports that her husband has noticed a recurrence of her loud snoring and witnessed apneas, despite her using her CPAP machine nightly as prescribed.
The prescription of which of the following medications is most likely responsible for the worsening of her sleep apnea?
Explanation: Benzodiazepines, such as lorazepam, are known to worsen obstructive sleep apnea. They act as central nervous system depressants and muscle relaxants, which can decrease the tone of the pharyngeal dilator muscles, making the upper airway more susceptible to collapse. This can lead to a recurrence or worsening of OSA, even in patients on CPAP therapy, sometimes requiring a pressure increase. SSRIs (sertraline), buspirone, and beta-blockers (propranolol) do not typically have this effect.
A 66-year-old man with a history of obesity and hypertension is diagnosed with paroxysmal atrial fibrillation after presenting with palpitations. An echocardiogram shows mild left atrial enlargement but is otherwise normal. His medication regimen for hypertension is effective. He snores loudly and often feels tired during the day.
Evaluation for which of the following underlying conditions is most important in the management of this patient's atrial fibrillation?
Explanation: Obstructive sleep apnea (OSA) is a strong and independent risk factor for atrial fibrillation (AF). The pathophysiology involves increased sympathetic tone, hypoxia, and large swings in intrathoracic pressure, all of which can trigger and perpetuate AF. In patients with AF, especially those who are obese and have symptoms of OSA, screening and treatment for OSA are crucial, as it can reduce the burden of AF and improve the success of rhythm control strategies.
A 54-year-old postmenopausal woman presents with a 3-year history of insomnia, fatigue, and difficulty concentrating. Her symptoms have been attributed to major depressive disorder, and she has had unsuccessful trials of two different SSRIs. She denies snoring, but her husband is a very heavy sleeper. Her BMI is 29 kg/m². She has a history of hypertension.
Given her refractory symptoms, which of the following is the most important diagnosis to consider?
Explanation: Obstructive sleep apnea can present atypically in women, particularly postmenopausal women. Instead of classic loud snoring and witnessed apneas, they may present with symptoms like insomnia, fatigue, morning headaches, and mood disturbances, which can be misdiagnosed as depression or anxiety. Given her refractory symptoms, risk factors (postmenopausal, overweight, hypertension), and the atypical presentation, OSA should be high on the differential diagnosis and warrants evaluation with a sleep study.
A 58-year-old man was started on CPAP for severe OSA three months ago. He reports his daytime sleepiness has improved, but he finds the therapy uncomfortable. He uses it for about 3 hours per night before taking it off. He complains specifically of a very dry nose and mouth in the morning.
Which of the following interventions is most likely to improve his comfort and adherence to therapy?
Explanation: Nasal dryness, congestion, and dry mouth are common side effects of CPAP therapy, caused by the constant flow of dry air. Adding heated humidification to the CPAP circuit warms and moistens the air, which can significantly alleviate these symptoms and improve patient comfort and adherence. Decreasing the pressure may render the therapy ineffective. A full-face mask might be necessary for mouth-breathers but may not solve the dryness issue. Hypnotics can worsen OSA and are generally avoided.
A 70-year-old man with a history of systolic heart failure (ejection fraction 35%) is evaluated for daytime sleepiness and fatigue. His wife reports his breathing at night is irregular, with periods of rapid, deep breathing alternating with periods where he stops breathing entirely. A sleep study confirms Cheyne-Stokes respiration with a central apnea-hypopnea index of 25 events/hour. He is on optimal medical therapy for his heart failure.
Which of the following is the most appropriate initial therapy for this patient's sleep-disordered breathing?
Explanation: This patient has central sleep apnea with Cheyne-Stokes respiration, a common finding in patients with advanced heart failure. While optimization of heart failure therapy is paramount, the next step for treating the sleep apnea itself is often a trial of continuous positive airway pressure (CPAP). CPAP can help stabilize breathing patterns and improve cardiac function. Adaptive servo-ventilation (ASV) is contraindicated in patients with an ejection fraction ≤45% due to evidence of increased mortality in this population. Theophylline and acetazolamide are not first-line therapies.
A 45-year-old man is being evaluated for risk of sleep-disordered breathing. He has a family history of sleep apnea. He drinks one glass of wine with dinner. He has a BMI of 36 kg/m². His neck circumference is 44 cm (17.5 inches).
Which of the following is the single greatest modifiable risk factor for the development of obstructive sleep apnea in this patient?
Explanation: Obesity is the strongest modifiable risk factor for obstructive sleep apnea. Excess adipose tissue deposition in the neck and pharyngeal structures narrows the upper airway, predisposing it to collapse during sleep. While alcohol consumption can worsen OSA, family history and male gender are non-modifiable risk factors, obesity (high BMI) is the most significant and modifiable contributor. Weight loss can lead to substantial improvement or even resolution of OSA in many patients.
A 59-year-old man with a long-standing history of untreated severe obstructive sleep apnea presents for a routine check-up. His blood pressure is 165/95 mm Hg despite adherence to a three-drug antihypertensive regimen including a diuretic, an ACE inhibitor, and a calcium channel blocker. He has no history of renal artery stenosis or primary aldosteronism.
His resistant hypertension is most likely mediated by which of the following mechanisms related to his sleep disorder?
Explanation: Obstructive sleep apnea is a common cause of secondary and resistant hypertension. The recurrent episodes of hypoxia and arousal during sleep lead to surges in sympathetic nervous system activity, which persist into the daytime. This chronic sympathetic activation contributes to elevated blood pressure that is often difficult to control with standard antihypertensive medications. Effective treatment of OSA with CPAP can significantly improve blood pressure control.
A 65-year-old man with a 15-year history of severe, untreated obstructive sleep apnea presents with progressive dyspnea on exertion and lower extremity edema. A transthoracic echocardiogram reveals right ventricular hypertrophy, right atrial enlargement, and an estimated pulmonary artery systolic pressure of 60 mm Hg. There is no evidence of left-sided heart failure or primary lung disease.
The patient's cardiac findings are most likely a consequence of which pathophysiologic mechanism?
Explanation: Untreated severe OSA can lead to pulmonary hypertension and subsequent right-sided heart failure (cor pulmonale). The underlying mechanism is chronic intermittent hypoxemia, which triggers hypoxic pulmonary vasoconstriction. Over time, this leads to remodeling of the pulmonary vasculature, sustained pulmonary hypertension, and pressure overload on the right ventricle, resulting in hypertrophy and eventually failure. While OSA is associated with systemic hypertension and atrial stretch (risk for atrial fibrillation), the development of isolated right heart failure is primarily driven by hypoxic pulmonary vasoconstriction.
A 50-year-old man with a BMI of 38 kg/m² is diagnosed with severe obstructive sleep apnea. During his evaluation, routine laboratory tests are performed. Fasting blood glucose is 120 mg/dL and hemoglobin A1c is 6.2%. Lipid panel shows elevated triglycerides.
Untreated obstructive sleep apnea is recognized as an independent risk factor for the development of which of the following metabolic conditions?
Explanation: There is a strong, bidirectional relationship between obstructive sleep apnea and metabolic syndrome. The intermittent hypoxia and sleep fragmentation associated with OSA can lead to increased sympathetic activity, inflammation, and hormonal changes that promote insulin resistance. Consequently, untreated OSA is an independent risk factor for the development of prediabetes and type 2 diabetes mellitus. This patient's laboratory results are already indicative of prediabetes.
A 57-year-old obese man with hypertension is being seen for a preoperative evaluation before an elective knee replacement. He denies excessive daytime sleepiness but his wife is present and states he snores 'like a freight train' and she has seen him stop breathing in his sleep. His neck circumference is 45 cm (17.7 in).
Which of the following is the most appropriate tool to quickly screen for this patient's risk of having obstructive sleep apnea?
Explanation: The STOP-BANG questionnaire is a validated screening tool used to assess the risk of obstructive sleep apnea, particularly in the perioperative setting. It assesses Snoring, Tiredness, Observed apnea, high blood Pressure, BMI (>35), Age (>50), Neck circumference (>40 cm), and male Gender. This patient has multiple positive criteria, placing him at high risk. The Epworth Sleepiness Scale assesses subjective sleepiness, which the patient denies, making it less useful for screening in his case. Oximetry and PFTs are diagnostic tests, not screening tools.
A 44-year-old man with a BMI of 27 kg/m² undergoes polysomnography for snoring and daytime fatigue. The results show an overall AHI of 14 events/hour. A detailed analysis reveals that his AHI is 38 events/hour while sleeping in the supine position but only 3 events/hour while sleeping in the lateral position. He spends approximately 40% of the night in the supine position.
Which of the following is the most appropriate initial management strategy for this patient?
Explanation: This patient has positional obstructive sleep apnea, where his apneic events occur predominantly or exclusively in the supine position. Since his AHI is normal when in the lateral position, the most targeted and least invasive initial treatment is positional therapy. This involves using devices or techniques (e.g., a special pillow or a wearable device that vibrates when he turns onto his back) to encourage him to sleep in a non-supine position. This can be highly effective for this specific subtype of OSA.
A 48-year-old woman is diagnosed with severe obstructive sleep apnea after an in-laboratory polysomnography study reveals an apnea-hypopnea index (AHI) of 45 events/hour. She has significant daytime somnolence that interferes with her work as an accountant. Her BMI is 32 kg/m².
Which of the following is the most appropriate initial treatment for this patient?
Explanation: Continuous positive airway pressure (CPAP) is the first-line treatment for moderate to severe obstructive sleep apnea. It acts as a pneumatic splint to keep the upper airway open during sleep, effectively treating the apneic events and improving daytime sleepiness. While weight loss is an important adjunctive therapy, it is not sufficient as a sole initial treatment for severe, symptomatic OSA. Mandibular advancement devices are typically reserved for mild-to-moderate OSA or for patients who cannot tolerate CPAP. UPPP is a surgical option with lower efficacy and is not a first-line therapy.