Sleep Medicine
Pulmonary and Critical Care Medicine · Sleep Medicine 🎯 Practice these cards
The most common cause of excessive daytime sleepiness is ____; most adults require ____ hours of sleep per night.
Insufficient sleep syndrome is the most common cause of excessive daytime sleepiness (EDS). Most adults require 7 to 8 hours of sleep; chronic sleep debt causes functional impairment and is associated with cardiovascular disease, glucose intolerance, and obesity. Sleepiness (difficulty staying awake) must be distinguished from fatigue (lack of energy).
Intrinsic causes of EDS include sleep-disordered breathing, ____, idiopathic hypersomnia, and restless legs syndrome/periodic limb movement disorder; extrinsic causes include insufficient sleep duration, ____ rhythm disturbance, drug/medical-related hypersomnia, and environmental sleep disorder.
EDS causes divide into extrinsic (circumstantial) and intrinsic (disease-related) processes. Intrinsic: sleep-disordered breathing (obstructive and central sleep apnea), narcolepsy, idiopathic hypersomnia, restless legs syndrome/periodic limb movement disorder, and circadian rhythm disorders from misalignment (e.g., dementia, blindness). Extrinsic: insufficient sleep duration, circadian rhythm disturbance (shift work, jet lag), drug/substance/psychiatric/medical-related hypersomnia, and environmental sleep disorder (noise, pets).
A ____-week sleep-wake diary is a simple initial tool for evaluating EDS; objective sleepiness is quantified by the ____ test, which is key to diagnosing narcolepsy and idiopathic hypersomnia.
Initial EDS evaluation starts with history of time available for and actually spent sleeping, sleep hygiene, and targeted symptom review. A 1- or 2-week sleep-wake diary promotes self-realization of suboptimal habits; wrist actigraphy gives more objective sleep-wake data. The multiple sleep latency test measures time to fall asleep across daytime nap opportunities and is key to diagnosing narcolepsy and idiopathic hypersomnia.
Jet lag is harder to adapt to with ____ward travel; symptoms persisting for at least ____ months in a shift worker meet criteria for shift work sleep disorder.
Jet lag occurs when the circadian clock is out of phase with local time after travel across multiple time zones; eastward travel is harder to adapt to than westward. Shift workers with excessive sleepiness, mood perturbations, and neurocognitive dysfunction persisting for at least 3 months meet criteria for shift work sleep disorder; management includes schedule change, protected daytime sleep, melatonin, and wake-promoting stimulants (e.g., modafinil) only if conservative measures fail.
In OSA, an apnea is complete cessation of airflow for at least ____ seconds with ____ respiratory effort; severity by AHI is mild ____-14 events/hour, moderate 15-____, and severe >____.
OSA is defined by sleep interruption from repetitive upper airway narrowing or collapse. Apneas are complete cessation of airflow for at least 10 seconds with persistent respiratory effort; hypopneas are >=30% airflow reduction for >=10 seconds with desaturation or arousal. Severity by AHI: mild 5-14 events/hour, moderate 15-30, severe >30. AHI does not capture hypoxic burden and correlates poorly with sleepiness.
The most important risk factor for OSA is ____ (attributable to excess weight in roughly ____% of cases); prevalence is about ____ times higher in men than in women, and rises in women after ____.
Obesity is the most important OSA risk factor: roughly 40-60% of OSA is attributable to excess weight, obese individuals carry a fourfold or greater risk, and a 10% weight gain raises AHI by more than 30%. Prevalence is about twice as high in men as in women; premenopausal women are relatively protected, and prevalence rises after menopause. Anatomic contributors include craniofacial narrowing (retrognathia/micrognathia), tonsillar hypertrophy, and macroglossia; absence of obesity never excludes OSA.
The most sensitive pretest indicator of OSA is sleep-related ____; the cardiovascular consequence with evidence supporting a causal link is systemic ____.
Sleep-related choking or gasping is probably the most sensitive pretest indicator of OSA; other symptoms include snoring, witnessed apneas, nocturia, morning headaches, nocturnal awakenings, and unrefreshing sleep. Current evidence supports a causal link between OSA and systemic hypertension; associations with heart failure, cardiac arrhythmias (e.g., atrial fibrillation), stroke, and diabetes are associative rather than proven causal.
The gold standard test for diagnosing OSA is in-laboratory ____; ____ sleep apnea testing is appropriate for uncomplicated patients with moderate-to-severe pretest probability.
Objective testing is required to diagnose OSA. In-laboratory polysomnography (PSG) is the gold standard and is recommended for mission-critical workers, complicated OSA, and comorbid heart failure, neuromuscular disease, or advanced pulmonary disease. Home sleep apnea testing is highly sensitive for patients with at least moderate to severe pretest likelihood and no underlying cardiopulmonary or neuromuscular disease; a negative home study in a high-probability patient should be followed by in-laboratory PSG.
First-line therapy for OSA is ____; ____ appliances are an option for mild-to-moderate disease or CPAP-intolerant patients, and ____ loss improves OSA severity.
Positive airway pressure (CPAP or auto-adjusting PAP) is the most effective OSA therapy and first-line treatment. Oral appliances, which advance the mandible, provide good control of mild to moderate OSA and are an option for CPAP-intolerant patients. Weight loss improves OSA severity and may be preferred therapy in minimally symptomatic mild OSA. Upper-airway surgery (e.g., maxillomandibular advancement, uvulopalatopharyngoplasty) is generally not first-line; bilevel PAP has no role in uncomplicated OSA.
In December 2024, the FDA approved ____, a dual GIP/GLP-1 receptor agonist, as the first medication for moderate-to-severe OSA in adults with ____, as an adjunct to diet and exercise.
In the SURMOUNT-OSA phase 3 trials, weekly tirzepatide (a dual GIP/GLP-1 receptor agonist) reduced AHI by roughly 24-29 events/hour versus placebo in adults with moderate to severe OSA and obesity, with about 40-50% achieving disease remission and 18-20% weight loss. In December 2024, the FDA approved tirzepatide as the first-ever medication for moderate to severe OSA in adults with obesity, as an adjunct to diet and exercise.
Central apneas occur with ____ respiratory effort; ventilatory overshoot drives Pco2 below the ____ threshold, and Cheyne-Stokes breathing in heart failure results from ____ circulation time.
Central sleep apnea is defined by pauses in airflow from loss of brainstem respiratory drive, with absent respiratory effort (in contrast to obstructive events). The core defect is ventilatory control instability: an exaggerated response to Pco2 causes ventilatory overshoot, driving Pco2 below the apneic threshold at which respiratory efforts cease. In heart failure, prolonged circulation time between the pulmonary capillaries and carotid chemoreceptors produces the crescendo-decrescendo pattern of Cheyne-Stokes breathing.
About ____% of OSA patients started on PAP develop treatment-emergent central apneas; management is to continue ____ and reassess rather than abandoning therapy.
Approximately 10% of patients started on positive airway pressure for OSA develop treatment-emergent (complex) central apneas, particularly at higher pressures. Significance is debated, and in many patients the central apneas dissipate as they acclimate to PAP; the recommended approach is to continue treatment and reassess rather than abandoning PAP.
Per AASM 2025, CSA treatment options include CPAP, ____ across most etiologies, and transvenous ____ nerve stimulation; ASV is contraindicated in heart failure with ____ ejection fraction.
CSA management targets modifiable risk factors: reduce/eliminate opioids and optimize heart failure therapy. The AASM 2025 guideline conditionally recommends CPAP for most CSA etiologies, acetazolamide across primary, heart-failure-related, medication-related, treatment-emergent, and high-altitude CSA, and transvenous phrenic nerve stimulation for primary and heart-failure CSA. ASV is contraindicated in heart failure with reduced ejection fraction (LVEF <=45%) after SERVE-HF showed increased mortality.
Obesity hypoventilation syndrome requires BMI >=____ plus awake daytime hypercapnia with Pco2 >____ mm Hg without other cause; overlap syndrome is OSA superimposed on ____, for which CPAP decreases mortality.
Obesity hypoventilation syndrome is defined by BMI >=30 kg/m2 with awake daytime hypercapnia (arterial Pco2 >45 mm Hg) without another cause; treatment is weight loss plus positive airway pressure (CPAP for stable ambulatory patients with severe OSA per ATS; bilevel PAP for hospitalized respiratory failure). The overlap syndrome is OSA superimposed on COPD, in which CPAP has been shown to decrease mortality.
In neuromuscular disease, ____ hypoventilation precedes daytime hypercapnia; NIPPV should start once daytime ____ appears, and supplemental ____ alone should never be given without ventilatory support.
In neuromuscular disease, respiratory muscle weakness (e.g., diaphragmatic weakness) causes sleep-related hypoventilation that typically precedes daytime hypercapnia; nocturnal desaturation worsens during REM atonia. Bilevel PAP or volume-assured NIPPV is indicated once daytime hypercapnia appears. Supplemental oxygen alone may further depress ventilation and should not be given without adjunctive ventilatory support.
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