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• Section Writer: Dr. Om J Lakhani
• Section Editor: Dr. Om J Lakhani

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FAQs on Sleep-Disordered Breathing (SDB) and Obstructive Sleep Apnea (OSA)

Q. What are the components of Sleep-Disordered Breathing?

• Obstructive Sleep Apnea (OSA)
• Central Sleep Apnea
• Periodic Breathing

Q. What are reasons for sleep disturbances in patients with diabetes?

• OSA-associated obesity
• Other types of sleep-disordered breathing
• Diabetic autonomic neuropathy
• Nocturia/polyuria
• Restless leg syndrome
• Hypoglycemia-induced sympathetic stimulation

Q. What is the definition of OSA?

• "OSA is a disorder characterized by obstructive apneas, hypopneas, and/or respiratory effort-related arousals caused by repetitive collapse of the upper airway during sleep."
• Daytime somnolence with ≥5 episodes of obstructive breathing per hour during sleep:
  • Apnea: Cessation of airflow for ≥10 seconds.
  • Hypopnea: ≥50% reduction in airflow for ≥10 seconds.

Q. What is the classical triad of OSA?

• Daytime somnolence
• Snoring
• Witnessed apnea during sleep

Q. What are the symptoms of OSA?

• Daytime sleepiness
• Nonrestorative sleep
• Loud snoring
• Witnessed apneas by a bed partner
• Awakening with choking or gasping
• Insomnia with frequent awakenings
• Morning headaches
• Nocturia
• Cognitive and mood changes

Q. Can insomnia be a symptom of OSA?

• Yes. 1/3rd of patients, especially females, report insomnia rather than daytime sleepiness (sleep maintenance insomnia).

Q. What are the well-defined risk factors for OSA?

1. Old age
2. Male gender
3. Obesity
4. Craniofacial abnormalities
5. Upper airway abnormalities
6. Family history, smoking, and nasal congestion

Q. What clinical examination findings suggest OSA?

• Narrow or crowded airway
• Obesity
• Large neck circumference (>17 inches)
• Craniofacial abnormalities (e.g., retrognathia)

Q. What medical conditions exacerbate the risk of OSA?

• Type 2 diabetes, hypothyroidism, PCOS, acromegaly, pregnancy, end-stage renal disease, CHF, obesity hypoventilation syndrome, chronic lung disease, stroke

Q. What questionnaires are used to screen for OSA?

• Epworth Sleepiness Scale (ESS): Score >9 prompts further investigation.
• Berlin Questionnaire
• STOP-BANG Questionnaire

Q. What is the gold standard for diagnosing OSA?

• Polysomnography (PSG).

Q. What are the diagnostic criteria for OSA based on PSG?

• Asymptomatic: ≥15 episodes of apnea, hypopnea, or RERA/hour.
• Symptomatic: ≥5 episodes/hour with associated symptoms like sleepiness, snoring, fatigue, or hypertension.

Q. What is the Apnea-Hypopnea Index (AHI)?

• Formula: (Apneas + Hypopneas) ÷ Total sleep duration (hours).

Q. How is OSA severity classified?

• Mild: AHI/RDI 5–14
• Moderate: AHI/RDI 15–30
• Severe: AHI/RDI >30

Q. What are the consequences and complications of OSA?

1. Motor vehicle accidents
2. Neuropsychiatric dysfunction
3. Cardiovascular disease
4. Pulmonary hypertension and right heart failure
5. Metabolic syndrome and Type 2 diabetes

Q. What is the epidemiological link between OSA and diabetes?

• 40% of OSA patients develop diabetes.
• 58% of diabetes patients have sleep-disordered breathing.

Q. What studies show evidence of a link between OSA and diabetes?

• Sleep Heart Health Study (SHHS)
• Wisconsin Sleep Study

Q. What are options for managing OSA?

1. Lifestyle changes
2. Oral appliances
3. Positive airway pressure therapy (CPAP/BiPAP/APAP)
4. Surgery for anatomical abnormalities

Q. What is hypoglossal nerve stimulation?

• A surgical technique using an implanted neurostimulator to stimulate the hypoglossal nerve.

Q. When is pharmacological therapy used for OSA?

• Limited role; drugs like theophylline and cannabinoids have been tested but are not widely recommended.

Q. What is done for persistent daytime sleepiness despite treatment?

• Modafinil may be considered.

Q. What are the modes of delivering positive airway therapy?

1. CPAP (Continuous)
2. BiPAP (Bi-level)
3. APAP (Auto-titrating)
4. Adaptive servo-ventilation

Pearl:

• Unexplained pulmonary hypertension may indicate OSA.