Obstructive Sleep Apnea: Symptoms, Diagnosis and Treatment

Obstructive Sleep Apnea (OSA) is a sleep-related breathing disorder characterized by recurrent episodes of partial or complete collapse of the upper airway during sleep. This collapse impedes airflow, leading to intermittent reductions in blood oxygen levels and brief arousals from sleep that fragment normal sleep architecture.

Common Causes and Risk Factors

The likelihood of upper airway collapse during sleep is influenced by anatomical factors and neuromuscular tone. Recognized risk factors include:

• Obesity: Increased adiposity around the neck and pharynx can narrow the airway lumen.
• Anatomy: Craniofacial features such as a narrowed posterior airway space, enlarged tonsils or adenoids, or a recessed mandible (retrognathia).
• Age and Gender: The prevalence of OSA tends to increase with age. It is more frequently diagnosed in males, though the risk in females rises after menopause.
• Substances: Alcohol and certain medications with sedative properties can decrease upper airway muscle tone.
• Genetics/Family History: Familial patterns may influence craniofacial structure and body fat distribution.

Symptoms and Warning Signs

Because OSA events occur during sleep, patients may not be aware of their breathing pauses. Symptoms are often categorized into nighttime occurrences (frequently reported by a bed partner) and daytime consequences.

Nighttime Symptoms:

• Loud snoring (though snoring alone does not confirm OSA).
• Witnessed apneas, where a bed partner observes pauses in breathing followed by snorting or gasping.
• Restless sleep or frequent awakenings.
• Waking up with a sensation of choking or gasping for air.

Daytime Symptoms:

• Excessive Daytime Sleepiness (EDS), such as falling asleep during quiet activities or in inappropriate situations.
• Non-restorative sleep, waking up feeling unrefreshed.
• Morning headaches, which may be related to factors including sleep fragmentation, fluctuations in intracranial pressure, or oxygen desaturation.
• Impaired concentration or mood changes.

Clinical Evaluation

Evaluation by a physician typically involves a detailed sleep history and clinical assessment, which may incorporate screening questionnaires to evaluate symptoms like daytime sleepiness.

Diagnostic Testing

The diagnosis of OSA is established through objective sleep testing ^[1].

• In-Lab Polysomnography (PSG): Conducted in a sleep laboratory, this comprehensive test monitors neurological, cardiac, and respiratory parameters, including brain waves, oxygen levels, breathing effort, and airflow.
• Home Sleep Apnea Testing (HSAT): Uses portable monitors to record respiratory parameters in the patient's home. According to current guidelines, HSAT may be appropriate for the diagnosis of OSA in uncomplicated adult patients who have an increased risk of moderate to severe OSA. It is generally not recommended for patients with significant comorbid medical conditions (e.g., severe cardiopulmonary disease) or when other sleep disorders are suspected.

Disease severity is commonly assessed using metrics such as the Apnea-Hypopnea Index (AHI), which quantifies the frequency of abnormal respiratory events per hour of sleep.

Treatment Principles

Management of OSA aims to maintain airway patency during sleep and mitigate associated health risks, which can include cardiovascular morbidities if left untreated.

1. Positive Airway Pressure (PAP) Therapy: PAP therapy (such as CPAP or APAP) is considered a primary and highly effective treatment for OSA ^[2]. It utilizes a device to deliver a continuous flow of air through a mask, acting as a pneumatic splint to keep the upper airway open.
2. Lifestyle Modifications: Strategies such as weight management and avoiding alcohol before sleep can be beneficial adjunctive measures. Weight loss in individuals with obesity can improve OSA severity. Positional therapy may be suggested for patients whose OSA occurs predominantly while sleeping on their back.
3. Oral Appliances: Custom titratable mandibular advancement devices can be an effective treatment alternative for selected adults, particularly those who prefer an oral appliance or cannot tolerate or use PAP therapy.
4. Surgical Interventions: Various upper airway surgeries may be considered in selected patients based on their specific anatomy and severity of disease.

When to Seek Medical Attention

Individuals experiencing symptoms suggestive of OSA, particularly excessive daytime sleepiness that interferes with daily function or poses a safety risk (such as drowsiness while driving), should seek medical evaluation.