Makindo Medical Notes

Sleep apnoea is classified into two main types: Central Sleep Apnoea (rare) and Obstructive Sleep Apnoea (OSA) (common). OSA occurs when the airway collapses or becomes blocked during sleep, leading to disrupted breathing.

Key Features of Obstructive Sleep Apnoea

• Excessive Daytime Sleepiness: A primary symptom assessed using the Epworth Sleepiness Scale.
• Fatigue and Poor Concentration: Many patients report persistent weariness and difficulty focusing.
• Heavy Snoring: Loud, disruptive snoring with episodes of witnessed apnoea during sleep.
• Nocturia and Morning Headaches: Waking up frequently at night to urinate and experiencing headaches upon waking.
• Non-restorative Sleep: Despite sleeping for adequate hours, patients feel unrefreshed in the morning.

Aetiology: Causes of Upper Airway Collapse

• Recurrent Occlusion: Airway occlusion occurs repeatedly at the pharyngeal level during sleep, leading to breathing interruptions.
• Negative Pressure Mechanism: Blockages may result from negative pressure generated during inhalation.
• Obesity and Anatomical Factors: Common in obese males with large neck circumferences and a history of snoring.
• Smoking: Smoking increases the risk of airway inflammation and collapse during sleep.
• Road Traffic Accidents (RTAs): Increased risk of single-vehicle accidents due to daytime drowsiness.
• Partner Observations: Partners often report episodes of apnoea during the patient's sleep.
• Avoid Sedation and Alcohol: These can further relax the airway, exacerbating OSA symptoms.

Investigations for Obstructive Sleep Apnoea

• Sleep Studies (Polysomnography): Measures O₂ saturation, EEG, EMG, oronasal airflow, respiratory effort, and snoring patterns. Profound drops in PO₂ and respiratory effort are common.
• Apnoea-Hypopnoea Index (AHI): More than 15 apnoeas (lasting 10 seconds or more) per hour is considered significant.
• Epworth Sleepiness Scale: A quick and useful tool to assess the severity of daytime sleepiness.

Risks Associated with Sleep Apnoea

• Systemic Hypertension: Strongly linked to high blood pressure and mild pulmonary hypertension due to chronic low oxygen levels during sleep.
• Cardiovascular Disease: Increased risk of myocardial infarction, arrhythmias, and strokes due to the strain OSA places on the cardiovascular system.
• Increased Risk of Accidents: Due to excessive daytime drowsiness, there is a higher likelihood of road traffic accidents, particularly single-vehicle collisions.

Management of Obstructive Sleep Apnoea

• Lifestyle Modifications: Avoid alcohol, smoking, and sedatives, which can exacerbate the condition. Weight loss is a key recommendation.
• Continuous Positive Airway Pressure (CPAP): The main treatment for moderate to severe OSA. CPAP keeps the airway open by delivering a steady flow of air. It reduces daytime sleepiness and decreases the risk of accidents.
• Oral Appliances: In mild cases or for those intolerant to CPAP, oral devices can help keep the airway open by adjusting the position of the jaw and tongue.
• Surgical Options: In cases of anatomical abnormalities, surgery may be considered to remove excess tissue or correct structural issues causing airway collapse.