Apnoea

Overview Of Apnoea

Apnoea refers to the temporary cessation of breathing. It can occur during sleep (sleep apnoea) or while awake, and its severity can range from brief interruptions to prolonged periods of no breathing. The most common form of apnoea is **obstructive sleep apnoea (OSA)**, which occurs when the muscles in the throat relax excessively during sleep, leading to a blockage in the upper airway. Another form is **central sleep apnoea**, where the brain fails to send the proper signals to the muscles that control breathing. **Complex sleep apnoea**, or treatment-emergent central apnoea, is a combination of both obstructive and central apnoea. Apnoea during sleep can lead to fragmented sleep and low blood oxygen levels, which may result in fatigue, cardiovascular issues, and an increased risk of other health problems. Non-sleep-related apnoea, such as during exercise or in the context of certain medical conditions, is less common but can be life-threatening if it occurs in a chronic or severe form.

Causes of Apnoea

• The causes of apnoea can be classified into obstructive, central, and mixed (complex) types, each with its underlying mechanisms: - Obstructive sleep apnoea: This is the most common form and occurs when the muscles in the throat relax excessively during sleep, causing a temporary blockage of the upper airway. Factors that contribute to this blockage include obesity, enlarged tonsils, a thick neck, a small jaw, or nasal congestion. - Central sleep apnoea: This occurs when the brain does not send the proper signals to the muscles that control breathing. Conditions such as heart failure, stroke, brainstem injury, or certain neurological disorders can lead to central apnoea. In this case, there is no physical blockage in the airway, but rather a failure in respiratory control. - Complex sleep apnoea: A combination of obstructive and central apnoea, complex sleep apnoea can occur in individuals with both types of apnoea. The underlying causes may include pre-existing OSA, heart disease, or treatment with positive airway pressure (PAP) devices that may exacerbate central apnoea in some cases.

Risk Factors of Apnoea

• Several factors increase the likelihood of developing apnoea, particularly sleep apnoea: - Obesity: Excess body weight, particularly in the upper body, increases the risk of airway obstruction during sleep. - Age: Sleep apnoea is more common in middle-aged and older adults, though it can occur at any age. - Gender: Men are more likely to develop sleep apnoea than women, though the risk for women increases after menopause. - Family history: A family history of sleep apnoea or other breathing disorders may increase an individual's risk. - Alcohol and sedative use: Alcohol and sedatives relax the muscles in the throat, which can exacerbate obstructive sleep apnoea. - Nasal congestion: Chronic nasal issues, such as allergies or sinus problems, can contribute to breathing difficulties and sleep apnoea. - Smoking: Smoking increases inflammation and fluid retention in the upper airway, making apnoea episodes more frequent and severe. - Heart disease: Conditions such as heart failure and atrial fibrillation are associated with an increased risk of central sleep apnoea.

Prevention of Apnoea

• Preventing apnoea involves managing risk factors and adopting healthy lifestyle practices: - Maintain a healthy weight: Obesity is a major risk factor for obstructive sleep apnoea, and weight loss can significantly reduce symptoms. - Avoid alcohol and sedatives: These substances relax the muscles of the airway, increasing the risk of airway obstruction. - Sleep on your side: Sleeping on your back can worsen sleep apnoea, while sleeping on your side may help reduce airway collapse. - Treat nasal congestion: If nasal congestion is present, using decongestants, nasal sprays, or allergy treatments may help reduce obstruction and improve breathing. - Quit smoking: Smoking exacerbates inflammation in the upper airway and increases the risk of apnoea. - Manage underlying health conditions: Properly managing conditions such as heart disease, obesity, and diabetes can reduce the risk of developing central sleep apnoea.

Prognosis of Apnoea

• The prognosis for individuals with apnoea depends on the severity of the condition, the presence of underlying health problems, and the effectiveness of treatment. If left untreated, severe obstructive sleep apnoea can increase the risk of cardiovascular problems, high blood pressure, diabetes, stroke, and even premature death. Central sleep apnoea is often associated with heart failure and other serious conditions. However, with appropriate treatment, including the use of CPAP or other devices, lifestyle changes, and medical management, the prognosis for most individuals with sleep apnoea can be significantly improved. Early intervention is key to reducing complications and improving quality of life.

Complications of Apnoea

• If left untreated, apnoea can lead to various health complications: - Cardiovascular issues: Apnoea, particularly sleep apnoea, is associated with an increased risk of high blood pressure, heart disease, stroke, and arrhythmias. - Daytime fatigue: The fragmented sleep caused by apnoea leads to persistent fatigue, which can impair daily functioning, productivity, and overall quality of life. - Cognitive impairment: Chronic sleep disruption can lead to memory problems, difficulty concentrating, and impaired decision-making. - Mental health issues: Anxiety, depression, and irritability can be exacerbated by the chronic fatigue and stress caused by untreated apnoea. - Type 2 diabetes: Untreated sleep apnoea has been linked to an increased risk of insulin resistance and the development of type 2 diabetes. - Accidents: Daytime sleepiness and fatigue increase the risk of accidents, including motor vehicle accidents and workplace injuries.

Related Diseases of Apnoea

• Apnoea is related to several other medical conditions: - Obstructive sleep apnoea (OSA): The most common form of apnoea, caused by physical obstruction of the airway. - Central sleep apnoea (CSA): A less common form of apnoea caused by a failure of the brain to signal breathing muscles. - Cheyne-Stokes respiration: A pattern of abnormal breathing seen in individuals with heart failure or stroke, characterized by periods of deep breathing followed by apnea. - Obesity hypoventilation syndrome (OHS): A condition in which obesity causes poor breathing and low oxygen levels during sleep. - Narcolepsy: A sleep disorder characterized by excessive daytime sleepiness, which may be associated with sleep apnoea in some individuals.

Treatment of Apnoea

The treatment of apnoea varies depending on the type and severity of the condition: - **Lifestyle modifications**: Weight loss, avoiding alcohol, and sleeping on one’s side can help reduce the severity of sleep apnoea. Smoking cessation and managing nasal allergies may also improve symptoms. - **Continuous positive airway pressure (CPAP)**: The primary treatment for obstructive sleep apnoea, CPAP involves wearing a mask that delivers a constant stream of air to keep the airway open during sleep. - **Positive airway pressure (PAP) therapy**: For central sleep apnoea, adaptive servo-ventilation (ASV) or bilevel positive airway pressure (BiPAP) may be used. These devices adjust pressure to support breathing patterns. - **Oral appliances**: Dental devices or mandibular advancement devices (MADs) can be used to reposition the lower jaw and tongue, helping to prevent airway collapse during sleep. - **Surgery**: Surgical options may be considered for severe cases of obstructive sleep apnoea. This can include removing enlarged tonsils or adenoids, repositioning the jaw, or surgery to remove excess tissue from the throat. - **Medications**: For central sleep apnoea, medications may be prescribed to stimulate breathing or improve heart function. Medications such as acetazolamide can help stimulate respiratory drive in patients with central apnoea.