The Different Types of Sleep Apnea

Sleep apnea is a prevalent yet often underdiagnosed sleep disorder that affects millions of individuals worldwide. Understanding the complexities of sleep apnea is crucial for accurate diagnosis, effective management, and improved patient outcomes.

Sleep apnea is a disorder characterised by repeated interruptions in breathing during sleep. These interruptions, known as apneas, occur when the upper airway becomes partially or completely blocked, leading to a temporary cessation of airflow. This disruption in breathing can occur multiple times throughout the night, resulting in fragmented sleep and reduced oxygen levels in the blood.

Types of Sleep Apnea

There are three primary types of sleep apnea, each with their own traits and characteristics.

Obstructive Sleep Apnea (OSA)

OSA is the most common type of sleep apnea, characterised by the repetitive episodes of complete or partial upper airway obstruction during sleep. In individuals with OSA, the relaxation of the throat and tongue in sleep becomes excessive, causing the soft tissue at the back of the throat to collapse and block the airway. The resulting obstruction leads to pauses in breathing, known as apneas, or shallow breathing, termed hypopneas.

Common symptoms of OSA include loud snoring, witnessed apneas or gasping during sleep, excessive daytime sleepiness, morning headaches and irritability.

Central Sleep Apnea (CSA)

CSA occurs when the brain fails to send proper signals to the muscles responsible for controlling breathing during sleep. Unlike OSA, which involves physical obstruction of the airway, CSA is characterised by a lack of effort to breathe. This may result from dysfunction in the brain’s respiratory control centres or underlying medical conditions affecting the central nervous system.

Symptoms of CSA may overlap with those of OSA and include episodes of interrupted breathing during sleep, daytime fatigue, difficulty concentrating and morning headaches.

Mixed Sleep Apnea

Mixed sleep apnea, as the name suggests, combines features of both obstructive and central sleep apnea. Individuals with mixed sleep apnea may experience periods of both upper airway obstruction and lack of respiratory effort during sleep.

Signs and Symptoms of Sleep Apnea

Symptoms of mixed sleep apnea may resemble those of OSA or CSA, depending on the predominant type of apnea experienced by the individual.

Several factors can contribute to the development of sleep apnea.

Obesity and Excess Weight

One of the most significant risk factors for obstructive sleep apnea (OSA) is obesity. Excess weight leads to the accumulation of fatty tissues around the upper airway, narrowing the air passage. This narrowing increases the likelihood of the airway collapsing or becoming obstructed during sleep, resulting in apneas and disrupted breathing patterns. The increased prevalence of obesity in modern society has contributed significantly to the rising incidence of sleep apnea.

Anatomical Abnormalities

Structural abnormalities in the upper airway can also predispose individuals to sleep apnea. These abnormalities may include a deviated septum, enlarged tonsils or adenoids, a small or recessed jaw, or a large tongue. Such anatomical variations can obstruct the airway or impede proper airflow during sleep, leading to episodes of apnea or hypopnea (shallow breathing).

Muscle Tone and Relaxation

During sleep, the muscles that support the airway naturally relax. However, in individuals with sleep apnea, this relaxation can become excessive, causing the throat muscles to collapse and block the airway. Factors such as age and alcohol consumption can further exacerbate muscle relaxation, increasing the risk of airway obstruction and apneas.

Neurological Factors

Central sleep apnea (CSA) occurs when the brain fails to send proper signals to the muscles responsible for controlling breathing. This disruption in the brain's respiratory control centre can result from conditions such as stroke, brainstem injury, or certain neurological disorders. Additionally, medications or substances that affect central nervous system function, such as opioids or certain sedatives, may also contribute to the development of CSA.

Genetic Predisposition

There is evidence to suggest a genetic component to sleep apnea, with familial clustering observed in some cases. Certain genetic traits or familial tendencies may predispose individuals to anatomical abnormalities, impaired muscle function, or alterations in respiratory control mechanisms, increasing their susceptibility to sleep apnea.

Hormonal Changes

Hormonal fluctuations, particularly in women, can influence the likelihood of developing sleep apnea. For example, hormonal changes during pregnancy or menopause may contribute to weight gain, fluid retention, or changes in upper airway muscle tone, all of which can increase the risk of sleep-disordered breathing.

Environmental and Lifestyle Factors

Several environmental and lifestyle factors can also exacerbate or contribute to sleep apnea. These may include smoking, exposure to second-hand smoke, high altitude, nasal congestion, and habitual use of sedatives or muscle relaxants. Additionally, sleeping position can play a role, as sleeping on one's back can increase the likelihood of airway obstruction in some individuals.

Treatments for Sleep Apnea

Tailoring treatment for each type of sleep apnea—obstructive sleep apnea (OSA), central sleep apnea (CSA), and mixed sleep apnea—requires a nuanced understanding of the underlying mechanisms and contributing factors. Here's a detailed exploration of treatment options for each type:

Obstructive Sleep Apnea

• Continuous Positive Airway Pressure (CPAP) Therapy: CPAP therapy is the gold standard treatment for moderate to severe OSA. It involves wearing a mask connected to a machine that delivers a continuous flow of air, effectively preventing the collapse of the upper airway during sleep. CPAP therapy helps maintain an open airway and reduces the frequency of apneas and hypopneas.
• Oral Appliance Therapy: Oral appliances, such as mandibular advancement devices, can be an effective treatment option for individuals with mild to moderate OSA or those who cannot tolerate CPAP therapy. These custom-fitted devices reposition the jaw and tongue to prevent airway obstruction during sleep, improving airflow and reducing snoring and apnea episodes.
• Lifestyle Modifications: Encouraging patients to adopt healthy lifestyle habits can complement other treatment modalities and improve OSA symptoms. Weight loss, regular exercise, avoidance of alcohol and sedatives before bedtime, and sleeping on the side instead of the back can all help reduce the severity of OSA and improve overall sleep quality.
• Surgical Interventions: In cases where conservative measures fail to provide adequate relief, surgical interventions may be considered to address anatomical abnormalities contributing to airway obstruction. Uvulopalatopharyngoplasty (UPPP), maxillomandibular advancement (MMA), and palatal implants are among the surgical options available for select patients with OSA.
• Positional Therapy: For individuals with positional OSA, devices such as positional therapy pillows or wearable devices can help discourage sleeping on the back, reducing the frequency of apneas and improving sleep quality.

Central Sleep Apnea

• Treatment of Underlying Medical Conditions: Since CSA often occurs secondary to underlying medical conditions affecting the central nervous system, such as heart failure, stroke, or opioid use, addressing these underlying issues is essential. Treating heart failure with medications, optimising oxygen therapy, or discontinuing medications that suppress respiratory drive may help alleviate CSA symptoms.
• Positive Airway Pressure Therapy: Adaptive servo-ventilation (ASV) therapy is a specialised form of positive airway pressure therapy designed to treat CSA by providing a variable level of pressure support to maintain a stable breathing pattern. ASV devices automatically adjust airflow based on the patient's respiratory patterns, delivering pressure support during inspiration and reducing pressure during expiration.
• Supplemental Oxygen Therapy: Supplemental oxygen therapy may be beneficial for some individuals with CSA, particularly those with concurrent hypoxemia. Oxygen supplementation can help improve blood oxygen levels and reduce the severity of respiratory disturbances during sleep.
• Medications: Medications that stimulate respiratory drive, such as acetazolamide or theophylline, may be considered in select cases to enhance breathing control and reduce the frequency of apneas. However, their use is generally reserved for patients with specific underlying conditions and should be carefully monitored.
• Adaptive Ventilation Strategies: Emerging technologies and adaptive ventilation strategies are being developed to provide more targeted and personalised treatment for CSA. These approaches aim to optimise ventilation based on individual respiratory patterns and minimise the risk of treatment-emergent central apneas.

Mixed Sleep Apnea

• Combination Therapy: Since mixed sleep apnea combines features of both obstructive and central sleep apnea, treatment often involves a combination of interventions targeting both components of the disorder. This may include CPAP therapy, oral appliance therapy, positional therapy, lifestyle modifications, and addressing underlying medical conditions contributing to respiratory instability.
• Individualised Approach: Treatment for mixed sleep apnea should be individualised based on the predominant type of apnea experienced by the patient and their overall health status. Close monitoring and periodic reassessment may be necessary to adjust treatment strategies as needed and optimise therapeutic outcomes.
• Multidisciplinary Care: Collaborative care involving sleep specialists, pulmonologists, cardiologists, and other healthcare professionals is essential for managing mixed sleep apnea comprehensively. A multidisciplinary approach allows for the integration of various treatment modalities and ensures that patients receive personalised care tailored to their specific needs and preferences.

Sleep apnea is a complex sleep disorder with significant implications for patient health and well-being. As healthcare professionals, it is imperative to remain vigilant for signs and symptoms of sleep apnea and to facilitate timely diagnosis and appropriate management. By understanding the underlying mechanisms, risk factors, and treatment options associated with sleep apnea, healthcare providers can play a pivotal role in improving the quality of life for individuals affected by this condition.

REFERENCES

• https://www.nhlbi.nih.gov/health/sleep-apnea
• https://www.medicalnewstoday.com/articles/types-of-sleep-apnea
• https://www.sleepfoundation.org/sleep-apnea

About Pro Health Care

Our ethos and core values have stemmed from the work of three prominent General Practitioners working within the Western Suburbs of Adelaide from which Pro Health Care was founded in 2007. The commitment, time and care they gave their patients over 35 years is the cornerstone of our philosophy.

Since then, our medical centres have been structured around our patients as we emphasise a holistic approach to managing health and well-being through doctor’s services and multi-disciplinary care — whether it be general medical, physiotherapy, podiatry or anything in between. The medical framework through which we operate focuses on collaborative reasoning and communication, a combination of values which we believe is the path to achieving the highest possible standards of care for our patients. Visit our website here.