Sleep Apnea and Its Impact on Urologic Health

Introduction:

Sleep is one of the necessities of the human body. Sound sleep is necessary for the proper functioning of several organs. Also, it helps in the process of rejuvenation. But, around 30 percent of the world's population is suffering from sleep-related disorders. Obstructive sleep apnea is a sleep-related breathing disorder. All over the world, around 936 million people suffer from obstructive sleep apnea. Sleep apnea not only causes sleep problems but is also related to multisystem disorders.

What Is Obstructive Sleep Apnea?

Obstructive sleep apnea is a sleep-related breathing disorder. Obstructive sleep apnea is caused by a complete or partial obstruction of the airflow during sleeping. The airflow of the upper respiratory tract is affected by this process,

A. Pathophysiology:

Repetitive episodes of narrowing of the upper respiratory tract cause obstructive sleep apnea. The most common site of obstruction is the nasopharyngeal region. During sleeping, the muscle of the neck and the floor of the mouth become relaxed. This relaxation causes a loss of muscle tone. This causes the collapse of the surrounding tissue structures of the upper respiratory tract. As a result, the airflow from the upper respiratory tract to the lungs is blocked. This is also responsible for the drop in the blood oxygenation level and a rise in the level of carbon dioxide. During expiration, decreased muscle tone causes caudal traction. This caudal traction is associated with a decreased cross-sectional area in the pharynx and decreased transmural pressure. Also, the narrowing of the pharyngeal lumen can be seen. This expiratory-related narrowing of the pharyngeal lumen increases the velocity of the airflow and decreases intraluminal static pressure. As a result, a decrease in lung volume can be seen. All these factors are associated with apnea (temporary cessation of breathing) and hypopnea (reduction in lung ventilation).

B. Risk Factors:

The potential risk factors for obstructive sleep apnea are:

1. Obesity: Excessive deposition of fat around the neck and the orofacial region is associated with increased pressure during sleeping.

2. Mandibular Growth: Mandibular growth is associated with an alteration in the muscle tone. Short mandible or abnormal growth of the mandible is related to the development of obstructive sleep apnea.

3. Morphology of Soft Palate: Palatal musculature plays an important role in obstructive sleep apnea. High palatal arch is associated with hyperactivity of the muscles of the soft palate, which is associated with an increased incidence of obstructive breathing during sleep . The shape and size of the uvula may also be associated with obstructive sleep apnea.

4. Tonsilar Hypertrophy: Tonsilar hypertrophy is associated with blockage of the upper airway tract.

5. Abnormality In the Airway Tract: Abnormalities of the upper airway tract, such as deviated nasal septum and tumor, can be associated with obstructive sleep apnea.

6. Habits: Habits such as chronic alcoholism and smoking are associated with an increased incidence of obstructive sleep apnea.

C. Symptoms:

The symptoms of obstructive sleep apnea include:

1. Snoring is one of the main symptoms of obstructive sleep apnea.

2. Patients often complain of a feeling of choking or breathlessness during sleeping.

3. Frequent history of arousal from sleep can be noticed.

4. Moning drowsiness, irregular sleeping cycle, fatigue all day, and headache can be seen.

What Are the Urological Manifestations of Obstructive Sleep Apnea?

Obstructive sleep apnea affects various renal systems. These are:

1. The chances of chronic kidney disease are high in patients suffering from diabetes and hypertension. Decreased oxygen level in the blood and sleep fragmentation is associated with the activation of the renin-angiotensin-aldosterone system. This causes an alteration in cardiovascular hemodynamics. This leads to the generation of free radicals. These free radicals are responsible for the damage to the kidney structures and ultimately lead to chronic kidney diseases.

2. Obesity is one of the root causes of obstructive sleep apnea. Obsetry is responsible for insulin resistance, lipid abnormalities, and hyperinsulinemia. These factors cause renal hyperfiltration and glomerulomegaly. As a result, proteinuria is developed.

3. Nocturia, or waking up from sleep due to the urge to urinate, is also seen in sleep apnea patients. The causative factor is a change in the intra-thoracic pressure and increased production of atrial natriuretic peptide (ANP, a type of cardiac hormone). A negative intrathoracic pressure caused by obstructive sleep apnea is responsible for increased venous return on the right side of the heart. This causes stretching of the myocardium and release of the atrial natriuretic peptide. This hormone causes activation of the renin-angiotensin-aldosterone system, renal vasodilation, and antidiuretic hormone inhibition. These factors lead to increased production of urine.

4. Nocturnal enuresis or sudden release of urine while sleeping. It is a rare complication of obstructive sleep apnea. It is mainly seen in childer suffering from sleep apnea and in postmenopausal women. Factors like bladder dysfunction and altered intrathoracic pressure are responsible for such complications.

5. As already discussed, intermittent hypoxia leads to oxidative stress. This causes altered bladder functioning, detrusor instability (spontaneous contraction muscles of the urinary bladder), and spontaneous contractions of the urinary bladder. Activation of cell survival signaling due to sleep apnea is also responsible for this. These factors lead to an overactive urinary bladder. This also causes sudden and frequent surges in urination.

6. Enlarged prostate is often seen in males suffering from sleep apnea. Oxidative stress and excessive secretion of inflammatory mediators lead to the excessive growth of the prostatic epithelial and stromal cells. This causes benign prosthetic hyperplasia.

What Are the Sexual Manifestations of Obstructive Sleep Apnea?

1. Erectile dysfunction is one of the severe complications of obstructive sleep apnea. Generation of free radicals and oxidative stress vascular endothelial dysfunctioning and downregulation of nitric oxide. Endothelin produced by these factors is responsible for penile tumescence (spontaneous erection of the penis).

2. Also, factors like peripheral neuropathy, high sympathetic activity, and psychological stress are related to erectile dysfunctions.

3. Low levels of testosterone may also cause low sex drive and erectile dysfunction. Lower concentration of oxygen and sleep fragmentation leads to disruption of the hypothalamic-pituitary-testicular axis. This causes lower levels of testosterone in the body.

What Are the Treatment Options?

Non-invasive treatment options for sleep apnea, like continuous positive airway pressure (CPAP), mandibular advancement devices, and transcutaneous electrical nerve stimulation (TENS), can be helpful in reducing symptoms of sleep apnea as well as urological complications.

Conclusion:

Obstructive sleep apnea is a breathing disorder that occurs during sleeping. Several factors like obesity, jaw defect, and medical conditions are responsible for such complications. Patients suffering from sleep apnea also may complain of symptoms like nocturia and chronic kidney diseases. Also, complications like erectile dysfunction are caused by sleep apnea. Non-invasive treatment options can be used for treating such complications.