The sleep is a natural and biological phenomenon to periodic character during which occurs a loss of consciousness and the reduction or partial suspension of the operation of the nerve centers, with the consequent decrease of the various physiological functions, such as circulation, respiration and metabolism. It also represents an important body function, contributing to the maintenance of the psychophysical balance.
The sleep disorders are very frequent and are associated with various kinds of pathologies, in fact:
1/3 of the population suffers from insomnia, 1/2 of patients with diabetes , hypertension , heart disease suffer from insomnia and 5% of the adult population has obstructive sleep apnea syndrome (OSAS, English: Obstructive Sleep Apnea Syndrome).
The alterations in the respiratory function of the obstructive type are among the most annoying sleep disorders which, if not treated, can negatively affect the social conditions and the health of those affected.
The obstructive sleep apnea syndrome is the most frequent form of respiratory sleep disorder, characterized by the collapse of the upper airways and by cyclic episodes of partial closure of the hypopharynx, with subsequent inspiratory efforts to reopen the passage of air. This syndrome is characterized by:
- repeated episodes of partial (narrowing) or complete obstruction of the upper airways;
- appearance of daytime drowsiness and / or impaired performance.
The “primum movens” of the syndrome would be the narrowing of the airways during sleep, caused in part by the reduction of over 20 pharyngeal muscles, which normally keep the upper airways pervade during sleep, and partly by excess soft tissue, due above all, but not exclusively, to excessively accumulated adipose tissue .
These changes cause repeated nocturnal episodes of partial or complete collapse of the airways, with marked reduction or complete cessation of the airflow.
In the first case there is hypopnea, characterized by a reduction in airflow of more than 50% of the baseline, hypoxaemia possible , accompanied by an important and persistent, but ineffective, thoraco-abdominal inspiratory effort that can also assume progressive features with sudden unblocking of the collapses and microrecaps (arousal) that can be detected at the electroencephalogram .
In the second case there is obstructive apnea with cessation of airflow, while thoracic and / or abdominal movements persist.
The International Classification of Sleep Disorders defines the interruption of the airflow capable of causing episodes of apnea or hypopnea that occurs with a duration of not less than 10 seconds. The Apnea-Hypopnea Index (AHI) is defined as the total number of episodes of apnea and hypopnea per hour of sleep.
A value> 5 / hour is abnormal and may be associated with excessive daytime sleepiness. Other forms of sleep apnea, less frequent, are: central sleep apnea and mixed apnea.
The central sleep apnea is due to the cessation of breathing resulting from a temporary interruption of the stimulus coming from the central nervous system . This form of apnea, in which the patency of the upper airways is maintained, is often related to cerebrovascular disease and cardiac decompensation (Cheyne-Stokes breath). Those affected have the phenomena of arousals.
Mixed apnea is a form of sleep apnea that begins as central but ends as an obstructive form with progressive respiratory effort. It is however considered as obstructive.
The syndrome of obstructive sleep apnea occurs in all ages and is certainly more common in men. 4% of men and 2% of women in the general population, between 30 and 60 years, have a high number of apneas per night and complain of excessive sleepiness during the day: therefore it has been calculated that about two million Italians can suffer of this disease, even if only in a small minority until now has been possible to put the diagnostic certainty.
Higher percentages, around 11%, were found in individuals over 60 years.
The people most at risk are those who have strong night snoring, who are overweight, who have high blood pressureand presenting physical abnormalities at the level of the nose or throat. Furthermore, sleep apnea syndrome seems to be more frequent in the same family groups, suggesting a possible cause on a hereditary basis.
The condition of overweight and obesity is one of the main predisposing factors. Increased symptom severity with increased body weight is observed in most patients .
Nasopharyngeal abnormalities that reduce the caliber of the upper airway are the other major risk factor. A generalized narrowing is quite common in most adults; however, anatomopathological anomalies such as adenotonsillar hypertrophy, especially in the pediatric age, and deviations of the nasal septum are often observed .
Other conditions, less frequent are: a short neck, hypothyroidism and acromegaly , excess smoking , use of sedatives and high consumption of alcohol . The presence of OSAS increases the risk for cardiovascular diseases, in fact it seems associated with an increase in stroke casesand sudden death .
The Sleep Apnea Syndrome (OSAS) is largely underdiagnosed, so much so that it is not detected in 93% of women and 82% of men with moderate-severe syndrome.
This is related to the fact that excessive daytime sleepiness, the main symptom of OSAS, is a condition that many people have difficulty in perceiving or otherwise quantifying, often because they confuse it with fatigue. It is usually the partner who raises the problem because he is annoyed and worried about the important snoring, habitual and accompanied by episodes of respiratory pauses.
The clinical investigation should focus on breathing disorders, quality of sleep, the functional state of the patient in the morning and during the day and on the risk factors.
Snoring and excessive drowsiness during the day are the most frequently reported symptoms.
Snoring is a common symptom in the general population: 35-45% of men and 15-28% of women are affected. As such it is not very predictive, but becomes more specific if there are also respiratory pauses with feelings of suffocation.
Excessive sleepiness is the most common daytime symptom and is due to a worsening of sleep quality. The degree of drowsiness can be determined in a subjective and objective way using specific standardized self-administered questionnaires.
An example is the Epworth Sleepness Scale (EES) characterized by 8 questions with a score of 0 to 3 for each question (total score of 10 or more, is indicative of excessive daytime sleepiness and therefore it is convenient to frame the patient).
Epworth Sleepiness Scale (ESS)
|Situations||Probability to sleep or fall asleep|
|to. Sitting while I read|
|b. Watching TV|
|c. Sitting, inactive in a public place (cinema, theater)|
|d. By car, with passenger, for an hour or more|
|is. In the afternoon, lying down, for a rest|
|f. Sitting, while I’m talking to someone|
|g. Sitting quietly after lunch (no alcohol)|
|h. In the car, stopped for a few minutes in traffic|
0 = I do not mind or sleep never
1 = I have some chance to sleep or fall asleep
2 = I have a moderate chance to sleep or fall asleep
3 = I have a high probability of falling asleep or falling asleep
Other typical symptoms of Sleep Obstructive Syndrome (OSAS) are: strokes of sleep while driving or in normal activities, headache and dry mouth when waking up, mood changes, reduced concentration, dysmnesias, urinary incontinence , hyperactivity diurnal, growth delays (in children).
Typical signs are: Body mass index , BMI > 29 Kg / m 2 , Neck circumference > 43 cm (males) or> 41 cm (females), measured at the level of the cricothyroid membrane, Oropharyngeal anomalies can determine caliber reductions of the first airways, such as, for example, deviation of the nasal septum , hypertrophy of the turbinates , tonsillar hypertrophy.
|Curated by Luigi Ferritto (1) , Walter Ferritto (2) , Giuseppe Fiorentino (3)
1) Department of Internal Medicine, Athena Clinic Villa dei Pini, Piedimonte Matese (CE);
2) Division of Internal Medicine, AGP Hospital Piedimonte Matese (CE);
3) UOC Physiopathology, Diseases and Respiratory Rehabilitation, AORN Monaldi, Naples
The gold standard for the diagnosis of the obstructive sleep apnea syndrome is represented by polysomnography , an investigation carried out with a device (polysomnograph) that allows: detecting apneas and hypopneas, allowing them to be classified into central, obstructive and mixed, show the desaturations and their entity and the alterations of heart rhythm, recognize the stage of sleep in which events occur. The electroencephalogram , the detection of eye movements and limbs can also be added . The survey allows to monitor the air flow to the nose and mouth, movements of the chest and abdomen, pulse oximetry and snoring.
This investigation makes it possible to diagnose OSAS and to study its severity as follows:
- Mild degree: apnea-hypopnea index between 5 and 14, at least 86% oxygen saturation and minimal morning disability. Dimly drowsiness may occur while watching television, or reading a book in a quiet room, or you are on a moving vehicle as a passenger. Such drowsiness may not occur every day.
- Moderate or moderate average: apnea-hypopnea index between 15 and 30, oxygen saturation between 80 and 85%. Episodes of drowsiness occur every day, usually in the course of very light activities requiring a moderate degree of attention, such as concerts, movies, theater events, group work and driving a vehicle. Because of the symptoms of moderate drowsiness there is an alteration of the quality of social or professional life resulting from tiredness or loss of concentration.
- Severe grade: upper apnea-hypopnea index 30 and oxygen saturation of 79% or less. The episodes of drowsiness occur every day arising in the course of physical activities that require limited or moderate attention. Symptoms of severe drowsiness may occur during lunch, conversation, guidance, walking, physical activities of various kinds, and may be the cause of severe social and occupational disabilities.
The first step of the therapy is weight loss, in fact a reduction of even 10% of body weight would be able to clinically improve the index of apnea-hypopnea.
Also the position of the body influences the onset of the problem: some subjects find benefit modifying the decubitus from the supine to the lateral position.
Among the measures designed to improve respiratory syndrome, sleep hygiene is also important, meaning that certain behaviors can be put in place to promote a night’s sleep. Among the most important: avoid the intake of alcohol and sedatives, before going to bed that reduce the tone of the muscles in the upper airways and prolonged apnea by delaying waking up, limiting smoking or better still not smoking, going to bed and getting up at times as constant as possible.
Positive pressure mechanical ventilation
The therapeutic hinge in the case of obstructive sleep apnea-hypopnea is not pharmacological but a device that allows mechanical ventilation with continuous positive pressure , called CPAP (acronym of Continuous Positive Airway Pressure) which, by insufflating constant positive pressure into the nose, allows to keep the upper airways open by overcoming the resistance to the origin of apnea-hypopnea episodes.
OPENING OF THE PHARYNGEAL TRACT OF THE AIRWAYS BY CPAP
Many clinical studies have shown that CPAP significantly reduces daytime sleepiness and improves quality of life. The effect is quite rapid: already after the first days patients get good benefits. A good percentage of patients accept, even in the long term, this device, especially those affected by the most severe forms.
Diagnosed with Sleep Obstructive Syndrome, the treatment depends on the severity of the syndromic picture and the possible co-morbidity :
- In the presence of an apnea-hypopnea index (AHI) ≥ 20 or an index of respiratory disorders (RDI) ≥ 30, the use of CPAP is indicated;
- In the presence of an apnea-hypopnea index (AHI) between 5 and 19 or an index of respiratory disorders (RDI) between 5 and 29 and in the presence of symptoms and / or concomitant associated cardiovascular diseases , there is an indication for treatment with CPAP.
- In the absence of symptoms and / or cardiovascular risk factors or comorbidities. Patients with AHI between 5 and 20 or an RDI between 5 and 29 do not require treatment with CPAP and it is only advisable to monitor over time with polysomnographic monitoring.
Surgical treatment of obstructive sleep apnea-hypopnea is aimed at the correction of any anatomical defects or obstructive abnormalities of the upper airway, generally indicated by maxillofacial surgeon or by anorino.
The most frequent operations are the nose and those of tonsillectomy , especially in children.
Obstructive sleep apnea-hypopnea syndrome is a very complex clinical condition that, if neglected, can lead to serious consequences. Because of snoring and episodes of apnea-hypopnea during sleep, there are changes in the function of the nerve centers that coordinate the respiratory movements and the fall of the tone of the dilator muscles of the upper airway, the pharmacological research has been directed towards products able to act at the level of the motor neurons that innervate this musculature.
The indication of modafinil that acts on a symptom without modifying the cause of the syndrome has been extended to the treatment of patients with nocturnal obstructive apnea-hypopnea in combination with CPAP therapy, to reduce excessive daytime sleepiness recently. The association with the CPAP is therefore necessary.
Conclusions and bibliography
OSAS is a common condition that is frequently undiagnosed. Excessive daytime sleepiness is the most predictive element of clinically significant sleep apnea, which is particularly useful for guiding the doctor to a correct diagnosis. Although it is now established that there is a causal relationship between sleep apnea syndrome and cardiovascular disease, there is still no recommendation to search for it in all subjects at risk, reserving management for cases with snoring symptoms, episodes of apnea and more significant sleepiness. .
The pivotal examination is polysomnography preceded by a careful history and use of self-administered questionnaires.
Treatment should be modulated according to the severity of the syndrome; starting with behavioral suggestions and adding treatment with CPAP, the only effective therapy for the immediate resolution of apneas and daytime symptomatology.