etiology of obstructive sleep apnea

OSAETIOLOGY & SYMPTOMPS

byDR.FAIZAN ALI

OSAAnatomic disorder bcoz of

etiology lies in anatomic area e.g upper airway obstruction,retrognathia,tonsillar hypertrophy,macroglossia etc

State dependant condition

OSAcan be defined as a cessation of

breathing during sleep because of a mechanical obstruction such as a retro positioning of the tongue in the airway, a large amount of tissue in the upper airway, or even a partially collapsed trachea.

(Semin Orthod 2009;15:63-69.)

HistoryObstructive sleep apnea (OSA) was first described by

Charles Dickens in 1837.

He coined the term “Pickwickian syndrome” but described a similar presentation of a typical OSA patient; obese, somnolent, and with an excessive appetite.

It was only in 1956 that Sidney Burwell carefully documented a case of an OSA patient, rationalized the signs and symptoms, and made a distinction between this disease and other illnesses.

OSACommon respiratory sleep

disorder characterized by1. snoring 2. episodes of breathing

cessation or absence of respiratory airflow (10 seconds) during sleep.

Characterized by

recurrent interruptions of breathing during sleep due to temporary obstruction of the airway by lax, excessively bulky, or malformed pharyngeal tissues (soft palate, uvula, and sometimes tonsils), with resultant hypoxemia and chronic lethargy.

(Epstein LJ, Kristo D, Strollo PJ, Friedman N, Malhotra A, Patil SP, Ramar K, Rogers R, Schwab RJ, Weaver EM, WeinsteinMD. Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults. Adult obstructive sleep apnea task force of the American Academy of Sleep Medicine. J Clin Sleep Med. 2009; 5:263-76)

OSA

Upper airway has three major functions:

1. ventilation, 2. swallowing3. speech. For ventilation, the

upper airway must remain patent, but for the other functions, it must narrow or close.

In addition, ventilation must be maintained when the nose is occluded or, alternatively, when the mouth is closed.

The apnea event is considered when the air flow is interrupted during sleep for a period of 10 s or more.

Hypopnea is a reduction of at least 50% of the breathing capacity combined with a saturation decrease of the oxyhemoglobin in at least 3%.

Narrowing of air way

Vibration of tissues of posterior airway

SNORING

Air flow obstruction

Hypoxemia&

HypercapniaSleep Arousal

Sleep architectureEDS

This disease affects an average 4% of adult males 2% of adult females increasing as of the fifth decade of life .

The prevalence of the diseasehas been found to be 8% in men 2% of women in the United States

(Semin Orthod 2009;15:94-98.)

About 80 percent to 90 percent of adults with OSA remain undiagnosed.

OSA occurs in about two percent of children and is most common at preschool ages

OSA with resulting daytime sleepiness occurs in

at least four percent of men and two percent of women

About 24 percent of men and nine percent of women have the breathing symptoms of OSA with or without daytime sleepiness

Risk factors according to American academy of sleep medicine

People who are overweight (Body Mass Index of 25 to 29.9) and obese (Body Mass Index of 30 and above)

Men and women with large neck sizes: 17 inches or more for men, 16 inches or more for women

Middle-aged and older men, and post-menopausal women

Ethnic minorities People with abnormalities of the bony and soft

tissue structure of the head and neck

Risk factors according to American academy of sleep medicine

Adults and children with Down Syndrome Children with large tonsils and adenoids Anyone who has a family member with

OSA People with endocrine disorders such as

Acromegaly and Hypothyroidism Smokers Those suffering from nocturnal nasal

congestion due to abnormal morphology, rhinitis or both.

Positive risk factorNeck circumference(Indicate upper body obesity)

greater than43.2 cmNasal septal deviation,Internal or external valve collapseTurbinate hypertrophy, Nasal polyps,chronic sinusitisMacro glossiaRetro positioning of mandibleEnlargement of upper airway soft tissue structuresInferior positioned hyoid bone

ObesityIncrease in size of

soft tissue structures in upper

airway

Dec. functional size of upper

airway

Predispose to OSA

Classification of OSAFujita et al simply categorized the

upper airway obstruction as Retro palatal Retro glossal.

The retro palatal level involves the soft palate, uvula, and palatine tonsils.

The retroglossal level involves the tongue base and supraglottic structures.

Fujita etType I obstruction is the presence

of restriction only at the retro palatal level.

Type II obstruction is the presence of restriction only at the retroglossal level.

Type III is the presence of both obstructions at both levels

Moore classification of OSAConsidered the airway obstruction

as a spectrum of disease, starting from primary snoring as the mildest form,to upper airway resistance syndrome (UARS) and then to the different degrees of OSA;

mild, moderate, and severe.

Index use for OSA AHI (A common measurement of sleep

apnea is the apnea-hypopnea index (AHI). This is an average that represents the combined number of apneas and hypopneas that occur per hour of sleep.)

RDI(respiratory distress index)Apnea index, Oxygen desaturation index (ODI)

Scales use to measure OSAMallampati ScaleFriedman ScoreThe Epworth sleepiness score,

Sleep nasoendoscopyIdentifies the level of and the degree of

obstruction when the patient is asleep. Obstructions are classified as palatal, multilevel, or tonguebased with a

grading system: Grade 1—palatal snoring; Grade 2—palatal level obstruction; Grade3—multisegmental involvement with

intermittent oro- and hypopharyngeal collapse;

Grade4—sustained multilevel collapse Grade5—tongue base obstruction.

Symptoms1. Loud irregular snoring.

2. Snorts, gasps, and other unusual breathing sounds during sleep.

3. Long pauses in breathing during sleep

Excessive daytime sleepiness

Hall mark of this diseasecauses impaired cognition increased accident rates multiple medical and dental disorder

5. Fatigue6. Obesity7. Changes in cognitive functions

such as alertness, memory, personality, or behavior

8. Impotence9. Morning headaches19

ConsequencesCardiovascular.1. Systemic hypertension2. Coronary heart disease3. Cardiac arrhythmias4. Sudden nocturnal death5. Other (stroke, pulmonary hypertension)

Social/behavioral.1. Drowsy driving/accidents2. Decreased work performance3. Poor quality of life19

4. Increased mortality20-22

Dentofacial featuresNarrow upper airway dental archesHypoplastic maxillaRetrognathic mandibleIncreased ant.facial heightIncreased craniocervical

angulation than normal

Post.buccal cross biteVertical maxillary excess