Apnea means a cessation of breathing. Sleep apnea is a sleep disorder with numerous short periods of cessation of breathing lasting for a few seconds to a minute in some cases. There are mainly three types of sleep apnea.
- Obstructive sleep apnea
- Central sleep apnea
- Mixed apnea
Obstructive sleep apnea is the commonest and occurs due to recurrent upper airway obstruction. Central sleep apnea occurs due to a decrease in the respiratory drive from the brain stem or due to respiratory depressant drugs like opiates and other narcotics. Mixed type as the name suggests is sleep apnea with components of both the obstructive and central type.
Excessive daytime sleepiness, loud snoring at night, periods of apnea during sleep, awakening with a feeling of tiredness and a headache, memory loss and poor judgment are some of the symptoms that are experienced or noted by others. A good sleep history with grading on the Epworth sleepiness scale and a sleep study (polysomnography) help in the diagnosis. For diagnosis, the standard definition is 15 apneas/hypopneas per hour of sleep where an apnea is a 10 second or longer period of breathing cessation or a hypopnea which is a 10 second or longer period of 50% reduction in breathing.
Causes
- Obesity is a risk factor, though almost 40% of people with sleep apnea are actually not obese. Middle aged males are at a higher risk.
- A family history of sleep apnea increases your chances of having it. In such families, the mandible or the jaw bone and the maxilla or the cheek bone are back-set and narrow the airway.
- Downs syndrome children are at risk of having sleep apnea
- Use of muscle relaxant drugs, narcotics, opiates, alcohol and sedative hypnotic drugs makes you prone to it
- A naturally narrow airway, a large tongue, enlarged adenoids, enlarged tonsils and nasal obstruction are other predisposing causes
- Anomalies of the jaw or soft palate which cause airway obstruction
- Children between 3 to 6 years of age can present with sleep apnea. Enlarged adenoids or enlarged tonsils are the usual causes in children.
- Recurrent occlusion of the airway (upper throat) at the level of the soft palate occurs due to relaxation of the muscles which keep the airway open, thus causing obstruction of the airway during sleep. This happens in those who have a narrow throat when awake. In them, the muscle tone of the upper airway muscles plays an important role in keeping the airway patent. During sleep, this muscles tone falls and the airway gets occluded. At this time, an effort is made to try and breathe causing a transient wakefulness which brings back the muscle tone to normal thus restoring the airway. No recollection of these short periods of wakefulness is present in the morning.This recurrent cycle of apnea followed by awakening repeats itself hundreds of times in one night and the sleep is very fragmented and you wakeup in the morning feeling tired.
- A previous stroke, a brain tumor, spinal cord injuries, muscular dystrophy, a neuromuscular condition like amyotrophic lateral sclerosis and sleeping at a high altitude induce central sleep apnea where there is a depressed ventilatory drive from the brain
- Acromegaly, a disorder of excessive growth hormone production and hypothyroidism also predispose individuals to sleep apnea by causing narrowing of the upper airway
Cure
- Medical management includes oral methyl xanthine, theophilline, antidepressants like mirtazapine. However sleep apnea usually does not respond well to oral drugs.
- Position / posture adjustment - Supine posture worsens the apneas. Hence sleeping sideways is helpful in reducing the number of apneas.
- Weight loss in the obese is thought to help decrease the pressure on the airway. Avoid drugs like sedatives, tranquilizers and alcohol.
- Oral Mechanical Devices like the Mandibular Advancement Device keep the airway open by pushing the lower jaw forward. A tongue retaining device prevents the tongue from falling backward and occluding the airway.
- Positive airway pressure - Delivering air through a mask through out the night at a positive pressure which helps to overcome the obstructing cause is the mode of treatment most commonly resorted to. Though initially it is difficult to adapt to, with time, the user sleeps better and does not seem to mind the mask or the machine. CPAP- Continuous Positive Airway pressure is the delivery of air at a constant pressure which is decided by your physician after a CPAP titration study to determine how much pressure works best for you. BiPAP - Bi-level Positive Airway Pressure provides a higher pressure during inhalation and a lower pressure during exhalation and is more comfortable. APAP- Auto-titration Positive Airway Pressure where pressure sensors adjust the pressure as needed by the user. It increases the pressure when there is obstruction to breathing and decreases the pressure when the airway is open.
- Supplemental oxygen inhalation will help those who have central sleep apnea
- Treatment of associated medical problems like neuromuscular diseases, congestive heart failure will help
- Surgery - some of the surgeries advocated are:
- Uvulopalatopharyngoplasty (UPPP) is a surgical procedure in which tissue from the back of the throat is removed. Usually the adenoids and tonsils are also removed.
- Laser-assisted Uvulopalatoplasty (LAUP) is done as an office procedure to remove excess tissue using laser therapy
- Radio-frequency ablation (RFA) using heat is done to destroy some tissue from the uvula, tongue and soft palate
- Tracheotomy is an emergency procedure done to save the life of a person who has a life threatening apnea. In this, an opening is made in the neck reaching the wind pipe so that breathing can occur.
- Nasal Surgeries like a Septoplasty to correct a deviated nasal septum, a turbinectomy to remove the turbinates, adenoidectomy or tonsillectomy to remove the adenoids or tonsils respectively
- Advancement surgeries- Genioglossus advancement in which a small part of the lower jaw is pushed forward to prevent the tongue from falling backward. Hyoid suspension surgery in which the Hyoid bone to which the tongue is attached is pulled forward. Maxiilo Mandibular Advancement (MMA) in which the cheek bone and the jaw bone are detached from the skull, moved forward and reattached.
- Pillar Surgery, where three little inserts are placed in the soft palate for support to prevent airway closure during sleep
