Experts say that
the main causes of OSA are:
· Old age
· Temporary or permanent brain injury
· Decreased muscle tone - could be caused by drugs, alcohol, a neurological problem, or some other disorder.
· Excess soft tissue around the airway; common with obese patients
· Something physical in the throat or mouth/jaw shape
When a person is asleep the muscles in the body relax and become limp, including the throat muscles. For most of us this is not a problem. However, the muscles of people with OSA become so limp that the airway constricts (narrows); the narrowing may become so severe that the airway closes up completely.
Initially, narrowing of the airway causes snoring.
If the airway becomes completely blocked the individual stops breathing for a few seconds - apnea occurs for a few seconds. If a sleeping person with OSA stops breathing they soon wake up, and quickly go back to sleep unaware that breathing had stopped.
If the airway is only partially blocked, breathing will become slow and shallow (hypopnea).
A bedfellow, or other people in the bedroom/dormitory may notice the patient stops breathing, will then suddenly gasp or grunt, wake up for a second or two, and then go back to sleep.
Most people have the occasional apnea during sleep, when breathing stops, following by a snort. People with OSA, however, have several episodes of no breathing while they sleep. For a diagnosis of OSA to be made, the patient should have at least five such episodes per hour. In very severe cases, a patient may have hundreds of episodes in one sleeping session.
Even though the patient with OSA may not be aware of the problem, if they woke up lots of times during the night their sleep was not a good quality restful one. Consequently, during the day they will feel unusually sleepy. People who snore loudly and feel sleepy during the night have probably got OSA.
OSA in children is usually caused by tonsils or adenoids that obstruct the airway.
The following groups of people have a higher risk of developing OSA:
· Diabetes - especially if the diabetes is not well controlled
· Individuals with hypertension (high blood pressure)
· Obese individuals
· People who regularly suffer from nasal congestion
· People whose inner jaw is set back further than normal
· People with enlarged tonsils or adenoids
· People with fat necks
· Smokers - regular smoking significantly increases the risk of OSA
· Regular alcohol consumption - alcohol is a sedative which can over-relax the throat muscles.
· Family history - people whose parent or sibling has/had OSA have a higher risk of developing it themselves.
· Down syndrome - people with Down syndrome are more likely to suffer from OSA, compared to the individuals.
· Some surgeries - OSA is a possible complication of pharyngeal flap surgery