Lifestyle diseases are on the rise in the world especially in India where the proportion of the middle class is increasing manifold. Hypertension, cardiovascular diseases, diabetes, increased lipids is just to name a few. We hear about sudden cardiac arrests and related deaths, irrespective of age and sex, very regularly nowadays; especially during sleep. It is also common to hear that these deaths are labelled as myocardial infarctions and that it is unfortunate! But, do you know that 75% of these “unfortunate” deaths could have been avoided if only he/she was diagnosed for a killer disease known as “OBSTRUCTIVE SLEEP APNEA (OSA)”. It is very commonly treated by sleep medicine specialists in the west in close collaboration with physicians and dentists. But here, in India, even the sleep physicians are finding it tough to get through to the patient due to the lack of awareness.
Now, what is OSA?
It is a self-explanatory term which describes the condition wherein the person is not able to breathe normally at sleep due to an obstruction in the airway. The upper airway occlusions comprises of the naso-pharyngeal blockages like polyps, adenoids or deviated septum; oro-pharyngeal occlusions like macroglossia or posterior mandibular positioning; velo-epiglotto-pharyngeal occlusions like tonsillitis or a long uvula; or even a large neck circumference (increased BMI). All these press upon the airway, leaving the person gasping for air to breathe. The tongue (the genioglossus attached to the mandible) is almost always the biggest troublemaker.
During sleep, when our whole body is at rest, the mandible falls backward pulling the tongue along with it, thus obstructing the airway space. For more details view the image above This results in lesser oxygen entering the body during sleep. Hence, the heart would need to pump out oxygen-rich blood at a higher pressure. Since, the oxygen intake is at a lower level, the resultant hypercapnia (increase in blood-CO2 level) sends signals to the brain which then asks the person to bring the tongue forward; which then drags the mandible upwards along with it; ending in clenching/grinding, waking up the patient (or a simple toss and turn) to start the breathing cycle again; thus saving him/her. Long term apnea leads to a weak heart killing the person, eventually, during sleep.
Sleep bruxism is now considered to be a physiological consequence of OSA as per new research. A clenching/grinding event occurs when an oxygen desaturation episode occurs.