Central sleep apnoea syndrome with upper airway collapse.

We report on an 83 yr old man with hypersomnia and central sleep apnoea (CSA). He had several possible causes for CSA, including a central nervous system lesion, hypocapnia and anatomical narrowing of the airway at the hypopharyngeal level. We postulate that reduced central respiratory drive occurring in conjunction with upper airway narrowing may have led to central apnoeas. These in turn could have facilitated a complete passive hypopharyngeal collapse at the end of each apnoea, as visualized by somnofluoroscopy. The CSA could also have been favoured by respiratory instability due to chronic hypocapnia.