Abnormalities of the Vertebrobasilar Arterial System Leading to Sleep Disorders.

INTRODUCTION

The abnormalities in the vertebrobasilar arterial system such as enlarged, tortuous or dilated arteries and aneurysms can generate pressure and distortion of brain structures especially in the medulla and pons. This brainstem compression by abnormal arteries can lead to various sleep disorders such as sleep related hypoventilation, central sleep apnea, obstructive sleep apnea, and positional sleep apnea.

AIM: To highlight brainstem compression due to vascular abnormalities as a cause of sleep disordered breathing.

METHODS

Manuscripts were identified using the National Institutes of Health PubMed literature search system. Search terms included sleep disorders, vertebrobasilar dolichoectasia, tortuous vertebral arteries, vertebrobasilar aneurysms, vascular compression and brainstem compression. Inclusion criteria required that the articles were written in English, highlighted both a sleep disorder and a vascular abnormality.

RESULTS

The literature search resulted in 10 case reports where vascular abnormalities were leading to sleep disorders. Out of these: four patients had central sleep apnea; three had sleep related hypoventilation; one had positional central sleep apnea; one had positional central apnea along with obstructive sleep apnea; and one had obstructive sleep apnea. The various vascular lesions identified were: megadolichobasilar artery; dolichoectatic vertebral artery; fusiform vertebrobasilar aneurysm; tortuous and elongated vertebral arteries; calcified vertebral artery and medullary telangiectasia.

CONCLUSIONS

Arterial compression of the respiratory centers in the pons and medulla can lead to central sleep apnea. Obstructive sleep apnea can also result from vascular compression of the medulla. The proposed mechanism is compression of nucleus ambiguus which controls pharyngeal tone. Pressure on cranial nerves IX and X can lead to pharyngeal dysfunction leading to occlusive apnea.