ESSENTIAL AND SECONDARY HYPERTENSION AND SLEEP-DISORDERED BREATHING -A UNIFYING HYPOTHESIS

Obstructive sleep apnea (OSA) is a disorder in which there is repetiti ve collapse and closing of the pharynx during sleep. There is growing evidence to suggest that this disorder is a major cause of essential h ypertension (EH) and that successful treatment of OSA can reduce the b lood pressure (BP) significantly. In addition many other patients with EH have milder forms of sleep related breathing disorders (SRBD) like snoring, and upper airway resistance syndrome (UARS) which, while not as severe as OSA, may be severe enough to also cause systemic hyperte nsion. We therefore propose a unifying hypothesis - that many patients with EH may have sleep related breathing disturbances (SRBD) and trea tment of these disorders may improve the BP. SRBD could also explain m any of the epidemiological, clinical, hereditary, biochemical, hematol ogical and physiological characteristics seen in EH. In addition, many types of secondary hypertension (those caused by excessive alcohol in take, chronic renal failure, diabetes, hypothyroidism or acromegaly) h ave a higher than normal prevalence of OSA and OSA may contribute to t he hypertension and organ damage found in these conditions as well. Th us SRBD may play an important role in the production of many cases of essential and secondary hypertension, and their early detection and tr eatment could reduce the hypertension and organ damage seen in these c onditions.