Sleep Apnoea: Missing the Forest for the Trees

Abstract

Because of the myriad ways in which syphilis could present we were all taught in medical school that 'he who knew syphilis knew medicine' [1]. The incidence of syphilis has declined tremendously, there being only 1451 cases of early infectious syphilis in England in 1981 [2]. In the United States there are about 10 cases (primary and secondary) per 100 000 population [3]. Sleep apnoea, whose myriad clinical manifestations in a Scottish population are described in this issue [4], is probably at least 10 to 50 times more common than syphilis. Sleep apnoea is common [5], dangerous [6], easily diagnosed [7], and usually easily (and inexpensively) treated [8,9]. For reasons that are unclear there is little in our medical training about sleep and its disorders. For example, in the large recent two-volume (3792 pages) edition of the Oxford Textbook of Medicine [2], there are 17 pages devoted to syphilis and less than four pages to the entire topic of 'sleep-related disorders of breathing'. Most hospitals have routinely available expensive tests to diagnose quite rare disorders. In my entire career I have seen one previously undiagnosed patient with phaeochromocytoma and two previously undiagnosed acromegalics. I can't count the hundreds of times house officers in our teaching hospitals have ordered tests to exclude these conditions. Given the fact that apnoea is common, diagnostic yield is high and treatment efficacious, it seems surprising that there are as yet relatively few centres in Canada that can diagnose and treat sleep disorders. As Dr Whyte has pointed out, there simply are not enough facilities in the United Kingdom either. Whyte et al. stress a myriad of clinical features seen in the apnoea patient which span several medical subspecialties. The most common presenting complaint of these patients is excessive daytime sleepiness and such patients may perceive this not to be a medical problem or the patient may be referred to their family practitioner or to a neurologist or psychiatrist. Although Whyte et al. found that 70 of their 80 patients complained of daytime sleepiness, this aspect of the history, as they pointed out, may be inaccurate. Objective tests which quantify sleepiness (the multiple sleep latency test) is pathological in almost all sleep apnoea patients. With this test patients will usually fall asleep in less than five minutes during each of five opportunities to nap during the daytime [10]. The danger of excessive daytime sleepiness to the patient and others cannot be overemphasized. The apparently long sleep latencies described by Whyte et al. differs from our experience. Almost all our patients with apnoea fall asleep within five minutes of'lights out'. The much longer intervals observed in this study may reflect differences in sleep stage scoring techniques.