Sleep complaints are ubiquitous in patients with medical illness. A recent survey of outpatients attending hospital clinics indicated that the vast majority of patients reported sleep disruption concomitant with their condition. The proportion with complaints (> 70%) was more than twice that among control subjects. Doctors rarely ask about sleep problems in the context of medical illness despite the fact that the patient’s first complaint disruption of sleep architecture in may be that a particular symptom caused sleep disruption.
There are specific reasons for sleep disruptions in patients with medical illness-for example, people are often deprived of sleep before an operation. Polysomnography has shown that there is a preoperative of sleep) reduction in slow wave sleep and that this is related to the anticipated importance of surgery. The increase in deep sleep that occurs after an operation is thought to facilitate the healing process.
A variety of sleep variables may be influenced by specific disorders and each of these effects is likely to differ. A decrease in deep (slow wave) sleep, for example, may lead to a sensation of having low energy, whereas repeated interruption of sleep may lead to daytime sleepiness.
Drugs may also disrupt sleep architecture by suppressing rapid eye movement (REM) sleep or by causing a withdrawal effect during the night. In both cases the drug clearly alters sleep, but the impact on health and recovery may differ.
Fatigue is common in several medical conditions. Clinicians, researchers, and patients themselves claim that the fatigue experienced in certain medical conditions differs qualitatively from the experience of tiredness or sleepiness. However, there have been few attempts to separate these states. In this article we provide an overview of the impact of medical disorders on sleep.
You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1677972/pdf/bmj00023-0050.pdf
Source: Shapiro CM, Devins GM, Hussain MR. ABC of sleep disorders. Sleep problems in patients with medical illness. BMJ. 1993 Jun 5;306(6891):1532-5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1677972/