Narcolepsy and Hypoglycaemia

Abstract

For some years now it has been recognized that the symptoms induced by hypoglycaemia may resemble narcolepsy. Cases of islet-celled pancreatic adenomas simulating narcolepsy have been described by Harris (7), Delay (4) and Wyke (18). The resemblance may be a superficial one, however, and Wyke observed in his case during a “sleepy attack” that “the EEG pattern bore no resemblance to that of natural or artificial sleep”. In a more recent paper Ziegler and Presthus (19) described thirteen patients who showed normal EEGs at blood glucose levels (induced by fasting and intravenous insulin) of from under 15 mg. per cent. to 54 mg. per cent. In eight of these patients there were no clinical symptoms; in the remaining five patients the symptoms were described as follows: “feel like a ton of lead”, “warm and sleepy”, “tired”, “drowsy and sweaty” and “dizzy and tired”. It seems, in fact, that the clinical description of drowsiness in hypoglycaemia may correspond either to no EEG changes or to various degrees of slowing rather than to the typical recurrent light sleep patterns characteristic of narcolepsy. It will be recalled that hypnosis too is ushered in by a sense of drowsiness but that the EEG changes are not those of sleep (1, 2, 5). Many hysterical trance states—often loosely, and unfortunately, described as narcolepsy—come into this category. In short, it is apparent that all that sleeps is not narcolepsy (6, 12, 13, 14).