Hypoglycaemia in Clinical Diabetes

36 SYMPTOMS OF HYPOGLYCAEMIA• neuroglycopenic symptoms are as strongly related to actual blood glucose concentrationsas are autonomic symptoms (Cox et al., 1993a)• people with insulin-treated diabetes cite autonomic and neuroglycopenic symptoms withequal frequency as the primary warning symptoms of hypoglycaemia (Hepburn et al., 1991).Low blood glucose detection – symptom interpretationThe correct detection of a symptom of hypoglycaemia does not always lead to correctinterpretation (Figure 2.2). After correctly detecting relevant symptoms, people fail to detectabout 26% of episodes of low blood glucose (Gonder-Frederick et al., 1997). There areseveral factors that could break a perfect relationship between detection and recognition,and some are discussed below. However, it should be appreciated that symptom detection(internal cues) is not mandatory for the detection of low blood glucose. Self-testing of bloodglucose or the information of family members (external cues) can lead to the successfulrecognition of hypoglycaemia without the patient having detected the episode by symptomaticperception (see Box 2.1).Correct knowledge about symptoms of hypoglycaemia is necessary for the detection oflow blood glucose. The lack of such knowledge among elderly people with diabetes inparticular gives cause for concern (Mutch and Dingwall-Fordyce, 1985). Of 161 diabeticpeople between ages 60 and 87, all of whom were injecting insulin or taking a sulphonylurea,only 22% had ever been told the symptoms of hypoglycaemia and 9% knew no symptomsat all! The percentages of the insulin-treated diabetic patients who knew that the followingsymptoms were associated with hypoglycaemia were as follows:• sweating (82%);• palpitations (62%);• confusion (53%);• hunger (51%);• inability to concentrate (50%);• speech problems (41%);• sleepiness (33%).Box 2.1Identification of hypoglycaemia• Internal cues – autonomic, neuroglycopenic and non-specific symptoms• External cues – relationship of insulin injection to meals, exercise and experienceof self-management• Blood glucose monitoring• Information from observers (e.g. relatives, friends, colleagues)