Observations in Hypoglycaemia III: C.S.F. Sugar and Coma

Abstract

Finding the blood-sugar level uncorrelated with the clinical symptoms of hypoglycaemia, Day and Niver (2) tried to establish the sugar level in the cerebro-spinal fluid as an indicator of the onset of coma. After examination of the sugar in both fluids every half hour from the injection of insulin until feeding of the patient, they found that coma began when the C.S.F. sugar reached a point between 30 and 15 mgm. per cent., whereas blood sugar was at its lowest point several hours before. The ratio C.S.F. sugar/blood sugar, normally between 10/8 and 10/6, was according to these authors “completely reversed” from the first hour after insulin injection onwards. They base their views on 43 observations of which only one was divergent, but no detailed figures are given. The four curves reproduced for illustration show the slow fall of C.S.F. sugar against the rapid falling blood-sugar level; but the alleged close correlation between coma and C.S.F. sugar can only be seen in one of the curves.