Arterial glucose levels generally remain at or above fasting levels for much of the time, during which period glucose or food is still being absorbed. Sometimes, in response to oral glucose, but only very rarely in response to a solid meal, and towards the end of the absorptive phase, glucose is removed from the glucose pool faster than glucose enters it from the gut, and genuine arterial hypoglycaemia, capable of producing acute neuroglycopenia, may occur. Venous blood glucose concentrations commonly fall to well below fasting levels under these circumstances and are not necessarily pathological (Fig. 20.24). However, they have in the past been extensively misconstrued as being indicative of idiopathic rebound (reactive) hypoglycaemia, often abbreviated simply to hypoglycaemia and, as such, responsible for a number of vague disturbances experienced by patients in the course of their everyday life.
