Insulin oedema and its clinical significance: metabolic studies in three cases.

Three patients with insulin-dependent diabetes mellitus are described in whom generalized oedema and weight gain followed the administration of excessive monocomponent insulins, in two cases associated with symptomatic hypoglycaemia. Serial measurements of plasma volume and transcapillary escape rate of albumin (TERA) using 125I-labelled albumin, serum colloid osmotic pressure (COP) using a membrane colloid osmometer, packed cell volume (PCV), and serum proteins, showed that oedema was associated with an increased plasma volume and TERA, while serum albumin and total protein concentration and serum COP were reduced. A reduction in daily insulin dose abolished hypoglycaemia and resulted in weight loss, natriuresis, diuresis, a reduction in plasma volume and TERA, and an increase in serum albumin, total protein, and COP. Strict metabolic control in previously poorly controlled patients may cause insulin-induced increments in plasma volume and albumin escape rate.