The Relation of Capillary Angiopathy and Diabetes Mellitus to Idiopathic Edema

Abstract

Eleven women with idiopathic edema aged 29 to 58 years were studied. Six were slightly to moderately obese. Standard and cortisone-glucose tolerance tests and measurements of aldosterone secretory rates were carried out in five by a double isotope procedure. The basement membrane of the capillaries of the gastrocnemius muscle were studied by electron microscopy and measured in the patients, in seven control subjects without edema, and two with edema. The aldosterone secretory rates measured during bed rest and repletion with sodium were within normal range. Three patients had an abnormal glucose tolerance test, and an additional 4 patients had abnormal cortisone-glucose tolerance tests. One patient developed gestational diabetes during the course of the study. One had symptomatic hypoglycemia during a glucose tolerance test. The basement membrane of the capillaries from the normal subjects had a mean thickness of 2600 [plus or minus] 3D 210 A. The mean area was 35 [plus or minus] 5[mu]2. The mean thickness of the basement membrane of the patients with idiopathic edema as a group was significantly increased to 4700 [plus or minus] SD 1900 over that of the normal control subjects (p< 0.05 > 0.02). Five individual subjects had capillary basement membranes significantly thicker than those of the controls. These stained less densely, were irregular, and had occasional splitting. All of the subjects with abnormal capillaries had a family history of diabetes or abnormal glucose tolerance. It is probably a coincidence of several factors that leads to the development of edema in these patients. The finding of microangiopathy suggests that one factor may be an increased permeability with increased extravasation of fluid from intravascular spaces on standing and the hypersecretion of aldosterone when ambulatory is secondary to this. The high incidence of diabetes and of abnormal carbohydrate tolerance in the patients and in their families suggests an interrelationship between diabetes and the mic roangiopathy.