MICROVASCULAR COMPLICATIONS
Dahl-Jorgensen K.
Ulleval
University Hospital, Oslo, Norway
Microvascular complications of diabetes include
retinopathy, nephropathy and neuropathy. The first signs of these
complications may develop in children and adolescents, particularly if
insulin treatment has been inadequate. The mechanisms by which
microangiopathy develop are not known, but probably include genetic
influences. Several biochemical changes may interact, one important change
being protein glycation. Important functional changes are increased organ
blood flow, increased vascular permeability, abnormal blood viscosity and
abnormal platelet and endothelial function. The structural hallmark of
diabetic microangiopathy is the thickening of the capillary basement
membrane which may lead to occlusive angiopathy and to tissue hypoxia and
damage.
Screening for microangiopathy should
start in children after 5-y duration of the disease and age of 10 years, or
earlier if the glycemic control has been poor. The screening should include
retinal examination through a dilated pupil or fundus photography, urinary
albumin excretion rate, blood pressure measurement and neurological
examination. Several intervention trials have shown that near normoglycemia
reduces the risk of microangiopathy. There is also a relationship between
glycemic control and the development of macrovascular disease and coronary
atheromatosis in diabetes, and the development of atheromatosis starts
early in life. There is a
curvelinear association between the risk of development and progression of
microangiopathy and mean blood glucose. Therefore, optimal insulin
treatment is important in children and adolescents.