Diabetic microvascular disease - Complications of diabetes

Complications of diabetes

Diabetic microvascular disease

Definition

Microvascular diabetic complications includes diabetic retinopathy, nephropathy and the neuropathies.

Aetiology

It is thought that microvascular complications are secondary to the metabolic derangements of diabetes, in particular hyperglycaemia. Good glycaemic control of diabetes and control of hypertension can reduce the incidence of complications.

Pathophysiology

Hyperglycaemia leads to glycosylation of proteins including haemoglobin, collagen and proteins of blood vessels by non-enzymatic means. This may impair the function of the proteins.

Intracellular hyperglycaemia in nerves, kidney, blood vessels and the lens which do not require insulin for glucose uptake. The excess intracellular glucose is metabolised to sorbitol and fructose increasing the osmolarity so that water is drawn into cells, causing cell injury.

Increased blood flow in the capillaries of the retina, kidney and other microcirculations could cause increased damage to the capillary wall. Other factors include smoking (at least as common in diabetics as nondiabetics) and hypertension.

An inherited factor has been postulated as some patients do not develop microvascular disease.