Diabetes affects both small and large size arteries. Diabetes is a risk factor for atherosclerosis. Other additive factors are smoking, hypertention and hyperlipidemia which acts along with diabetes to promote atherosclerosis.

If the medium sized/large arteries like coronary and popliteal arteries are affected, it is called Macrovascular disease. If small size arteries like retinal, kidney glomeruli are affected, it is called Microvascular disease.

MACROVASCULAR COMPLICATIONS

1. Ischemic Heart Disease (IHD)

First Fatty Streak is formed by endothelial dysfunction, macrophage lipid accumulation, smooth muscle cell proliferation, smoth muscle cell migration to intima, lipid accumulation, extra cellular matrix changes.

This fibrofatty plaque grows by further inflammation, formation and organization of thrombus, calcification. Plaque growth leads to stenosis of arteries, formation of thrombus leading to occlusion and aneurysms.

All these changes also occurs in coronaries leading to Myocardial infarction, serious complication in diabetics.

2. Stroke

The same mechanisms as described above leads to cerbral infarctions especially middle cerebral artery.

85% of strokes are the results of either thrombosis at the site of atheromatous plaque or emboli arising from atheromatous plaque.

3. Peripheral Vascular Disease

Peripheral arteries like renal, stomach, arms and legs are affected. When an artery is blocked or narrowed, the part of the body supplied by that artery does not get enough blood supply. This leads to pain due to ischemia and organ death.

MICROVASCULAR COMPLICATIONS

Unlike macrovascular disease, microvascular disease is specific to diabetes. Most important three sites that face this danger are retina, renal glomerulus and nerves.

1. Retinopathy

Background retinopathy is the earliest feature of retinopathy. On ophthalmoscopy, capillary microaneurysms, hemorrhages, hard exudates are seen. There is no treatment for background retinopathy but regular checkups by an ophthalmologist is necessary.

Maculopathy (macular edeme, perimacular hemorrhages, exudates) is identified by decreasing visual acuity.

Proliferative retinopathy is characterized by formation of new vessels which are fragile and leading to vitrous hemorrhages and loss of vision. Fibrous tissue developed may contract and cause retinal detachment.

2. Nephropathy

When glomeruli are affected, this causes microalbuminuria. After many years, slowly intermittent albuminurai develops and sometimes frank nephrotic syndrome.

When arterioles are affected, this leads to ischemic lesions of the kidney.

Urinary tract infections are common in diabetics.

3. Neuropathy

Due to nerve ischemia from occlusion of blood vessels of nerves (called vasa vasorum) or accumulation of fructose and sorbitol, which disrupts the structure and function of nerves.

Neuropathy is manifested by many ways like sensory polyneuropathy, autonomic neuropathy, acute painful neuropathy, cranial nerve lesions, isolated peripheral nerve lesions and diabetic amyotrophy.