The presence of large amount of glucose in the blood leads to injury and dysfunction of many tissues. This dysfunction of tissues leads to many complications. The greater is the sugar level the greater is the degree of complication. The more is the duration of hyperglycaemia, the more is the severity of the complication. So, a patient who keeps diabetes under control can delay the onset of these complications and thereby prolong his life.
The complications can be broadly divided into acute complications and chronic complications. The acute complications are the ones which occur quickly and can be treated easily, while the chronic ones are the ones that appear late and last for a longer duration.
1. Diabetic Ketoacidosis(DKA) for Type 1 diabetes and for some cases of type 2 diabetes.
2. Hyperglycemic Hyperosmolar state(HHS) for type 2 diabetes.
DKA and HHS are associated with absolute or relative insulin deficiency, volume depletion and acid base abnormalities.
The chronic complications can be grouped into four major categories.
VASCULAR COMPLICATIONS AND CARDIOMYOPATHY:
The first complication that results due to hyperglycaemia is in blood vessels. The altered lipid metabolism in diabetics leads to formation of atheromatous plagues and their deposition along the inner wall of the blood vessels which leads to occlusion of the lumen of the blood vessel. This is called atherosclerosis. This occlusion of the lumen of the blood vessels leads to reduced blood supply to the organs which leads to iscahemia and thereby necrosis of the tissue supplied by that blood vessel.
The narrow blood vessels result in hypertension which may in turn lead to Myocardial Infarction. This is cardiomyopathy. The atherosclerosis also increases the risk of stroke. The diminished blood supply also leads to the gangrene of the lower extermity which may lead to diabetic foot.
The complications of blood vessels can be grouped into macrovascular and microvascular complications. The macrovascular complications include large and medium sized arteries whereas the microvascular complications involve capillaries in the target organs. Cardiomyopathy is due to macrovascular complications while nephropathy, neuropathy and retinopathy are due to microvascular complications.
Diabetic neuropathy is seen in both type 1 and type 2 diabetes. It may manifest as mononeuropathy, polyneuropathy or autonomic neuropathy. In addition to hyperglycaemia neuropathy worsens with smoking and increase in BMI (Body Mass Index) of the person. In neuropathy both myelinated and unmyelinated nerve fibers are damaged.
In mono and polyneuropathy there is distal sensory loss. In some patients there may also be Hyperaesthesia, Dysaesthesia and Paraaesthesia. There may also be numbness, tinglng, sharpness or burning that begins in the distal part of the limbs and then spreads proximally. Pain is usually present in lower limbs. It occurs at rest and worsens during night. There may also be sensory loss and loss of ankle reflex. As per latest research vibration therapy has proved to be very useful in reducing the symptoms of numbness and tingling and pain in the lower limb caused by diabetic neuropathy.
In autonomic neuropathy there may be damage to both cholinergic and adrenergic neurons which may result in a variety of symptoms based on the nerves involved. The symptoms may be cardiovascular, genitourinary, gastrointestinal etc. The symptoms may be resting tachycardia, orthostatic hypotension, hydronephrosis of upper limb, anhydrosis of lower limb, bladder emptying abnormalities, gastroparesis, etc. Neuropathy should be taken care of or else the foot may get calloused or ulcerated because of constant injury and friction which is not being perceived as a result of neuropathy.
Diabetes has been the culprit for blindness of people in the age of 20 to 74 years. Diabetic retinopathy and macular oedema are the causes of blindness. Retinopathy is classified into proliferative and non proliferative stages. The cause is defect in the microvasculature of the retina which is due to diabetes.
There is microalbuminuria seen nearly 10 years after onset of type 2 diabetes. This later results in gross proteinuria. Hypertrophy of kidney and glomerular hyperperfusion occur in the first few years after onset of type 2 diabetes. Structural changes occur in kidney like basement membrane thickening and mesangial expansion. The patient with diabetic nephropathy will also have diabetic retinopathy.
The above mentioned are the major and most common complications of type 2 diabetes. Besides there are also some other minor complications like Diarrhea, gastropareis, uropathy, sexual dysfunction, dermatological complications, infections, cataract, glaucoma, periodontal disease and hearing loss.