Complications of diabetes are due to high sugars and damage to the small and big blood vessels mainly.
High sugars can cause frequent skin and deeper tissue infections. Infections are common, more severe, often require prolonged treatment and may turn serious if not treated fast and appropriately.
In case of very high sugars (DKA or Hyperosmolar states) a person may become unconscious and this may be life threatening. Severe dehydration, salt and water imbalance, accumulation of acids, decreased kidney function may supervene. Treament in hospital is required for patients.
Long term complications are due to blood vessel and nerve tissue damage.
In feet painless wounds (trophic ulcers) may occur and not heal for months. If infected secondarily even amputations may result.
Damage to retina is called retinopathy. In most countries now, diabetes is the major cause of blindness. Regular check up by eye doctors and laser treatment of newly formed blood vessels may prevent blindness at a later stage.
Damage to nerves may cause numbness usually more in hands and feet. Involvement of nerves supplying muscles can cause weakness in moving limbs. Involvement of nerves supplying bladder and large intestines may result in disturbance in acts of passing urine and defecation. Constipation , diarrhea and retention of urine may occur.
Long term diabetes can damage kidney in multiple ways. The details can be seen later in the kidney care part.
Involvement of coronary arteries results in high risk of heart attacks and angina. Similarly strokes causing paralysis etc occur with a much higher frequency in diabetics.