Diabetes control is vital to prevent several acute and chronic complications. Acute complications include diabetic ketoacidosis, hyperosmolar coma, infections, hypoglycaemic episodes etc.

Some of the chronic or long term complications include eye, kidney and nerve damage. Several other problems and lifestyle habits are responsible for worsening diabetes. These include smoking, elevated cholesterol levels, obesity, high blood pressure, and lack of regular exercise.

Some of the common long term complications of diabetes and their pathophysiology include:–

• Weight loss – this is seen due to los of glucose and calories in urine.
• Poor wound healing, gum and other infections – this occurs due to increased blood glucose providing a good source of nutrition to microbes and due to a diminished immunity.
• Heart disease - this occurs due to changes in the large blood vessels leading to coronary, cerebral, and peripheral artery diseases, atherosclerosis, dyslipidemia etc. Damage to the large blood vessels is called macrovascular damage.
• Diabetic retinopathy or eye damage – this occurs due to damage of the fine blood vessels of the retina in the eye due to long term exposure to high blood sugar.
• Kidney damage – similar damage to small and large blood vessels of the kidneys. Initially there is proteinuria or increased outflow of protein and may lead to end stage renal disease (ESRD).
• Nerve damage – this can affect the arms and legs and is called stocking-glove numbness/tingling. It can also affect autonomic functions leading to impotence, erectile dysfunction, difficulty in digestion or gastroparesis etc.
• Diabetic foot – this occurs due to peripheral nerve damage as well as blood vessel affliction due to long term diabetes. Little trauma, sores and blisters go unnoticed due to lack of sensation and peripheral vascular disease impairs healing and allows infection.
• Diabetic encephalopathy - this is damage to the brain due to long term uncontrolled blood glucose. There is a risk of dementia and cognitive decline.

Diabetic Ketoacidosis

This is caused in type 1 diabetes where there is complete lack of insulin and reliance on fatty acids for energy. This uncontrolled lipid breakdown leads to formation of ketones and causes acidosis and ketonemia. This is acute and dangerous and always a medical emergency.

On presentation at hospital, the patient in DKA is typically dehydrated, and breathing rapidly and deeply. This is called Kussmaul’s breathing. There may be severe abdominal pain. The level of consciousness is typically normal until the patient slips into coma. There may be severe fall of blood pressure, shock and death. Urine analysis will reveal significant levels of ketone bodies. Prompt, proper treatment usually results in full recovery.

Non-Ketotic Hyperosmolarity or Hyperosmolar nonketotic state (HNS)

This is caused due to extreme rise of blood sugar (over 300mg/dl or 16 mmol/L). This is seen in type 2 diabetics. There is just enough insulin to suppress ketone synthesis. The high blood sugar leads to excessive concentration or osmolarity of blood which in turn leads to diuresis and collapse of the blood vessels and cardiovascular shock.

The concentrated blood glucose osmotically draws out water from the cells into the blood and the kidneys eventually begin to dump glucose into the urine. This results in loss of water and an increase in blood osmolarity. Patient is severely dehydrated. The body's cells become progressively dehydrated and there is additional electrolyte imbalances.

As with DKA, urgent medical treatment is necessary, commonly beginning with fluid volume replacement. Lethargy may ultimately progress to a coma.

Hypoglycemia

This is caused due to abnormally low blood glucose and is an acute and life threatening condition. It may be the side effect of insulin injections or oral anti-diabetes pills.

There are several tell-tale symptoms of hypoglycaemia like palpitations, sweating, feeling of dread and this may lead to dizziness, unconsciousness or even coma. Severe untreated may lead to death. In most cases, hypoglycemia is treated with sugary drinks or food. In severe cases, an injection of glucagon or an intravenous infusion of dextrose is used for treatment.