Diabetes: Types, Causes, Symptoms & Complications

Diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. Blood glucose is your main source of energy and comes from the food you eat. Insulin, a hormone made by the pancreas (beta-cells of langerhans) helps glucose from food get into your cells to be used for energy.

  • The hormones of the anterior pituitary, adrenal cortex, thyroid and alpha cells of the islets of langerhans are glycogenic, they increase the supply of glucose, possibly they could increase the demand, decrease the secretion or antagonise and inhibit the action of insulin.the body release hormones that raise blood glucose levels to provide a quick source of energy for coping the stress. In the stress condition diabetes mellitus may precipitate with genetic predisposition.
  • Diabetes Insipidus is a condition that shares some of the systems of diabetes mellitus. large urine output, great thirst and sometimes a large appetite. But in diabetes insipidus these are symptoms of a specific injury, not a collection metabolic disorders.The impaired pituitary gland produce less antidiuretic hormone, a substance that normally helps the kidneys retain water.


Diabetes is on increase in India. The multicenter ICMR study showed a prevalence of 25% in the urban and 1.8% in rural population above the age of 15 years. One in every eight individuals in India is a diabetic. The revised WHO figures for the year 2025 is 57.2 million diabetic in India. The average age for the onset of diabetes is around 40 years while it is around 55 years in other countries.


Type 1 (IDDM):

In Insulin Dependent Diabetes Mellitus, also known as juvenile diabetes patients depend on Insulin. There is usually sudden onset and occur in the younger age group and there is an inability of pancreas to produce adequate amount of insulin. This may be caused by virus or autoimmunity. The child is usually underweight. Acidosis is fairly common.

Genetics: Inheritance is polygenic. About 50% of heritability is contributed by HLA class 2 genes.

Infections: Coxsackie or other virus infections. virus may trigger an autoimmune reaction in the pancreatic islets and it impairs Insulin secretion and destroy the beta-cells.

Acute Stress: The body releases adrenaline, noradrenaline and cortisol hormones that raise blood glucose levels to provide a quick source of energy for coping with stress.


Type 1 diabetes signs and symptoms can appear relatively suddenly and may include:

  • Increased thirst
  • Frequent urination
  • Bed-wetting in children who previously didn’t wet the bed during the night
  • Extreme hunger
  • Unintended weight loss
  • Irritability and other mood changes
  • Fatigue and weakness
  • Blurred vision


Over time, type 1 diabetes complications can affect major organs in your body, including heart, blood vessels, nerves, eyes and kidneys. Maintaining a normal blood sugar level can dramatically reduce the risk of many complications. Eventually, diabetes complications may be disabling or even life-threatening.

Heart and blood vessel disease: Diabetes dramatically increases your risk of various cardiovascular problems, including coronary artery disease with chest pain (angina), heart attack, stroke, narrowing of the arteries (atherosclerosis) and high blood pressure.

Nerve damage (neuropathy): Excess sugar can injure the walls of the tiny blood vessels (capillaries) that nourish your nerves, especially in the legs. This can cause tingling, numbness, burning or pain that usually begins at the tips of the toes or fingers and gradually spreads upward. Poorly controlled blood sugar could cause you to eventually lose all sense of feeling in the affected limbs.

Kidney damage (nephropathy): The kidneys contain millions of tiny blood vessel clusters that filter waste from your blood. Diabetes can damage this delicate filtering system. Severe damage can lead to kidney failure or irreversible end-stage kidney disease, which requires dialysis or a kidney transplant .

Pregnancy complications

High blood sugar levels can be dangerous for both the mother and the baby. The risk of miscarriage, stillbirth and birth defects increases when diabetes isn’t well-controlled. For the mother, diabetes increases the risk of diabetic ketoacidosis, diabetic eye problems (retinopathy), pregnancy-induced high blood pressure and preeclampsia.

Type 2 (NIDDM):

Non- Insulin Dependent Diabetes Mellitus, is non insulin dependent and develops slowly and is usually milder and more stable. Insulin may be produced by pancreas but action is impaired. This form mainly in adults and the person is usually overweight. Acidosis is frequent. The majority of patients improve with weight loss and are maintained on diet therapy. Women who had large babies are also prone to develop this type of diabetes later in life.

Genetics: NIDDM is not HLA-linked and have no evidence that autoimmunity or viruses have anything to do with its development.

Lifestyle: Obese and underactive usually they overeat.

Age: Middle age and elderly.

Abdominal Fat: High waist fat.

Pregnancy: Because levels of plasma insulin is raised by the action of placental hormones thus placing a burden on the insulin secreting cells of the pancreatic islets.


Signs and symptoms of type 2 diabetes often develop slowly. In fact, you can have type 2 diabetes for years and not know it. Look for:

  • Increased thirst
  • Frequent urination
  • Increased hunger
  • Unintended weight loss
  • Fatigue
  • Blurred vision
  • Slow-healing sores
  • Frequent infections
  • Areas of darkened skin, usually in the armpits and neck


Type 2 diabetes can be easy to ignore, especially in the early stages when you’re feeling fine. But diabetes affects many major organs, including your heart, blood vessels, nerves, eyes and kidneys. Controlling your blood sugar levels can help prevent these complications.

Although long-term complications of diabetes develop gradually, they can eventually be disabling or even life-threatening. Some of the potential complication of diabetes occur:

Slow healing: If left untreated, cuts and blisters can become serious infections, which may heal poorly. Severe damage might require toe, foot or leg amputation.

Hearing impairment: Hearing problems are more common in people with diabetes.

Skin conditions: Diabetes may leave you more susceptible to skin problems, including bacterial and fungal infections.

Sleep apnea: Obstructive sleep apnea is common in people with type 2 diabetes. Obesity may be the main contributing factor to both conditions. Treating sleep apnea may lower your blood pressure and make you feel more rested, but it’s not clear whether it helps improve blood sugar control.

Alzheimer’s disease: Type 2 diabetes seems to increase the risk of Alzheimer’s disease, though it’s not clear why. The worse your blood sugar control, the greater the risk appears to be.

Malnutrition Related Diabetes Mellitus (MRDM):

Recently, a third type of Malnutrition Related Diabetes Mellitus, MRDM called by WHO has been categorized as a separate entity. This type of diabetes is mainly seen in some tropical countries like India and it occurs in young people between 15-30 years of age. Generally people with MRDM are lean and undernourished. In this type of diabetes require insulin. In contrast to type 1 diabetes, these patients generally do not develop ketoacidosis when insulin injections are discontinued.


Diabetes like type 1 are caused by factors that our immune system mistakenly destroys insulin, which cannot be prevented. Whereas type-2 diabetes can be prevented with better food choices, increased activity, and weight loss. After being tested, your doctor will suggest the treatment.