Diabetes and it's types | Diabetes Mellitus

 Introduction to Diabetes 

Diabetes is generally defined as “any disorder characterized by excessive urine excretion”

There are two types of Diabetes 

1) Diabetes Mellitus 

 2) Diabetes insipidus

What is Diabetes Mellitus 

Diabetes mellitus is a metabolic disorder of glucose,it is a absolute or relative deficiency of insulin which results in hyperglycemia (increase blood glucose level). 

Diabetes mellitus is a common clinical condition and third major cause of death in many developed countries, about 1/5th of individual's above the age of 50, Bearing this disease.  

Deficiency of Insulin leads to increased blood glucose level.

Thus, due to this high blood glucose, the entry of glucose into the cells is inefficient. Hence, all body cells are starved of glucose.

Insulin Dependant Diabetes Mellitus(DDM)

 It is also known as Juvenile-onset or Type-I Diabetes Mellitus.

There is absolute deficiency of insulin due to viral or auto-immune destruction of B-cells of the islets of Langerhans of pancreas, thus glucose cannot enter into the cells and cannot get metabolized to provide energy.

The destruction of B-cells is gradual i.e.It takes many years after the autoimmune attack, but the symptoms appear abruptly when 80-90% of the B-cells have been destroyed.

It occurs usually during childhood or puberty. Patients are usually undernourished.

Among all the diagnosed diabetics, 10 to 20 percent are found to have insulin dependent diabetes mellitus.

Genetic predisposition is moderate i.e. inheritance is not common.

Metabolic alterations due to hypoglycemia result in serious complications.

Ketoacidosis, a life threatening acute complication is common.

Plasma insulin levels are initially low but later on become absent.

Patients are unresponsive to oral hypoglycemia agents and therefore always need exogenous insulin.

2. Non-Insulin Dependant Diabetes Mellitus (NIDDM)

It is also called Adult-onset or Type-II Diabetes Mellitus.

There is relative deficiency of insulin as well as the unresponsiveness of receptors of insulin on the surface of the target cells, thus glucose can not enter into the cells and cannot get metabolized to provide energy.

NIDDM develops gradually without obvious symptoms and is often an incidental finding. NIDDM does not involve viruses or auto immune destruction of B-cells of the islets of Langerhans of pancreas.

It occurs usually after the age of 35. Patients are usually obese.Among all the diagnosed diabetics, 80 to 90% are found to have NIDDM.

Genetic predisposition is very strong i.c. inheritance is most likely.

Metabolic alterations are milder than that observed in IDDM.

Hyperosmolar Hyperglycemic State(HHS) or Coma, is an acute complication and is common.Plasma insulin levels are normal or even high.

What is Diabetes insipidus (DI):-

It is a metabolic disorder due to absolute or relative deficiency of Antidiuretic hormone (ADH), resulting in failure of tubular reabsorption of water from kidneys and the Consequent passage of a large amount of urine and excessive thirst.

DI results in primary loss of water from the extracellular fluid, causing hyperosmotic dehydration. DI has nothing to do with glucose metabolism.

Primary or Central DI: It is the absolute deficiency of ADH due to a defect in the posterior pituitary gland. The posterior pituitary gland is unable to secrete ADH at all.

Secondary or Nephrogenic DI: It is the relative deficiency of ADH owing to a defect in the ADH receptors present in the kidneys. The ADH level is normal or above normal.