Diabetes Mellitus

INTRODUCTION

Diabetes mellitus is a disease which is known to everybody nowadays. It is to be noted with astonishment that DM has an attracting global importance as it is rocking the world as a non-infectious epidemic/pandemic. “SUGAR” is the common name given to DM by the Indian layman. Actually, it comprises a group of common metabolic disorders that share the phenotype of hyperglycemia (increased level of glucose in blood plasma). Nowadays, it is one of the leading causes of morbidity and mortality because Diabetes mellitus causes secondary pathophysiologic changes in the multiple organ system. Most likely, the complications of DM are adult blindness; non-traumatic lower extremity amputations (diabetic foot); end stage renal disease (ESRD); neuropathy etc. In the forecoming days it is presumed to be increasing day by day due to an increase in factors contributing to hyperglycemia, which may include dietetic irregularities, metabolic dysfunction, lack of exercise, stress, and busy lifestyle.

ETIOLOGICAL CLASSIFICATION

Recent studies in the etiologies and pathogenesis of Diabetes mellitus lead to a revised classification. Recent changes in classification reflect an effort to classify DM as the basis of the pathogenesis process leading to hyperglycemia, as opposed to criteria such as age of onset or type of therapy. Some forms of Diabetes mellitus are characterized by an absolute insulin deficiency or a genetic defect leading to defective insulin secretion, whereas other forms share insulin resistance as their underlying etiology. Diabetes mellitus has two broad categories designated as type1 and type2.

TYPE 1 Diabetes mellitus (previously designated as IDDM): Type 1 DM is categorized into two subgroups, i.e., type 1A and type 1B. Type 1A results from autoimmune ß cell destruction, which usually leads to insulin deficiency; where as type 1B DM occurs due to lack of immunologic marker inductive of an autoimmune destructive process of the ß cells. Type 1 DM is hereditary in character and develops before the age of 30 years. The patient is young, lean and thin, and has an absolute requirement for insulin therapy.

TYPE 2 Diabetes mellitus (previously designated as NIDDM): Type 2 DM is characterized by a variable degree of insulin resistance, impaired insulin secretion, and increased glucose production. Type 2 DM more typically develops with increase in age; it also occurs in children, particularly in obese adults.It does not require insulin therapy.

GDM : This type of Diabetes mellitus is recognized during pregnancy. It is due to insulin resistance related to its metabolic changes.

MODY : It is a subtype of Diabetes mellitus is characterized by autosomal dominant inheritance, early onset of hyperglycemia and impairment in insulin secretion. It is also divided into MODY1, MODY2, MODY3, MODY4, and MODY5 according to genetic defect of beta cell function characterized by mutation in Hepatocyte nuclear transcription factor (HNF), glucokinase, HNF1 a, insulin promoter factor (IPF), HNF1 ß.

OTHER CAUSES:

Drug or chemical induced Diabetes mellitus: Some drugs such as Nicotinic acid, Glucocorticoids, Thyroid hormones, Diazoxide betaadrenergic agonists, Thiazides, ß blockers etc causes DM.
Endocrinal Diseases: This includes Hyperthyroidism, Hypersecretion of Adrenal cortex, Hyperpituitarism, Cushing’s syndrome, Pheochromocytoma, Acromegaly, Somatostatinoma.
Diseases of Pancrease: This includes Pancreatitis, Cystic Fibrosis, Hemochromatosis, Pancreatopathy, Cancer of pancreas, Pancreactectomy.
Other Genetic Syndrome sometime associated with DM like as Down’s syndrome, Klinefelter’s Syndrome, Turner’s syndrome, Huntington’s corea.

RISK FACTORS FOR TYPE 2 Diabetes mellitus