Diabetes mellitus

INTRODUCTION

Diabetes mellitus (DM) is traditionally described as a syndrome of disordered metabolism with hyperglycemia due either to an absolute insulin deficiency or reduction of its biologic effectiveness or both. DM is coming as a global epidemic especially in Asian counties. India is now called as the diabetic capital of the world.

CLASSIFICATION

NIH Diabetes Data Group, in 1979, traditionally divided diabetes into two main types viz. – non-insulin dependent DM (NIDDM) and insulin dependent DM (IDDM). In 1997, the ADA and WHO recommended a change in classification, with etiology being the defining criteria. This classification has introduced the terms, type 1 and type 2 diabetes mellitus, to replace IDDM and NIDDM, respectively.

DIAGNOSIS AND CLINICAL PRESENTATION

Type 1 Diabetes Mellitus

It is a severe disorder and is associated with ketosis in untreated state. The disorder is homogenous and can
occur at any age, although it is most common in lean young individuals who usually present with dramatic symptoms. The disease is characterized by insulinopenia, low C-peptide and elevated glucagon indicating specific b-cell defect. The b-cell defect is most commonly due to autoimmune attack, while in approximately 5% subjects no cause is identifiable. If not treated with insulin the disorder can be fatal, i.e. the patients are dependent on insulin for their survival (5a).

Type 2 Diabetes Mellitus

It is considered to be a heterogeneous disorder, which afflicts individuals who have relative insulin deficiency, coupled with insulin resistance. The individuals are usually obese adults, not requiring insulin to prevent ketoacidosis. They may need exercise, diet, and oral hypoglycemic agents to control glycemia till late in the natural history of the disease, when insulin may be needed. Recently, however, type 2 DM has been found also to occur at a younger age. Some investigators consider type 2 DM to be a facet of Syndrome X (Reaven’s syndrome) comprising of hyperinsulinemia, dyslipidemia, hypertension and hyperglycemia.

Other specific types of diabetes

There are several other types of diabetes, which could result from genetic defects of pancreatic function, pancreatic disease, endocrinopathies, chemicals, abnormalities in insulin action, infections, mutations in the insulin receptor, mutations of mitochondrial DNA and other genetic syndromes.