Physiology · Endocrine System

Diabetes mellitus: physiological basis

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Definition

  • Diabetes mellitus: insulin deficiency or resistance leaves tissues unable to use glucose despite hyperglycemia, "starvation in the midst of plenty".
  • Normal fasting blood glucose70 to 99 mg%
  • Diabetes is diagnosed at fasting glucose 126 mg% or more, on more than one occasion.

Classification of Diabetes Mellitus

Etiological classification of diabetes mellitus

Category

I. Insulin deficient (Type 1 DM)

Subtypes
Immune mediated (Type 1a); non-immune mediated (Type 1b)

II. Insulin resistant or deficient

Subtypes
A. Polygenic (Type 2 DM): insulin resistance, β-cell failure. B. Monogenic: MODY, LADA, PNDM

III. Other specific types

Subtypes
Pancreatic disease; excess insulin-antagonist hormones; drug-induced; viral infection; genetic syndromes

IV. Gestational DM

Subtypes
Diabetes induced by pregnancy