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Diabetes mellitus (DM)

Glucose and fat metabolism

  • Brain requires 1mg/kg/min of glucose
  • Increase in blood glucose level (BGL) causes insulin to be secreted into portal circulation
  • Insulin augmented by incretin effect (GLP/GIP)

Glucose transporters

  • GLUT-1
  • GLUT-2 – glucose sensors in B cells (insulin)
  • GLUT-3 – neurones and placenta (partial insulin)
  • GLUT-4 – adipose and muscle (insulin)

Pathology

  • B cells have sulfonurea (close potassium channels > increase potassium intracellularly > calcium increases intracellularly > insulin secretion (C peptide is an index for insulin secretion)

Type-1 (T1-DM)

  • T cell mediated auto immune destruction of islets (insulinitis w/ infiltration)
  • Islets cell auto-antibodies present before T1-DM
  •   HLA-DR3 , coxsachie, CMV, EBV,

Metabolic disturbances

  • hyperglycaemia > glycosuria, dehydration > fatigue, polyuria, nocturia, thirst, polydipsia, urinary tract infection
  • weight loss (due to lipolysis/proteolysis)
  • ketoacidosis ( Beta oxidation )

Type 2 (T2-DM)

  • insulin resistance (IR) causes an increase in insulin secretion > chronic demand leads to insulin deficiency
  • adipose tissue release free fatty acids (FFA), FFA compete with glucose for b oxidation fuel supply in peripheral tissues
  • adipokines (via adipoctyes) decrease the sensitivity for insulin
  • IR may be associated w/ HTN, dyslipidemia, PCOS
  • Insulin concentration in blood is enough to inhibit b oxidation/lipolysis therefore ketoacidosis and weight loss is rarely observed.

Other forms

  • MODY ,    LADA ,   Bronze diabetes , Frank diabetes , PCOS, acromegaly

Clinical features

  • Hyperglycemia > polydipsia, blurred vision, fatigue, polyuria, candidias, headache
Diagnosis
  • Dipstick – glucose/ketones (nitroprusside)
  • C peptide (insulin secretion index, for T1-DM)
  • WHO diagnostic criteria
  • FPG >7mmol/L
  • RPG >11.1mmol/L
  • HbA1C – 1% increase is 2mmol/l increase of glucose
    • 1 abnormal value for symptomatic and 2 for asymptomatic
  • OGTT – for impaired fasting glucose/impaired glucose tolerance

Treatment

  • Usually set out by NICE guidelines. However doctors should follow hospital protocols. DM treatment
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