Diabetes mellitus

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Diabetes mellitus

• Dr. Essam H. Jiffri

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Introduction

• - Diabetes mellitus is a heterogeneous group of
  disorders characterized by hyperglycaemia,
  glycosuria and associated abnormalities of lipid
  and protein metabolism.
• -It is common, affecting up to 2 of Westem
  populations, 17 in Saudi Arabia.

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Introduction

• -Insulin metabolism is abnormal in diabetes,
  either because of
• reduced secretion or
• to insensitivity to its effects.
• -Two main types of Diabetes
• Insulin-dependent (IDDM or type 1 diabetes
  mellitus, formerly juvenile-onset)
• Non-insulin-dependent (NIDDM or type 2 diabetes
  mellitus, formerly maturity onset)

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Classification of diabetes mellitus
Insulin- Dependent (Type I) Diabetes
Non-Insulin- Dependent (Type 2) Diabetes
Malnutrition Related Diabetes Mellitus
Impaired Glucose Tolerance
Gestational Diabetes Mellitus
Secondary Diabetes
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1- Insulin- Dependent (Type I) Diabetes

• -Insulin secretion is absent or severely reduced
  in IDDM as a result of immunological destruction
  of beta- cells in the islets of Langerhans.
• -Circulating islet cell antibodies are found in
  the majority of patients at presentation and
  infiltration of the islets by T lymphocytes also
  occurs.

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1- Insulin- Dependent (Type I) Diabetes

• -Genetic factors are important in the development
  of IDDM-individuals with human leukocyte antigen
  (HLA) system antigens DR3 and DR4 have increased
  susceptibility for IDDM.
• -The environmental event effects, usually a viral
  infection, particularly with
• Coxsackie B4 or
• mumps.

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1- Insulin- Dependent (Type I) Diabetes

• -Most cases of IDDM present before 30 years of
  age.
• -The clinical presentation is often acute, with
  polyuria, polydipsia, polyphagia, weight loss and
  tiredness developing over several days and
  ketosis may be present.

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2-Non-Insulin-Dependent (Type 2) Diabetes

• -Non-insulin-dependent diabetes is a
  heterogeneous group of disorders in which several
  features contrast with those found in IDDM.
• -NIDDM has been divided by the World Health
  Organization (WHO) into two main groups
• Obese
• Non-obese

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2-Non-Insulin-Dependent (Type 2) Diabetes

• - Insulin secretion is retained, although it is
  inadequate to control blood glucose levels.
• - There is resistance to the effects of insulin
  in due to reduced insulin receptors
• -Genetic factors are a more important
  aetiological factor in NIDDM than IDDM.
• -Identical twins have a near 100 chance and the
  risk of developing NIDDM is higher than IDDM if a
  parent has the disease.

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2-Non-Insulin-Dependent (Type 2) Diabetes

• -There are no HLA associations and no islet cell
  antibodies are found.
• - Not all patients with NIDDM are over weight,
  there is a clear association with obesity.
• - Obese patients develop NIDDM either have
• diminished pancreatic reserve or
• a secretory defect in the pancreatic beta-cells

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2-Non-Insulin-Dependent (Type 2) Diabetes

• -Clinical onset is usually in middle age and the
  prevalence increases with age.
• - NIDDM is often detected by urine testing during
  a routine medical examination.
• - Patients may complain of polyuria and
  polydipsia, ketosis is rare.

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3- Malnutrition-Related Diabetes Mellitus

• -Found mainly in developing countries due to
  protein-deficient diabetes.
• -The aetiology of these is not clear.

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4- Diabetes Associated with Other Disorders
(Secondary Diabetes)

• - Diabetes may occur in association with other
  conditions, particularly pancreatic disorders
  such as
• chronic pancreatitis
• haemochromatosis may cause destruction of
  beta-cells.

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4- Diabetes Associated with Other Disorders
(Secondary Diabetes)

• -Endocrinopathies (endocrine disorders) which
  result in
• - increased secretion of counter-regulatory
  hormones can induce insulin resistance.
• -Diabetes occurs in association with several
  genetic disorders, including
• Turner's syndrome
• Down's syndrome

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5- Gestational Diabetes Mellitus

• - Gestational diabetes occurs for the first time
  in pregnancy.
• - Glycosuria is common because the renal
  threshold for glucose is exceeded.
• - Complications can occur due to blood glucose
  concentrations in both mother and fetus.
• - Glucose tolerance reverts to normal after
  delivery in most cases many later develop frank
  diabetes.

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6- Impaired Glucose Tolerance

• -Impaired glucose tolerance (IGT) is an
  asymptomatic condition
• -Diagnosed on the basis of the response of blood
  glucose to the ingestion of a standard oral
  glucose solution (oral glucose tolerance test,
  OGTT 75g anhydrous sugar in 300 ml water, blood
  and urine samples taken at 2h).

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KEY POINTS
Type 1 diabetes mellitus is characterized by
insulin deficiency

• Type 2 diabetes mellitus is characterized
• by insulin resistance

• Diabetes mellitus is diagnosed by
• clinical features and blood glucose
• measurements or an oral glucose tolerance test.