1. Diabetes mellitus
Dr. Essam H. Jiffri

2. 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.

3. 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)

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

5. 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.

6. 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.

7. 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.

8. 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

9. 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.

10. 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

11. 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.

13. 3- Malnutrition-Related Diabetes Mellitus
-Found mainly in developing countries due to protein-deficient diabetes.
-The aetiology of these is not clear.

14. 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.

15. 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

16. 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.

17. 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).

18. 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.