Diabetes mellitus

Objectives Definition of Diabetes. Symptoms of Diabetes. Types of Diabetes. Lab diagnosis of Diabetes.

Diabetes mellitus (DM) is a a heterogeneous group of diseases characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. The term diabetes mellitus describes a metabolic disorder of multiple aetiology characterized by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both. The effects of diabetes mellitus include long–term damage, dysfunction and failure of various organs. What is diabetes?

Diabetes mellitus may be associated with characteristic symptoms such as thirst, polyuria, blurring of vision, and weight loss. The most severe forms, ketoacidosis or a non–ketotic hyperosmolar state may develop and lead to coma and death, in absence of effective treatment. It is common, affecting up to 2% of Westem populations, 17% in Saudi Arabia.

Diabetes Long-term Effects The long–term effects of diabetes mellitus include progressive development of retinopathy with potential blindness, nephropathy that may lead to renal failure, and/or neuropathy with risk of foot ulcers, amputation, Charcot joints, and sexual dysfunction. People with diabetes are at high risk of cardiovascular disease (CVD).

Burden of Diabetes The development of diabetes is projected to reach pandemic proportions over the next 10-20 years. International Diabetes Federation (IDF) data indicate that by the year 2025, the number of people affected will reach 333 million – 90% of these people will have Type 2 diabetes. In most Western societies, the overall prevalence has reached 4-6%, and is as high as 10-12% among 60-70-year-old people.

-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).

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

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.

1- Insulin- Dependent (Type I) Diabetes -The environmental event effects, usually a viral infection, particularly with: Coxsackie B4 mumps. -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.

2-Non-Insulin-Dependent (Type 2) Diabetes -NIDDM has been divided by the World Health Organization (WHO) into two main groups: Obese Non-obese

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 etiological 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.

2-Non-Insulin-Dependent (Type 2) Diabetes - Not all patients with NIDDM are over weight, there is a clear association with obesity. - Obese patients develop NIDDM either have: diminished pancreatic reserve. a secretory defect in the pancreatic beta-cells.

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.

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

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.

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

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.

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).

Lab diagnosis * Glucose : 80-120 mg/dl [normal ranges] Fasting and 2h-postprandial. * Hemoglobin A1c Reflects weighted average of blood glucose concentration over the preceding 2-3 months [how high blood glucose is, and how long it has been elevated]. * Others: - Fructosamine, glycated albumin. – C-peptide, insulin. – Microalbumin.

Management of DM A B C Diet and Exercise Insulin Therapy The major components of the treatment of diabetes are: Diet and Exercise A Oral hypoglycaemic therapy B Insulin Therapy C