DIABETES MELLITUS

Diabetes mellitus (DM) is a metabolic disorder resulting from a defect in insulin secretion, insulin action, or both. DM is associated with chronic hyperglycemia and disturbances of carbohydrate, lipid and protein metabolism. As the disease progresses tissue or vascular damage ensues leading to severe diabetic complications such as retinopathy, neuropathy, nephropathy, cardiovascular complications.

Classification of DM T YPE I D IABETES M ELLITUS Type I diabetes is primarily a disease of the young. It was previously known as insulin dependent diabetes mellitus (IDDM ) or juvenile-onset diabetes. The etiology is most often autoimmune in origin, but idiopathic destruction of B-islet cells may also occur without evidence of autoimmunity. This autoimmune process may be presented in the form of autoantibodies against various islet cell components.

T YPE II D IABETES M ELLITUS It is previously known as noninsulin dependent diabetes mellitus (NIDDM) or adult-onset diabetes, is the most prevalent form of diabetes, accounting for over 90% of all cases of diabetes. It is commonly manifested by middle-aged adults. Type II diabetes is usually associated with visceral obesity, which is closely related to the presence of insulin resistance.

Type I (IDDM) Type II (NIDDM) Incidence10%90% AgeUnder 20 yearsAbove 40 years OnsetRapidSlow AutoantibodiesPresentAbsent Level of blood insulin Low or absentNormal or high TreatmentInsulin injection Diet control, Physical exercise, Oral hypoglycemic drugs and Insulin in late stages

M ETABOLIC C HANGES IN DIABETES MELLITUS : Carbohydrate metabolism Decreased glucose uptake, glycolysis and glycogenesis. Increased glycogenolysis and gluconeogenesis. These changes lead to hyperglycemia, glucosuria, polyuria and polydipsia.

2) Lipid metabolism Decreased lipogenesis and increased lipolysis. This leads to increased plasma FFA, hypertriglyceridemia, hypercholesterolemia, ketoacidosis and atherosclerosis. 3) Protein metabolism Decreased protein synthesis and increased protein breakdown. This leads to muscle weakness.

Diagnosis of DM Many patients with diabetes remain asymptomatic for long periods, so that the first presentation of the disease is frequently a chronic complication. Symptoms include polyuria, polydipsia, polyphagia, prolonged time of wound healing, and weight loss.

T ESTS FOR D IAGNOSIS AND A SSESSMENT OF DM C ONTROL I- Fasting and 2-hour post-glucose or postprandial (PP) plasma glucose levels Non-diabetic healthy subjects will have: Fasting plasma glucose < 100 mg/dL, - Two-hours value (2-h PP) < 140 mg/dL. Patients with diabetes mellitus will have: Fasting plasma glucose > 126 mg/dL, 2-hour value in (2-h PP) >200 mg/dL

Impaired glucose tolerance (IGT): The condition represents an intermediate category between normal and diabetes. Patients with impaired glucose tolerance may be at increased risk of developing DM. NormalIGTDiabetes FPG (mg/dL) < ≥ hour PG (mg/dL) < 140 mg≥ < 200≥ 200

II-Measurement of Glycosylated hemoglobin (HbA1C): HbA1C is a form of hemoglobin to which glucose is attached. It is level is dependent on the average plasma glucose concentration over the previous 3 months. So, this test is used to monitor blood glucose level in diabetic patient and to assess response to treatment. HbA 1c ≥ 6.5% are diagnostic of diabetes mellitus 8% or more indicate poorly controlled cases.

III- Oral Glucose Tolerance Test (OGTT)