Diabetes Mellitus: Definition and Types

Diabetes mellitus is an endocrine disorder characterized by abnormal metabolism of carbohydrates, fats, and proteins.
It is a group of metabolic diseases characterized by increased levels of glucose in the blood resulting from defects in insulin secretion, insulin action, or both.

Occurs mainly in children and young adults, but can also develop at any age.
Characterized by autoimmune, cell-mediated, and selective destruction of the insulin-producing beta cells of the pancreatic islets in genetically predisposed persons.
Results in low endogenous insulin secretion, impaired fat and protein metabolism, and inhibited lipolysis, leading to excessive production of fatty acids.
Low plasma insulin levels decrease protein synthesis, leading to increased breakdown of structural proteins and weight loss.

Occurs in people 30 years and above, and obese individuals.
Characterized by the pancreas producing insufficient endogenous insulin due to impaired insulin action, leading to increased hepatic glucose production and decreased insulin-mediated glucose uptake due to post-receptor defects.
Affected by two factors: insulin resistance and a marked decrease in the ability of the pancreas to produce insulin.

Sugar and carbohydrate foods are broken down in the bowel and absorbed into blood as glucose.
Glucose is stored as glycogen in the liver by the action of insulin.
When sugar in blood rises above a certain level, the kidneys excrete excess sugar in urine, leading to large quantities of urine passed in an attempt to get rid of excess sugar.
The excess urine leads to thirst, while the continuous drain of glucose from the body depletes tissues of vital energy supplies.
In severe cases, since carbohydrates are no longer available, fat is mobilized from adipose tissues and broken down to produce energy.

Urine: output is increased, pale in color, high specific gravity (1.030-1.040), and sugars present
Blood: normal fasting sugars are about 4.5 mmol/l and rise to about 6.5 mmol/l (120 mg/100 ml) after a meal in diabetes; it may be over 11 mmol/l
Oral glucose tolerance test: 75g of glucose is given orally to the fasting patient, and samples are taken every ½ hour for 2 hours; if the glucose levels in 2 hours are more than 10 mmol/l, it's diagnostic

To achieve and maintain satisfactory blood glucose levels
Maintenance of desirable weight
To prevent or delay the development of cardiovascular, renal, and neurological complications

It's a major factor in the control of diabetes mellitus
The patient's energy requirements are calculated according to stature, age, sex, occupation, with the aim of attaining or maintaining a reasonable body weight, controlling blood glucose levels, and normalizing blood lipids and blood pressure
The proportion of prescribed calories allocated to each food is approximately 50-60% carbohydrates, 20-30% fats, and 10-20% proteins
Food intake is usually best divided into 3 meals a day

Type 2 diabetes: oral anti-diabetic agents (e.g., biguanides, sulphonylureas, thiazolidinediones, alpha-glucosidase inhibitors, and meglitinides)
Type 1 diabetes: insulin injection (e.g., porcine insulin, human actrapid insulin, and humulin lente)

Patients on multiple dose insulin or sulphonylureas should do self-monitoring of blood glucose
At least prior to meal and snacks, at bedtime, prior to exercise, and after treating low blood glucose until they are normal

Regular physical activity improves metabolic control, increases insulin sensitivity, improves cardiovascular health, and helps with weight loss and its maintenance
There are two types of exercises: aerobic or endurance exercises (e.g., walking, running) and anaerobic or resistance exercises (e.g., lifting weights)

Patients are provided with knowledge and skills on self-care management of their diabetes, including blood glucose monitoring, body weight monitoring, foot care, personal hygiene, healthy lifestyle/diet or physical activity, identifying targets for control, and stopping smoking.