SYMPTOMS
A common symptom of diabetes mellitus is weight reduction caused by the loss of fluids and fat; this is because of the inability of the body to break down carbohydrates. Other symptoms are passing copious amounts of urine; increased thirst; disturbances of vision; limb numbness; genital itching; cessation of menstruation in women; and a tendency to boils and skin infections. About half of people affected are undiagnosed for some years until high glucose levels are detected in samples of blood or urine during medical tests.
TREATMENT AND MANAGEMENT
The aim of treatment in all types of diabetes is to keep the blood glucose level as normal as possible by administering insulin, or by providing glucose reduction therapy. Diet involves ensuring that meals and snacks are so timed that the body’s insulin levels do not become overwhelmed.
Hypoglycaemia results from excessive amounts of insulin or sulphonylureas; lack of food; or excessive exercise. It may occur in non-diabetics; in diabetics it occurs as a result of insulin overdose and lack of carbohydrates. Hypoglycaemia produces a low blood glucose level, leading to eventual collapse and possibly coma. It is vital for such patients to swallow some form of sugar quickly following symptoms of sweating, confusion, faintness, or palpitations. The opposite condition, hyperglycaemia, occurs when there is an excess of glucose in the blood because of lack of insulin treatment. Unless quickly treated in hospital, hyperglycaemia may lead to coma and death.
Generally, insulin is self-administered by patients by injection, or with automatic drug injectors attached to the body. Small pen-sized injectors containing a cartridge of insulin can be carried in the pocket for ease and speed of treatment. Diabetes mellitus occurs in two major forms, the symptoms and treatment of which are described below.
NON-INSULIN DEPENDENT DIABETES MELLITUS
Also known as Type 2, this is the commonest form of the condition. Formerly known as adult-onset diabetes, it usually affects people aged over 40 and progresses gradually. In this type the pancreas has not ceased to produce insulin, but the quantity is insufficient, or the hormone is not stimulating the glucose uptake in muscles and tissues required for energy. The result is a build-up of glucose in blood and urine.
Although the cause of this malfunctioning is unclear, non-insulin dependent diabetes mellitus tends to run in families. Other risk factors, such as increasing age, obesity, and a sedentary lifestyle, probably contribute to its increased incidence in developed countries.
Non-insulin dependent diabetes mellitus can often be controlled initially by diet alone, or in combination with tablets that reduce the amount of blood glucose. There are two main types of blood glucose-reducing drugs: sulphonylureas work mainly by stimulating the pancreas’s islet cells (known as the islets of Langerhans) to produce more insulin, and biguanides increase the effectiveness of insulin on cells. Eventually, however, patients may need insulin injections.
The aim is to maintain blood glucose at levels that are as normal as possible and to prevent obesity, thus lowering the attendant risk of cardiovascular disease. Acarbose, the first of a new group of drugs called alpha-glucosidase inhibitors, was introduced for treating non-insulin dependent diabetes mellitus in 1993. By restricting the action of alpha-glucosidase, which helps digest sugars and starch in the intestine, acarbose can limit an increase in blood glucose levels after eating.
INSULIN-DEPENDENT DIABETES MELLITUS
Sometimes called Type 1 or juvenile-onset diabetes, this type of diabetes mellitus commonly occurs in children and young adults and progresses rapidly. It is caused by failure of the pancreas to produce insulin. The autoimmune defence system (the reaction of the body’s immune system to normal cells as though they were of foreign origin) against disease is believed to incorrectly identify the islet cells as foreign and destroy them. Insulin-dependent diabetes mellitus may also be triggered by viruses and certain environmental chemicals in the presence of an inherited predisposition to the disease.
This form of diabetes requires immediate treatment by both diet and injections since it can quickly prove fatal. If the body cannot absorb glucose from food, it starts to break down body fat as an alternative source of energy; this leads to a build-up of toxic compounds called ketones, which results in coma. There are each year an estimated l4.2 new cases of this type of diabetes per 100,000 children aged under 15.
FUTURE APPROACHES
Future approaches to diabetes mellitus being explored include various insulin delivery systems to speed body uptake; drugs that protect the pancreatic islet cells from autoimmune attack; transplant of islet cells or pancreas; and an artificial pancreas.
