Diabetes mellitus is a chronic or lifelong condition that affects your body’s ability to use the energy found in food.
There are three major types of diabetes: type 1 diabetes, type 2, and gestational diabetes. All types of diabetes mellitus have something in common.
Normally, your body breaks down the sugars and carbohydrates you eat into a special sugar called glucose. Glucose fuels the cells in your body. But the cells need insulin, a hormone, in your bloodstream in order to take up the glucose and use it for energy.
With diabetes mellitus, either your body doesn’t make enough insulin or it can’t use the insulin it does produce, or a combination of both. Since the cells can’t take up the glucose, it builds up in your blood.
High levels of blood glucose can damage the tiny blood vessels in your kidneys, heart, eyes, or nervous system. That’s why diabetes, especially if left untreated, can eventually cause heart disease, stroke, kidney disease, blindness and nerve damage to nerves in the feet. It has been estimated that about one-third of adults with diabetes do not know they have it.
About one million cases of diabetes are diagnosed each year, and it is the direct or indirect cause of at least 200 000 deaths each year.
Type 1 diabetes
The body stops producing insulin or produces too little insulin to regulate blood glucose level.
This type affects about 5% of all people with diabetes. It is typically diagnosed during childhood or adolescence. It used to be referred to as juvenile-onset diabetes or insulin-dependent diabetes mellitus.
This insulin deficiency can occur at any age due to destruction of the pancreas by alcohol, disease, or removal by surgery. Type 1 diabetes also results from progressive failure of the pancreatic beta cells, the only cell type that produces significant amounts of insulin.
Type 1 diabetes require daily insulin injections.
Type 2 diabetes
Although the pancreas still secretes insulin, the body of someone with type 2 diabetes is partially or completely incapable of responding to insulin.
This is often referred to as insulin resistance. The pancreas tries to overcome this resistance by secreting more and more insulin. People with insulin resistance develop type 2 diabetes when they fail to secrete enough insulin to cope with their body’s demands.
It is typically diagnosed during adulthood, usually after age 45 years. It was once called adult-onset diabetes mellitus, or noninsulin-dependent diabetes mellitus.
These names are no longer used because type 2 diabetes does occur in young people even children, and some people with type 2 diabetes require insulin therapy.
Type 2 diabetes is usually controlled with diet, weight loss, exercise, and/or oral medications.
However, more than half of all people with type 2 diabetes will require insulin to control their blood sugar levels at some point during the course of their illness.
This form of diabetes occurs during the second half of pregnancy. Although gestational diabetes typically resolves after delivery of a baby, a woman who develops gestational diabetes is more likely than other women to develop type 2 diabetes later in life.
This is quite a common condition related to diabetes. In people with prediabetes, the blood sugar level is higher than normal but not yet high enough to be considered diagnostic of diabetes.
Prediabetes increases a person’s risk of developing type 2 diabetes, heart disease, or stroke.
Prediabetes can typically be reversed (without insulin or medication) by lifestyle changes, such as losing a modest amount of weight and increasing physical activity levels. Weight loss can prevent, or at least delay, the onset of type 2 diabetes.
Approximately 20% more adults are now believed to have this condition and may develop diabetes within 10 years unless they change their lifestyle.
Type 1 diabetes is an autoimmune disease. The body’s immune system specifically attacks the cells in the pancreas that produce insulin. A predisposition to develop type 1 diabetes may run in families, but genetic causes (a positive family history) are much more common for type 2 diabetes. Environmental factors, like viral infections, may also contribute to type 1 diabetes.
Type 2 diabetes has strong genetic links, so type 2 diabetes tends to run in families. Several genes have been linked to type 2 diabetes, and many are under study related to type 2 diabetes. However, lifestyle plays a major role in type 2 diabetes and the following are the risk factors:
Type 1 diabetes is usually recognised in childhood or early adolescence, often in association with an injury or illness (such as a virus or urinary tract infection).
The extra stress can cause diabetic ketoacidosis (DKA). Symptoms of ketoacidosis include nausea and vomiting. Dehydration and often serious disturbances in blood levels of potassium and other factors follow. Without treatment, ketoacidosis can lead to coma and death.
Symptoms of type 2 diabetes are often subtle and may be attributed to aging or obesity. A person may have type 2 diabetes for many years without knowing it.
Type 2 diabetes can be precipitated by steroids and stress. If not properly treated, type 2 diabetes can lead to complications such as blindness, kidney failure, heart disease and nerve damage.
Common symptoms of both type 1 and type 2 diabetes:
• Fatigue, or feeling constantly tired: In diabetes, the body is inefficient and sometimes not using glucose for fuel. The body switches over to metabolising fat, partially or completely, as a fuel source. This process requires the body to use more energy. The end result is feeling fatigued or constantly tired.
• Unexplained weight loss: People with diabetes are unable to process many of the calories in the foods they eat. Thus, they may lose weight even though they eat an apparently appropriate or even an excessive amount of food. Losing sugar and water in the urine and the accompanying dehydration also contributes to weight loss.
• Excessive thirst (polydipsia): A person with diabetes develops high blood sugar levels, which overwhelms the kidney’s ability to reabsorb the sugar as the blood is filtered to make urine. Excessive urine is made as the kidney spills the excess sugar. The body tries to counteract this by sending a signal to the brain to dilute the blood, which translates into thirst. The body encourages more water consumption to dilute the high blood sugar back to normal levels and to compensate for the water lost by excessive urination.
• Excessive urination (polyuria): Another way the body tries to rid the body of the extra sugar in the blood is to excrete it in the urine. This can also lead to dehydration because a large amount of water is necessary to excrete the sugar.
• Excessive eating (polyphagia): If the body is able, it will secrete more insulin in order to try to manage the excessive blood sugar levels. With type 2 diabetes, the body resists the action of insulin. One function of insulin is to stimulate hunger. Therefore, higher insulin levels lead to increased hunger. Despite eating more, the diabetic person may gain very little weight and may even lose weight.
• Poor wound healing: High blood sugar levels prevent white blood cells, which are important in defending the body against bacteria and also in cleaning up dead tissue and cells, from functioning normally. When these cells do not function properly, wounds take much longer to heal and become infected more frequently. Long-standing diabetes is also associated with thickening of blood vessels, which prevents good circulation, including the delivery of enough oxygen and other nutrients to body tissues.
• Infections: Certain infections such as frequent yeast infections of the genitals, dental infections, skin infections, and frequent urinary tract infections may result from suppression of the immune system by diabetes and by the presence of glucose in the tissues, which allows bacteria to grow. These infections can also be an indicator of poor blood sugar control in a person known to have diabetes.
• Altered mental status: Agitation, unexplained irritability, inattention, extreme lethargy, or confusion can all be signs of very high blood sugar, ketoacidosis or hypoglycemia (low sugar). Thus, any of these in a diabetic patient merit the immediate assessment of blood glucose.
• Blurry vision: Blurry vision is not specific for diabetes but is frequently present.