This post is mainly for the medical students and junior doctors to refresh their memory

Blood Sugar and Diabetes Mellitus.

Diabetes has now become a major health problem worldwide. Research suggests that in another 10 years 75% of the world adult population will suffer from diabetes. It used to be a disease of the western population but with increasing wealth in India and China, it is predicted that it will soon become a major problem in these two countries.

Sugar in our blood is essential for life, as glucose is the primary source of energy for all living cells in the body. Glucose is absorbed and transported from the intestine to the cells. With the help of the hormone insulin the cells use the sugar for their metabolism. What is not used by the cells is stored in organs like the liver. The body tightly regulates the blood sugar level
It is remarkable that despite widely variable intervals between meals or the occasional consumption of meals with excessive sugar, the level of glucose in the blood remains within the normal range. The delicate balance is done through hormones (such as glucagon, cortisol and catecholamines which increase the glucose level and insulin, which decreases the level). The blood sugar level is lowest in the morning before you start eating and rises 1 or 2 hours after every meal to its highest level. In a normal individual it ranges from 70 mg/dl to 120 mg/dl (4 to 6.5 mmol/L) with occasional slightly lower or higher values.
When blood sugar levels drop too low (hypoglycaemia) a person feels lethargic with diminished mental function, irritability, weakness of muscles or sometimes even develop fits. It can lead to unconsciousness and can be fatal. Hypoglycaemia is more dangerous than hyperglycaemia (excess sugar).

In diabetes mellitus the cells are unable to use the circulating sugar effectively because of lack of insulin or because very little insulin is produced.

In type 1 diabetes the insulin producing cells of pancreas secrete little or no insulin. In type 2 diabetes, insulin is secreted but in a reduced amount and in addition there is resistance by the cells to use the insulin. Type 1 diabetics will require insulin injections, whereas type 2 diabetes can often be managed with dietary and lifestyle changes.

How do we know whether it is type 1 or type 2 diabetes?

If diabetes is detected before the age of 40, it is likely to be type 1 diabetes. Type 2 diabetes usually occurs in older people. Type II diabetes is more common than Type I diabetes. However it may only be picked up during a routine medical check-up. There are a number of diagnostic tools for differentiating type 1 from type 2 diabetes. Insulin can be measured, but in the early stages of type 1 diabetes some insulin may still be produced. Type 1 is an auto immune disease and hence anti-islet cell antibodies and anti-insulin antibodies may be detected. Also people with type 2 do not generally have ketones present in their urine.

Physicians distinguish type 1 and type 2 diabetes by performing a blood test called the C-Peptide. If the C-Peptide is negative it means that the person is not making insulin and that they have type 1 diabetes and if the C-Peptide is positive it means that the person is making insulin and that they have type 2 diabetes.

Symptoms

The symptoms of Type I diabetes may come on suddenly and can be severe. They include:
• Excessive thirst
• Passing water frequently
• Feeling tired and light headed
• Loss of weight.

In Type 2 Diabetes Symptoms may be mild or you may not even be aware of it. Symptoms often come on gradually and they include:
• Excessive thirst
• Passing water frequently
• Unexplained weight loss
• Painful legs
• Feeling tired
• Delayed wound healing
• Changes in sensation
• Blurred vision

Today we are seeing a rapid rise in the number of cases with type 2 diabetes. Most experts agree that this rise is because of:
• An ageing population
• Increasing number of people with obesity
• Unhealthy food being consumed
• Lack of exercise among the population

If we can persuade the population to take a note of this and adopt the necessary lifestyle changes we will see a rapid fall in the incidence of type 2 diabetes.

Long-term hyperglycaemic causes many of the health problems including heart disease, eye, kidney, and nerve damage. People with diabetes are up to five times more likely to have cardiovascular disease and stroke than those without diabetes. Peripheral vascular changes contribute to delayed wound healing, ulcers and infection involving the feet. This has contributed to increased amputations of the lower limb.

Treatment of Diabetes

There is no cure for diabetes. Treatment is aimed at keeping blood glucose to near normal levels.

Type 1 diabetes:
Type 1 diabetes develops because the body in unable to produce (enough) insulin. This will mean that the person affected by it will need regular insulin injections to maintain normal blood sugar levels. The type of insulin and the amount of insulin required will be decided by the health professional after a few blood tests are done.

Type 2 diabetes
In type 2 diabetes insulin is still being produced by the body but may be in a smaller amount. In addition the cells that use sugar may be showing some resistance to insulin. Here it may be possible to maintain blood sugar levels by making a few lifestyle changes, such as eating a healthy diet and exercising regularly. If the diabetes is still not controlled you may need medication to control sugar levels. Usually it will be a tablet. In later stages if oral medication is not adequate then insulin injections may be needed. Here again the health professional will decide on the type of medication required. And will monitor the blood sugar levels to check if the treatment is adequate.

Investigations
When diabetes is suspected, a fasting blood glucose level and a postprandial level (2 hours after ingesting 75gms of glucose) should be done. Impaired glucose tolerance is indicated when the blood sugar level is between 7.8 and 11.1 mmol/l (140 and 200 mg/dl) and Diabetes when equal or above 11.1 mmol/l (200 mg/dl). Fasting and postprandial levels of glucose indicate the level at the time when the blood sample is taken. When the sugar level is on the border line of suggesting diabetes and we need a clearer picture before we say you are a diabetic we should check the blood for HbA1c.

HbA1c is an overall marker of what the average levels of blood sugar are over a period of 2 to 3 months. It is also the test done to assess whether the diabetes is properly controlled when on treatment. For normal people, the range is 20-41 mmol/mol (4-5.9%) For people with diabetes, an HbA1c level of 48 mmol/mol (6.5%) is considered good control. For people with diabetes this is important as the higher the HbA1c, the greater the risk of developing diabetes-related complications.

For diabetics to maintain good control the American Diabetes Association recommends a post-meal glucose level of less than 10 mmol/L (180 mg/dL) and a fasting plasma glucose of 3.9 to 7.2 mmol/L (70–130 mg/dL).