Diabetes mellitus is a condition in which patients have high blood sugar. It is a common condition and affects 8.6% of the population in Singapore. This is an increase from 4.7% in 1984. It is an important condition because there are many complications that can occur as a result of diabetes mellitus. These can be divided broadly into those that occur in the short term (the acute complications) and those that occur over a long time (the chronic complications).
Before we go into details of these complications, there is one very important message that we must get across to you as patients and members of the public. These complications are preventable. Although this is not true in every case, well controlled diabetes mellitus through your own efforts and working with your doctor and other health workers, will at least delay the onset of these complications. Patients with diabetes mellitus can live healthy, active, rewarding lives.
Types of Diabetes Mellitus
There are 2 major types of diabetes mellitus.
Type 1 diabetes mellitus has also been known as juvenile-onset diabetes mellitus or insulin dependant diabetes mellitus. This is the less common type and usually occurs in young persons below the age of 35. In this condition, the body is unable to produce insulin. Insulin is a hormone produced by the pancreas, a gland that is in the abdomen. Insulin is a hormone that controls the use of different fuels for energy. It is especially important because it allows the body to use glucose (simple sugar) instead of fats. When there is no insulin, the body cannot use or store the glucose that comes from food and this causes the blood sugars to become very high. Instead, the body uses fat as a source of fuel giving rise to some of the acute complications of diabetes mellitus.
Type 2 (adult-onset or non-insulin requiring) diabetes mellitus is much more common and is the type of diabetes that affects most Singaporeans. In this type of diabetes, there is no shortage of insulin (at least at the start of the disease). Instead, the cells and tissues of the body are unable to respond to the insulin produced by the pancreas. They have "insulin resistance." (see cartoon below).
This type of diabetes commonly occurs in persons who are overweight and have high blood pressure. There are often other family members who also have the disease.
NORMALLY IN THE BODY:
DIABETES TYPE 2: INSULIN RESISTANCE
|There are several symptoms that you may experience if you have diabetes mellitus. You may feel very thirsty and pass lots of urine. You may also find that you are losing weight and that you feel tired all the time. Sometimes, patients complain of blurred vision. Others notice itching around the genitals, suffer from frequent skin infections or notice that that wounds take a long time to heal.
If you have any of these symptoms, particularly if you are overweight, have high blood pressure or close family members with diabetes mellitus, you should see your doctor to ask him/her to test you for diabetes mellitus.
|Diabetes is diagnosed via a blood test and not a urine test. If you have the above symptoms, it may be possible to make the diagnosis on 1 blood test. However, if the blood sugar is not very high, you may require 2 separate blood tests on different days. Sometimes an oral glucose tolerance test is required. For this test, you will be required to see your doctor in the morning after fasting for at least 8 hours. This means that you should not eat or drink anything except water the night before the test. You should have been eating a normal diet for 3 days prior to the blood test and not exercise heavily the day before the test. Your doctor will give you a very sweet drink containing glucose and will take blood from you after 1 and 2 hours to decide if you have diabetes mellitus.
Acute complications of diabetes include those in which the blood sugar is high (hyperglycaemia) and those in which the blood sugar is low (hypoglycaemia)
Hypoglycaemia is covered in another section so we will only cover hyperglycaemic diabetic emergencies in this section. These include diabetic ketoacidosis and hyperosmolar non-ketotic coma.
Diabetic ketoacidosis occurs when there is insufficient insulin to deal with the amount of sugar in the blood stream. When this occurs, the body uses fat as an energy source and this results in the production of ketones that accumulate in the body. These ketones also appear in the urine and can be detected with a simple urine labstix test.
Diabetic ketoacidosis often occurs in type 1 diabetes mellitus when the patient does not give him/herself insulin injections. In type 2 diabetes mellitus, it usually occurs when a patient has some other illness at the same time. This would include all types of infections or fever such as urine infection or chest infections. Other types of stressful events can also lead to diabetic ketoacidosis such as a heart attack.
Symptoms of diabetic ketoacidosis
The symptoms of diabetic ketoacidosis include thirst, passing large volumes of urine, feeling very tired, nausea, vomiting and abdominal pain. Others may notice very deep, rapid breathing and a fruity smell on the breath. In severe cases, patients can become drowsy and become unconscious. This is an emergency and you must be seen immediately in a hospital.
You can prevent diabetic ketoacidosis by taking your insulin and medication regularly, especially when you are sick. When you are unwell, you should monitor your blood sugar frequently and give additional insulin when the blood sugar is high. Your doctor or diabetes nurse educator should be able to give you some advice on how to make these adjustments. If you are unable to eat, you should see your doctor as you may need to be put on a drip until you recover from your illness.
Compared to diabetic ketoacidosis, which can occur very quickly, hyperosmolar non ketotic coma occurs more gradually. You may feel thirst and pass large volumes of urine. This will result in your becoming more and more dehydrated. You will feel tired and may lose weight. Usually the urine ketones are negative or present only in small quantities. Patients may become more and more drowsy and become unconcious. This condition is more common in type 2 diabetes mellitus and may occur because of insufficient medication. More commonly, it occurs due to some other illness or injury such as infection. Once again, if the blood sugar is very high and you feel very unwell, it is important to consult you doctor quickly as this is also a diabetic emergency.
Apart from the acute diabetic emergencies, high blood sugar does not cause death or disabilty in itself. Most of the disability from diabetes mellitus results from the chronic complications of diabetes mellitus and we stress again, these are preventable.
The complications of diabetes mellitus affect many organs in the body and these include the eyes, heart, feet, kidneys, and the nervous system.
Eye disease in diabetes mellitus
Diabetes mellitus can affect the eye in many ways. Cataracts and glaucoma are more common in patients with diabetes mellitus. In addition, it can affect the part of the eye at the back which is responsible for sensing light and colour, the retina. In the retina, small vessels become "leaky" resulting in the formation of exudates, which are the yellow areas seen in the picture below. If these exudates are too close to the most sensitive area of the retina, the macula, this can impair your vision.
Diabetes mellitus also causes weakness in the blood vessel walls causing them to bulge and form microaneurysms. Generally, all persons with diabetes mellitus develop some of these microaneurysms or exudates if they have diabetes for a sufficient length of time. Unless the exudates are very close to the macula, they and the microaneuryms are harmless and will not impair your vision. We call this "background retinopathy." In fact, almost all persons who have diabetes mellitus for 20 years have changes that are due to background retinopathy.
Patients who have diabetes mellitus can also develop "proliferative retinopathy". In these cases, new blood vessels grow on the retina. These new blood vessels are fragile and can bleed giving rise to haemorrhage in the eye and this can lead to blindness.
It is important to pick up the changes due to maculopathy and proliferative retinopathy early as laser therapy can reduce the likelihood of loss of vision. In order to make sure that this is carried out at the right time, you need to go for regular eye screening. It is recommended that you have your eyes screened when you first find out you have type 2 diabetes mellitus. If they are normal, you should continue to have screening once a year. If there are any abnormalities that require attention, your doctor will refer you to an ophthalmologist (eye specialist) for treatment. Patients with type 1 diabetes mellitus do not require eye screening until 3 years after the diagnosis has been made and then once a year thereafter.
Screening can take 2 forms. Many centres can carry out fundal photography where a photograph is taken of the back of you eye allowing a doctor to look for any changes on the retina. The photograph will serve as a permanent record. In Singapore, the polyclinics have this service available. Contact your nearest polyclinic to find out when they have this service available as there are 2 cameras that move to various polyclinics at various times of the year. When a fundal camera is not available, your doctor can look at the retina directly using an instrument called an ophthalmoscope. Most doctors who manage diabetes will have an ophthalmoscope that can be used to examine the eyes carefully. Remember that your doctor has many patients to look after and make it a point to remind him or her of the time to examine your eyes.
Diabetic eye disease is one of the reasons we must try to keep the blood sugar under strict control, the DCCT has shown us that good control of blood sugar results in less eye disease and even if you already have eye disease, it can prevent it from getting worse.
Diabetes mellitus and the heart
Coronary artery disease or blockage of the arteries supplying the heart is the major cause of death in patients with diabetes mellitus. It can result in heart attacks, heart failure or angina. The risk of developing coronary artery disease in diabetic patients is known to be several times higher at every level of cholesterol. The multiple risk factor intervention trial (MRFIT) found that coronary artery disease risk in diabetic subjects at any given plasma cholesterol level was approximately four times greater than in non-diabetic patients. This is especially true in women who lose their "natural" protection against heart disease.
With respect to heart disease, diabetes mellitus is more than just a problem of high blood sugar. In contrast to eye and kidney disease, good blood sugar control alone is not enough to prevent the development of heart disease. Diabetes mellitus is associated with widespread abnormalities in the blood. Of particular importance to heart disease are the blood lipids, which includes cholesterol and triglyceride. High triglyceride and low HDL cholesterol (the good cholesterol) is often seen in diabetic patients. In addition, the LDL cholesterol (the bad cholesterol) in diabetics may be 10-15% higher than in non-diabetics.
Are diabetics with coronary heart disease at greater risk from morbidity and mortality?
In addition to the high risk of developing coronary artery disease, studies suggest that when diabetics develop blockage in the arteries supplying the heart, this is more extensive than in non-diabetic individuals. An acute myocardial infarction (heart attack) in patients with diabetes mellitus is associated with some special features. The risk of death following a heart attack is higher in diabetic individuals. The long term prognosis of survivors of heart attacks amongst diabetics is also less favourable than in non-diabetics. Further, patients with diabetes mellitus (DM) are more likely to have painless or unrecognised heart attack..
Can we prevent heart disease in diabetic patients?
Yes! Patients with diabetes mellitus should never smoke.
What about cholesterol lowering?
We cannot answer this question directly from the available scientific evidence at this time. There is good evidence from studies conducted in Australia and New Zealand, Norway and the United States of America, that lowering blood cholesterol levels will lower the risk of heart disease in patients with diabetes mellitus. Given the very high risk of heart disease in patients with diabetes mellitus, most doctors would agree that it is important to maintain low levels of blood cholesterol. When this cannot be achieved through changes in the diet and with exercise, it may become necessary to use drugs to lower the lipid levels. We await the results of several new studies designed specifically to answer this question in diabetics and we hope to keep you posted regarding the results. We can start to expect the results of these large studies around the year 2000.
Kidney disease in diabetes mellitus
30-50% of patients with diabetes mellitus may develop kidney disease. Diabetes mellitus is now the more common cause of kidney failure requiring dialysis in Singapore. Kidney disease can be prevented.
Kidney disease in diabetes mellitus usually follows a set pattern. It begins with the appearance of small amounts of a protein called albumin in the urine. This is called microalbuminuria and can be detected using specialised tests. It is important to screen for this stage of diabetic kidney disease because aggressive treatment can normalise the kidney function at this time. Speak to your doctor about a test for urine microalbumin. As with eye disease, this stage of kidney disease produces no symptoms and you will not know you have it unless you test for it. This should be done at the time of diagnosis for type 2 diabetes mellitus and yearly thereafter. Those with type 1 diabetes mellitus can wait 3 years before doing their first test.
Later on, the amount of protein increases and patients reach a stage called nephrotic syndrome. This stage may be associated with swelling of the ankles or abdomen. As the disease progresses, the patient can eventually develop kidney failure. These later stages of kidney disease are not reversible, ie. Your kidneys cannot return to normal. However, treatment at this time can still slow down the progression of kidney disease. This is important as it will delay your requirement for dialysis, sometimes as much as 5-10 years.
Important factors in the prevention of kidney disease
- Good control of your blood sugar.
- Good control of blood pressure.
- Use of drugs called Angiotensin converting enzyme inhibitors (ACE inhibitors)
- Cessation of smoking
- Control of blood lipids
- A low protein diet
Treatment of any urine infections. Patients with diabetes mellitus are especially prone to develop urine infections. If you have symptoms of pain when you pass urine, pass urine very frequently or more than twice at night or if you develop fever, you should see your doctor to test your urine for any infection so that you can be given appropriate treatment.
a) Diabetic Diet
A diabetic diet is one which promotes a healthy balanced diet for all individuals rather than a diet for the sick. The total energy needs of the individual will be calculated at a level to achieve and/or maintain a desirable body weight. The proportion of energy from each of the major energy groups is such that 50-60% of energy should be derived from carbohydrate, 25-30% from fat and 15-20% from protein (The protein intake may need to be reduced in renal disease).
Do not delay or skip your meals or snacks (if allowed) as this may lead to fluctuations of your blood sugar levels. If in doubt, you should seek medical nutrition therapy from a qualified dietitian who will help tailor a meal plan to suit your lifestyle and medical condition.
Regular exercise is an important part of diabetes control and should be part of your daily routine.
- Helps insulin to work better and lower your blood glucose.
- Lowers the blood pressure and cholesterol levels.
- Strengthens the heart and improves blood circulation.
- Reduces body fat and control body weight.
Select an exercise program
The type of exercise that is suitable for you depends on your age, physical fitness and preferences. You may need to consult your doctor or nurse educator when planning for an exercise program. Choose an exercise that you would enjoy doing. Brisk walking, jogging and cycling are good examples. Exercise regularly, every day if you can or at least 3 times a week and 30 minutes for each session. Plan your programme, start slowly and gradually. Increase the amount of exercise you do each session.
Always start with warm up (stretching) for 5 – 10 minutes follow by the actual exercise, and end with cool down exercise, just as you would do for the warm up.
Points to remember:
- Test your blood glucose before and after exercise. It is not safe to exercise if your blood glucose is above 15 mmol/L, if you are feeling unwell or if there are ketones in your urine.
- If blood glucose is low, eat a snack.
- If blood glucose is normal, you do not need a snack unless you are doing some strenous exercise.
- Alternatively, you can reduce your insulin dose before exercise. Consult your doctor or nurse educator on what is best for you.
- Always carry quick sugar, such as glucose tablets candy etc. With you when you exercise (especially if you are on insulin). Hypoglycaemia (Low blood sugar) may occur during or after exercise due to increased transport of glucose into the muscles by insulin.
- If possible, exercise with your spouse or a friend.
c) Oral medication
When diabetes cannot be controlled by diet and exercise alone, your doctor may prescribe tablets. Medication is not a substitute for an appropriate diet and regular exercise. It is meant to help patients achieve better control of blood glucose after they have tried to do so with appropriate lifestyle modification.
The tablets are not insulin . Insulin cannot be taken orally it would be destroyed by digestive enzymes.
The tablets are effective only when the pancreas still produces some insulin. Therefore they are prescribed for people with Type 2 diabetes mellitus.
Medication currently available for the treatment of diabetes mellitus can be divided into 3 broad categories as shown in the table below
||Make the pancreas release insulin and lowers blood sugar
|Help cells in the body respond more effectively to insulin ie. reduce insulin resistance.
||Lactic acidosis. Sometimes it can cause some abdominal discomfort, nausea or diarrhoea. To avoid this, patients can start with a lower dose and take the tablets together with meals initially. Not appropriate for people with renal / liver impairment.
|Slow sugar absorption in the intestine. Prevent sudden increase in blood glucose that occur after eating.
e.g. flatus (gas)
Important points about the use of oral medications
Take them regularly at the prescribed times
- Sulphonylureas – should be taken half an hour before food
- Biguanides - should be taken half an hour after food.
- Alpha-glucosidase Inhibitors- should be taken with meals.
You may take more than one type of medication at the same time, once a day or as many as 3 times a day. It is important to take medication as prescribed by the doctor, not only when you think your blood glucose is high.
If you are ill and unable to eat, you still need to take your tablets, because your sickness can raise your blood glucose. Eat your normal meals if you can. If you cannot eat your usual meals, take at least the carbohydrate in the form of fruit juices, soft drinks.
Store your tablets at room temperature Do not use if they are passed the expiry date or if the tablets are discoloured.
Take it at the same time each day. You may want to take your medication with the same time when you do a routine activity. e.g brushing teeth to help you to remember your medication. Always keep your medicines with you when travelling. Take enough for the trip, plus extras
d) Insulin Injections
This section provides information about what insulin is, how it works, and how it is administered to lower/maintain blood glucose of 4 - 8 mmol/litre.
Types of Insulin: Approximate effect/action *
||5 - 30 mins
||1 - 3 hrs
||4 - 8 hrs
||1 - 2 hrs
||4 - 12 hrs
||16 - 24 hrs
|Premixed (Short & Intermediate)
||2 - 12 hrs
||16 - 24 hrs
||8 - 24 hrs
||28 - 36 hrs
Variation between and within patients may occur *depending upon injection site and technique, insulin dosage, diet and exercise. Some insulins are available in penfill-catridges, and and may be more convenient, especially when travelling.
Advice for Patient on Insulin Injection
- Try to have your injection at the same time each day
- Eat 20 - 30 minutes after your injection (except for new insulin Lispro)
- Throw away used needles and syringes in a used bottle with a screw cap
Storage of Insulin
- Write the date on the bottle when you open it. An opened bottle of insulin will expire 2 months after it is opened and must be discarded at this time
- Keep the opened bottle of insulin with syringes to be used again in a box
- Never freeze insulin; keep it in the door of refridgerator. Penfill cartridges do not require refrigeration when they are in use. Do not leave insulin in the sun or unattended in your car.
- It is important to rotate your injection sites because repeated injection at the same site causes fat to accumulate at that area. This results in poor absorption of the insulin when injected. It is also unsightly.
- Shift each injection site by 1 finger space and do not inject bruised area.
- The abdomen is preferred because it is easy to inject than the limbs, and the absorption rate is constant.
- Download the figure and use it to assist you with rotation of sites
Before you inject, if you have pre-drawn your insulin in the syringe:
- Take it out from the refrigerator half an hour before injection
- If it is the milky insulin, you have to invert the bottle 2-3 times to dissolve the suspension just before injecting
- Clean the skin before, and after injecting press slightly with an alcohol swab
e) Monitoring of glycaemic control
Diabetes mellitus is a life-long condition. Blood sugar levels vary between different times of the day and can fluctuate with activity, emotional stress or illness. The disease can also progress. Good blood sugar level control today does not mean that the blood glucose control will be good for the rest of your life without any change in treatment. Since we aim to achieve lifelong control of blood sugar, it is important that we monitor the control of our blood sugar regularly. When there is a change, a higher dose of medication may be needed. Alternatively, a different type of medication or insulin may be required.
There are 2 ways to monitor the adequacy of your blood glucose control
Regular visits to your doctor
You should visit you doctor regularly, at least once in 3 months and more often if your diabetes is not well controlled. Your doctor can check your blood sugar. However, this will only tell you what your blood glucose is at that time and not what it has been over the last few months. Your doctor can also measure the level of glycosylated haemoglobin in your blood. Haemoglobin is the red substance in the red blood cells that carry oxygen. When the red cells are exposed to glucose in the blood, glucose attaches itself to the haemoglobin in the red cells and forms glycosylated haemoglobin in the blood. Since each red blood cells lives for 2-3 months in the blood stream, the amount of glycosylated haemoglobin in the blood gives an average of the blood sugar over the last 2-3 months. You should aim for a normal glycosylated haemoglobin. Ask your doctor what the normal level is because the value is different depending of the laboratory where the test is carried out. Even though we now have this test available, it is important to remember that this is an average of the blood glucose. A good result can be due to very well controlled diabetes mellitus or it can result for a combination of very high blood sugar at some times and very low blood sugar (hypoglycaemia) at others resulting in that same average. To avoid the latter situation, you need to get an idea of how well your blood sugar is controlled between your appointments with your doctor. Since your doctor cannot be with you all the time, it is important that you or your family member takes responsibility for the day to day monitoring of blood sugar levels.
Home blood glucose monitoring
A person with diabetes cannot always be in the care of a doctor or nurse every hour and every day. This is especially if the person is independent, active and has to work. Therefore learning to test blood sugar levels by him/her self is essential.
The results from the self-checks provide information about how meal intake, timing, medication, exercise and stress affect blood sugar levels.
How often a blood sugar level check is done depends on
- What treatment is used
- What goals of treatment are
Discussion with your doctor or nurse educator is necessary to find out what your goals of treatment are.
Frequency options (1 – 8 times a day)
- before each meal and at bedtime
- fasting and 2 hours after each meal
- before and 2 hours after each meal
- once a day, a different time each day
- twice a day, once fasting and one more at different times of the day
- fasting only.
For options 1, 2, 3 and 6 – checks can be done every day or one day a week or 2 – 3 days a week.
For options 4 and 5 – checks must be done at least 3 days a week to obtain a better profile.
When ill, it may be necessary to check the blood sugar as often as 4 hourly.
The tighter the required control, the more often you will need to check you blood sugar.
Monitoring can be less frequent if the blood sugar level has stabilised.
How do I measure my blood sugar?
You need to obtain a drop of blood by pricking your finger with a small needle(see hints).
The drop of blood is then applied to the specific area or pad on a test strip and after a fixed amount of time, depending on which strip is used, the results can be read in one of two ways.
- Results from the test can be read by wiping the blood from the strip after the required length of contact with the strip.The enzyme on the strip would have reacted with the amount of glucose in the blood. How much reaction takes place will be determined by the level of sugar in the blood. The reaction causes the strip to change colour. By visually comparing the colour of the strip and the colours on a graded chart, the level of sugar can be read.
- Results can also be read using a glucose meter (this is more accurate and is the method that we would encourage).
- As with all things, practice is what makes the steps easier to remember.
- Always wash your hands before starting. This will make sure you do not have any juices from fruits etc on your skin which will give an inaccurate result.
- Always make sure you have everything you need in front of you. This will save you from constantly searching for things while doing the test.
- Meters usually come in a carrying case. You may want to put what you need together in it. Remember to top up.
Each individual has a his / her own target range. This depends on how old you are, which type of diabetes and the duration of the diabetes. This target range would vary when there are changes in your state of health and lifestyle. How much control you want or your doctor suggests you need will also play a part is setting your target. Please refer to your doctor or diabetes nurse to get a proper assessment so you can both set your target ranges.
What to do with the results
Keep a consistent record of the results you get. Note the pattern of results at different times of the day. If there are any great changes in the result from your "usual" pattern consider the following:
1) Does what you feel at the time match the test result. eg. Do you have symptoms of hypoglycaemia when your blood sugar read low on your glucometer?
2) Did you wash your hands ?
3) Are the steps you took in order ?
4) Do the codes on your strips and meter match ?
5) Did you have enough blood on the test pad ? (too little will give a result that is too low)
6) What was time of the last meal / snack ?
(if the test was done too close to the meal times i.e. less than 2 hours, your results are likely to be higher).
7) Has there been any changes in your eating pattern / meal content / life style ?
8) Do you have a fever / flu / coughing ?
9) Have you been taking your medication properly ?
If the change is due to (1) treat accordingly, consult your diabetes nurse / doctor for the immediate treatment method of hypoglycaemia or hyperglycaemia if you do not already know this.
If the change is due to (2) to (4), repeat immediately correcting the step that was not done properly.
If the change is due to (5) repeat at a more appropriate time.
If the change is due to (7) to (9) continue monitoring closely and consult your doctor / diabetes nurse as soon as you can.
Complications arising from treatment
||The most common complication that arises from treatment of diabetes mellitus is hypoglycaemia or low blood sugar. This occurs when the intake of sugar is less than that used. It can occur because the patient does not eat after taking medication or injections. Alternatively, it can happen when too much sugar is used up by the body such as may occur after exercise or too much medication. When the blood sugar becomes too low, it affects the brain so that the person may be irritable or confused. They may feel weak or suffer from blurred vision. In severe cases, the patient can lose conciousness or have convulsions (fits). At the same time, the body responds by producing other hormones such as adrenaline. This results in tremors or shakiness of the limbs, sweating, a fast heart rate and feelings of hunger.
Hypoglycaemia is a recognised complication of good glucose control and occurs more frequently when the blood sugar is well controlled. It is important that patients with diabetes mellitus learn to recognise the symptoms of hypoglycaemia so that they can deal with them appropriately.
The treatment of hypoglycaemia is to recognise the symptoms early and quickly take a source of glucose such as a snack.
|Liquids are more rapidly absorbed from the intestine and a drink such as a soft drink, milo or fruit juice may quickly reverse the effects. Alternatively, patients with diabetes mellitus can carry glucose tablets (such as dextrosol) 2 or 3 of which can be taken quickly if they experience hypoglycaemia.
Another complication that occurs in patients who are on insulin injections is the thickening of the skin and accumulation of fat at the injection site. This occurs when you do not rotate your injection sites regularly and can be dealt with by avoiding injections at that site.