DIABETES
Updated 12/11/23
Introduction
Diabetes is a metabolic disease causing high blood glucose levels. If untreated, there are severe long-term effects on the body. There are two types of diabetes. Type 1 usually develops in younger people and is caused by insufficient insulin production by the pancreas. In Type 2 diabetes, insulin is present but the body’s cells fail to respond to it. Type 2 diabetes usually develops in older people, hence it’s common name ‘adult onset diabetes’. However, it should be noted that it is also becoming increasingly common in obese younger people.
Diabetes is common, affecting approximately 6% of the UK population.The majority of cases (90%) are Type 2 diabetes. If it cannot be controlled by dietary measures, it will require medication in the form of tablets or insulin (or both) to stop glucose levels rising too high.
Terminology
The terms ‘blood glucose’ and ‘blood sugar’ can be used interchangeably. The former is technically more correct, but the latter rolls more easily off the tongue.
What does insulin do in the body?
Insulin is produced in the pancreas and is the primary regulator of carbohydrate and fat metabolism. It inhibits fat breakdown and promotes glucose uptake and storage as starch (glycogen) in the liver and muscles. These effects lead to a fall in blood glucose levels.
For information – the importance of glycogen as an energy store
Glycogen supplies short-term energy requirements and is therefore essential for maintaining normal blood glucose levels during exercise. How much glycogen you have in your body affects how long and/or how intensively you can exercise. A typical adult stores approximately 300-400 g in muscles and 70-100 g in the liver. This is roughly equivalent to about 1500-2000 calories. When you deplete your glycogen levels, you may feel like you “hit the wall.” i.e. fatigue and inability to continue exercise. People who are well-trained can store more glycogen to exercise harder and longer than those who are untrained or sedentary. A trained muscle holds almost three times the amount of glycogen than an untrained muscle. There is an important lesson here for us in MR. On long rescues that are physically demanding, you need to eat periodically. Although trained people can burn fat, the main energy source for intense exercise is always glucose.
If diabetes is not well controlled, life threatening consequences can follow. In MR, we need to be aware of the complications that can ensue when a diabetic’s blood glucose levels rise or fall to dangerous levels.
The significance of high & low blood glucose in Diabetes
Imbalances between the tendency of the blood sugar to rise or fall on its own and the diabetic patient’s ability to control the levels can lead to two types of problems:
HYPERglycaemia (high blood glucose) can occur in a previously-undiagnosed diabetic when they first become diabetic, and in known diabetics if the dose of medication is too low, they have eaten excessive amounts of sugar or if they become acutely ill.
HYPOglycaemia (low blood glucose) occurs if the dose of medication is too high or the patient fails to eat enough for the body’s requirements (particularly during exercise).
Extreme hyper- and hypoglycaemia are life-threatening conditions
Hyperglycaemia tends to develop slowly and could occur, for example, in a wild camper who is diabetic and has forgotten to take his insulin with him, or who gets an infection (e.g. chest). Another example is a casualty we were called to who used a battery-operated pump to inject a small dose of insulin continuously. However, the pump failed and by the time we arrived on scene, their BM was 17.3 mmol/l. There is nothing we can do about hyperglycaemia on the hill.
Hypoglycaemia can develop quickly or slowly. If left untreated, it will cause irreversible brain damage. This is something we can treat, but it must be done so extremely urgently. For example, the diabetic we were called to had a BM of 1.6, and that was after having been given glucogel by a bystander!
We use the Blood Glucose Monitor to take a blood glucose reading to help us distinguish between the two.
Blood Glucose Readings
In a non-diabetic person, the normal level of blood glucose as shown on a glucose meter using the BM (Boehringer Mannheim) test is between 4 – 8 mmol/l if checked within two hours of a meal, or 4 – 5.5 mmol/l if fasting (occasionally a little lower – down to 3.5). In diabetics, although the fasting level should ideally be similar to a non-diabetic person, in many cases, it is higher if they are poorly controlled.
In all people, blood glucose levels rise and fall depending on the length of time since their last meal and the amount of activity undertaken. Very low readings below 3 mmol/l can occasionally be seen in healthy individuals if they have engaged in extreme prolonged exercise to the point of exhaustion. For example, a 25y non-diabetic male had a BM of 2.5, having done prolonged exercise with little food.
How to take a blood glucose (BM) reading
Open a testing strip. All strips should have been pre-calibrated for use with our tester, so you don’t have to worry about calibrating them.
NOTE: Be careful not to contaminate the strip by touching the sampling end when removing it from the packaging.
Insert the end of the strip with the small microchip strip into the BM tester.
The device should automatically turn on if the strip has been inserted correctly.
A picture of a drop of blood being placed onto the testing strip should flash on the screen.
Swab the skin from where the blood sample will be obtained with an antiseptic wipe. Note: contamination of the skin with sugary material will cause the BM to over-read.
One of the least painful sites to take a sample is said to be the outside of the little finger.
Take a lancet and carefully twist the grey tab until it comes out.
NOTE: Just keep twisting until it comes loose.Do not pull on the tab or you will fire the lancet and not be able to use it to draw blood.
Place the end from which the tab has been removed firmly against the casualty’s skin and press the trigger on the side of the lancet.
You should hear a click when it fires.
The needle will then retract back into the housing to prevent inadvertent injury to you.
Dispose of the lancet in a sharps box.
Gently squeeze the area around where you have just pricked them to bring out a drop of blood. Wipe away the first drop of blood with a dry swab.
Take the BM tester and hold the end of the testing strip against the second drop of blood while it takes up a sample. Then wait whilst it’s analysed.
After a few seconds a reading should appear on the screen.
Make a note of this on the cas card as the tester will automatically shut off after a minute (though the reading will be stored in the internal memory for future reference).
Cover the skin from where you took the sample with a swab, as it will continue to ooze for a minute or so.
Please note – the lancets can be unreliable and multiple attempts may be required in order to draw blood.
Hypoglycaemia
Terminology: the term ‘hypo’ is short for ‘hypoglycaemic attack’
Hypoglycaemia is more likely to be seen in MR than hyperglycaemia. It is very common in insulin-dependent diabetics (at least two per week in some cases). An estimated 2–4% of deaths of people with type 1 diabetes have been attributed to hypoglycaemia. To make matters worse for these people, warning signs and symptoms may not be exhibited at all, or until blood glucose levels are so dangerously low that they don’t have time to act. It’s as though they get used to running slightly low so they don’t register that glucose levels are dropping until very late.
It is not possible to define hypoglycaemia precisely on the basis of a specific blood glucose concentration in people with diabetes. People with poorly-controlled diabetes can suffer symptoms of hypoglycaemia at plasma glucose concentrations higher than those required to elicit symptoms in non-diabetic individuals
Hypoglycaemia can also develop in diabetics taking some oral anti-diabetic drugs. These drugs have a long duration of action so can cause severe, prolonged hypoglycaemia.
Hypoglycaemia can develop quickly or slowly. If left untreated and it gets worse, it will always cause irreversible brain damage.
IF LEFT UNTREATED, HYPOGLYCAEMIA WITH RESULT IN PERMANENT BRAIN DAMAGE
This is because brain cells require glucose to function. When blood glucose levels fall, the brain is no longer able to function. If the levels get very low, seizures will occur. If the hypoglycaemia is not relieved, permanent brain damage will result.
Hypoglycaemic seizures
These must be treated urgently with sugar first of all. If you can’t get sugar into them because of the convulsions, give glucagon.
Midazolam (see seizures for more details) may also be needed in addition to treating the hypoglycaemia, as the convulsions from the seizure will use up glucose and rapidly worsen the situation. However, the priority is to give sugar.
Causes of Hypoglycaemia
For a diabetic, the key to avoiding hypoglycaemia is to get the right balance between how much medication (particularly insulin) they take and how much food they eat. If the balance is in favour of the medication, then the blood glucose will fall. In addition to medication, a number of other factors can cause a fall in blood glucose levels. It is important that you understand this as it will help you manage a casualty with a low blood glucose:
Exercise (active muscles take glucose from the blood stream).
Exhausted individuals can have low blood sugar readings, and if extreme, can progress to clinically apparent hypoglycaemia.
Fasting (either complete food abstinence or insufficient food for the level of exercise being undertaken).
Shivering (muscle activity burns sugar).
Alcohol (increases insulin secretion and impairs glucose mobilisation in the body).
Many other non-diabetes drugs can be associated with a low blood sugar. For example atenolol (an angina drug) impairs glucose production in the liver and it reduces the signs and symptoms of hypoglycaemia so it is harder to diagnose.
A blood glucose reading in combination with the casualty’s history, signs and symptoms is key to determining a diagnosis of either hypo or hyperglycaemia.
History
Ask the casualty if they:
About their diabetes
Are a diabetic
Take insulin or tablets to control their illness
Have missed their normal dose?
Have taken too much insulin by accident?
Food
Have not eaten normally?
What and when did they last eat?
Are they very hungry?
How much have they exercised today?
Hypoglycaemia
Do they have a headache, dizziness, sweaty or blurred vision?
Have had a hypo in the past, and if so, what symptoms did they have
Have previously been admitted to hospital for a hypo?
Have ever been admitted to intensive care for treatment?
Look for a medic alert bracelet or necklace if they are confused or unconscious.
Symptoms
Symptoms usually start when blood sugar falls to around 3 mmol/l. However, some people will get symptoms at a higher blood sugar level if they normally run high due to poorly-controlled diabetes. Their body gets used to having a high glucose so that even a BM in the normal range will give symptoms of hypoglycaemia.
Typical symptoms of hypoglycaemia are:
Hunger
Yawning, tiredness and weakness
Being unsteady and tripping over their feet
Argumentative, irritable, aggressive, panicky or irrational behaviour
Difficulty with speech
Light-headed, blurred vision, confused or reduced level of consciousness
Adrenaline effects e.g. tremor, palpitations, anxiety
Warning: the typical signs of hypoglycaemia may be absent in the following situations
Symptoms of hypoglycaemia may be idiosyncratic and unique to a given individual. Thus, many people with diabetes learn their unique symptoms based on their experience – but you may not recognise them.
Some drugs, such as β-blockers, reduce the symptoms and signs of hypoglycaemia. If you’re not sure whether a drug that the casualty is taking could have this effect, get medical advice.
Insulin-dependent diabetics whose control is very tight (i.e. they adjust their dose of insulin to achieve a blood glucose that is normal), often lose their symptoms and thus manifest the syndrome of “hypoglycaemia unawareness”. The importance of this is that they tolerate very low levels of glucose without symptoms until it the blood glucose gets so low that the brain cannot continue. They then suddenly drop to the ground. One diabetic patient we rescued to told us that on a number of occasions, she suddenly collapsed in the street. When her BM was checked by the paramedics, it was <1 !!
Unconscious patient (for any reason, including hypoglycaemia)
Seizures already occurring.
THEREFORE IF IN DOUBT, ALWAYS CHECK BLOOD GLUCOSE
Typical symptoms of hypoglycaemia are also described in the diagrams below (note: the spelling in the cartoon below is the American way of spelling hypoglycaemia)
Signs
Look for:
BM below 3mmol/l
Sweating
Pale
Increased heart rate
Raised blood pressure
Severity
Because symptoms can vary between individuals, they are not a good guide to the severity of hypoglycaemia.
A simple rule is that hypoglycaemia is considered to be severe if the patient requires the assistance of another person to deal with it.
It is important not to define “severe” by a precise BM reading for two reasons: (1) The actual level can be different in different people; (2) There is a risk that if the casualty’s BM is slightly higher, you might erroneously discount hypoglycaemia as the cause of their illness.
Rule 1
If they have symptoms of any sort that could be due to hypoglycaemia, give sugar, even before checking the BM.
Rule 2
Check BM. If it is <4 mmol/l, give sugar.
REMINDER: In severe cases this is a Medical Emergency as urgent as cardiac arrest
Treatment
Significant hypo- and hyperglycaemia both cause impaired conscious level.
If you are unsure which the casualty is suffering from, give sugar. No harm will be done by giving sugar to someone whose BM is high.
Treat low blood glucose readings IMMEDIATELY
In mild hypoglycaemia (BM 3-4 mmol/l), the casualty should be able to take things orally so it is usually sufficient just to give foods that release sugar quickly e.g. dextrose tablets. Give as much as is needed to improve conscious level.
If the casualty is unable to eat, then use a fast acting sugar solution such as Glucogel. This is used buccally and absorbed rapidly through the lining of the mouth.
In severe hypoglycaemia (as defined above), give glucagon (I.M injection) as well to mobilise glucose stored in the liver (see below for more information about glucagon). If the casualty is unconscious, place them into the recovery position and then use a gloved finger to rub Glucogel into the gums.
Beware: Glucogel can pool and block the airway in unconscious and semi-conscious casualties. Do not give excessive amounts at a time and monitor for airway problems.
Glucogel and glucagon must always be followed up by the administration of slower release sugar in the form of food. This is because the fast acting forms wear off quickly so that some time later, the blood glucose levels will drop back again. Use slow release foods such as bread (sandwiches), cereals, biscuits, peanuts etc.
Remember – shivering uses lots of energy so try to keep the casualty warm to help them conserve energy. In addition, people who have had a hypo are always cold. It’s a simple response by the body to reduce the metabolic rate (and therefore heat production) to conserve energy.
If hypoglycaemic seizures occur:
Give sugar first
If you can't give sugar give glucagon
Treat with midazolam (if necessary) AFTER you have started to treat the hypo.
The seizures will stop on their own once the blood sugar returns towards normal.
Never give midazolam alone to a hypoglycaemic patient with seizures.
Glucagon
Glucagon is a hormone produced naturally in the body by the pancreas. In fact it is produced alongside insulin.
The normal doses of glucagon are 1 mg (the whole vial) IM if >12 years old and 0.5 mg (half the vial) IM for children under 12. It will also work if given just under the skin (subcutaneously). Glucagon takes about 15 minutes to work so it isn’t quick.
After treatment with glucagon, the casualty should [start to] recover in around 10-15 minutes.
Whilst they are unconscious, turn them into the recovery position.
How to prepare and administer Glucagon
Glucagon is supplied as a powder which has to be mixed with the contents of the syringe (see below).
Give food on awakening. The effects of glucagon will wear off after about 90 minutes.
Glucagon can cause nausea and vomiting, but this will settle fairly quickly. However, while it is present, it will interfere with providing food or liquid. It can also cause a rapid heart rate.
If glucagon has not worked after 15 minutes:
Make sure you have the right diagnosis. If in doubt, check the BM in case there was an error when you did the reading the first time and something else is causing the unconsciousness.
The manufacturers state that a second dose can be given. However, intravenous glucose would be preferable, but this will have to be given by a healthcare professional.
When re-checking BM in this situation, prick a different site on the body to get the blood sample.
Beware – Glucagon is much less effective in some situations:
A hypothermic or severely exhausted casualty (because their sugar reserves are used up).
Prolonged fasting (for the same reason)
Excess alcohol consumption
If the casualty has inadvertently taken an overdose of insulin
Signs of Improvement
Look for:
Recovered consciousness – this is the most important
Increased BM reading
Heart rate returning to normal
It is important to continue to monitor casualties with hypoglycaemia even after they recover. Get them to eat and drink regularly to avoid another fall in blood glucose (known as rebound hypoglycaemia)
.
Hyperglycaemia
Hyperglycaemia only occurs in diabetics. It takes some time (hours to days) to develop to dangerous levels and will often be self-managed. Hyperglycaemia is very rare in MR. If you are called specifically for this, it is likely to be severe.
Patients with severe hyperglycaemia usually have a triggering cause such as:
Infection
Heart attack
Not taken the right dose of insulin
Drug abuse
History
Typical symptoms:
Frequent urination
Increased thirst
Blurred vision
Fatigue
Headache
Very high BM (can be in the 50’s)
In semi-conscious or unconscious cases:
Dehydration (can be 10 litres down)
Fast heart rate
Hyperventilation
Abdominal tenderness
Reduced level of consciousness (despite high blood glucose levels, the brain can’t use it without insulin)
Pear drop smell on the breath
Treatment
As a general rule, immediate evacuation to hospital, regardless of conscious level. However, the final decision will depend on how ill the patient is and how long they have been that way.
Severe Cases
In very ill patients, particularly those who are semi-conscious or unconscious and have been ill for many hours, the only things we can offer on the hills are:
Airway management (if they are unconscious)
Oxygen (if a chest infection could have triggered the diabetic instability)
Team members who can cannulate can give 1000 ml saline intravenously in young patients. In older patients, just give 250 ml.
Immediate evacuation to hospital.
Do not give them a load of water to drink. This will dilute the electrolytes (sodium; potassium; etc.) in their already depleted circulation.
IMPORTANT – Even if it is available, you must NEVER give any insulin (NO EXCEPTIONS!). The fall in blood sugar will be uncontrolled and it will be accompanied by a drop in potassium levels which can cause a life-threatening arrhythmia.
Mild Cases
In patients who are basically well but whose BM is just starting to rise, we have a bit more flexibility. For example, the casualty we were called to that had a BM of 17.3 mmol/l because her insulin pump had failed. However, just after we arrived, she discovered a replacement cassette in her rucksack so she gave herself some insulin. This is entirely acceptable. The lady was fully conscious, her blood sugar had only started to rise over the last 3-4 hours so it was still very early in the process, and she had a very good understanding of her condition and was well used to managing it. She knew exactly what needed to be done. By the time we got her down to the vehicles, her BM was down to 13.3 mmol/l and she was feeling much better. If we had intervened and prevented her from self-administering insulin, we would have done her a major dis-service.