Hypoglycaemia (low blood sugar)

and Carola Felchner, science journalist

Marian Grosser studied human medicine in Munich. In addition, the doctor, who was interested in many things, dared to make some exciting detours: studying philosophy and art history, working on the radio and, finally, also for a Netdoctor.

More about the experts

Carola Felchner is a freelance writer in the medical department and a certified training and nutrition advisor. She worked for various specialist magazines and online portals before becoming a freelance journalist in 2015. Before starting her internship, she studied translation and interpreting in Kempten and Munich.

More about the experts All content is checked by medical journalists.

Hypoglycemia is the medical term for low blood sugar. A blood sugar level that is too low is particularly dangerous for the brain because it relies on sugar as an energy source. The body reacts to the deficiency with stress symptoms such as sweating, racing heart and tremors. Severe hypoglycaemia is even life-threatening. Diabetics in particular are repeatedly affected by this. Read everything you need to know about the causes, symptoms, and treatment of hypoglycemia.

Brief overview

• What is hypoglycemia? Hypoglycaemia, i.e. a drop in the blood sugar level below 50 mg / dl
• Symptoms: i.a. Trembling, racing heart, pale skin, cravings, possibly nausea, headache, difficulty concentrating
• Causes: Hypoglycemia occurs when the body uses more glucose than is available. Possible triggers are e.g. diabetes mellitus and other metabolic disorders, hormonal disorders, intolerances, medication.
• First aid: The blood sugar level can often be normalized again with sweetened drinks or glucose. In severe cases, an infusion may be necessary.
• Dangers: Severe hypoglycaemia can lead to seizures, paralysis, respiratory and circulatory disorders and unconsciousness. In extreme cases, severe hypoglycaemia can be fatal.

Hypoglycemia: description

Hypoglycemia (colloquially: low blood sugar) is when the concentration of blood sugar (glucose) falls to values ​​below 50 milligrams per deciliter (mg / dl).

Normally, in healthy people, various hormones ensure that the glucose concentration in the blood remains within a certain range. In the fasted state, it is between 70 and 100 mg / dl.

If the blood sugar drops too low, various symptoms occur such as restlessness, cravings, tremors and palpitations, later also confusion and finally coma.

When hypoglycaemia becomes noticeable varies from person to person. In some people, the signs of hypoglycaemia appear at levels well above 50 mg / dl, while others do not feel any symptoms even at lower levels.

Prevent hypoglycemia

Diabetics are more likely to suffer from hypoglycaemia. Unfortunately, they feel the symptoms of hypoglycaemia late or not at all. It is all the more important that those affected know in which situations the blood sugar levels could be too low.

In special training courses - carried out either by a doctor or a diabetes advisor - people with diabetes learn how to recognize an impending hypoglycaemia in good time and how to react to it correctly.

Hypoglycemia: symptoms

A low level of sugar means great stress for the organism. Above all, the body must ensure the supply of the brain, which is dependent on glucose as an energy carrier. In addition, it accelerates glycogenolysis (breakdown of glycogen into glucose) and the formation of new sugar (gluconeogenesis). This is achieved by the fact that the adrenal glands increasingly release the stress hormones cortisol and adrenaline into the blood.

The typical symptoms of hypoglycaemia develop as a result:

• Dizziness
• internal restlessness and irritability
• sudden sweating (cold sweat)
• Tremble
• Pale skin
• Palpitations and an increase in blood pressure
• Cravings, sometimes nausea and vomiting

Symptoms of severe hypoglycaemia

The lack of glucose in the brain can also cause neurological symptoms as the hypoglycaemia progresses. Signs are then:

• headache
• Fatigue and weakness
• Difficulty concentrating and disorientation
• Speech disorders
• Paralysis, rarely even symptoms of paralysis
• Unconsciousness, fainting
• Seizures
• Coordination problems

Hypoglycaemia: Symptoms During Sleep

Many diabetics are afraid of falling into hypoglycaemia while sleeping. In fact, hormonal counter-regulation does not work as well at night as it does when awake. The symptoms of hypoglycaemia at night are the same as during the day. However, most of the time the sleeper does not notice it, but only sleeps badly. So if you feel inexplicably exhausted during the day, you should talk to your doctor about it. It may be due to a nightly drop in blood sugar. Then it can help to adjust the dosage of the diabetes medication (especially the basal insulin), to have a bite to eat before going to bed and to avoid exercise and alcohol late in the evening.

Hypoglycemia: causes and possible diseases

Hypoglycaemia always occurs when the body uses more glucose than it has available. Normally, when blood sugar levels drop, hormones trigger the release of glucose from stores (that is, the breakdown of glycogen), causing blood sugar levels to rise again. However, this mechanism can be disrupted - either because hormonal regulation is not working or because glycogen stores are empty.

Even if the blood sugar is used up very quickly, e.g. B. Exercise, the result is sometimes hypoglycaemia. Exercise in diabetes is safe if you eat enough.

There are many possible causes of hypoglycemia. Most often, however, diabetics are affected. Often, however, other metabolic disorders, hormonal disorders and liver diseases are also the triggers for hypoglycaemia.

Hypoglycemia in diabetics

The fact that people with diabetes mellitus slip relatively often into hypoglycemia seems illogical at first sight. Because with diabetics the problem is actually a permanently increased glucose level in the blood, because the blood sugar lowering hormone insulin either no longer works properly or is produced in too small quantities. So why can diabetics have too low blood sugar?

Medication application error

Mostly (but not always) mistakes in therapy are to blame. Diabetes is treated with drugs that lower blood sugar - oral hypoglycemic drugs and / or insulin injections.

In the case of oral diabetes drugs, the so-called sulfonylureas (such as glibenclamide) in particular can cause hypoglycaemia in the event of an overdose. The drugs stimulate the pancreas to release more insulin into the blood.

Diabetic people usually administer insulin injections themselves. They always have to adjust the dosage according to how many carbohydrates a planned meal contains and how physically active they are. However, if patients inject too much insulin (for example because they overestimate the amount of carbohydrates in a meal or are unusually active), hypoglycaemia can result.

In the case of insulin, however, it is not only the amount administered that is relevant, but also the time before food is injected. If it is injected too early or gastric emptying is delayed due to a high fat or protein content, the blood sugar level will drop before new glucose gets into the blood. However, hypoglycaemia can also occur if a diabetic injects mealtime insulin but then does not eat anything.

It is also important that the patient always injects the insulin into the subcutaneous fat and not accidentally into the muscle. Because from there the hormone might get into the bloodstream too quickly.

Hypo from alcohol

Some factors can further reduce the level of glucose in the blood. Alcohol, for example, reduces the release of glucose from the liver and thus increases the risk of hypoglycemia.

Hypoglycaemia: Exercise

Physical exertion and sport also lower the blood sugar level and thus the need for insulin or blood sugar-lowering tablets. The result is sometimes hypoglycaemia.

Hypoglycaemia: thyroid gland

The thyroid can also play a role. Hypoglycaemia can "accidentally" occur in the case of an underactive thyroid gland (as yet undiscovered). This is because the malfunction improves the cells' insulin sensitivity, so that the blood sugar gets into the cells more quickly.

Excessive insulin production

In type 2 diabetes mellitus, insulin production is often increased at the beginning of the disease. The body tries to compensate for the reduced effectiveness of the hormone. After eating, the excess amount of insulin transports too much of the accumulating glucose into the cells. This phenomenon is known as postprandial hypoglycemia.

Hypoglycemia without diabetes

Although it usually occurs in connection with diabetes, hypoglycaemia is also possible without diabetes.

Hormonal causes of hypoglycaemia

Various hormonal disorders can trigger hypoglycaemia, which usually occurs together with other symptoms. For example, hypoglycaemia can be due to an underactive adrenal cortex. This produces various hormones, including cortisol and adrenaline. Both help the body counteract hypoglycemia. If the hormone production in the adrenal gland is impaired, this effect does not occur.

The adrenal cortex does not work independently, but is controlled by the pituitary gland (pituitary gland). If their function is restricted, the adrenal cortex also produces fewer hormones. In addition, TSH and somatotropin are formed in the pituitary gland - two hormones that directly or indirectly increase blood sugar levels. An underactive pituitary is therefore often associated with hypoglycaemia.

Insulinomas are rare, mostly benign tumors in the pancreas that produce more and more insulin in an uncontrolled manner. Those affected repeatedly suffer from initially inexplicable hypoglycaemia.

Glucagon is particularly important for increasing the concentration of glucose in the blood. However, a glucagon deficiency alone as the cause of hypoglycaemia rarely occurs.

Hypoglycemia from fasting and dieting

An improper diet can also lead to hypoglycaemia - especially extreme fasting and diets that are too strict. But if you skip a meal, you don't have to worry about slipping into threatening hypoglycaemia. The body usually has enough reserves to make up for a temporary lack of glucose. However, if there are additional risk factors such as previous alcohol consumption or the use of certain medications, you should ensure that carbohydrates are replenished in good time.

Other causes of hypoglycemia without diabetes

There are many other triggers of hypoglycemia, for example:

• severe liver disease in which the breakdown of glycogen and the formation of new glucose are impaired. The body cannot compensate for low blood sugar.
• Disorders of the carbohydrate metabolism: These include, for example, diseases in which the build-up of glycogen and thus the storage of glucose is disturbed (glycogenoses).Fructose intolerance (fructose intolerance) also often leads to hypoglycaemia.
• Too much sugar in one fell swoop: If you ingest a lot of sugar at once, the body reacts by releasing a large amount of insulin. This can lead to an excess of the hormone, which then lowers the blood sugar level too much - what is known as reactive hypoglycemia. In this way, hypoglycaemia can occur in healthy people.
• Dumping Syndrome: This phenomenon occurs mainly in people who have had part of their stomach removed. The food pulp then suddenly enters the intestine in large quantities. As a result, large amounts of glucose accumulate in the blood, which leads to an excessive release of insulin and, after a few hours (which is why the exact term is "late dumping"), leads to hypoglycaemia.
• Impaired food intake: There are diseases that prevent the body from absorbing enough glucose from the intestines. One example of this is celiac disease - a form of gluten intolerance that damages the intestinal lining.
• Medicines such as certain sulfonamide antibiotics and some beta blockers can also trigger hypoglycaemia. Normally, the use of these drugs alone does not cause hypoglycemia. This only arises in interaction with other risk factors.
• Chronic alcohol abuse: On the one hand, alcoholics are often malnourished; on the other hand, alcohol itself causes blood sugar levels to drop.
• Diabetes during pregnancy: The fetus gets used to the excessively high glucose levels in the mother's blood and produces more insulin. After the birth, this excess insulin leads to hypoglycaemia in the child for a few days.

Hypoglycemia: what to do if you have hypoglycaemia?

Slight hypoglycaemia in non-diabetics (with dizziness, paleness, palpitations, but fully conscious) can often be remedied by simple measures: Give the person concerned glucose and / or sugary drinks (e.g. sweetened tea, cola) and make them calm Surroundings. He then usually recovers quickly. If not, call an ambulance.

If the hypoglycaemia is more severe and the person concerned has lost consciousness, you must bring him into a stable lateral position and call the emergency doctor immediately!

First aid for diabetics

Diabetics are particularly likely to suffer from hypoglycaemia. Many are prepared for such an emergency by always having a blood glucose meter close at hand. If there are signs of hypoglycaemia, you should first measure your blood sugar level in order to determine the extent of the glucose deficiency. The further procedure depends on the measurement result:

First aid for mild hypoglycaemia (40 - 50 mg / dl)

Diabetics can still help themselves if they have a low level of sugar:

• Eat some glucose (around 20 grams is recommended).
• Alternatively, you can drink a glass (approx. 200 ml) of sweetened tea, fruit juice, cola or lemonade (no light products, of course!).
• Measure the blood sugar level again after 15 minutes. If it is still not higher than 50 to 60 mg / dl, you should consume glucose or sugared drinks again.
• If the blood sugar level has improved, you should stabilize it by having a small meal containing carbohydrates, e.g. B. fruit, bread, sweetened yogurt.

First aid for severe hypoglycaemia (<40 mg / dl)

In severe hypoglycemia, diabetics rely on outside help from first aiders. If the diabetic is still conscious, the first aid is similar to the one above: supply of approx. 30 grams of quickly digestible carbohydrates (preferably in the form of glucose or sweetened drinks), blood sugar control, stabilization of the blood sugar level with a small meal.

If the diabetic is unconscious, you should react as follows:

• Call an ambulance immediately.
• Place the unconscious person in the stable side position.
• Remove leftover food or loose dentures from the victim's mouth.
• Inject 1 milligram of glucagon under the skin or into a muscle (e.g. thigh muscle), if available.
• If the person with hypoglycaemia regains consciousness, give him glucose or sweet drinks.

Warning: Never try to give anything to an unconscious person! There is a risk of suffocation!

Hypoglycemia: what does the doctor do?

Pronounced hypoglycemia is a potentially life-threatening condition that should always be treated by a doctor. Because if it progresses, the hypoglycemia ultimately leads to what is known as hypoglycemic shock. The affected person then becomes unconscious and can fall into a coma. In the event of impaired consciousness with a suspicion of hypoglycaemia, you should therefore always call an emergency doctor.

Medical history (anamnesis)

Since the symptoms of hypoglycaemia can also occur in other diseases, a doctor will first obtain important information about the patient's history (anamnesis). For example, he asks about existing underlying diseases (such as diabetes), the use of medication and previous alcohol consumption.

Blood glucose testing

A quick measurement of the blood sugar level is also important. For this purpose, portable devices are available that can reliably determine the current sugar level within a few minutes from a small drop of blood.

glucose

If the suspicion of hypoglycaemia is confirmed, the doctor will administer glucose to the patient. As long as he is still conscious and responsive, he can absorb it in the form of glucose or sugary drinks. If nothing else is at hand, sweets will do the same, for example candy. However, depending on the composition, it then takes longer for the blood sugar level to rise.

Glucose Infusion

If you have severe hypoglycaemia with impaired consciousness or if you have nausea and vomiting, the doctor must give the glucose as an infusion directly into the vein. During the infusion, he regularly checks the patient's blood sugar levels to avoid overdosing.

Administration of glucagon

Another way to raise blood sugar levels quickly is to give glucagon. However, this only works if the glycogen stores are not empty, i.e. the patient has not fasted for a long time or has physically exerted a lot. Glucagon also does not work in patients with disorders of the glycogen metabolism (glycogenosis) or after extensive alcohol consumption.

Important investigations

Various examinations help the doctor to find out the cause of the symptoms. These include, for example:

• special X-ray examination of the biliary tract, gall bladder and ducts of the pancreas (ERCP)
• H2 breath test
• Urine test

Hypoglycemia: dangers of hypoglycaemia

Severe hypoglycaemia (blood sugar <40 mg / dl) can have serious consequences. There is a risk of seizures and paralysis, respiratory and circulatory disorders and unconsciousness. Sometimes such severe hypoglycemia ends in a coma.

When is hypoglycemia deadly?

There is no clear threshold from which hypoglycaemia ends in death. The individual constitution and the duration of the hypoglycaemia are decisive.

However, fatal courses in hypoglycaemia are quite rare. According to statistics, severe hypoglycaemia does not even occur in one in 100 type 2 diabetics per year. However, they are more common in the much rarer type 1 diabetes.

People over the age of 70, patients with kidney failure, patients who have to take a lot of medication and people who eat poorly are particularly susceptible to severe hypoglycaemia and its consequences.

This is how the body regulates blood sugar

Every cell in our organism has to be supplied with energy. The body gains this energy by utilizing various nutrients. The most important of these energy sources is the sugar molecule glucose. Carbohydrates that humans take in with food are nothing more than such sugar compounds. Most of them are broken down into glucose while still in the digestive tract, which is then absorbed into the bloodstream.

The body also has other options for generating energy, for example by breaking down fat and protein. But the direct intake of carbohydrates is very important, especially for a quick energy supply.

In addition, there are cells that obtain their energy exclusively through the breakdown of glucose (glycolysis). These include, above all, the nerve cells in the brain and spinal cord. They are therefore vitally threatened with hypoglycemia.

How is blood sugar controlled?

It is important that the blood sugar level remains constant within a narrow range, i.e. neither too low nor too high. With hypoglycemia, the body lacks the necessary energy supply. On the other hand, excessively high glucose concentrations lead in the long term to a wide variety of damage, especially to blood vessels and nerve cells.

Control hormones: insulin and glucagon

The control of the blood sugar values ​​is usually done automatically via hormones, primarily via insulin and glucagon:

• Insulin is the only hormone that can lower the level of sugar in the blood. It is produced by the pancreas and ensures that glucose is absorbed in muscle, fat and liver cells. In muscle and liver cells, numerous glucose molecules combine to form what is known as glycogen, the storage form of sugar. The body releases insulin mainly after ingesting food because larger amounts of glucose then enter the blood from the digestive tract.
• Glucagon is, so to speak, the antagonist of insulin. It causes the blood sugar level to rise by causing the breakdown of glycogen into individual glucose molecules (glycogenolysis). These then pass from the cells into the blood. In addition, glucagon promotes gluconeogenesis, i.e. the new production of glucose from protein building blocks (amino acids).

Other hormones that cause blood sugar levels to increase are adrenaline, cortisol, the growth hormone somatotropin (STH) and the thyroid hormone thyroxine.

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