The brain uses a lot of energy and needs glucose to function. Because the brain cannot store or manufacture glucose, it needs a continuous supply.
The typical signs of low blood sugar include hunger, trembling, heart racing, nausea, and sweating. Hypoglycemia is commonly linked with diabetes, but many other conditions can also cause low blood sugar.
In this article, we will discuss the causes, diagnosis, and treatment of hypoglycemia. We will also look at ways of preventing it from occurring.
Fast facts on hypoglycemia
Here are some key points about hypoglycemia. More detail and supporting information is in the main article.
- hypoglycemia is not a disease, it is caused by other conditions
- early symptoms of hypoglycemia can include hunger, sweating, and trembling
- a common cause of hypoglycemia is diabetes
- alcohol abuse and kidney disorders can also lower blood sugar levels
Symptoms of hypoglycemia
Common symptoms of hypoglycemia include dizziness and tremors.
Early signs and symptoms of mild hypoglycemia (in adults and children) usually include:
- tremor (trembling/shakiness)
- irritability, perhaps argumentative
- pallor (face goes pale)
- heart palpitations
- accelerated heart rate
- tingling lips
When hypoglycemia is more severe, sometimes called diabetic shock, the following signs or symptoms may occur:
- concentration problems
- irrational and disorderly behavior (similar to somebody who is drunk)
- unable to eat or drink
- seizures (uncommon)
- loss of consciousness (uncommon)
- coma (uncommon)
Some people experience low blood sugar during the night; signs that this might be happening include:
- crying out in the night
- feeling tired or irritable when waking
- sweating during the night more than would be expected
Treatment for hypoglycemia
There are two possible treatment approaches for hypoglycemia:
- Immediate treatment - treating the abnormally low blood sugar attack (hypoglycemia).
- Treating the underlying cause.
A patient with abnormally low blood sugar needs to eat or drink something with sugar as soon as possible to end the hypoglycemia attack.
For rapid results, glucose tablets, sugar lumps, sweets, or a glass of fruit juice are ideal. This should be followed by slower-release carbohydrates, such as cereals, bread, rice, or fruit. If an individual with diabetes has checked their blood glucose and treated the hypoglycemia they should wait 15-20 minutes and check their blood sugar again. If the blood glucose is still low, the process should be repeated - eat some glucose, wait about 15-20 minutes, then check blood sugar again.
It is important for people with diabetes to stick to regular eating times - this is vital for keeping blood glucose levels as stable as possible.
If hypoglycemia symptoms are severe, and the individual cannot treat themselves, somebody else will need to apply honey, treacle, jam, or Glucogel to the inside of the cheeks and then gently massage the outside of the cheeks.
The individual should start feeling better within 10-20 minutes.
If the patient loses consciousness, they should be placed into the recovery position and administered a glucagon injection - this should be done by a qualified healthcare provider, or somebody who knows what to do. If this is not possible, the patient must be taken to the emergency department of a hospital urgently.
If the patient has lost consciousness, solids or liquids (food or drink) should not be placed into their mouths as it could block their airways.
Causes of hypoglycemia
Hypoglycemia can occur for several reasons. It often happens when a person with diabetes takes too much insulin.
Blood sugar regulation
The digestive system breaks down carbohydrates from the food we eat into different types of sugar molecules, one of which is glucose - the body's main source of energy.
Glucose enters the bloodstream after we eat. However, glucose needs insulin - a hormone produced and excreted by the pancreas - before it can enter a cell. In other words, a cell would starve of energy if there were no insulin around, regardless of how much glucose there was.
After eating, the pancreas automatically releases the right amount of insulin to move the glucose in our blood into the cells, therefore lowering the blood sugar level. Any surplus glucose goes into the liver and muscles in the form of glycogen (stored glucose).
Insulin is responsible for bringing excess blood sugar levels back to normal.
If glucose levels have dropped because an individual has not eaten for a while, the pancreas secretes glucagon - another hormone - which triggers the breakdown of stored glycogen into glucose, which is then released into the bloodstream, thus bringing glucose levels back up.
Hypoglycemia and diabetes
People with type 1 diabetes do not produce insulin, while those with type 2 diabetes have cells which do not respond properly to insulin - they both tend to suffer from rising blood-glucose levels, meaning that cells do not get enough energy.
People with both types of diabetes usually need to take medication such as insulin or other drugs to bring their blood sugar levels down.
If a person with diabetes takes too much insulin, their blood sugar levels can drop too low - this is hypoglycemia.
A person who takes insulin may take a normal amount of insulin for that time of day, but may have eaten much less than usual, or done exercise - meaning that their insulin requirement for that moment is lower than usual.
In other words, taking too much insulin does not necessarily mean that the patient increased the dosage; it just means that the insulin taken in was more than the body needed at that moment.
This can also happen when taking other types of diabetes drugs that cause the body to release too much insulin from the pancreas.
Other causes of hypoglycemia
Some medications - if somebody who does not have diabetes takes diabetes medication they may develop hypoglycemia. Quinine, a drug used for malaria, can also cause hypoglycemia. Taking high doses of salicylates, which are used for treating rheumatic disease, or propranolol for hypertension (high blood pressure) may also trigger a serious drop in blood sugar levels.
- Alcohol abuse - the liver can stop releasing stored glucose into the bloodstream if somebody has been drinking heavily.
- Some liver diseases - drug-induced hepatitis can cause hypoglycemia.
- Kidney disorders - people with kidney disorders may have problems excreting medications, this can result in abnormally low blood sugar levels.
- Not eating enough - people with eating disorders, such as anorexia nervosa, may find that their blood sugar levels drop dramatically.
- Insulinoma - this is a tumor in the pancreas which can make the pancreas produce too much insulin.
- Increased activity - increasing the amount of physical activity one carries out can lower blood sugar levels for some time.
- Endocrine problems - some disorders of the adrenal and pituitary glands can lead to hypoglycemia. Children with these disorders are more likely to develop abnormally low blood sugar levels than adults.
- Reactive hypoglycemia (postprandial hypoglycemia) - this is when the pancreas produces too much insulin after a meal.
- Tumors - tumors in other parts of the body (not the pancreas) can cause hypoglycemia. This is very rare.
- Severe illness - during times of critical illness, many different organs can be affected, including the pancreas; this can lead to hypoglycemia.
Diagnosis of hypoglycemia
Diagnosis of hypoglycemia is done by measuring blood sugar levels.
Anybody who has a hypoglycemic attack, but does not know why, should see a doctor as soon as possible. The doctor will probably order a blood test to measure blood sugar levels.
They will also ask about symptoms, and whether they improve after the hypoglycemia has been corrected (after blood sugar levels return to normal).
The doctor will need to check the patient's medical history, whether he/she has been taking any medications, and whether there have been any recent bouts of heavy drinking.
This is a collection of three criteria - known as Whipple's criteria - that suggest an individual's signs and symptoms are caused by a pancreatic tumor. The three criteria of Whipple's Triad are:
- signs and symptoms of hypoglycemia
- at the time of symptoms, a blood test showed low plasma glucose levels
- when glucose is raised to normal levels, symptoms go away
Some patients may not show signs and symptoms during their initial doctor's visit. If this is the case, the patient may be asked to fast for a specified period, usually overnight. This allows hypoglycemia to occur so that a diagnosis can be made.
Some patients may have to be hospitalized and undergo a longer period of fasting. If the patient exhibits symptoms after having something to eat, blood sugar levels will need to be tested after eating.
- Checking blood glucose levels - this involves keeping a regular check on blood sugar levels and knowing how to identify the onset of symptoms.
- Eat regularly - keep to an eating routine.
- Alcohol - a heavy drinking session can trigger hypoglycemia. Individuals with type 1 diabetes should stick to the daily alcohol limits recommended by a doctor, and eat something after having a drink.
- Exercise - eat carbohydrate-rich food before exercising.
- Be ready - children with type 1 diabetes should always carry a container of sugary fruit juice or a candy bar so that they are ready if symptoms are felt.
- Let people know - if someone is susceptible to attacks of hypoglycemia, friends, colleagues, and family members should be made aware.
- ID - individuals with diabetes should carry an ID form. If anything happens, healthcare providers, emergency services, and others will know what to do sooner.
- Individuals with diabetes - follow the diabetes management plan carefully.
- Individuals without diabetes that have episodes of hypoglycemia - eat small quantities of food frequently throughout the day.