By Dr Ananya Mandal, MD
Hypoglycaemia refers to low blood glucose that occurs as a reaction to various stimuli in patients with diabetes mellitus. This occurs when the blood glucose drops below the normal level. Levels of blood glucose below 70 mg/dl are considered below normal.
Mechanism of hypoglycaemia and its symptoms
Hypoglycaemia occurs when there is not enough glucose in the blood to provide the energy the body requires.
This means that the brain is also deprived of glucose. This may cause convulsions/seizures and unconsciousness. Although most of the cells in the body may make do with fatty acids or other fuels for energy, the neurons in the brain need glucose for energy.
The brain does not require insulin to absorb glucose, unlike muscle and adipose tissue, and they have very small internal stores of glycogen. Glycogen in the liver cells may be broken down to glucose and released into the blood when glucose levels are low.
Low glucose is called hypoglycaemia and very low levels of glucose may produce unconsciousness or hypoglycaemic coma (also termed insulin shock). When there is excessive insulin in the body like in insulinomas or insulin producing cell tumors that clinical manifestations may include these insulin shocks. This is a less common reason for hypoglycaemic coma though.
Most of the cases are caused due to insulin overdoses or accidental excess insulin in blood. There have been a few reported cases of murder, attempted murder, or suicide using insulin overdoses
Insulin hypoglycaemia causes
Causes of insulin hypoglycaemia include:
Those on insulin who:
- Did not have their meal or snack on time or skipped or delayed a meal
- Did not eat enough
- Took more insulin or diabetes medicine than needed for the meal
- Exercised or were more active than usual
- Drank alcohol but skipped a meal
Symptoms of hypoglycaemia
The signs and symptoms of hypoglycemia are mild, moderate or severe. These can be listed as:
- Mild Hypoglycemia – this is seen in early stages of lowered blood glucose. Symptoms include:
- Rapid heart rate
- Blurred vision
- Numbness or tingling around mouth and lips
- Moderate Hypoglycemia – this stage occurs if the early stages are not treated. Symptoms include:
- Mood swings
- Lack of concentration
- Slowing and slurring of speech
- Poor coordination
- Severe Hypoglycemia – there may be convulsions/seizures or unconsciousness. These patients need to be taken to the hospital immediately and require emergency treatment.
Some diabetics on therapy for very long may develop hypoglycemic unawareness. These persons do not feel the symptoms of hypoglyecemia unless the levels are too low. The first symptoms may be those of severe hypoglycaemia – convulsions or passing out.
How can insulin hypoglycaemia be treated?
Signs and symptoms of hypoglycemia vary from person to person. Those with diabetes should get to know their signs and symptoms and be aware of their symptoms. Those with frequent attacks of hypoglycaemia may need a change in their insulin therapy plan.
Usual immediate treatment includes a blood sugar check and one of the following treatments:
- 3 or 4 glucose tablets
- 15gms of glucose equivalent
- 4 ounces (half a cup) of any fruit juice
- 4 ounces (half a cup) of a regular (not diet) soft drink
- 8 ounces (a cup) of milk
- 5 or 6 pieces of hard candy
- 1 tablespoon of sugar or honey
The next step is to recheck blood glucose in 15 minutes to make sure it is 70 mg/dL or above. If the level continues to be low the emergency foods need to be re-administered. If the next meal is an hour or more away, a snack should be eaten once the emergency foods have raised the blood glucose level to 70 mg/dL or above.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)
Last Updated: Nov 4, 2012