Hypoglycaemia

Hypoglycaemia, also known as low blood sugar, is a condition characterised by a fall in blood sugar to levels below 70 mg/dL (3.9 mmol/L). This condition is particularly important for medical professionals, including dentists, to understand due to its rapid onset and potential severity. The condition can cause symptoms ranging from mild discomfort to life-threatening complications.

Signs and Symptoms

Hypoglycaemic symptoms are categorised into neuroglycopenic symptoms and adrenergic symptoms. Neuroglycopenic symptoms result from low glucose levels in the brain and include headache, blurred vision, tiredness, unusual behaviour, confusion, lightheadedness, difficulty speaking, seizures, and loss of consciousness. Adrenergic symptoms are caused by the body's reaction to low glucose in the brain and include fast heart rate, pounding heartbeat, sweating, clamminess, tremors, nervousness, hunger, irritability, nausea, pins and needles sensation, and pale skin colour.

Diagnosis

The diagnosis of hypoglycaemia relies on Whipple's triad: the presence of hypoglycaemic symptoms, a blood glucose measurement below 70 mg/dL (3.9 mmol/L), and resolution of symptoms after blood glucose levels return to normal. For those without a history of diabetes, further blood tests, including insulin, C-peptide, proinsulin levels, and an oral hypoglycaemic agent screen, may be necessary.

Causes

Diabetics

For diabetics, hypoglycaemia is most commonly caused by medications used to treat diabetes, such as insulin, sulfonylureas, and biguanides. Other contributing factors include fasting, increased physical activity, alcohol consumption, and kidney disease. Recurrent episodes can lead to hypoglycaemic unawareness, where symptoms present at dangerously low blood glucose levels.

Non-Diabetics

In non-diabetics, causes include serious illnesses (e.g., sepsis, liver, and kidney failure), medications, surreptitious insulin use, alcohol misuse, hormone deficiencies, inborn errors of metabolism, insulinomas, non-B cell tumours, post-gastric bypass postprandial hypoglycaemia, autoimmune hypoglycaemia, and neonatal hypoglycaemia.

Treatment

Self-Treatment

For conscious individuals, self-treatment involves consuming 10–20 grammes of a carbohydrate to raise blood glucose levels to a minimum of 70 mg/dL (3.9 mmol/L). Suitable options include glucose tablets or gel, sugary juice, soft drinks, candy, or honey. Blood glucose should be measured after 15–20 minutes to ensure levels have normalised.

Assistance by Family, Friends, or Co-Workers

Family, friends, and co-workers of diabetics should be educated on recognising hypoglycaemia and administering quick treatments. If the hypoglycaemic person is unconscious, a glucagon kit may be used, and emergency services should be called immediately.

Medical Treatment

In healthcare settings, treatment depends on symptom severity and intravenous access. Conscious patients may receive food, drink, or glucose tabs or gel. Intravenous access allows for the administration of 25 grammes of 50% dextrose. Without intravenous access, intramuscular or intranasal glucagon may be used.

Prevention

Diabetics

For diabetics, prevention strategies include patient education on recognising symptoms, adjusting medication doses, and frequent blood glucose monitoring. Continuous glucose monitors and insulin pumps can significantly improve blood glucose control and help prevent hypoglycaemia.

Non-Diabetics

Prevention in non-diabetics depends on the underlying cause. Hormone replacement, tumour resection, or dietary adjustments may be necessary. Medications like diazoxide and octreotide can help manage certain conditions that lead to hypoglycaemia.

Epidemiology

Hypoglycaemia is common in type 1 diabetics and those with type 2 diabetes on certain medications. Type 1 diabetics typically experience two mild episodes per week and one severe episode per year. Mortality due to hypoglycaemia occurs in 6–10% of type 1 diabetics. Hypoglycaemia is less common in type 2 diabetics not taking insulin, glinides, or sulfonylureas.

History

James Collip first discovered hypoglycaemia while working on insulin purification in 1922. He observed that excessive doses of insulin caused convulsions, coma, and death in rabbits, which helped him define insulin activity.

Etymology

The term hypoglycaemia is derived from Greek, meaning 'low blood sugar,' from hypo- (under), glykys (sweet), and haima (blood).

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Self-assessment MCQs (single best answer)

What blood glucose level defines hypoglycaemia?

Which of the following is a neuroglycopenic symptom of hypoglycaemia?

What is the first step in diagnosing hypoglycaemia according to Whipple's triad?

Which medication is commonly associated with hypoglycaemia in diabetics?

What is the recommended self-treatment for a conscious individual experiencing hypoglycaemia?

What should be done if a hypoglycaemic person is unconscious?

What is a common prevention strategy for diabetics to avoid hypoglycaemia?

Which of the following is NOT a cause of hypoglycaemia in non-diabetics?

How many severe hypoglycaemic episodes per year does a typical type 1 diabetic experience on average?

Who discovered hypoglycaemia while working on insulin purification?