Hypoglycaemia

Exam Cram

• Hypoglycaemia can be caused by excessive insulin, oral diabetic medications, endocrine causes or starvation

• Presentation: hunger, tiredness; autonomic features (sweaty, palpitations), confusion/ seizure/ coma

• Diagnosis: blood sugar < 4mmol

• Management: 25g of sugar (IV or gel) and consider cause

Outline

Background

• Insulin is produced in beta cells in pancreas. 

• Insulin lowers blood glucose levels, facilitating cellular sugar uptake. 

• C-peptide is a waste product, proportional to the amount of insulin made. 

Presentation

Acute episode

• Loss of consciousness, collapse, seizure

• Proceeding hunger, sweating

• Symptoms improved with sugar

Background

• Episodic pre-syncopal episodes

• Weight gain (hyperinsulinaemia)

• Consider access to insulin, diabetic drugs (works in hospital setting or family member diabetic)

Investigations

• Blood sugar < 4mmol

• Insulin, c-peptide levels

• Urinary sulphonureas

Diagnosis

Diagnostic criteria: (acute hypoglycaemia event)- blood sugar < 4 mmol & symptoms responsive to blood sugar

Differentials: primary CNS cause of seizure (epilepsy, space occupying lesion), syncope (vasovagal, cardiac), postural hypotension

Classification: based on aetiology

• Diabetes related (type 1,2): accidental / iatrogenic overdose

• Deliberate overdose- source from family, work, self

• Insulinoma

• Alcohol (increases insulin secretion)

Management

Acute

Administer c. 25g of sugar 

1. Ask for help: pull peri-arrest buzzer if seizure, severely reduced GCS or BSL << 3

2. Acutely raise blood glucose

   1. Oral glucose if able to swallow & compliant

      • Glucogel (20g per packet) x2 or high sugar equivalent

   2. IV Glucose

      • 10% Dextrose 200mls

      • 20% Dextrose 100mls 

      • 50% Dextrose 50mls

   3. IM Glucagon 1mg 

3. Long term carbohydrate: to prevent reoccurance

   1. Oral: e.g. bread

   2. IV continue dextrose 5-10%

Investigate cause

Concern for hypoglycaemia events requires medical admission: 

1. 72 Fast with blood sugar monitoring

   • Consider urinary sulphonyurea

2. Blood sugar, Insulin and C-peptide during attack

Conditions Insulin level C-peptide level

Insulinoma High High

Factious hyperglycaemia High Low

T1DM Low Low

T2DM Mildly raised Mildly raised

Resources and References

Written in 2025