Diabetic Emergencies in Pre-Hospital Care
Diabetes mellitus affects over 4.3 million people in the UK, making diabetic emergencies one of the most frequently encountered presentations in pre-hospital care. As a student paramedic, you need to be able to rapidly distinguish between hypoglycaemia, diabetic ketoacidosis (DKA), and hyperosmolar hyperglycaemic state (HHS) — conditions that can look superficially similar but require very different management approaches. Getting it wrong can be fatal.
Understanding the Pathophysiology
All three conditions stem from disordered glucose regulation, but via distinct mechanisms. A solid grasp of the underlying pathophysiology will help you reason through unfamiliar presentations rather than relying on pattern-matching alone.
Hypoglycaemia
Hypoglycaemia occurs when blood glucose falls below 4 mmol/L, depriving the brain of its primary fuel source. It develops rapidly — often within minutes — and is most commonly caused by excess insulin relative to carbohydrate intake. Common triggers include missed meals, increased physical activity, excess insulin administration, or alcohol consumption (which inhibits hepatic gluconeogenesis).
The autonomic response kicks in first — the patient may appear sweaty, pale, tremulous, and anxious. As glucose falls further, neuroglycopenic symptoms dominate: confusion, aggression, slurred speech, and ultimately seizures or loss of consciousness. Importantly, some patients — particularly those with longstanding diabetes or those on beta-blockers — may not display the classic autonomic warning signs, presenting directly with altered consciousness.
Diabetic Ketoacidosis (DKA)
DKA predominantly affects patients with Type 1 diabetes, though it can occasionally occur in Type 2. It develops over hours to days when a profound lack of insulin causes the body to switch to ketone production as an alternative fuel source. Free fatty acids are metabolised in the liver, producing ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone), which accumulate and cause a metabolic acidosis.
The classic biochemical triad of DKA is: hyperglycaemia (typically >11 mmol/L), ketonaemia (≥3 mmol/L or significant ketonuria), and acidosis (venous pH