Diabetic Emergencies: DKA, HHS & Hypoglycaemia

Diabetic Emergencies in Pre-Hospital Care

Diabetes mellitus affects over 4.3 million people in the UK, making diabetic emergencies among the most common calls a paramedic will attend. Whether you're a student paramedic on placement or preparing for your OSCEs, understanding the pathophysiology, recognition, and pre-hospital management of diabetic crises is essential. This article covers the three main presentations you'll encounter: diabetic ketoacidosis (DKA), hyperosmolar hyperglycaemic state (HHS), and hypoglycaemia.

Hypoglycaemia: The Most Common Diabetic Emergency

Hypoglycaemia is defined as a blood glucose level below 4 mmol/L, although symptoms can vary between individuals. It is most commonly seen in patients taking insulin or sulphonylureas (e.g. gliclazide), and can deteriorate rapidly without prompt treatment.

Recognition

The clinical picture ranges from mild to life-threatening. Key signs and symptoms include:

• Sweating, pallor, and tremor
• Confusion, agitation, or unusual behaviour
• Tachycardia and palpitations
• Seizures or loss of consciousness in severe cases
• Blood glucose below 4 mmol/L on point-of-care testing

Pre-Hospital Management

Always perform a structured ABCDE assessment and obtain a blood glucose reading early in any patient with an altered level of consciousness or unusual behaviour. JRCALC guidelines direct management based on the patient's level of consciousness:

• Conscious and able to swallow: Oral glucose — 15–20g of fast-acting carbohydrate (e.g. Glucogel, Lucozade). Repeat blood glucose after 10–15 minutes and re-treat if still below 4 mmol/L. Follow with a long-acting carbohydrate snack.
• Unconscious or unable to swallow: Intramuscular glucagon 1mg (adults) or IV glucose — typically 10% glucose 150–200ml IV per JRCALC guidance. Note that glucagon is less effective in patients with depleted glycogen stores (e.g. alcohol misuse or prolonged starvation).

Document response to treatment carefully. Consider conveyance to ED if the patient does not recover satisfactorily, has taken a long-acting insulin or sulphonylurea, is alone, or if there is any clinical concern. A full "treat and leave" pathway requires meeting specific JRCALC criteria and shared decision-making with the patient.

Diabetic Ketoacidosis (DKA)

DKA is a life-threatening emergency predominantly seen in patients with Type 1 diabetes, though it can occur in Type 2. It results from an absolute or relative insulin deficiency, leading to hyperglycaemia, ketogenesis, and a metabolic acidosis.

Pathophysiology in Brief

Without insulin, cells cannot utilise glucose. The body switches to fatty acid metabolism, producing ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone). This leads to a high anion gap metabolic acidosis. Osmotic diuresis from hyperglycaemia causes significant dehydration and electrolyte loss — particularly potassium — which can be dangerous during treatment.

Recognition

DKA typically develops over hours to days. Classic features include:

• Blood glucose usually above 11 mmol/L (can occasionally be lower — "euglycaemic DKA")
• Ketonaemia (blood ketones ≥3 mmol/L) or significant ketonuria
• Kussmaul breathing — deep, sighing respirations as the body compensates for acidosis
• Smell of acetone on the breath ("pear drops")
• Nausea, vomiting, and abdominal pain
• Signs of dehydration: dry mucous membranes, tachycardia, reduced skin turgor
• Reduced GCS in severe cases

Pre-Hospital Management

DKA is primarily a hospital-managed condition, but your pre-hospital interventions are important:

• High-flow oxygen if SpO2 is below 94%
• Obtain IV access and commence cautious IV fluid resuscitation with 0.9% sodium chloride — aim to correct dehydration without precipitating cerebral oedema (a particular concern in paediatric patients)
• Continuous cardiac monitoring — hypokalaemia can cause life-threatening arrhythmias
• Pre-alert the receiving hospital; DKA requires urgent medical review and an insulin infusion protocol
• Do not delay transport — definitive management requires hospital-level care

Hyperosmolar Hyperglycaemic State (HHS)

HHS is predominantly seen in older patients with Type 2 diabetes and carries a higher mortality than DKA — up to 15–20% in some studies. It develops more slowly, often over days to weeks, making it easy to miss in its early stages.

Pathophysiology and Differences from DKA

In HHS, there is sufficient residual insulin to suppress lipolysis and ketogenesis, so significant ketoacidosis does not develop. However, profound hyperglycaemia (often above 30 mmol/L) and hyperosmolarity cause severe dehydration. Fluid deficits of 8–10 litres are not uncommon.

Recognition

• Very high blood glucose — typically above 30 mmol/L
• Markedly elevated plasma osmolality (calculated: 2[Na+] + glucose + urea)
• Profound dehydration without significant ketosis or acidosis
• Gradual onset neurological features: confusion, drowsiness, focal deficits, or seizures
• Often a precipitating cause: infection, MI, stroke, or medication changes

Pre-Hospital Management

As with DKA, hospital admission is essential. Key pre-hospital priorities include:

• ABCDE assessment with airway protection if GCS is impaired
• IV access and careful fluid resuscitation with 0.9% sodium chloride — correction must be slow to avoid osmotic demyelination syndrome
• Cardiac monitoring — these patients are at high risk of thromboembolic events
• Pre-alert with a clear handover including glucose level, GCS, and haemodynamic status

Key Differentials: Comparing the Three Conditions

Being able to quickly differentiate between these conditions on scene is a core clinical skill. Use your glucometer and, where available, a ketone meter to guide your assessment:

• Hypoglycaemia: BG below 4 mmol/L, rapid onset, responds to glucose
• DKA: BG elevated, ketones high, acidosis, Kussmaul breathing, predominantly Type 1
• HHS: BG very high (often above 30 mmol/L), no significant ketosis, slow onset, older Type 2 patient

Always consider other causes of altered consciousness — hypoglycaemia can mask a concurrent stroke, and hyperglycaemia can develop secondary to other acute illnesses. A thorough history from the patient, family, or care records is invaluable.

Clinical Pearls for Student Paramedics

• Check blood glucose on every patient with an altered GCS — it takes seconds and saves lives
• Know your JRCALC guidelines and your Trust's specific clinical practice guidelines (CPGs) for hypoglycaemia management — they may differ slightly
• Potassium shifts are critical in both DKA treatment and hypoglycaemia reversal with glucagon — understand the physiology
• An ECG is invaluable: hypokalaemia causes U waves and flattened T waves; hyperkalaemia causes peaked T waves and a broad complex — both are risks in diabetic emergencies
• Always look for a precipitating cause: infection, missed insulin doses, illness, or dietary changes