Managing Hypo- & Hyperglycaemia, and the Medications Used to Treat Diabetes

1. Managing Hypoglycaemia

Hypoglycaemia is usually defined as a blood glucose below 4.0 mmol/L, though symptoms and the threshold for treatment vary by individual, especially in those with hypo unawareness or tight targets in pregnancy.

Conscious and able to swallow — the "15/15 rule"

1. Give 15–20g fast-acting carbohydrate. E.g. 150–200ml fruit juice or non-diet fizzy drink, 4–5 glucose tablets/dextrose tablets, or a glucose gel. Avoid chocolate/biscuits as the first-line treatment — fat slows absorption.
2. Recheck blood glucose after 15 minutes.
3. Still below 4.0 mmol/L? Repeat the fast-acting carbohydrate. Can repeat up to 3 times before escalating and seeking medical review.
4. Once above 4.0 mmol/L, give a longer-acting carbohydrate (e.g. slice of toast, 2 biscuits, next meal if due) to prevent rebound hypo.
5. Review the cause — missed meal, exercise, wrong insulin dose/timing, alcohol, interacting medication — and document/adjust the care plan accordingly.

Conscious but unable to safely swallow / uncooperative

1. Do not give oral treatment — aspiration risk.
2. Glucogel/dextrose gel can sometimes be massaged into the buccal mucosa in small amounts if the patient can protect their airway, but this is a judgement call, not a substitute for the steps below if in doubt.
3. Glucagon 1mg IM (adult) if trained/available and no contraindication (ineffective in glycogen-depleted states — starvation, chronic alcohol excess, adrenal insufficiency).
4. Escalate for IV access and treatment as below.

Unconscious, seizing, or severe hypoglycaemia

1. ABCDE approach, protect the airway, call for emergency help per local protocol.
2. IV glucose — typically 10% glucose infusion (e.g. 150–200ml over 15 min) is preferred in hospital over concentrated 20%/50% boluses, which are more sclerosant and prone to overshoot; follow local trust guideline/PGD.
3. IM Glucagon 1mg if IV access is delayed or unavailable.
4. Recheck glucose every 10–15 minutes until stable and conscious level recovers, then give oral longer-acting carbohydrate once safe to swallow.
5. Monitor for rebound hypo, especially with long-acting insulin or sulfonylureas on board — these patients often need extended observation (sulfonylurea-induced hypos in particular can be prolonged and recurrent).

2. Managing Hyperglycaemia

Hyperglycaemia management depends heavily on context: an isolated high reading in someone otherwise well is managed very differently from suspected Diabetic Ketoacidosis (DKA) or Hyperosmolar Hyperglycaemic State (HHS).

Simple/isolated hyperglycaemia (no ketones, well patient)

1. Check blood glucose and ketones (blood or urine) to rule out evolving DKA, particularly in Type 1 patients.
2. Encourage hydration with sugar-free fluids.
3. Correction dose of rapid-acting insulin if on an insulin regimen and a correction factor/sick-day plan is in place.
4. Identify the trigger — illness/infection, steroids, missed doses, diet, stress, pump/device failure.
5. Sick day rules: never stop insulin during illness (doses may need increasing), monitor glucose and ketones more frequently, maintain fluid and carbohydrate intake.

DKA — outline of hospital management

1. ABCDE, IV access, bloods (glucose, ketones, VBG, U&Es, FBC, cultures if infection suspected), continuous cardiac monitoring if severe/K⁺ abnormal.
2. Fixed-rate IV insulin infusion — typically 0.1 unit/kg/hour soluble insulin, per local protocol. Do not stop long-acting basal insulin.
3. IV fluid resuscitation — 0.9% sodium chloride, front-loaded, then rate-adjusted; caution and slower rates in young people (cerebral oedema risk) and the elderly/cardiac disease.
4. Potassium replacement guided by hourly/2-hourly levels — insulin drives K⁺ into cells and hypokalaemia is the major risk to monitor for.
5. Add 10% glucose infusion once blood glucose falls below ~14 mmol/L, alongside the ongoing fixed-rate insulin, to allow ketone clearance to continue safely.
6. Monitor hourly: capillary glucose, ketones (aim for ketone fall ≥0.5 mmol/L/hr and bicarbonate rise ≥3 mmol/L/hr), VBG, and clinical status until resolution criteria are met.
7. Resolution: ketones <0.6 mmol/L, venous pH >7.3/bicarb >18, and patient eating/drinking — then transition back to subcutaneous insulin, overlapping the SC dose with the IV infusion by at least 30–60 minutes to prevent rebound ketosis.
8. Treat the precipitant (infection, missed insulin, new diagnosis, illicit substance use, pump failure) and arrange diabetes team follow-up/education before discharge.

HHS — outline of hospital management

1. Fluid resuscitation is the priority — 0.9% sodium chloride, more cautious/slower rate than DKA given typically older patients and very high osmolality; large fluid deficits (often 100–220 ml/kg) need to be corrected gradually, generally over 48+ hours.
2. Insulin is usually withheld initially or given at a low rate (e.g. 0.05 unit/kg/hr) — glucose often falls substantially with fluids alone, and dropping it too fast risks central pontine myelinolysis and cardiovascular collapse.
3. VTE prophylaxis — HHS carries a high thrombosis risk due to hyperviscosity.
4. Monitor osmolality, glucose and electrolytes closely and involve senior/specialist review — these patients are often frail with comorbidities.

3. Diabetes Medications by Class

Insulins

Non-insulin agents (mainly Type 2)

4. What an Interviewer Will Likely Probe

1. Scenario questions. "A patient calls you with a glucose of X and symptoms Y — talk me through what you'd do." Expect to structure your answer logically (assess → treat → recheck → escalate → educate).
2. Sick day rules. Being able to explain these clearly to a patient is a core competency — especially insulin never being stopped, and SGLT2 inhibitors being paused temporarily during acute illness.
3. Holistic/education focus. A diabetes specialist nurse role leans heavily on patient education, self-management support, and MDT working (dietitians, podiatry, ophthalmology screening, psychological support) — not just acute treatment algorithms.
4. Awareness of national guidance. Familiarity with NICE guidelines (NG17 Type 1, NG28 Type 2, NG18 in children/young people) and local Trust DKA/HHS protocols is often asked about directly.
5. Safeguarding and holistic risk. Recognising when recurrent hypos or poor control might reflect wider issues — mental health, insulin omission, social/financial barriers to self-care.

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