Evaluation and Management of Hypoglycaemia

Hypoglycaemia is a plasma glucose low enough to cause symptoms or harm; the conventional biochemical threshold is <70 mg/dL.

Three levels: Level 1 (alert value) <70 mg/dL; Level 2 (clinically significant) <54 mg/dL; Level 3 (severe) — any glucose with cognitive impairment requiring external assistance.

Whipple's triad confirms true hypoglycaemia: compatible symptoms + a documented low plasma glucose + relief of symptoms when glucose is raised.

Hypoglycaemia is the critical limiting factor in achieving glycaemic targets in older adults with diabetes.

Patient factors: polypharmacy, frailty, high comorbidity burden, cognitive impairment, renal disease, low body mass, low HbA1c, erratic or reduced food intake, inability to self-administer treatment safely.

Drug factors: sulphonylureas — particularly long-acting glibenclamide — and insulin, especially twice-daily premixed and basal-bolus regimens.

Non-diabetic causes to remember: sepsis, hepatic failure, adrenal insufficiency, hypopituitarism, malnutrition and alcohol excess, insulinoma, non-islet-cell tumour hypoglycaemia (IGF-2 mediated), post-gastrectomy dumping, quinolones, quinine, and beta blockers which mask warning symptoms.

Autonomic: palpitations, tremor, sweating, hunger, anxiety.

Neuroglycopaenic: behavioural change, confusion, focal neurological deficit, seizure, coma.

Autonomic warning symptoms are blunted with age → hypoglycaemia unawareness. Presentation is often atypical — falls, delirium, “dizziness”, or a stroke mimic — and the symptomatic threshold in older people may differ from the conventional cut-off.

Confirm with a laboratory glucose, not a meter reading alone; document Whipple's triad.

In a person already on glucose-lowering drugs, the medication review IS the evaluation — no endocrine work-up is needed. Establish the pattern (nocturnal, pre-meal, post-exercise), timing relative to doses, renal function, and recent weight or appetite loss.

In a non-diabetic, take a critical sample during the episode: insulin, C-peptide, proinsulin, beta-hydroxybutyrate, sulphonylurea screen, cortisol. High insulin + high C-peptide → insulinoma or sulphonylurea (differentiated by the drug screen) High insulin + low C-peptide → exogenous insulin administration Low insulin + low ketones → IGF-2 mediated / non-islet-cell tumour Low insulin + high ketones → alcohol, starvation, cortisol deficiency E. Acute management

Conscious and able to swallow — the “rule of 15”: give 15–20 g fast-acting carbohydrate (glucose tablets or gel, 3–4 teaspoons of sugar in water, 150 mL fruit juice), recheck at 15 minutes, repeat up to three times, then give a long-acting carbohydrate snack to prevent recurrence.

Unable to swallow or unconscious: IV 25% dextrose 75–100 mL (or 10% dextrose 150–200 mL) via a large vein, or IM/SC glucagon 1 mg. Glucagon is ineffective in alcoholic, malnourished or hepatic glycogen-depleted patients.

Sulphonylurea-induced hypoglycaemia is prolonged and relapsing — admit, run a 10% dextrose infusion, observe for at least 24–48 hours; octreotide may be used for refractory cases. Never discharge such a patient after a single correction.

Always identify and treat the precipitant: missed meal, sepsis, worsening renal function, deliberate or accidental dose error, alcohol.

Relax targets by health status: healthy older adult HbA1c <7.5%; complex/intermediate health <8.0%; very complex or poor health <8.5%. Frail patients per EDWPOP: 7.6–8.5%. Avoid HbA1c below 7% in the frail.

Deintensify and deprescribe: replace glibenclamide with gliclazide or a glinide if meals are irregular; simplify basal-bolus to basal-only insulin; prefer agents with no intrinsic hypoglycaemia risk — metformin, DPP4 inhibitors, SGLT2 inhibitors, GLP-1 receptor agonists.

Re-evaluate the entire treatment plan after any Level 2 or Level 3 event; assess frailty, functional status and life expectancy at every review; educate patient and carer, give sick-day rules, and check the capacity to self-administer treatment.