Hypoglycaemia — SAQ

Stem

A candidate is asked to manage a classic presentation of Hypoglycaemia in an exam setting. Use precise definitions, scores, doses, and decision thresholds.^[1]

Core knowledge (model answer backbone)

Hypoglycaemia is plasma glucose low enough to cause symptoms (typically under 3.0 mmol/L / 54 mg/dL). It produces a biphasic clinical syndrome: first autonomic / sympathetic activation (sweating, tremor, palpitations, anxiety) at glucose about 3.2 mmol/L (58 mg/dL), then neuroglycopenia (confusion, drowsiness, seizures, coma, and at its extreme, death) as glucose falls below 3.0 mmol/L. In adults in the community the dominant cause is glucose-lowering therapy in diabetes (insulin, sulfonylureas, glinides); in non-diabetics, insulinoma, non-islet cell tumour hypoglycaemia (IGF-II), adrenal insufficiency, alcohol, sepsis/critical illness, and autoimmune insulin syndrome must each be excluded. The diagnostic cornerstone is Whipple's triad.^[1] (symptoms + low documented glucose + relief with glucose). Treatment is layered: mild — 15-20 g fast-acting oral carbohydrate, recheck after 10-15 minutes and repeat if still low;^[2] severe (unconscious or unable to swallow) — IV 10% dextrose or IM glucagon 1 mg, but glucagon is ineffective in sulfonylurea overdose and depleted glycogen states, and octreotide (50 mcg SC/IV with further doses 6-hourly) is added for sulfonylurea poisoning.^[3] Recurrent hypoglycaemia causes hypoglycaemia-associated autonomic failure (HAAF) — the autonomic warning shifts to lower glucose — which 2-3 weeks of scrupulous avoidance largely reverses.

Red flags

• Altered conscious level, seizure, or coma with capillary glucose under 3.0 mmol/L — severe hypoglycaemia; treat now (IV 10% dextrose or IM glucagon 1 mg), do not wait for lab^[2]
• Patient on insulin or sulfonylurea who is confused, drowsy or aggressive — check glucose before assuming non-metabolic cause
• Hypoglycaemia in a NON-diabetic — always abnormal; admit, draw the diagnostic 'trough' samples during the episode, then investigate
• Recurrent severe hypoglycaemia, hypoglycaemia unawareness, or recent severe episode driving a vehicle — DVLA-safety critical; relax glucose targets and use CGM

High-yield structure examiners expect

Cover: Overview & Definition, Classification, Epidemiology & Risk Factors, Pathophysiology, Clinical Presentation, Differential Diagnosis.

Key doses / thresholds (from topic teaching)

• Responsive adult: 15-20 g oral glucose or sucrose, recheck after 10-15 min, repeat if still low; follow with long-acting carbohydrate.^[2]
• Unresponsive adult: IV 10% dextrose or IM glucagon 1 mg; needle-free intranasal glucagon 3 mg is non-inferior.^[2]
• Sulfonylurea overdose: octreotide 50 mcg SC or IV, then three further 50 mcg doses every 6 h; dextrose only as needed; observe 12 h after therapy stops.^[3]
• Insulin overdose: IV dextrose infusion maintaining glucose 5.5-11 mmol/L; enteral feeding if alert.
• Counterregulatory hormones activate about 3.6-3.8 mmol/L (65-68 mg/dL); autonomic symptoms about 3.2 mmol/L (58 mg/dL); neuroglycopenia about 2.7-2.8 mmol/L (49-51 mg/dL); cognitive impairment below 3.0 mmol/L.
• Severe hypoglycaemia = an episode requiring another person's assistance (ACCORD/ADVANCE definition).^[1]

Questions

a) Define the condition and give the most important classification or severity framework used in exams. (3 marks)

• Clear one-line definition matching standard teaching.
• Named classification / stages / types with discriminating features.
• One sentence on why classification changes management.^[1]

b) Outline pathophysiology in a mechanism chain that explains the main clinical features. (3 marks)

• Initiating insult → intermediate pathway → end-organ effect.
• Link at least two symptoms/signs to mechanism.
• Mention one complication pathway (e.g. shock, perforation, herniation, arrhythmia).^[1]

c) List discriminating clinical features and bedside assessment. (3 marks)

• Classic presentation plus one atypical group (elderly, pregnancy, child, immunocompromised).
• Named signs/manoeuvres if relevant.
• What must never be missed on exam/bedside (pregnancy test, airway, glucose, etc.).^[1]

d) Investigations with thresholds and one named score if applicable. (3 marks)

• First-line tests and what positive findings mean.
• Gold-standard or definitive investigation when needed.
• Score components reproduced exactly if a named score is standard for this topic.^[1]

e) Immediate resuscitation and definitive management with doses where standard. (3 marks)

• ABC / time-critical steps first.
• First-line drug(s) with agent + dose + route (or procedure steps).
• Escalation triggers (theatre, ICU, thrombolysis window, antidote, etc.).
• Disposition and safety-netting.^[2]

Marking tips

Full marks require specificity (numbers, names, doses) not generic "give antibiotics/fluids." Regional practice (ICMR / NICE / AHA) may be cited as alternative where relevant.^[1]

References3ShowHide

1. [1]Cryer PE, Axelrod L, Grossman AB, et al. Evaluation and management of adult hypoglycemic disorders: an Endocrine Society Clinical Practice Guideline J Clin Endocrinol Metab, 2009.PMID 19088155
2. [2]Villani M, de Courten B, Zoungas S. Emergency treatment of hypoglycaemia: a guideline and evidence review Diabet Med, 2017.PMID 28477413
3. [3]Glatstein M, Scolnik D, Bentur Y. Octreotide for the treatment of sulfonylurea poisoning Clin Toxicol (Phila), 2012.PMID 23046209