Hypoglycaemia

General Medicine

Plasma glucose <70 mg/dL (3.9 mmol/L) with autonomic / neuroglycopenic symptoms (Whipple's triad).

Etiology

  • Insulin / sulfonylurea overdose
  • Missed meal, exercise, alcohol
  • Adrenal insufficiency, sepsis, liver failure
  • Insulinoma (rare)

History taking

  • Drug timing, meals, exercise
  • Awareness of hypoglycaemia
  • Recurrent episodes

Examination

  • General: vitals, pallor, icterus, oedema, lymphadenopathy
  • Focused system examination
  • Look for red-flag findings

Red flags

  • Loss of consciousness, seizure
  • Persistent neurological deficit

Differential diagnosis

  • See differentials section per chief complaint

Recommended investigations

  • CBC, basic metabolic panel as indicated
  • Targeted disease-specific tests

Diagnosis

  • Clinical diagnosis supported by targeted investigations

Initial treatment / management

  • Conscious: 15 g fast carbs (glucose tabs / juice), recheck in 15 min
  • Unconscious: IV dextrose 25 g or IM glucagon 1 mg

Drug therapy

  • Identify and stop offending drug
  • Adjust insulin / OHA

Follow-up advice

  • Review in 2–4 weeks or earlier if worsening
  • Monitor response to therapy and adverse effects

Patient counselling

  • Carry glucose source
  • Educate family on glucagon
  • Inform DVLA / equivalent if recurrent

Referral criteria

  • Refer if diagnostic uncertainty, complications, or failure of first-line therapy

Clinical pearls

  • Sulfonylurea hypoglycaemia can recur for 24–72 h — admit

References

  • Harrison's Principles of Internal Medicine, 21e
  • NICE / WHO guidelines (current edition)

Educational outpatient guide — verify against local guidelines before clinical use.

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