ABSTRACT
Onset Rapid (≤24 h) Gradual (days-weeks) Blood glucose Usually 11-17 mmol/L,
but may be greater ≥50 mmol/L
Volume depletion Present Severe Abdominal pain Common Rare Confusion Rare Common Focal neurology No Sometimes
Sweating Tiredness Anxiety Poor coordination Nausea Visual disturbances Palpitations Drowsiness Hunger Altered behaviour Paraesthesia Confusion
Ataxia Focal neuropathy Seizures Coma
steroid requirement
• Shock: • ↑HR • ↓BP • ↓ Urine output
• Hypoglycaemia: • Confusion • ↓ Level of consciousness
• Hydrocortisone: • 100 mg IV initially • At least 50 mg IM every 6 h until better (IM doses prevent a rapid
drop-off in steroid levels) • Glucose IV (if hypoglycaemic) • Investigate and treat precipitant cause e.g. infection
HYPONATRAEMIA
• Na+ <135 mmol/L • Severe (Na+ <120 mmol/L)
• Na+ loss through urine. • Increased fluid in the blood:
• ECF = extracellular fluid volume; determined by sodium concentration and relies upon tight physiological control
• In hyponatraemia there is a decreased Na+:water ratio in the ECF
all cause hyponatraemia
• ABC • If very unwell, consider management in critical care:
• Severe CNS symptoms: hypertonic (1.8%, 3%) saline – do not give without discussion with seniors
• Hypovolaemic: replace fluid loss with 0.9% saline and stop diuretics • Euvolaemic: fluid restriction to 1500 mL/24 h until Na+ corrects • Hypervolaemic: furosemide and ACE inhibitors • SIADH can be managed long term with fluid restriction,
demeclocyline or vasopressin receptor antagonists
HYPERNATRAEMIA
• Na+ >145 mmol/L Aetiology
insipidus suspected
dehydrated patients • Decrease urine volume: salt restriction, thiazide diuretics • Hypovolaemic: 0.9% saline slowly unless the patient is in severe shock
(avoid rapid correction!) • Normovolaemic: oral fluids • Insert urinary cathether: assess urine output • Haemodialysis: if patient is in renal failure
It is important to recheck electrolytes frequently during fluid correction!
