Lecture 7 - Hypo & Hypernatraemia

Question 1

What is hypo & hypernatraemia typically both caused by?

Answer 1

Usually caused by fluid imbalances not because there’s too much or little sodium in the blood.

Question 2

What is hypernatraemia and its typical causes?

Answer 2

• Plasma Na+ >146mmol/L and an increased solute:water ratio in body fluids
• Osmotic diuresis (uncontrolled diabetes), fluid loss without replacement (sweating, vomiting etc), diabetes insipidus, primary aldosteronism

Question 3

What is hyponatreamia, its symptoms & its causes?

Answer 3

• Na+ concentration lower than 130mmol/L, usually due to an increase in water
• Agitation, nausea, coma
• Diuretics (cause loss of Na+ without replacing water), water overload, increased ADH release etc.

Question 4

How is hyponatreamia treated?

Answer 4

• Depends on cause
• Fluid restriction almost always works, however if we take away too much fluid, Pontine demyelination occurs.
• Infusion of hypertonic saline + furosemide can be used in symptomatic patients too