Metabolic alkalosis

Question 1

what is the electrolyte cause of metabolic alkalosis

Answer 1

loss of hydrogen ions OR gain of bicarbonate

Question 2

Problems with which areas of the body commonly cause a metabolic alkalosis?

Answer 2

It is due mainly to problems of the kidney or gastrointestinal tract

Question 3

Specific causes of metabolic alkalosis

Answer 3

vomiting / aspiration
diuretics
liquorice, carbenoxolone
hypokalaemia
primary hyperaldosteronism
Cushing’s syndrome
Bartter’s syndrome

Question 4

Mechanism of development of metabolic alkalosis

Answer 4

• activation of RAAS
• aldosterone causes reabsorption of Na+ in exchange for H+ in the distal convoluted tubule

E.g. ECF depletion (vomiting, diuretics) → Na+ and Cl- loss → activation of RAAS → raised aldosterone levels

hypokalaemia, K+ shift from cells → ECF, alkalosis is caused by shift of H+ into cells to maintain neutrality