Metabolic Acidosis and Alkalosis

Question 1

Anion gap equation
-normal anion gap

Answer 1

(Na+K) - (Cl+HCO3) = 10-18

Question 2

Causes of metabolic acidosis with a normal anion gap

Answer 2

ABCD
Addisons
Bicarb loss - GI, renal tubular acidosis
Chloride
Drugs - acetazolamide

Question 3

Causes of metabolic acidosis with raised anion gap

Answer 3

KULT
Ketones - DKA, alcohol
Uremia - renal failure
Lactate - hypoxia, shock, sepsis, metformin toxicity
Toxins - ethylene glycol, methanol, salicylates

Question 4

Salicylate overdose

Answer 4

Early stimulation of resp centers => resp alkalosis
Renal failure => metabolic acidosis

Question 5

Renal tubular acidosis
-what is it
-types

Answer 5

When the kidneys are unable to maintain pH balance => hyperchloremic metabolic acidosis

Type 1 - distal tubule cannot secrete H into urine
-no HK exchange => hypokalemia
-acidosis is buffered by CaPO4 release from bones => renal stones
Causes
-idiopathic
-RA, SLE, Sjogrens

Type 2 - proximal tubule cannot reabsorb HCO3
-increased K excretion

Type 3 - carbonic anhydrase deficiency

Type 4 - reduced aldosterone => hyperkalemia, reduced ammonium excretion

Question 6

Metabolic alkalosis causes

Answer 6

Loss of H
-vomiting
-primary hyperaldosteronism/pseudohyperaldosteronism from liquorice/Cushings - Na exchanged for H
-hypokalemia

Increased HCO3
-diuretics - fluid loss concentrates HCO3
-liquorice