Acid Base

Question 1

causes of hyperchloremic (normal AG) acidosis

Answer 1

GI loss: diarrhea

Renal: RTA

Question 2

causes of AG acidosis

Answer 2

MUDPILES

Question 3

causes of metabolic alkalosis

Answer 3

1. loss of H+
   - GI loss: vomiting, NG suction
   - Renal: Hyperaldosteronism
2. alkali ingestion: milk alkali syndrome

Question 4

delta-delta

Answer 4

for every 1 increase in AG, HCO3- should fall by 1

Question 5

what is the expected metabolic compensation for respiratory acidosis?

Answer 5

Acute: for every 10mmHg increase in PCO2, 1mEq/L rise in bicarb
Chronic: for every 10mmHg increase in PCO2, 3-4mEg/L rise in bicarb

Question 6

what is the expected respiratory compensation for metabolic acidosis?

Answer 6

Winter’s formula: expected pCO2=1.5*[HCO3-] +8 +/- 2

Or cover the 7

Question 7

what is the expected metabolic compensation for respiratory alkalosis?

Answer 7

Acute: for every 10mmHg decrease in PCO2, 2mEq/L decrease in bicarb
Chronic: for every 10mmHg decrease in PCO2, 4mEq/L decrease in bicarb

Question 8

what is the expected respiratory compensation for metabolic alkalosis?

Answer 8

0.7mmHg rise in pCO2 for every 1mEq/L rise in HCO3

Question 9

distal/Type 1 RTA

Answer 9

impaired H+ secretion in distal tubule

Question 10

labs in distal/ type 1 RTA

Answer 10

low serum [HCO3-] 5.5
Urine AG +
hypokalemia

Question 11

tx distal / type 1 RTA

Answer 11

potassium bicarbonate

Question 12

negative UAG in presence of metabolic acidosis

Answer 12

means there is an extra-renal problem (kidneys are acting appropriately and eliminating lots of Cl- as NH4Cl)

Question 13

positive UAG in presence of metabolic acidosis

Answer 13

renal problem (RTA) b/c low NH4Cl excretion

Question 14

proximal / type 2 RTA

Answer 14

proximal tubule can’t resorb enough bicarb –> bicarbonaturia

Question 15

labs in proximal / type 2 RTA

Answer 15

low serum [HCO3-] 12-16mEq/L
urine pH5.5 if serum bicarb exceeds tubular bicarb threshold
UAG neg
hypokalemia - worse w/ alkali therapy

Question 16

tx for proximal / type 2 RTA

Answer 16

potassium bicarb

Question 17

fanconi syndrome

Answer 17

generalized proximal tubular dysfunction –> type 2 RTA, glycosuria, aminoaciduria, phosphaturia, bicarbonaturia, etc…)

Question 18

type 4 RTA

Answer 18

lack of aldosterone effects in principal cells of distal tubules –> inhibits K+ and H+ secretion

Question 19

labs in type 4 RTA

Answer 19

low serum bicarb (mild - 16-20mEq/L)
variable urine pH
hyperkalemia

Question 20

type 4 RTA tx

Answer 20

tx underlying etiology (mineralocorticoid deficiency for ex., hypoadrenalism)
loop diuretics
fludrocortisone

Question 21

aspirin toxicity

Answer 21

results in:

1. hyperventilation –> respiratory alkalosis
2. AG metabolic acidosis (salicylate)

Question 22

metabolic alkalosis - urine chloride measurement

Answer 22

Urine Cl- < 25 mEq/L = kidneys are working
- possible causes: vomiting, CF, low Cl- intake
Urine Cl- > 40 mEq/L = kidney defect
- possible causes: aldosterone excess, genetic (Liddle’s, Bartter’s, Gitelman’s), alkali load, diuretic