Acid-Base Disorders

Question 1

What is the range of urine pH?

Answer 1

4.4-8.0

Question 2

What is the normal urine pH?

Answer 2

6.0

Question 3

What falsely elevates urine pH?

Answer 3

Proteus infection (UTI)

Question 4

How do fruit/veggies affect pH?

Answer 4

citrate is broken down into bicarb, raising pH

Question 5

In what form is a fixed amount of acid excreted each day?

Answer 5

H2PO4-

Question 6

What is titrated by the kidneys to excrete acid as needed?

Answer 6

NH3 (traps protons in the lumen)

Question 7

What are the three mechanisms of developing metabolic acidosis?

Answer 7

loss of bicarb, low H+ excretion, excess H+ production/intake

Question 8

What is the compensation for metabolic acidosis?

Answer 8

for every 1 decrease in bicarb, PCO2 drops by 1.2

Question 9

What is the compensation for metabolic alkalosis?

Answer 9

for every 1 increase in bicarb, PCO2 increases by 0.7

Question 10

What is the compensation for respiratory acidosis?

Answer 10

acute: for every 10 inc in PCO2, bicarb inc by 1
chronic: for every 10 inc in PCO2, bicarb inc by 4

Question 11

What is the compensaiton for respiratory alkalosis?

Answer 11

acute: for every 10 dec in PCO2, 2 dec in bicarb
chronic: for every 10 dec in PCO2, 5 dec in bicarb

Question 12

What is an anion gap?

Answer 12

Na-(Cl+HCO3) > 12

Question 13

What is the differential for anion gap metabolic acidosis?

Answer 13

Glycols
Oxoproline (acetaminophen)
L-lactate (humans)
D-lactate (bacteria)
Methanol
Aspirin
Renal failure
Ketoacidosis

Question 14

What is the differential for metabolic acidosis with anion gap and osmolal gap?

Answer 14

glycols, methanol

Question 15

What is the differential for osmolal gap without acidosis?

Answer 15

isopropyl alcohol poisoning, mannitol, sorbitol, glycine, dextran

Question 16

What is the differential for metabolic acidosis without anion gap?

Answer 16

Acute kidney injury
Chronic kidney injury
Carbonic anhydrase inhibitors
Renal tubular acidosis
Ureteroenterostomy
Expansion of volume
Diarrhea/Diuretics (K-sparing)

Question 17

What is the differential for metabolic alkalosis?

Answer 17

Bartter syndrome
Aldosteronism
NG suction
Gitelman syndrome
Excess alkali
Renin
Emesis
Diuretics

Question 18

What is the relationship between serum K and HCO3 reabsorption

Answer 18

inverse

Question 19

Describe the generation phase of metabolic alklalosis in vomiting.

Answer 19

Na, HCl, H2O lost in vomit; excess Na, HCO3 generated (alkaline tide); chloride is reabsorbed due to hypovolemia; excess HCO3 is lost in urine with Na, K;

Question 20

Describe the maintenance phase of metabolic alkalosis in vomiting.

Answer 20

decreased volume increases aldosterone (excrete H+), and promotes reabsorption of Na, Cl, bicarb

Question 21

How do diuretics cause hypokalemic alkalosis?

Answer 21

loss of NaCl in urine decreases volume, which activated SNS and RAAS, which activates ENaC, leading to a negative lumen and secretion of H+ and K+

Question 22

What are the urine Na/Cl levels in the generation and maintenance phases of vomiting metabolic alkalosis?

Answer 22

generation: Na>15, Cl<15
maintenance: Na<15, Cl<15

Question 23

What are the urine Na/Cl levels in current and remote uses of diuretic metabolic alkalosis?

Answer 23

current: Na>15, Cl>15
remote: Na<15, Cl<15

Question 24

What are the urine Na/Cl levels in the initial and escape phases of hyperaldosteronism metabolic alkalosis?

Answer 24

initial: Na<15, Cl<15
escape: Na>15, Cl>15