Jan10 M2-Acid Base Pathophysiology

Question 1

most common acid base disturbance + compensation

Answer 1

metabolic acidosis. compensate by hyperventilating

Question 2

3 mechanisms that lead to metabolic acidosis

Answer 2

• increased acid production or accumulation
• loss of bicarb
• impaired renal acid excretion

Question 3

3 mechanisms of met acidosis by increased acid production

Answer 3

1. lactic acidosis
2. ketoacidosis (often uncontrolled DM)
3. Ingestions (aspirin, methanol, ethylene glycol = antifreeze)

Question 4

2 mechanisms of met acidosis by loss of bicarb

Answer 4

1. GI loss (diarrhea, pancreatic, etc.)

2. RTA (renal tubular acidosis) type 2 (proximal)

Question 5

3 mechanisms of met acidosis by decreased acid excretion by the kidneys

Answer 5

1. Renal failure (decreased NH4+ excretion)
2. Type 1 RTA (distal)
3. Type 4 RTA (hyperaldo)

Question 6

anion gap formula and used when

Answer 6

Na - (Cl + HCO3) = AG

Used in METABOLIC ACIDOSIS

Question 7

normal AG value + what AG indicates in MA

Answer 7

10. indicates that there are unmeasured anions associated with an acid (ex. lactic acid: H+ + lactate)

Question 8

why is bicarb low in AGMA

Answer 8

because the H+ that came with the extra anion is consuming the bicarb. you’re left with low bicarb and more anions

Question 9

conditions where there is no AG and why is there no AG

Answer 9

RTA (type 1 distal, 2 proximal, 4 hypoaldo) or GI losses: pure bicarb loss

Question 10

normal blood albumin

Answer 10

40g/L

Question 11

how to correct anion gap value when hypoalbuminemia and why

Answer 11

-2.5 for every -10g/L because albumin is an anion

Question 12

AGMA possible causes

Answer 12

Methanol
Uremia (renal failure)
Diabetic ketoacid..
Propylene glycol
Isoniazid, iron
Lactic acidosis
Ethylene glycol
Salicylates (aspirin)

Question 13

how to quickly tell if an AGMA is due to methanol or ethylene glycol

Answer 13

calculate the osmolal gap: measured osms - calculated osms (2xNa + glucose + urea)

Question 14

normal osmolal gap + formula

Answer 14

measured osms - (Nax2 + glucose + urea). normal is 12

Question 15

caution using osmolal gap

Answer 15

ethanol causes osmolal gap but isn’t a cause for acidosis

Question 16

does ethanol cause acidosis

Answer 16

no

Question 17

NAGMA differential

Answer 17

loss of bicarb (GI) or renal failure and can’t excrete NH4+ or RTA (type 1,2 or 4)

Question 18

RTAs that are acid excretion impairment vs RTAs that are loss of bicarb

Answer 18

loss of bicarb: RTA 2 proximal

acid excretion impairment: RTA 1 distal and RTA4 hypoaldo

Question 19

lactic acidosis: normal prod daily and from what

Answer 19

15 mmol/kg daily. plasma conc is 0.5-1.6 mmol/L. glucose anaerobic metabolism

Question 20

lactic acidosis indicates what

Answer 20

low tissue O2 delivery

Question 21

DKA (diabetic ketoacidosis) happens how

Answer 21

lack of glucose in the cells so burn fatty acids and products are acids

Question 22

in DKA, what is something that accentuates the acidosis

Answer 22

high glucose in the blood creates osmotic diuresis so left volume contracted

Question 23

rule for IV bicarb as treatment for MA (when to give) + other thing that must be done to treat

Answer 23

when low pH and bicarb below 10 + fix primary disturbance (ex. give insulin if ketoacidosis)

Question 24

urine pH in RTA

Answer 24

­­above 5.5. not good bc if blood acid, urine should be too

Question 25

type 1 RTA pathophgy

Answer 25

-H ATPase or H-K ATPase failure or poisoning
-deficient NH4+ prod
(distal, alpha int cells)

Question 26

why can have hypokalemia and hyperCa in RTA type 1

Answer 26

K not reabsorbed properly

Ca resorption from bone bc acid is buffered by the bone

Question 27

Type 2 RTA pathophgy 3-4 causes

Answer 27

defective or poisoned PCT or Fanconi syndrome or acetazolamide (CAi) and bicarb not reabsorbed

Question 28

Type 4 RTA 2 types

Answer 28

hypoaldo (aldo deficiency) or aldo resistance

Question 29

3 main symptoms of hypoaldo

Answer 29

low BP, hyperK, slightly low bicarb

Question 30

urine pH in RTA type 4

Answer 30

below 5.5

Question 31

treatment for RTAs

Answer 31

RTA type 1 and 2: give bicarb (sodium citrate and will get converted 1:1 to bicarb)
RTA type 4: give aldo p.o. (fluorinef)