Metabolic Acid-Base

Question 1

How does albumin affect anion gap?

Answer 1

Every 1 G/dl that serum albumin is <4.0, add 2.5 to anion gap

Question 2

INC Anion Gap Metabolic Acidosis Causes

Answer 2

AMPLE SUDS + GOLD MARRK
Alcohol
Methanol
Paraldehyde
Lactic Acid

Salicylates
Uremia
DKA
Starvation

Glycols
Oxyproline (5-)
L-Lactate
D-Lactate

Methanol
Aspirin
Rhabdomyolysis
Renal failure
Ketoacidosis

Question 3

Normal Anion Gap Metabolic Acidosis

Answer 3

HARDUP

Hyperalimentation
Acetazolamide
RTA
Diahrea
Ureterosigmoidostomy
Pancratic fistulae

Question 4

Urine Anion Gap

Answer 4

(Una+Uk)-Ucl

> 0 -> Renal
<0 -> GI

Question 5

Causes of metabolic alkalosis

Answer 5

• H+ Loss/ HCO3 addition
• Volume Contraction
• Exogenous load

Question 6

How do diuretics lead to metabolic alkalosis

Answer 6

Inhibition of Na Reabsoprtion -> INC distal NA reclamation via aldosterone -> H+ lumen secretion -> generation + resorption of HCO3

Question 7

Respiratory Compensation for Metabolic Acidosis

Answer 7

Winters Formula:

pCO2 = (1.5 X [HCO3-] + 8 +/- 2

Question 8

When does the urinary anion gap become unreliable?

Answer 8

• Polyuria
• Urine pH exceeding 6.5
• Urinary ammonium is excreted with anion other than chloride (ketoacids, salicylates, Penicillin)

Question 9

Urinary Osmolal Gap

Answer 9

(2X[Na])+(2X[K]) + (Urine Urea Nitrogen/2.8)+(Urine Glucose/18)

OR

(2×[Na+]+2×[K+])+(urine urea nitrogen)+(urine glucose) in millimoles/L

<40 mmol/L in normal anion gap acidosis indicates impairment of excretion of urinary ammonium

Question 10

Chloride resistant Metabolic alkalosis

Answer 10

• Mineralcorticoid excess or sever hypokalemia
• Cl < 40 mmol/L
• NaCl administration does NOT correct
• Diuretic-induced is the exception