Nephrology

Question 1

Winter’s formula

Answer 1

pCO2 = (1.5 x HCO3) + 8 +/- 2

Question 2

Anion gap

Answer 2

Na - (Cl + HCO3)
Normal anion gap = 8 to 12 mEq/L

Question 3

What are the findings in RTA type 1? What is the mechanism of type 1 RTA?

Answer 3

Urine pH > 5.5, serum K low, urinary anion gap positive
Inability to acidify the urine in the distal nephron

Question 4

Type 2 RTA mechanism
Type 2 RTA findings

Answer 4

Inability to reabsorb bicarbonate in the proximal tubule
pH <5.5 or normal, K low or normal, urinary anion gap negative or normal

Question 5

Type III RTA Mechanism
Type III RTA Mechanism findings

Answer 5

Defects in both reabsorption of bicarbonate in the proximal tubule and acid excretion in the distal nephron
pH >5.5, serum K low, urinary anion gap positive

Question 6

Type IV RTA Mechanism
Type IV RTA findings

Answer 6

Aldosterone deficiency or resistance leads to hyperkalemia and decreased acid secretion in the distal nephron as well as reduced proximal tubule generation of ammonia
pH variable, serum K high, urine anion gap positive

Question 7

Patient presents with tea or cola-colored urine found to be hypertensive, edematous. Recently dx with strep pharyngitis. Patient has had decreased urinary output. UA shows proteinuria, RBC casts. Cr elevated above normal. What is the most likely diagnosis? What are findings on histology

Answer 7

Post streptococcal glomerulonephritis
Low C3 and normal C4