Renal Case Presentation - Fitzpatrick

Question 1

What region of the kidney accounts for most of the reabsorption of bicarbonate?

Answer 1

PCT ~ 85%

Question 2

Alkaline urine

Answer 2

Will help dissolve any uric acid crystals that have precipitated in the kidney

Question 3

The higher the percentage of a drug that is excreted in the urine (in lab work) tells you what?

Answer 3

It is excreted in urine - so kidney is major clearance organ if number is high
Ex. cisplatin 23%

Question 4

What does a high mineracorticoid activity number indicate?

Answer 4

Kidney problems

Question 5

Cisplatin

Answer 5

Via epithelial cell toxicity, vasoconstriction in the renal microvascular and pro-inflammatory effect
Frequently associated with anemia - kidney site of erythropoietin
Stable in plasma and high Cl- milieu

Question 6

Cisplatin and nephrotoxicity

Answer 6

1/3 patients get it
Starts ~ 10 days after starting tx
Manifested as decreased GFR, higher serum creatinine and reduced serum magnesium and potassium levels
The concentration of platinum achieved in the renal cortex is several fold greater than that in plasma and other organs

Question 7

Cisplatin dose limiting toxicity

Answer 7

Renal - direct kidney damage
Severe nausea/vomiting
Ototoxicity - acoustic nerve damage

Question 8

How does Cisplatin enter cells?

Answer 8

Diffusion and Cu2+ transporter

Question 9

Acute nephrotoxicity produced by?

Treatment?

Answer 9

Uric acid

Tx - allopurinol - xanthine oxidase inhibitor

Question 10

Tumor lysis syndrome

Answer 10

Ppt interstitial urate crystals with inflammatory response
K+ release - hyperkalemia
DNA release:
1. nucleotides - hyperphosphatemia
2. Purines –> uric acid –> hyperuricemia

Question 11

Table showing percentage of administered drug in the urine and the rate of drug elimination from the body. Which can be correctly predicted from this information?

Answer 11

The degree of exposure of the nephron to each drug

Question 12

Tumor lysis syndrome tx

Answer 12

Push IV fluids - increase excretion of urate and phosphate
K+-binding resin - hyperkalemia
Allopurinol - reduces formation of urate, does not affect circulating urate or crystals in tissue
Calcium supplementation

Question 13

Hyperkalemia

Answer 13

Even mild needs to be treated asap

Question 14

Renal disposition of urate

Answer 14

50% tubular secretion
40% tubular reabsorption
10% excreted

Question 15

Hyperuricemia

Answer 15

Urine alkalinization prevents renal ppt of uric acid

But may increase the risks for nephrocalcinosis

Question 16

How to increase urinary pH

Answer 16

Acetazolamide - alkaline diuresis

Decreases PT bicarb reabsorption

Question 17

Allopurinol

Answer 17

Inhibits xanthine oxidase - prevents conversion of purines into uric acid
Can be used to prevent tumor lysis syndrome

Question 18

Pt taking drug to tx acute lymphocytic leukemia. Which of the following circumstances will necessitate a significant reduction in the doses of drug to prevent its accumulation to toxic levels?

Answer 18

Pt taking allopurinol for prophylaxis of tumor lysis syndrome

Question 19

Pulmonary edema is an example of?

Answer 19

Iatrogenic complication

-excessive hydration

Question 20

Loop diuretics

Answer 20

Thick ascending limb of Henle

Question 21

What can blunt loop diuretic response?

Answer 21

NSAIDS

• inhibit organic anion transport of loop diuretics into lumen
• NSAIDS inhibit cyclooxygenase and block prostaglandin-dependent renal blood flow

Question 22

Deficits of prostaglandins in kidney leads to?

Answer 22

Na+ and H2O retention (edema)

Mild HTN

Question 23

Diuretics that work on distal tubule?

Answer 23

Thiazide diuretics

-enter via glomerular filtration = less exposure at low GFR

Question 24

What is contra-indicated in pt being treated for pulmonary edema secondary due to overzealous hydration during management of cisplatin nephrotoxicity?

Answer 24

NSAIDS