Renal Case Presentation - Fitzpatrick Flashcards
What region of the kidney accounts for most of the reabsorption of bicarbonate?
PCT ~ 85%
Alkaline urine
Will help dissolve any uric acid crystals that have precipitated in the kidney
The higher the percentage of a drug that is excreted in the urine (in lab work) tells you what?
It is excreted in urine - so kidney is major clearance organ if number is high
Ex. cisplatin 23%
What does a high mineracorticoid activity number indicate?
Kidney problems
Cisplatin
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
Cisplatin and nephrotoxicity
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
Cisplatin dose limiting toxicity
Renal - direct kidney damage
Severe nausea/vomiting
Ototoxicity - acoustic nerve damage
How does Cisplatin enter cells?
Diffusion and Cu2+ transporter
Acute nephrotoxicity produced by?
Treatment?
Uric acid
Tx - allopurinol - xanthine oxidase inhibitor
Tumor lysis syndrome
Ppt interstitial urate crystals with inflammatory response
K+ release - hyperkalemia
DNA release:
1. nucleotides - hyperphosphatemia
2. Purines –> uric acid –> hyperuricemia
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?
The degree of exposure of the nephron to each drug
Tumor lysis syndrome tx
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
Hyperkalemia
Even mild needs to be treated asap
Renal disposition of urate
50% tubular secretion
40% tubular reabsorption
10% excreted
Hyperuricemia
Urine alkalinization prevents renal ppt of uric acid
But may increase the risks for nephrocalcinosis
How to increase urinary pH
Acetazolamide - alkaline diuresis
Decreases PT bicarb reabsorption
Allopurinol
Inhibits xanthine oxidase - prevents conversion of purines into uric acid
Can be used to prevent tumor lysis syndrome
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?
Pt taking allopurinol for prophylaxis of tumor lysis syndrome
Pulmonary edema is an example of?
Iatrogenic complication
-excessive hydration
Loop diuretics
Thick ascending limb of Henle
What can blunt loop diuretic response?
NSAIDS
- inhibit organic anion transport of loop diuretics into lumen
- NSAIDS inhibit cyclooxygenase and block prostaglandin-dependent renal blood flow
Deficits of prostaglandins in kidney leads to?
Na+ and H2O retention (edema)
Mild HTN
Diuretics that work on distal tubule?
Thiazide diuretics
-enter via glomerular filtration = less exposure at low GFR
What is contra-indicated in pt being treated for pulmonary edema secondary due to overzealous hydration during management of cisplatin nephrotoxicity?
NSAIDS
