Nephrology

Question 1

____ is the most important aspect of kidney function with respect to adjustment of drug dosing, and it cannot be measured easily by direct measures.

Answer 1

GFR

Question 2

Factors that affect creatinine

Answer 2

1. Age 2. Body Mass 3. Sex 4. Diet high in protein, 5. Drugs affecting Creatinine secretion (i.e. cimetidine, trimethoprim, probenecid)

Question 3

Cockcroft-Gault Equation

Answer 3

140-age(years) X IBW (kg)/ (72 X Scr (mg/dl)) X 0.85 for females

Question 4

IBW Equation

Answer 4

Male: 50 Kg + 2.3 * (inches over 5 ft)

Female 45 + 2.3 (inches over 5 ft)

Question 5

MDRD Facts

Answer 5

1. Usually the basis for the eGFR seen in patient charts, 2. does not use a weight/based on BSA 3. underestimates eGFR for heavy people, overestimates for underweight people

Question 6

CKD- EPI Formula

Answer 6

CKD Epidemiology Collaboration formula, this equation is more precise than the MDRD equation.

Question 7

Jeliffe Equation

Answer 7

Use when height and weight in adults are unavailable

Question 8

Salazar-Corcoran

Answer 8

Equation for obese individuals

Question 9

Schwartz Equation

Answer 9

For use in children.

Question 10

Stages of Kidney Disease based on GFR

Answer 10

Stage 1: Kidney damage with normal GFR >90 ml/imin
Stage 2: Kidney damage with mild reduction in GFR 60-89 ml/min
Stage 3: Moderate Dec in GFR, 30-59 ml/min
Stage 4: Severe Dec in GFR, 15-29 ml/min
Stage 5: Kidney Failure, < 15 ml/min or on dialysis

Question 11

____ is the cause of 50% of CKD cases in the US

Answer 11

Diabetes

Question 12

30-300 mg of creatinine per gram in urine

Answer 12

microalbuminuria

Question 13

> 300 mg of creatinine per gram in the urine

Answer 13

macroalbuminuria

Question 14

Macroalbuminuira Treatment for Normotensive Patient

Answer 14

Treat with an ACE-I or ARB

Question 15

What is the most important reason to avoid use of an ACE-I in a patient with CKD and HTN?

Answer 15

Bilateral Renal Artery Stenosis (obviously angioedema with previous treatment as well)

Question 16

_____ is the cause for CKD in 25-30% of patients.

Answer 16

HTN

Question 17

HTN treatment in CKD without albuminuria, preferred treatment?

Answer 17

No preferred agent.

Question 18

Which stages of CKD is it appropriate to use thiazides? Loops? Potassium-Sparing?

Answer 18

Thiazide: Stages 1-3
Loops: any, often used in stages 4-5
Potassium Sparing: Use caution in stages 4 & 5, especially if on ARB/ACE-I

Question 19

Preferred Beta-blocker in Renal Dz

Answer 19

Metoprolol (reason is some b-blockers like atenolol have an extended half-life in renal dz.

Question 20

Signs and Symptoms of Uremia

Answer 20

Nausea/Vomitting, Anorexia, taste changes, constipation, Dry skin, itching, Altered mental status (encephalopathy)

Question 21

Nutritional Considerations for Patients with CKD (not on dialysis)

Answer 21

1. Protein Restriction (often limited to 0.4- 0.8 g/kg/day however this can leaded to malnourishment once patient gets to dialysis.
2. Sodium Restriction (no more than 3 g/day)
3. Potassium Restriction to 2-4 g/day
4. Phosphorus Restriction beginning at CKD stage 3, less than 800mg/dl.

Question 22

Additional Nutritional Considerations for Patients with CKD on dialysis

Answer 22

1. Magnesium
2. Aluminum (both from antacids)
3. Fluid

Question 23

Goals of Anemia Management in CKD on ESA

Answer 23

Hemoglobin should not exceed 10 g/dl, dose should be decreased or interrupted if Hgb exceeds 11 g/dl.

Question 24

Starting Dose for Epoetin Alfa

Answer 24

50-150 units/kg 3 times per week, w/o dialysis can typically be given 1 x per week at higher dose.

Question 25

Starting Dose for Darbepoetin

Answer 25

0.45 mcg/kg, can be given as infrequently as every 4 weeks. In HD every 1-2 weeks.

Question 26

Monitoring Parameters for ESA Use

Answer 26

1. Monitor Hbg every 2 weeks until stable, then monthly 2. Dose increases should not be made more often than once monthly and usually not in increments greater than 25%. 3. Dose decreases should be made anytime Hgb rise exceeds 1 g/dl in any 2 week period or above desired value. 4.

Question 27

Iron Therapy Targets

Answer 27

``` Ferritin: 200-500 ng/ml Transferrin saturation (TSAT) > 20% ``` (oral therapy is appropriate for stages 3 or 4), but patients undergoing HD must receive parenteral iron.

Question 28

Hyperphosphatemia and Hypocalcemia occur in CKD because....

Answer 28

Due to the kidney's inability to activate vitamin D, which reduces the amount of calcium that is absorbed from the gut as well as circulating calcium. Reduces phosphorus elimination

Question 29

Low free calcium concentrations in CKD...lead to...

Answer 29

increased levels of PTH, which leads to bone demineralization.

Question 30

KDOQI Therapy Goals for Calcium (mg/dl)

Answer 30

Stage 3 & 4: Normal | Stage 5: 8.4-9.5 mg/dl

Question 31

KDOQI Therapy Goals for Phosphorus (mg/dl)

Answer 31

Stage 3 & 4: 2.7-4.6 | Stage 5: 3.5-5.5

Question 32

KDOQI Therapy Goals Calcium X Phosphate product

Answer 32

Always want < 55

Question 33

KDOQI Therapy Goals for iPTH (pg/ml)

Answer 33

Stage 3: 35-70 Stage 4: 70-110 Stage 5: 150-300

Question 34

Corrected Calcium Formula

Answer 34

serum calcium + 0.8 X (4- serum albumin)

Question 35

Phosphate Biner Therapy- Calcium Products

Answer 35

1. Must take with meals! 2. Calcium Containing Agents: Calcium Carbonate is inexpensive, chewable, OTC Calcium acetate (PHOSLO) is more potent Hypercalcemia can limit use of calcium-based products. Also recent data suggestions vascular calcification and extra-skeletal calcification concerns. Total dose of Calcium should not exceed 2000 mg/dl. (elemental 1500mg/dl)

Question 36

Sevelamer

Answer 36

Brand Name: Renagel Nonabsorbable dietary resin that binds phosphorus Good option for hypercalcemic patients. Some drug interactions:cyclosporin, mycophenolate, FQ's, Thyroid Meds.

Question 37

Lanthanum Carbonate

Answer 37

Brand Name: FosRenol | Also non absorbable dietary resin that binds phosphorus, Tasteless, chewable wafer, contraindicated in children.

Question 38

Active Vitamin D Analogs- Calcitriol

Answer 38

Use to reduce PTH, orally and parenterally, oral agent appears to increase GI absorption more causing hypercalcemia/hyperpohsphatemia.

Question 39

Active Vitamin D Analogs- Paricalcitol

Answer 39

use to reduce PTH Oral & Parenteral Lower incidence of hypercalcemia/hyperphosphatemia than with calcitriol IV at the end of HD = 100% adherence

Question 40

Active Vitamin D Analogs- Doxercalciferol

Answer 40

Reduces PTH, oral/parenteral/requires hepatic activation, lower incidence of hypercalcemia than with calcitriol

Question 41

Active Vitamin D Analogs-Cinacalcet HCL

Answer 41

Brand Name: Sensipar Lowers PTH MOA: Calcimimetic agents that binds to the calcium receptor on the PT gland. increases calcium receptor sensitivity which reduces PTH secretion. Only Oral Expensive (reserved for patients with hypercalciema/ not responding to phosphate binders) Caution seizure disorders Must monitor Serum Ca and PO4 within 1 week of therapy, and after dose titration. PTH should be measured within 1-4 weeks of therapy. Use in conjunction with vitamin D and phosphate binders, not mono therapy Initial Dose: 30 mg/day with dose adjustment every 1-2 weeks. Take with food or shortly after a meal. Avoid in patients with serum calcium less than 8.4mg/dl.

Question 42

Changes in Drug Absorption that can occur in CKD

Answer 42

1. lower drug absorption due to drug interactions (antacids/iron with FQ) 2. Lower secondary to uremia gastritis, uremia neuropathy, diabetic gastropathy 3. Lower secondary to change in gastric ph (more alkaline) 4. Lower secondary to decreased first pass metabolism by the liver.

Question 43

Changes in Protein Binding in CKD/Drug Interactions

Answer 43

Decrease protein = decreased binding sites for chloramphenicol, pheyntoin, warfarin, diazepam, furosemide, valproic acid, pentobarbital, salicylate.

Question 44

Drugs and Hormones that are partially metabolized by the Kidneys

Answer 44

Lower metabolism can occur in CKD. Acetaminophen, calcitonin, cephalothin, growth hormone, imipenem, insulin, isoproterenol, meperidine, morphine, salicylate, sulindac.

Question 45

Accumulation of Metabolites in CKD

Answer 45

Morphine, propoxyphene, procainamide, meperidine

Question 46

Indications for Renal Replacement Therapy (A-E-I-O-U)

Answer 46

``` A- Acide base E- Electrolyte disorders I- Intoxications O- Fluid Overload U- Uremia (general rule if BUN >100 or Scr >10) ```

Question 47

Drug Removal by Dialysis

Answer 47

1. small molecular weight 2. low protein binding 3. small volume of distribution (found solely in the blood) 4. Hydrophillic

Question 48

The Most important characteristic of HD for drug removal is....

Answer 48

whether the hemodialyzer is a low or high flux dialyzer

Question 49

Is there a difference in outcomes in HD vs. PD?

Answer 49

No patient outcomes are similar. However PD is not as efficient at removing drugs or solutes as HD per unit of time. PD typically is a dextrose solution, DM patients will need more insulin. There is a newer agent Icodextrin on the market that may be an answer.

Question 50

Peritonitis Clinical Presentation & Treatment

Answer 50

Clinical Presentation: Cloudy dialysate, abdominal pain, abdominal tenderness, fever, nausea, elevated WBC Treatment: Intraperitoneal antibiotics: catheter removal for selected organisms First and third gen cephalosporins together (example cefazolin and ceftazidime) Vancomycin and gent can be used less desirable. Patients with residual renal function or automated PD will need higher antibiotic doses.