Nephrology

Question 1

1. A 75-year-old man (height 73 inches, weight 92.5
   kg; baseline serum creatinine [SCr] 0.9 mg/dL)
   presents to your institution with abdominal pain
   and dizziness. He has a brief history of gastroenteritis
   and has had nothing to eat or drink for
   24 hours. His blood pressure reading while sitting
   is 120/80 mm Hg, which decreases to 90/60 mm
   Hg when standing. His heart rate is 90 beats/minute.
   His basic metabolic panel shows sodium (Na)
   135 mEq/L, chloride (Cl) 108 mEq/L, potassium
   (K) 4.7 mEq/L, carbon dioxide (CO2) 26 mEq/L,
   blood urea nitrogen (BUN) 40 mg/dL, SCr 1.5 mg/
   dL, and glucose 188 mg/dL. He has no known drug
   allergies. Which initial treatment of this patient’s
   acute kidney injury (AKI) is best?
   A. Administer furosemide 40 mg intravenously ×
   1 dose.
   B. Insert Foley catheter to check for residual urine.
   C. Administer fluid bolus (500 mL of normal
   saline solution).
   D. Administer insulin lispro 3 units subcutaneously.

Answer 1

1. Answer: C
   Initial treatment of AKI requires identifying and reversing
   (if possible) the insult to the kidney. This patient’s
   symptoms and presentation are consistent with prerenal
   azotemia because of volume depletion, so fluid administration
   would be the best choice (Answer C is correct).
   The patient has no suggestion of obstruction (e.g.,
   distended abdomen, history of benign prostatic hypertrophy)
   (Answer B is incorrect). Diuretic administration
   would be inappropriate because it would worsen
   his volume depletion and probably further impair his
   kidney function (Answer A is incorrect). Fluid management
   is critical to managing AKI, necessitating a
   careful patient assessment. Although his glucose concentration
   is elevated, insulin is not necessary at this
   time (Answer D is incorrect).

Question 2

2. A 44-year-old man is admitted with gram-negative
   bacteremia. He receives 4 days of parenteral aminoglycoside
   therapy and develops acute tubular
   necrosis (ATN). Antibiotic therapy is adjusted on
   the basis of culture and sensitivity results. Which
   laboratory value is most consistent with this
   presentation?
   A. BUN/SCr ratio greater than 20:1.
   B. Urinalysis with no casts visible.
   C. Fractional excretion of sodium (FENa) more
   than 2%.
   D. Urinary sodium less than 20 mEq/L.

Answer 2

2. Answer: C
   The patient has intrinsic AKI (i.e., ATN).
   Aminoglycosides can cause direct damage to the
   tubules. In ATN, the BUN/SCr ratio would be normal
   (10–15:1), whereas an elevated BUN/SCr ratio (greater
   than 20:1) reflecting hypovolemia is common in prerenal
   azotemia (Answer A is incorrect). Urinary sodium
   of less than 20 mEq/L is also a marker of hypovolemia
   and would be consistent with prerenal azotemia AKI
   (Answer D is incorrect). Fractional excretion of sodium
   also distinguishes prerenal and intrinsic renal damage.
   A low FENa (less than 1%) in an oliguric patient
   suggests that tubular function is still intact, whereas
   a FENa greater than 2% is common in intrinsic renal
   failure (Answer C is correct). Cellular debris is often
   present in intrinsic renal failure because of renal tubular
   cell death or damage, whereas a normal urinalysis
   would be more consistent with prerenal AKI (Answer
   B is incorrect).

Question 3

3. Which of the following pharmacokinetic parameters
   describes a drug that will be most effectively
   removed by hemodialysis?
   A. Serum protein binding 90% and volume of
   distribution of 2.5 L/kg
   B. Serum protein binding 30% and volume of
   distribution of 2.5 L/kg
   C. Serum protein binding 90% and volume of
   distribution of 0.3 L/kg
   D. Serum protein binding 30% and volume of
   distribution of 0.3 L/kg

Answer 3

3. Answer: D
   While the method of dialysis can affect the extent of
   drug removal, the pharmacokinetic properties of medications
   is also important in determining drug removal.
   Drugs that are highly protein bound (>90%) are not
   well dialyzed because of the large molecular weight of
   the binding proteins (Answers A and C are incorrect).
   Those drugs that are widely distributed (i.e., volume
   of distribution > 2 L/kg) are also poorly removed by
   dialysis because such a small amount of drug is in the central compartment (Answers A and B are incorrect).
   A drug that has a relatively small volume of distribution
   (0.3 L/kg) and low protein binding (30%) will be most
   effectively removed by dialysis (Answer D is correct).

Question 4

4. A 45-year-old man (weight 59 kg, height 70 inches)
   has a long history of cancer and malnutrition. His
   SCr is 0.5 mg/dL. Carboplatin will be initiated,
   for which an accurate estimate of kidney function
   is critical. Which group of parameters is best
   to use when estimating kidney function using the
   Cockcroft-Gault equation?
   A. Actual body weight and measured SCr.
   B. Actual body weight and SCr rounded to 1 mg/
   dL.
   C. Ideal body weight and measured SCr.
   D. Ideal body weight and SCr rounded to 1 mg/dL.

Answer 4

4. Answer: A
   This patient is likely producing less creatinine, given
   his cancer, malnutrition, and associated decrease in
   muscle mass. Because his actual body weight is less
   than his ideal body weight, it is a better indicator of
   creatinine production; thus, it should be used in the
   Cockcroft-Gault formula (Answers C and D are incorrect).
   Although there is concern about the low SCr concentration
   in patients with malnutrition, measured SCr
   for use in the Cockcroft-Gault formula provides a better
   estimate of renal function than rounding the value to 1
   mg/dL (Answers B and D are incorrect). Answer A is
   correct because it incorporates actual body weight and
   the measured SCr concentration.

Question 5

5. A 59-year-old patient who has had CKD category
   G5D for 10 years has hypertension, coronary
   artery disease, mild heart failure with reduced
   ejection fraction (HFrEF), and type 2 diabetes.
   Medications are as follows: epoetin 10,000
   units intravenously three times/week at dialysis,
   renal multivitamin once daily, atorvastatin
   20 mg/day, insulin, and calcium acetate 1334 mg
   three times daily with meals. Laboratory values
   are as follows: hemoglobin (Hgb) 9.2 g/dL,
   parathyroid hormone (PTH) 300 pg/mL, Na 140
   mEq/L, K 4.9 mEq/L, SCr 7.0 mg/dL, calcium
   9 mg/dL, albumin 3.5 g/dL, and phosphorus
   4.8 mg/dL. His serum ferritin concentration is
   80 ng/mL and transferrin saturation (TSAT) is
   14%. Mean corpuscular volume, mean corpuscular
   hemoglobin concentration, and white blood cell
   count (WBC) are all normal. He is afebrile. Which
   is best for managing this patient’s anemia?
   A. Increase epoetin.
   B. Add oral iron.
   C. Add intravenous iron.
   D. Maintain current regimen; patient is at goal.

Answer 5

5. Answer: C
   This patient’s Hgb is not at goal (greater than 10 g/dL),
   so maintaining the current regimen would not be appropriate
   (Answer D is incorrect). Iron studies show the
   patient is iron deficient, with TSAT less than 30% and
   ferritin less than 500 ng/mL (Answer A is incorrect).
   Increasing the epoetin dose would not increase red
   blood cell production in the absence of adequate iron.
   Although a trial of oral iron might be indicated in non–
   dialysis patients with CKD, patients on HD should be
   given intravenous iron as first line (Answer B is incorrect;
   Answer C is correct).

Question 6

6. A 60-year-old patient (weight 72 kg) with a history
   of diabetes and hypertension is in the intensive
   care unit after having a myocardial infarction
   about 1 week ago with secondary heart failure.
   He now has pneumonia. He has been hypotensive ago, his SCr was 1.0 mg/dL. His urinary output has
   steadily been declining for the past 3 days, despite
   adequate hydration, with 700 mL of urinary output
   in the past 24 hours. His medications include intravenous
   dobutamine, nitroglycerin, and cefazolin.
   Yesterday, his BUN and SCr were 32 and 3.1 mg/dL,
   respectively; today, they are 41 and 3.9 mg/dL. His
   urinary osmolality is 290 mOsm/kg. His urinary
   sodium is 45 mEq/L, and there are tubular cellular
   casts in his urine. Which type of AKI is this patient
   most likely experiencing?
   A. Prerenal azotemia.
   B. ATN.
   C. Acute interstitial nephritis (AIN).
   D. Hemodynamic/functional-mediated AKI.

Answer 6

6. Answer: B
   The presence of hypotension despite adequate hydration,
   a normal BUN/SCr ratio (10–15:1), urinary osmolality,
   and presence of urinary casts all point to ATN
   (Answer B is correct). Prerenal AKI is unlikely, considering
   adequate hydration, high urinary sodium (greater
   than 40 mEq/L), and lack of high urinary osmolality
   (Answer A is incorrect). Functional AKI would look
   similar to prerenal AKI on urinalysis with low urinary
   sodium and no tubular casts (Answer D is incorrect).
   Classically, AIN would present with eosinophils in the
   urine (Answer C is incorrect).

Question 7

7. You are evaluating a study comparing epoetin and
   darbepoetin with respect to their efficacy on mean
   Hgb concentrations. Both drugs are initiated at the
   recommended dose, and the Hgb concentration is
   checked at 4 weeks. Fifty patients are in each group.
   The mean Hgb in the epoetin group is 12.1 g/dL and
   is 12.2 g/dL in the darbepoetin group. Which statistical
   test is best for this comparison?
   A. Paired t-test.
   B. Independent (unpaired) t-test.
   C. Analysis of variance.
   D. Chi-square test.

Answer 7

Nephrology
ACCP Updates in Therapeutics® 2022: Pharmacotherapy Preparatory Review and Recertification Course
2-343
7. Answer: B
Hemoglobin represents continuous data. Because
each treatment is administered to a separate group of
patients, the data are not paired (i.e., they are unpaired)
(Answer A is incorrect). Assuming the data are normally
distributed, continuous unpaired data should be
evaluated using a t-test (Answer B is correct). Analysis
of variance can be used for continuous data, but only
when three groups of data are compared (Answer C is
incorrect). A chi-square test is used for nominal data
(Answer D is incorrect).

Question 8

8. A pharmacoeconomic study compared the use of
   erythropoiesis-stimulating agents with various
   Hgb concentrations. The primary outcome of this
   study was cost per quality-adjusted life-year gained.
   Which best describes this economic evaluation?
   A. Cost-minimization.
   B. Cost-effectiveness.
   C. Cost-benefit.
   D. Cost-utility.

Answer 8

8. Answer: D
   A cost-utility analysis is an extension of the costeffectiveness
   analysis in which the outcomes measured
   are lives saved, adjusted for changes in quality of life,
   measured as quality-adjusted life-years (Answer D
   is correct). A cost-minimization study compares the
   costs and consequences of two or more interventions
   that have equivalent outcomes, so the primary focus is
   on cost (Answer A is incorrect). A cost-effectiveness
   analysis compares costs and consequences to determine
   which treatment can achieve the best outcomes at
   the lowest cost (Answer B is incorrect). A cost-benefit
   analysis measures costs and consequences in monetary
   terms; this analysis may be useful to compare costs
   with unrelated outcomes (Answer C is incorrect).

Question 9

9. A 58-year-old woman is being evaluated for AKI.
   Laboratory test results include serum sodium 134
   mEq/L, BUN 35 mg/dL, SCr 1.8 mg/dL, urinary
   sodium 24 mEq/L, and urinary creatinine 14.3
   mg/dL. Which is the best estimate of this patient’s
   FENa?
   A. 0.8%.
   B. 1.25%.
   C. 2.3%.
   D. 4.4%.

Answer 9

9. Answer: C
   Calculating the FENa helps assess AKI to help differentiate
   prerenal from ATN: FENa = [(urinary sodium)/
   (serum sodium)]/[(urinary creatinine)/(SCr)] × 100 =
   [(24 mEq/L)/(134 mEq/L)]/[(14.3 mg/dL)/(1.8 mg/dL)] ×
   100 = 2.3% (Answer C is correct). This FENa greater
   than 2% would be most consistent with ATN (Answers
   A, B, and D are incorrect).

Question 10

10. A 55-year-old man has a history of hypertension.
    His eGFR is 48 mL/minute/1.73 m2 and urinary
    albumin/creatinine ratio (ACR) is 28 mg/g. Which
    best depicts what this patient’s goal blood pressure
    should be less than, according to the Kidney
    Disease: Improving Global Outcomes (KDIGO)
    guidelines?
    A. 130/80 mm Hg.
    B. 140/90 mm Hg.
    C. 140/80 mm Hg.
    D. 130/90 mm Hg.

Answer 10

10. Answer: B
    The KDIGO guidelines provide recommendations for
    blood pressure goals for patients with CKD according
    to the severity of proteinuria. This patient is considered
    to have normal to mildly elevated albuminuria, with an
    ACR less than 30 mg/g. Patients with albuminuria in
    this category (A1) should have a goal blood pressure of
    less than 140/90 mm Hg (Answer B is correct). A goal
    blood pressure of less than 130/80 mm Hg would be
    desired for a patient with moderate to severe (category
    A2) albuminuria (Answer A is incorrect). Answer C is incorrect because the diastolic blood pressure goal is
    too low (80 mm Hg). Answer D is incorrect because the
    systolic blood pressure goal is too low (130 mm Hg).

Question 11

11. A 66-year-old man has an eGFR of 55 mL/minute/
    1.73 m2. His ACR is 100 mg/g. His Hgb is currently
    13.2 g/dL, with normal red blood cell indices
    without treatment. Which best reflects the recommended
    minimum frequency of Hgb monitoring in
    this patient?
    A. Monthly.
    B. Every 3 months.
    C. Every 6 months.
    D. Every 12 months.

Answer 11

11. Answer: D
    This patient whose eGFR is 55 mL/minute/1.73 m2
    would be classified as having stage 3 CKD because his
    eGFR is less than 60 mL/minute/1.73 m2. He does not
    currently have anemia because his Hgb concentration
    is greater than 13 g/dL. Therefore, Hgb should be monitored
    according to his CKD stage. For stage 3 CKD,
    monitoring is recommended at least every 12 months
    (Answer D is correct). For patients with stage 4 and
    stage 5 CKD who are not yet receiving dialysis, monitoring
    should occur at least every 6 months (Answer
    C is incorrect). Monitoring should occur at least every
    3 months once patients in stage 5 CKD are receiving
    dialysis (Answer B is incorrect). Monthly monitoring is
    never recommended for a patient who is not currently
    anemic (Answer A is incorrect).

Question 12

12. A 68-year-old patient has diabetes, hypertension,
    and an eGFR of 40 mL/minute/1.73 m2. Medications
    include a renal multivitamin once daily, simvastatin,
    lisinopril, and hydrochlorothiazide. Laboratory
    values are as follows: Hgb 11.2 g/dL, immunoassay
    for PTH 200 pg/mL, Na 138 mEq/L, K 4.9 mEq/L,
    calcium 8.6 mg/dL, albumin 3.5 g/dL, phosphorus
    5.8 mg/dL, and 25-hydroxyvitamin D 45 ng/mL.
    Which is best to prevent CKD–mineral and bone
    disorder (MBD) in this patient?
    A. Ergocalciferol.
    B. Calcium acetate.
    C. Calcitriol.
    D. Cinacalcet.

Answer 12

12. Answer: B
    Many factors can contribute to the development of
    CKD-MBD, including hyperphosphatemia, hypocalcemia,
    decreased vitamin D and decreased production
    of active 1,25-dihydroxyvitamin D, and hyperparathyroidism.
    Although this patient’s PTH concentration
    is elevated, it may be related to hyperphosphatemia.
    Therefore, the first approach would be to administer a
    phosphate binder such as calcium acetate to decrease his
    serum phosphate concentrations. A calcium-containing
    phosphate binder such as calcium acetate is acceptable
    with a corrected serum calcium concentration is the
    low-normal range [measured Ca + (0.8)(4 – serum albumin)
    = 8.6 mg/dL + (0.8)(3.5 – 3.0) = 8.6 + 0.4 = 9.0 mg/
    dL] (Answer B is correct). Ergocalciferol is not necessary
    in this patient because the 25-hydroxyvitamin D
    concentration is greater than 30 ng/mL, indicating adequate
    intake (Answer A is incorrect). The 2017 KDIGO
    CKD-MBD guidelines suggest that calcitriol should not
    be routinely used in G3–G5 CKD, but in G4–G5 CKD
    for patients with severe and progressive hyperparathyroidism
    (Answer C is incorrect). Cinacalcet is reserved
    for patients with hyperparathyroidism despite normalization
    of phosphate when hypercalcemia is present
    (Answer D is incorrect).

Question 13

Patient Case
Questions 1–5 pertain to the following case.
A 48-year-old African American man (weight 70 kg) with a history of type 2 diabetes, hypertension, and osteoarthritis
is admitted to the intensive care unit after an acute myocardial infarction. He was initially hypotensive, requiring
3 L of intravenous fluid. His blood pressure is now 100/65 mm Hg. Medications before admission include nicotine
patch, metformin 500 mg orally twice daily, lisinopril 20 mg/day, acetaminophen 650 mg every 6 hours for joint pain,
and aspirin 81 mg/daily. Before admission, his kidney function was normal (SCr 1.0 mg/dL); however, during the
past 24 hours, his kidney function has declined (BUN 20 mg/dL, SCr 2.1 mg/dL). Serum sodium is 140 mEq/L and
serum potassium is 4.4 mEq/L. Urinary volume has been 300 mL over the past 12 hours through urinary catheter.
His urine shows muddy casts. His urinary sodium is 45 mEq/L and urinary creatinine is 20 mg/dL. He has edema
and pulmonary congestion.
1. Which is the best assessment of this patient’s AKI?
A. KDIGO stage 1 AKI.
B. KDIGO stage 2 AKI.
C. KDIGO stage 3 AKI.
D. Too early to assess for AKI.

Answer 13

1. Answer: B
   This patient has AKI on the basis of either the increase
   in SCr of greater than 0.3 mg/dL in the past 24 hours or
   the decrease in urinary output of less than 0.5 mL/kg/
   hour (Answer D is incorrect). The patient’s SCr concentration
   has increased by more than 1.9 times baseline,
   so it is not stage 1 (Answer A is incorrect). The SCr
   concentration has not increased more than 3 times baseline
   or achieved a concentration of greater than 4 mg/
   dL, and the patient has not required RRT, so it should
   not be classified as stage 3 (Answer C is incorrect). His
   urinary output of greater than 0.3 mL/kg/hour is also
   not consistent with stage 3 AKI. The increase in SCr of
   2.0–2.9 times baseline and the patient’s urinary output
   of less than 0.5 mL/kg/hour for more than 12 hours are
   both consistent with stage 2 AKI (Answer B is correct).

Question 14

A 48-year-old African American man (weight 70 kg) with a history of type 2 diabetes, hypertension, and osteoarthritis
is admitted to the intensive care unit after an acute myocardial infarction. He was initially hypotensive, requiring
3 L of intravenous fluid. His blood pressure is now 100/65 mm Hg. Medications before admission include nicotine
patch, metformin 500 mg orally twice daily, lisinopril 20 mg/day, acetaminophen 650 mg every 6 hours for joint pain,
and aspirin 81 mg/daily. Before admission, his kidney function was normal (SCr 1.0 mg/dL); however, during the
past 24 hours, his kidney function has declined (BUN 20 mg/dL, SCr 2.1 mg/dL). Serum sodium is 140 mEq/L and
serum potassium is 4.4 mEq/L. Urinary volume has been 300 mL over the past 12 hours through urinary catheter.
His urine shows muddy casts. His urinary sodium is 45 mEq/L and urinary creatinine is 20 mg/dL. He has edema
and pulmonary congestion.

2. Which best depicts this patient’s FENa?
   A. 0.32%.
   B. 0.67%
   C. 1.5%.
   D. 3.4%.

Answer 14

2. Answer: D
   Fractional excretion of sodium can help distinguish prerenal
   AKI from intrinsic AKI. This calculation requires
   both urinary and serum concentrations of sodium and
   creatinine from a spot urine sample: FENa = [(urinary
   sodium/serum sodium)/(urinary Cr/SCr)] × 100 =
   [(45/140)/(20/2.1)] × 100 = 3.4% (Answer D is correct;
   Answers A–C are incorrect). This is greater than 2%
   and is consistent with decreased sodium reabsorption
   and increased renal sodium excretion.

Question 15

3. Which is the best classification of this patient’s AKI?
   A. Prerenal azotemia.
   B. Intrinsic renal disease.
   C. Postrenal obstruction.
   D. Functional AKI.

Answer 15

3. Answer: B
   This patient has AKI, probably because of ATN, a
   type of intrinsic renal failure (Answer B is correct).
   Hypotension despite rapid fluid resuscitation can cause
   ATN. The rapid rise in SCr, the BUN/SCr ratio of about
   10:1, and the presence of muddy casts on urinalysis
   all suggest ATN. The FENa greater than 2% is also
   consistent with intrinsic AKI. There is no evidence of
   prerenal causes (volume depletion). The absence of an
   elevated BUN/SCr ratio greater than 20:1 and absence
   of low urinary sodium and low FENa are all suggest it
   is not prerenal AKI (Answer A is incorrect). Although
   lisinopril can cause a functional AKI, this usually
   occurs with initiation of therapy and presents similarly
   to prerenal AKI (Answer D is incorrect). Answer C is
   incorrect because there is no evidence of obstruction
   in this patient with urinary output present through the
   urinary catheter.

Question 16

4. Which medication should be discontinued because of its risk for worsening kidney function in this patient?
   A. Lisinopril.
   B. Nicotine patch.
   C. Acetaminophen.
   D. Aspirin.

Answer 16

4. Answer: A
   One strategy in managing AKI is to remove potentially
   nephrotoxic drugs, either direct toxins or medications
   that alter intrarenal hemodynamics. The following
   orders are common for patients in AKI: no ACEIs,
   ARBs, NSAIDs, or intravenous contrast. However,
   low-dose aspirin can be continued without adversely
   affecting kidney function (Answer D is incorrect). It is
   also important to remove (or reduce the dose of) agents
   that are cleared renally. Metformin, which accumulates
   in decreased kidney function, should temporarily be
   discontinued at this time because of an increased risk
   of lactic acidosis, not because of an adverse effect on
   kidney function (Answer C is incorrect). In this case,
   lisinopril is most likely to affect kidney function, so it
   should be discontinued (Answer A is correct). Unlike
   NSAIDs, acetaminophen does not interfere with prostaglandin
   synthesis peripherally; thus, it does not cause
   hemodynamically mediated AKI (Answer B is incorrect).

Question 17

5. Which is most appropriate to add at this time?
   A. Intravenous 0.9% sodium chloride.
   B. Hydrochlorothiazide.
   C. Furosemide.
   D. Fluid restriction

Answer 17

5. Answer: C
   This patient presents with ATN, anuria, and volume
   overload. Although loop diuretics have not been shown
   to improve clinical outcomes in patients with AKI,
   they may increase urinary output, which will help with
   fluid and electrolyte balance. In addition, this patient
   is hypervolemic, so a trial of intravenous loop diuretics
   would be appropriate (Answer C is correct). Adding
   0.9% sodium chloride (Answer A) would worsen fluid
   overload. Hydrochlorothiazide (Answer B) would not
   be appropriate because thiazide diuretics are unlikely
   to be effective with such poor kidney function. Fluid
   restriction (Answer D) may be necessary if furosemide
   fails to increase urinary output, but it would not be the
   first-line approach.

Question 18

6. A 67-year-old man is referred for intermittent chest pain. His medical history is significant for CKD KDIGO
   category G3a, type 2 diabetes, and hypertension. Medications include enalapril, hydrochlorothiazide, and
   pioglitazone. Laboratory values include SCr 1.8 mg/dL, glucose 189 mg/dL, Hgb 12 g/dL, and hematocrit
   (Hct) 36%. His physical examination is normal. The treatment plan is elective cardiac catheterization. Which
   is best for hydration?
   A. 0.9% sodium chloride.
   B. 0.45% sodium chloride.
   C. 5% dextrose/0.45% sodium chloride.
   D. Oral hydration with water.

Answer 18

6. Answer: A
   Intravenous 0.9% sodium chloride is considered the
   most effective hydration for preventing contrast-induced
   nephropathy (Answer A is correct). The other
   solutions, particularly oral, would not be appropriate
   because they are less effective at extracellular volume
   expansion (Answers B, C, and D are incorrect).
   Although not listed as a choice, intravenous sodium
   bicarbonate solutions have also been evaluated in this
   setting and offer no advantage over normal saline.

Question 19

7. After the administration of radiocontrast, which best represents the optimal time to reevaluate renal function
   to assess for the development of contrast-associated nephropathy?
   A. 6 hours.
   B. 24 hours.
   C. 4 days.
   D. 7 days.

Answer 19

7. Answer: B
   Contrast-associated nephropathy is associated with an
   acute rise in BUN and SCr within 24–48 hours, with
   a peak at 3–5 days. Monitoring of SCr at 24 hours
   (Answer B is correct) will help identify the development
   of contrast-associated nephropathy. In contrast,
   6 hours is too early to detect a significant change
   (Answer A is incorrect), and waiting more than 48 hours
   would delay the detection of renal damage (Answers C
   and D are incorrect).

Question 20

Questions 8–11 pertain to the following case.
A 55-year-old man has a history of hypertension and newly diagnosed type 2 diabetes. He denies alcohol use but
does smoke cigarettes (1 pack/day). His medications include atenolol 50 mg/day and a multivitamin. At your pharmacy,
his blood pressure is 149/92 mm Hg. His ACR is 400 mg/g. A recent SCr is 1.9 mg/dL, which is consistent
with a value measured 3 months earlier. His eGFR is 50 mL/minute/1.73 m2.
8. Which category best reflects his kidney disease, according to the KDIGO criteria?
A. G2.
B. G3a.
C. G3b.
D. G4.

Answer 20

8. Answer: B
   The patient’s CKD should be classified as KDIGO category
   3a (GFR 45–59 mL/minute/1.73 m2) (Answer
   B is correct), which can be calculated by the MDRD
   formula or Cockcroft-Gault. The five categories range
   from mild kidney damage (G1) to kidney failure (G5).
   A patient’s CKD would be classified as category G2 if
   the GFR were 60–89 mL/minute/1.73 m2 (Answer A
   is incorrect), category G3b if the GFR were 30–44
   mL/minute/1.73 m2 (Answer C is incorrect), or category
   G4 if the GFR were 15–29 mL/minute/1.73 m2 (Answer
   D is incorrect).

Question 21

9. Using the KDIGO categorization, which best assesses this patient’s albuminuria?
   A. Category A1.
   B. Category A2.
   C. Category A3.
   D. Nephrotic-range proteinuria

Answer 21

9. Answer: C
   The KDIGO guideline also provides guidance on categorizing
   albuminuria according to the urinary ACR.
   This patient has category A3, or severely increased
   albuminuria, given the patient’s ACR greater than 300
   mg/g (Answer C is correct). Category A2 is moderately
   increased albuminuria with an ACR of 30–300 mg/g
   (Answer B is incorrect). Category A1 is an ACR less
   than 30 mg/g (Answer A is incorrect). Nephrotic-range
   proteinuria requires protein excretion exceeding 3 g/day
   (Answer D is incorrect).

Question 22

10. Assuming that nonpharmacologic approaches have been optimized, which is best to limit the progression of
    his kidney disease?
    A. Add nifedipine.
    B. Add diltiazem.
    C. Add enalapril.
    D. Increase atenolol.

Answer 22

10. Answer: C
    Given the diagnosis of diabetes mellitus and the presence
    of severe albuminuria, this patient probably has
    diabetic nephropathy. Progression will be accelerated
    by smoking, poor diabetes control, and poor blood pressure
    control. In patients with diabetes, a target A1C of
    less than 7% is associated with a decrease in the rate
    of disease progression. Blood pressure control of less
    than 130/80 mm Hg in patients also decreases the progression
    of kidney disease. The standard of care in
    patients with diabetic nephropathy is ACEIs (evidence
    for reduced mortality and reduced progression of CKD) or ARBs (evidence for reduced progression but no mortality
    data), so enalapril (Answer C) is the best choice.
    A nondihydropyridine (Answer B) might be initiated in
    patients who cannot tolerate ACEI or ARB therapy, but
    this would not be a choice yet. Dihydropyridine therapy
    (Answer A) is not recommended in diabetic nephropathy
    because of conflicting literature on its efficacy. An
    increase in atenolol (Answer D) might control blood
    pressure, but inhibition of the renin-angiotensin system
    is still the best answer. In addition, a meta-analysis
    evaluating atenolol in patients with hypertension and
    diabetes mellitus found either no difference or worse
    outcomes.

Question 23

11. Enalapril is added to this patient’s regimen. Two weeks later, he returns for a follow-up. His blood pressure is
    139/89 mm Hg. A repeat SCr is 2.3 mg/dL, and serum potassium is 5.2 mEq/L. Which is the best recommendation
    for this patient?
    A. Add chlorthalidone 50 mg/day. Monitor blood pressure, SCr, and K in 2 weeks.
    B. Change enalapril to diltiazem extended release. Monitor blood pressure, SCr, and K in 2 weeks.
    C. Change enalapril to valsartan.
    D. Increase atenolol.

Answer 23

11. Answer: A
    The patient’s blood pressure is not at goal (should be
    less than 130/80 mm Hg). To improve blood pressure
    control and increase the effect of the ACEI, chlorthalidone
    should be added (Answer A). Monitoring of SCr
    and serum potassium is appropriate in this patient. The
    SCr increase is less than 30%, so enalapril should be
    continued, making Answers B and C incorrect. Adding
    chlorthalidone will also counter the tendency for hyperkalemia.
    Answer D would likely lower blood pressure
    but would not be the preferred approach because renal
    protection would probably not be improved.

Question 24

12. A study compared use of an ARB alone and in combination with an ACEI in patients with CKD. Acute kidney
    injury occurred in 80 of 724 patients (11%) receiving monotherapy and 130 of 724 patients (18%) receiving
    combination therapy. Given this information, which most accurately depicts the number of patients needed to
    harm?
    A. 7.
    B. 14.
    C. 50.
    D. 105.

Answer 24

12. Answer: B
    Calculation of the number needed to harm (NNH) is
    similar to calculation of the number needed to treat but
    is focused on a negative outcome. In this study, the risk
    of AKI was 11% in the monotherapy group and 18%
    in the combination therapy group, a difference of 7%.
    The NNH is calculated as 1/(absolute risk increase) =
    1/(0.07) = 14.3. Hence, the best estimate is that one
    additional patient would develop AKI for about every
    14 patients treated with combination therapy compared
    with ARB therapy alone (Answer B is correct; Answers
    A, C, and D are incorrect). When calculating the NNH,
    it is best to round the number down to the nearest whole
    number, in contrast to calculating the number needed to
    treat, when the number is rounded up.

Question 25

13. A 70-year-old man is being assessed for HD access. He has a history of diabetes mellitus and hypertension but is otherwise healthy. Which HD access modality is best to use in this patient? A. Subclavian catheter. B. Tenckhoff catheter. C. Arteriovenous graft. D. Arteriovenous fistula.

Answer 25

13. Answer: D A native arteriovenous fistula (Answer D) is the preferred access for chronic HD. If an arteriovenous fistula cannot be constructed, a synthetic arteriovenous graft (Answer C) is considered second line. A subclavian catheter (Answer A) would be a poor choice because of the greater risk of infection and thrombosis and because of the poor blood flow obtained through a catheter. A Tenckhoff catheter (Answer B) is incorrect because this is a catheter for peritoneal dialysis

Question 26

14. A patient undergoing long-term HD has intradialytic hypotension. After nonpharmacologic approaches have been optimized, which medication is best to manage his low blood pressure? A. Levocarnitine. B. Sodium chloride tablets. C. Fludrocortisone. D. Midodrine.

Answer 26

14. Answer: D The best-studied agent is midodrine, an α1-agonist (Answer D). Levocarnitine (Answer A) has been tried, but data are limited on its benefit. Fludrocortisone (Answer C) is a synthetic mineralocorticoid that is used for hypotension in other situations; however, its primary mechanism is caused by sodium and water retention in the kidney; therefore, this drug is less likely to work. Sodium chloride tablets (Answer B) would not work acutely, and they should generally be avoided.

Question 27

15. A patient with CKD on peritoneal dialysis presents with fever and abdominal pain. She also notes that her peritoneal dialysate has become cloudy. Laboratory evaluation of dialysate reveals many white blood cells, primarily neutrophils. Gram stain and culture of the fluid are ordered. According to the 2016 International Society for Peritoneal Dialysis Peritonitis Recommendations, which is the best empiric therapy for this patient? A. Intravenous metronidazole plus gentamicin. B. Intravenous clindamycin plus vancomycin. C. Cefazolin plus ceftazidime instilled intraperitoneally. D. Vancomycin instilled intraperitoneally.

Answer 27

15. Answer: C Empiric coverage for the treatment of peritoneal dialysis– related peritonitis should include activity against both gram-positive and gram-negative organisms (Answers B and D are incorrect). Intraperitoneal administration is preferred to intravenous administration. Cefazolin will provide activity against Staphylococcus unless an area has a high rate of methicillin-resistant organisms (Answer C). The choice of antibiotic for gram-negative coverage can include a third-generation cephalosporin with activity against Pseudomonas (e.g., ceftazidime, cefepime) (Answer C) or an aminoglycoside. Short-term use of an aminoglycoside should not adversely affect residual renal function. For patients with dialysis-related peritonitis, empiric anaerobic coverage is unnecessary (Answers A and B are incorrect).

Question 28

Questions 16 and 17 pertain to the following case. A 60-year-old patient on HD has had ESRD for 10 years. His HD access is a left arteriovenous fistula. He has a history of hypertension, coronary artery disease, mild HFrEF, type 2 diabetes, and a seizure disorder. Medications are as follows: epoetin alfa 14,000 units intravenously three times/week at dialysis, a renal multivitamin once daily, atorvastatin 20 mg/day, insulin, calcium acetate 2 tablets three times daily with meals, phenytoin 300 mg/day, and intravenous iron 100 mg/month. Laboratory values are as follows: Hgb 10.2 g/dL, PTH 800 pg/mL, Na 140 mEq/L, K 4.9 mEq/L, SCr 7.0 mg/dL, calcium 9.5 mg/dL, albumin 2.5 g/dL, and phosphorus 7.8 mg/dL. Serum ferritin is 550 ng/mL, and TSAT is 32%. The red blood cell count indices are normal. His WBC is normal, and he is afebrile. 16. Which is most likely contributing to this patient’s relative epoetin resistance? A. Hyperparathyroidism. B. Iron deficiency. C. Phenytoin therapy. D. Infection.

Answer 28

16. Answer: A Hyperparathyroidism is associated with epoetin resistance in patients on HD (Answer A). Although iron deficiency is the most common cause of epoetin deficiency, this patient’s laboratory results do not indicate iron deficiency (Answer B) because TSAT is greater than 30% and serum ferritin is greater than 500 ng/mL. Phenytoin therapy (Answer C) has been associated with anemia in other patient populations but not in patients on HD. Infection (Answer D) and inflammation are very common causes of epoetin deficiency in patients on HD, but nothing in this patient’s presentation suggests an infectious or inflammatory process.

Question 29

17. In addition to diet modification and emphasizing adherence, which is best for managing this patient’s hyperparathyroidism? A. Increase calcium acetate. B. Change calcium acetate to sevelamer and add cinacalcet. C. Hold calcium acetate and add intravenous vitamin D analog. D. Add intravenous vitamin D analog.

Answer 29

17. Answer: B This patient needs treatment for his elevated PTH (800 pg/mL), which places him at high risk of renal osteodystrophy and vascular calcification. He has high serum phosphorus, and although the measured serum calcium concentration is normal, his corrected calcium concentration is elevated, given the presence of hypoalbuminemia (corrected calcium is 10.7 mg/dL). Current phosphate binder therapy is contributing to calcium exposure; therefore, calcium acetate should be discontinued and sevelamer initiated; also, cinacalcet should be added, which will lower PTH and, potentially, serum calcium (Answer B is correct). Answer A is incorrect because increasing the calcium acetate may worsen the hypercalcemia. Answer C is incorrect for two reasons. First, the patient needs some type of phosphate binder; second, intravenous vitamin D analogs can worsen hypercalcemia and are not very effective at reducing elevated PTH in the presence of hyperphosphatemia. Answer D is incorrect because intravenous vitamin D analogs can worsen hypercalcemia and are not very effective at reducing elevated PTH in the presence of hyperphosphatemia. Because this patient also has a seizure disorder, close monitoring of serum calcium concentrations is recommended with the introduction of cinacalcet and discontinuation of calcium acetate. Significant reductions in serum calcium can lower the seizure threshold and potentially worsen seizures.

Question 30

18. A 40-year-old patient on dialysis with a history of grand mal seizures takes phenytoin 300 mg/day. His albumin concentration is 3.0 g/dL. His total phenytoin concentration is 5.0 mcg/mL. Which best interprets the phenytoin concentrations? A. Subtherapeutic; a dose increase is needed. B. Therapeutic; no dosage adjustment is needed. C. Toxic; a dose reduction is needed. D. Not interpretable.

Answer 30

18. Answer: B The presence of kidney failure and low serum albumin concentrations results in an increased free fraction of phenytoin, so the measured phenytoin concentration cannot be assumed to be subtherapeutic because it is less than 10 mcg/mL (Answer A is incorrect). However, the concentration can be interpreted with proper adjustment for the presence of renal failure and the patient’s measured serum albumin (Answer D is incorrect). Use of the formula that adjusts for hypoalbuminemia in a patient with normal renal function would indicate the concentration is subtherapeutic, but this is not appropriate for a patient on dialysis (Answer A is incorrect). Using the correction equation for a patient with renal failure (adjusted phenytoin concentration = concentration measured/[(0.1 × albumin) + 0.1] = (5.0 mcg/mL)/ [(0.1 × 3.0) + 0.1] = (5.0)/(0.4) = 12. 5 mcg/mL) gives a corrected phenytoin concentration within the therapeutic range (Answer B is correct; Answer C is incorrect).

Question 31

Self-Assessment Questions Answers and explanations to these questions can be found at the end of the chapter. Questions 1–3 pertain to the following case. R.B. is a 50-year-old woman who has been on hemodialysis (HD) for 9 years. Her medical history includes end-stage renal disease (ESRD) secondary to type 2 diabetes (DM), diabetic neuropathy, hypertension, and gastroesophageal reflux disease. She generally adheres to her dialysis prescription. Current medications include: calcium acetate 667 mg 1 capsule with meals three times a day, insulin glargine 10 units every morning and insulin aspart 3–5 units with meals, ranitidine 150 mg once daily, aspirin 81 mg once daily, renal multivitamin 1 tablet daily, gabapentin 600 mg once daily at bedtime, and atorvastatin 20 mg once daily. She receives epoetin alfa 8000 units intravenously and paricalcitol 2 mcg intravenously at each dialysis session. The patient received dietary counseling and states that she adheres to her diet as closely as possible. Her serum albumin concentration is 4.0 g/dL. Her most recent laboratory values show intact parathyroid hormone (PTH) 700 pg/ mL, calcium 10.4 mg/dL, and phosphorus 6.8 mg/dL. 1. Which is the best recommendation for controlling R.B.’s phosphorus concentration? A. Increase calcium acetate to 2 capsules three times a day. B. Discontinue calcium acetate and initiate calcium carbonate 1000 mg with meals and 500 mg with snacks. C. Discontinue calcium acetate and initiate aluminum hydroxide 1 g with meals and snacks. D. Discontinue calcium acetate and initiate sevelamer carbonate 1600 mg with meals three times a day.

Answer 31

1. Answer: D This patient’s PTH, calcium, and phosphorus values are not at goal. Answer A is incorrect because it would add more calcium load. Answer B similarly gives a calcium product to someone whose calcium concentration is too high already. Aluminum should be avoided in patients with CKD because of the risk of aluminum intoxication (Answer C is incorrect). Sevelamer is the best choice because it lowers phosphorus while avoiding additional calcium administration. Sevelamer dosage may have to be adjusted to reduce phosphate concentrations to goal (Answer D is correct).

Question 32

2. For R.B., the nephrology team considers the addition of cinacalcet to directly reduce the PTH concentration. Which laboratory value is most important to monitor for safety? A. Liver function. B. Calcium. C. PTH. D. Creatinine.

Answer 32

2. Answer: B Cinacalcet is a good choice for this patient because both the high calcium and the high phosphorus values limit the use of vitamin D analogs. However, serum calcium values should be monitored closely because hypocalcemia can occur. Hypocalcemia may lead to seizures (most likely in patients with a history of them), and/or QT prolongation (Answer B is correct). Parathyroid hormone should also be monitored because its concentration should decrease, but this is a sign of efficacy (Answer C is incorrect). Liver function tests may be performed, but serious liver problems are rare (Answer A is incorrect). Creatinine does not have to be monitored in a patient already receiving dialysis (Answer D is incorrect).

Question 33

3. R.B.’s epoetin dose has been unchanged for 6 months. Most recently, her laboratory values were as follows: hemoglobin 8.8 g/dL, transferrin saturation (TSAT) 14%, and serum ferritin 90 ng/mL. In the past month, her hemoglobin concentration was 9.4 g/dL. There are no obvious signs of infection or bleeding.Which therapeutic changes would be most appropriate to manage this patient’s anemia? A. Administer intravenous iron sucrose 100 mg with each dialysis session for 10 dialysis sessions. B. Counsel the patient to take ferrous sulfate 325 mg twice daily with meals. C. Initiate folic acid 1 mg orally once daily. D. Increase the epoetin dose to 10,000 units intravenously with each HD session.

Answer 33

3. Answer: A This patient’s anemia has worsened while receiving epoetin therapy, most likely because of iron deficiency. Answer A is a recommended iron-loading regimen. Patients undergoing dialysis universally require parenteral iron to maintain iron stores (Answer A is correct). Oral iron is not recommended in patients receiving HD. It is unlikely to provide sufficient iron to overcome the anemia and replenish body stores (Answer B is incorrect). Folic acid is already being administered to this patient with her renal multivitamin, and it does not address the primary problem of iron deficiency (Answer C is incorrect). Although increasing the epoetin dose might increase the patient’s hemoglobin concentration minimally, it is not appropriate without first addressing the patient’s iron deficiency. In addition, it will increase dialysis-related costs with little benefit to the patient (Answer D is incorrect

Question 34

4. Which drug is most likely to be removed by high-flux HD? Water Solubility Molecular Weight (Da) Volume of Distribution (L/kg) Drug A Moderate 180 1 Drug B High 1400 7 Drug C High 250 0.3 Drug D Low 300 2 A. Drug A. B. Drug B. C. Drug C. D. Drug D.

Answer 34

4. Answer: C For a drug to be dialyzed, it should be water soluble (Answers A and D are incorrect). In addition, drugs with relatively large volumes of distribution are not effectively removed by dialysis because the drug is in the tissues (Answer B is incorrect). With high-flux membranes, molecules of up to 20,000 Da molecular weight are removed, so molecular weight is not an issue with any of these drugs. Consequently, drug C is most likely to be removed by dialysis (Answer C is correct).

Question 35

5. An adult patient with stage 5 chronic kidney disease (CKD) who is receiving maintenance automated peritoneal dialysis (PD) is experiencing abdominal pain, fever, and cloudy dialysate bags. The nephrology team suspects peritonitis and wants to initiate empiric antibiotic therapy. Which is the best empiric antibiotic therapy for this patient? A. Oral ciprofloxacin and metronidazole. B. Intraperitoneal vancomycin alone. C. Intravenous gentamicin alone. D. Intraperitoneal cefazolin and ceftazidime

Answer 35

5. Answer: D This patient has the classic signs and symptoms of PD-associated peritonitis. Immediate treatment is indicated. Empiric therapy must cover both gram-positive species (Staphylococcus spp. and Streptococcus spp.) and gram-negative species (including Pseudomonas spp.). Answer D is best at covering both, and the drugs are administered by the preferred, intraperitoneal route. Answer A uses oral medications and provides insufficient gram-positive coverage. In addition, the anaerobic coverage provided by metronidazole is not recommended for empiric treatment of PD-related peritonitis. Answer B provides only gram-positive coverage. Answer C is incorrect because it has inadequate gram-positive coverage and uses the intravenous route.

Question 36

Questions 6 and 7 pertain to the following case. A.M. is a 54-year-old man who presents with diagnosed type 2 DM. His serum creatinine (SCr) concentration is 1.6 mg/dL, and a spot albumin/creatinine ratio (ACR) is 410 mg/g. His blood pressure is 145/89 mm Hg and hemoglobin A1C (A1C) is 7.1%. 6. Which would provide the best therapeutic intervention at this time to slow A.M.’s diabetic kidney disease progression? A. Clonidine. B. Lisinopril. C. Metoprolol. D. Amlodipine.

Answer 36

6. Answer: B The presence of albuminuria category A2 or greater indicates that an ACEI or ARB is beneficial to reduce intraglomerular pressure and slow kidney disease progression (Answer B is correct). Because this patient’s blood pressure is above goal, lowering it would be beneficial. However, neither clonidine, metoprolol, nor amlodipine decrease proteinuria significantly (Answers A, C, and D are incorrect).

Question 37

7. Which dietary intervention is best to reduce A.M.’s albuminuria? A. Protein-restricted diet. B. Omega-3 fatty acid administration. C. Low-carbohydrate (Atkins) diet. D. Low-potassium diet.

Answer 37

7. Answer: A Protein restriction to 0.8 g/kg/day or less will likely reduce albuminuria and is the best choice (Answer A is correct). Omega-3 fatty acids have not been studied in diabetic kidney disease (Answer B is incorrect). Atkins diet is not recommended because it tends to be a high-protein diet (Answer C is incorrect). A low-potassium diet would be appropriate for a patient with advanced kidney disease (not this patient) to prevent hyperkalemia but would not affect disease progression (Answer D is incorrect).

Question 38

8. A 76-year-old woman presents with an acute febrile illness that includes diarrhea and generalized aches. She has been taking ibuprofen for pain for the past 48 hours and presents to the emergency department feeling “awful.” Her laboratory tests and physical examination suggest she is not volume depleted. Her SCr has doubled since her last visit 1 year ago. Her physician believes she has acute kidney injury (AKI). A urinalysis does not reveal red blood cells (RBCs), white blood cells, or cellular casts. Which is the most likely diagnosis in this case? A. Prerenal AKI. B. Hemodynamically mediated AKI. C. Intrinsic AKI.

Answer 38

8. Answer: B This is a typical presentation of hemodynamically mediated AKI. In this case, the NSAID is inhibiting vasodilating prostaglandins in the afferent arteriole (Answer B is correct). Prerenal kidney injury refers to abrupt changes in kidney function caused by low-flow states to the kidney (e.g., hypotension; Answer A is incorrect). Intrinsic AKI includes acute tubular necrosis and acute interstitial nephritis. The presentation and a urinalysis confirming absence of cellular casts rule out this option (Answer C is incorrect). Postrenal failure is usually caused by obstruction, and there is no reason to suspect obstruction in this patient (Answer D is incorrect).

Question 39

Questions 1 and 2 pertain to the following case. A 62-year-old man presents with a history of hypertension and newly diagnosed type 2 diabetes (DM). He reports occasional alcohol use and smokes 1 pack of cigarettes/day. His medications include hydrochlorothiazide and valsartan. His current blood pressure is 130/80 mm Hg. A spot urine dipstick shows ACR 350 mg/g. A recent SCr is 2.3 mg/dL (SCr was 2.4 mg/dL 6 months ago). His eGFR is 29 mL/minute/1.73 m2. 1. Which category best classifies this patient’s GFR? A. Stage G3a. B. Stage G3b. C. Stage G4. D. Stage G5.

Answer 39

1. Answer: C The patient has stage G4 CKD (GFR 15–29 mL/minute/1.73 m2), which can be calculated by the MDRD or CKD-EPI equations, provided in the eGFR. The patient has had stable function for more than 3 months.

Question 40

2. Which best represents this patient’s albuminuria category? A. A1. B. A2. C. A3. D. A4.

Answer 40

2. Answer C The patient has an ACR greater than 300 mg/g, classifying this patient’s albuminuria as A3.

Question 40

3. A 72-year-old woman (height 63 inches, weight 48 kg; ideal body weight 52.4 kg) presents to the clinic. She is visibly small and frail. Her SCr, unchanged from the past year, is 0.4 mg/dL. Which is the best method to assess kidney function in this patient? A. Cockcroft-Gault. B. Modification of Diet in Renal Disease (MDRD). C. CKD-EPI. D. 24-hour urine collection for CrCl.

Answer 40

3. Answer: D Clinicians should be aware that all creatinine-based equations to estimate kidney function will provide overestimations if the SCr is low because the patient has low muscle mass. Some clinicians “round up” the SCr in these patients to 0.8 or 1.0 mg/dL, but few data support this approach, and rounding up can underestimate kidney function. If an accurate measure of kidney function is required, a 24-hour urine collection for CrCl assessment should be ordered.

Question 41

4. A 60-year-old man presents with a medical history of hypertension and newly diagnosed type 2 DM at the clinic. He reports neither alcohol consumption nor smoking. His only medication is atenolol 25 mg daily. His current blood pressure is 155/96 mm Hg and heart rate is 76 beats/minute. His ACR is 350 mg/g. A recent SCr is 1.9 mg/ dL. His eGFR is 37 mL/minute/1.73 m2. Enalapril is added to this patient’s regimen. Two weeks later, he presents back to his physician. His blood pressure is 145/93 mm Hg. A repeated SCr measurement is 2.3 mg/dL, and his serum potassium is 5.2 mEq/L. Which is the best recommendation for this patient? A. Change enalapril to diltiazem (Cardizem CD). Monitor blood pressure, SCr, and potassium concentration in 2 weeks. B. Add chlorthalidone 12.5 mg daily. Monitor blood pressure, SCr, and potassium concentration in 2 weeks. C. Change enalapril to valsartan. D. Increase atenolol

Answer 41

4. Answer: B The patient’s blood pressure is not at goal (it should be less than 130/80 mm Hg or SBP<120 mmHg depending on guideline). To improve blood pressure control and enhance the effect of the ACEI, chlorthalidone should be added to the regimen (Answer B is correct). Adding chlorthalidone will also counter the tendency for hyperkalemia. Monitoring of SCr and serum potassium concentration is appropriate for this patient. There is less than a 30% increase in SCr, so enalapril should be continued (Answers A and C are incorrect). Increasing atenolol would probably lower blood pressure but is not the preferred intervention because renal protection would likely not be enhanced (Answer D is incorrect).

Question 42

Questions 5 and 6 pertain to the following case. A 73-year-old man presents with a 20-year history of type 2 DM and stage G5 CKD. He is not receiving dialysis. He presents with dyspnea on exertion and fatigue. His blood pressure is 157/70 mm Hg. Fecal occult blood findings are negative. Medications include enalapril 10 mg daily, amlodipine 10 mg daily, rosuvastatin 10 mg daily, furosemide 40 mg daily, insulin glargine 12 units at bedtime, insulin aspart 4–6 units before meals, and calcium acetate 667 mg three times daily with meals. His BUN and SCr values are 75 mg/dL and 6.5 mg/dL, respectively. One year ago, his SCr was 4.9 mg/dL. Other pertinent laboratory values include serum potassium 6.2 mEq/L, CO2 18 mEq/L, phosphorus 4.2 mg/dL, glucose 150 mg/dL, hemoglobin 8.9 g/dL, and eGFR 8 mL/minute/1.73 m2. Serum ferritin is 259 ng/mL, serum iron is 30 mcg/dL, and transferrin saturation (TSAT) is 28%. 5. Which is the most likely cause of anemia in this patient? A. Absolute iron deficiency. B. Dietary deficiency. C. Erythropoietin (EPO) deficiency. D. Enalapril.

Answer 42

5. Answer: C This patient has stage 5 CKD, so anemia caused by EPO deficiency should be high on the differential diagnosis (Answer C is correct). Although iron deficiency can be common in patients with CKD, this patient’s iron study results are in the normal range (Answer A is incorrect). A dietary deficiency causing anemia is usually linked to iron deficiency (Answer B is incorrect). Angiotensin-converting enzyme inhibitors have been linked to epoetin resistance, but the effect is unlikely to be this dramatic (Answer D is incorrect).

Question 43

6. The patient in case 5 starts intermittent hemodialysis (HD). Three months later, he is tolerating HD well. His most recent hemoglobin measurement is 9.5 g/dL. His serum ferritin concentration is 70 ng/mL and TSAT is 12%. His blood pressure and fluid status are reasonably well controlled, and his other electrolytes are at goal. His medications are unchanged except that he now receives epoetin alfa 3000 units intravenously three times weekly with dialysis. Which is the most appropriate next step for this patient? A. Add oral iron. B. Add intravenous iron. C. Increase the epoetin alfa dose. D. Maintain therapy because the patient is at goal.

Answer 43

6. Answer: B From the laboratory values, this patient has iron deficiency (Answer D is incorrect). Oral iron is not recommended for patients undergoing dialysis because it is generally ineffective and has significant GI adverse effects and drug interactions (Answer A is incorrect). Increasing the epoetin dose might increase the hemoglobin concentration, but excessive doses of epoetin would be required, which would not be cost-effective (Answer C is incorrect). Intravenous iron should be administered (Answer B is correct).

Question 44

7. A 60-year-old patient undergoing HD presents with a 10-year history of ESRD. His HD access is a left arteriovenous fistula. He has a history of hypertension, coronary artery disease, mild congestive heart failure, type 2 DM, and a seizure disorder. His medications are as follows: epoetin 14,000 units intravenously three times weekly at dialysis, a multivitamin (Nephrocaps) once daily, atorvastatin 20 mg daily, insulin glargine 8 units at bedtime, calcium acetate 2 capsules three times daily with meals, phenytoin 300 mg daily, and intravenous iron sucrose 100 mg monthly. Laboratory values are as follows: hemoglobin 10.2 g/dL, intact parathyroid hormone (PTH) 800 pg/mL, sodium 140 mEq/L, potassium 4.9 mEq/L, SCr 7.0 mg/dL, calcium 9 mg/dL, albumin 2.5 g/dL, and phosphorus 7.8 mg/dL. Serum ferritin is 300 ng/mL, and TSAT is 32%. The patient’s RBC indices are normal. His white blood cell count is normal. He is afebrile. Which is most likely contributing to relative epoetin resistance in this patient? A. Iron deficiency. B. Hyperparathyroidism. C. Phenytoin therapy. D. Infection.

Answer 44

7. Answer: B Hyperparathyroidism is associated with epoetin resistance in patients receiving HD (Answer B is correct). Although iron deficiency is the most common cause of epoetin resistance, the laboratory results for this patient do not indicate iron deficiency (Answer A is incorrect). Phenytoin therapy has been associated with folate deficiency in other patient populations but is not likely the primary issue when receiving HD (Answer C is incorrect). Infection and inflammation are common causes of epoetin deficiency in patients undergoing HD, but nothing in this patient’s presentation suggests an infectious or inflammatory process (Answer D is incorrect).

Question 45

8. A 45-year-old patient has hypertension, type 2 DM (diet controlled), and CKD (eGFR 40 mL/minute/1.73 m2). Medications include atenolol, valsartan, and hydrochlorothiazide. He has no health insurance. His most recent laboratory values were within limits except for serum phosphorus, which, for the second month in a row, was 5.1 mg/dL. Serum calcium concentration is 9.0 mg/dL, albumin concentration is 4 g/dL, and intact PTH concentration is 40 pg/mL. Which is the most appropriate intervention? A. Add calcium carbonate with meals. B. Begin a low-phosphorus diet. C. Add sevelamer carbonate with meals. D. Add calcitriol.

Answer 45

8. Answer: B This patient has hyperphosphatemia. Other than serum phosphorus, his laboratory values are normal. The first-line intervention is dietary restriction of phosphorus (Answer B is correct). Answers A and C are phosphate-binding medications, which may be considered if dietary restriction is insufficient to control phosphate. If a phosphate binder is used, the calcium dose should be restricted (Answers A and C are incorrect). Calcitriol is sometimes used for patients with CKD to raise serum calcium concentration; however, this patient’s calcium concentration is not low (Answer D is incorrect).

Question 46

9. A 70-year-old man is being assessed for HD access. He has a history of DM and hypertension. Which best describes the dialysis access with the lowest rate of complications and the longest life span and is thus the best access to use? A. Subclavian catheter. B. Tenckhoff catheter. C. Arteriovenous graft. D. Arteriovenous fistula.

Answer 46

9. Answer: D A native arteriovenous fistula is the preferred access for chronic HD (Answer D is correct). If an arteriovenous fistula cannot be constructed, a synthetic arteriovenous graft is considered second line (Answer C is incorrect). A subclavian catheter is a poor choice because of the increased risk of infection and thrombosis and because of the poor blood flow obtained through a catheter. Catheter use should be limited to emergency and short-term situations as well as when all other access options have been exhausted (Answer A is incorrect). A Tenckhoff catheter is used for PD (Answer B is incorrect).

Question 47

10. A 40-year-old patient receiving HD has a history of grand mal seizures. He takes phenytoin 300 mg daily. His albumin concentration is 3.0 g/dL. His total phenytoin concentration is 5.0 mg/dL. Which best interprets this patient’s phenytoin concentrations? A. The concentration is subtherapeutic, and a dose increase is warranted. B. The concentration is therapeutic, and no dosage adjustment is required. C. The concentration is toxic, and a dose reduction is required. D. The concentration result is uninterpretable

Answer 47

10. Answer: B The presence of kidney failure and low albumin concentration results in an increased free fraction of phenytoin. Using the correction equation gives a corrected concentration of 12.5 mg/L, which is therapeutic (range 10–20 mg/L). A free phenytoin concentration can also be obtained.