Nephrology Flashcards
1
Q
- 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.
A
- 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).
2
Q
- 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.
A
- 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).
3
Q
- 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
A
- 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).
4
Q
- 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.
A
- 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.
5
Q
- 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.
A
- 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).
6
Q
- 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.
A
- 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).
7
Q
- 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.
A
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).
8
Q
- 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.
A
- 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).
9
Q
- 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%.
A
- 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).
10
Q
- 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.
A
- 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).
11
Q
- 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.
A
- 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).
12
Q
- 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.
A
- 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).
13
Q
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.
A
- 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).
14
Q
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.
- Which best depicts this patient’s FENa?
A. 0.32%.
B. 0.67%
C. 1.5%.
D. 3.4%.
A
- 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.
15
Q
- Which is the best classification of this patient’s AKI?
A. Prerenal azotemia.
B. Intrinsic renal disease.
C. Postrenal obstruction.
D. Functional AKI.
A
- 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.
16
Q
- 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.
A
- 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).
17
Q
- Which is most appropriate to add at this time?
A. Intravenous 0.9% sodium chloride.
B. Hydrochlorothiazide.
C. Furosemide.
D. Fluid restriction
A
- 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.
18
Q
- 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.
A
- 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.
19
Q
- 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.
A
- 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).
20
Q
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.
A
- 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).
21
Q
- Using the KDIGO categorization, which best assesses this patient’s albuminuria?
A. Category A1.
B. Category A2.
C. Category A3.
D. Nephrotic-range proteinuria
A
- 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).
22
Q
- 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.
A
- 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.
23
Q
- 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.
A
- 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.
24
Q
- 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.
A
- 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.
25
Q
- 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.
A
- 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
26
Q
- 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.
A
- 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.
27
Q
- 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.
A
- 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).
28
Q
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.
A
- 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.
29
Q
- 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.
A
- 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.
30
Q
- 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.
A
- 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).
31
Q
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.
A
- 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).
32
Q
- 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.
A
- 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).
33
Q
- 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.
A
- 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
34
Q
- 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.
A
- 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).
35
Q
- 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
A
- 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.
36
Q
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.
A
- 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).
37
Q
- 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.
A
- 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).
38
Q
- 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.
A
- 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).
39
Q
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.
A
- 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.
40
Q
- Which best represents this patient’s albuminuria category?
A. A1.
B. A2.
C. A3.
D. A4.
A
- Answer C
The patient has an ACR greater than 300 mg/g, classifying
this patient’s albuminuria as A3.
40
Q
- 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.
A
- 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.
41
Q
- 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
A
- 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).
42
Q
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.
A
- 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).
43
Q
- 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.
A
- 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).
44
Q
- 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.
A
- 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).
45
Q
- 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.
A
- 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).
46
Q
- 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.
A
- 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).
47
Q
- 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
A
- 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.
