CCRN Renal Exam 2025 Questions and
Answers
A 24-year-old man has been diagnosed with acute kidney injury as a result of
severe hemorrhaging after a motor vehicle collision. Which of the following would
be expected laboratory values for this patient?
A.
Low urinary osmolality, high urinary sodium concentration
B.
High urinary osmolality, high urinary sodium concentration
C.
Low urinary osmolality, low urinary sodium concentration
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,D.
High urinary osmolality, low urinary sodium concentration - ANSWER-D
A high urinary osmolality (usually greater than 900 mOsm/kg) and a low urinary
sodium concentration (usually less than 20 mEq/L) are normal physiologic
responses to hypoperfusion in patients with normal kidneys.
Test Taking Tip
Consider that the kidney would want to conserve sodium and water with blood
loss. If the kidney is holding onto sodium, little is excreted into the urine, so
urinary sodium is low. If the kidney is holding onto water, little is excreted into the
urine, so it is concentrated and osmolality is increased. Choose the "High urinary
osmolality, low urinary sodium concentration" option.
29-year-old woman has been a patient in the critical care unit for 2 weeks with
acute tubular necrosis (ATN) as a result of crush injuries experienced in a motor
vehicle collision. She was normotensive on admission. What would be the most
common explanation for her ATN?
A.
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,Rhabdomyolysis
B.
Hemorrhage
C.
Creatinine release
D.
Cardiac dysrhythmias - ANSWER-A.
The most common cause for ATN in a normotensive patient who has experienced
crush injuries is rhabdomyolysis with resultant myoglobinuria. Rhabdomyolysis is
acute muscle destruction and is associated with myoglobinuria. Myoglobin released
from muscle cells may cause acute kidney injury by having a direct toxic effect on
tubule epithelial cells or inducing intratubular cast formation.
Test Taking Tip
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, The key points in this question are that she had a crush injury and that she was not
hypotensive. Hemorrhage or dysrhythmias significant enough to cause ATN
certainly would cause hypotension, so eliminate "Hemorrhage and Cardiac
Dysfunction." Creatinine is a normal waste product that normal kidneys easily
excrete, so eliminate option "Creatinine release." Rhabdomyolysis causes
myoglobin release, which is toxic to the renal tubules, especially in large amounts
as would occur in a crush injury. Choose the "Rhabdomyolysis" option.
A patient admitted with Goodpasture syndrome has developed acute tubular
necrosis. The patient's phosphorus level is 6.5 mg/dl. Control of the phosphorus is
important to avoid complications from which of the following?
A.
Hyponatremia
B.
Hypocalcemia
C.
Hypernatremia
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Answers
A 24-year-old man has been diagnosed with acute kidney injury as a result of
severe hemorrhaging after a motor vehicle collision. Which of the following would
be expected laboratory values for this patient?
A.
Low urinary osmolality, high urinary sodium concentration
B.
High urinary osmolality, high urinary sodium concentration
C.
Low urinary osmolality, low urinary sodium concentration
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,D.
High urinary osmolality, low urinary sodium concentration - ANSWER-D
A high urinary osmolality (usually greater than 900 mOsm/kg) and a low urinary
sodium concentration (usually less than 20 mEq/L) are normal physiologic
responses to hypoperfusion in patients with normal kidneys.
Test Taking Tip
Consider that the kidney would want to conserve sodium and water with blood
loss. If the kidney is holding onto sodium, little is excreted into the urine, so
urinary sodium is low. If the kidney is holding onto water, little is excreted into the
urine, so it is concentrated and osmolality is increased. Choose the "High urinary
osmolality, low urinary sodium concentration" option.
29-year-old woman has been a patient in the critical care unit for 2 weeks with
acute tubular necrosis (ATN) as a result of crush injuries experienced in a motor
vehicle collision. She was normotensive on admission. What would be the most
common explanation for her ATN?
A.
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,Rhabdomyolysis
B.
Hemorrhage
C.
Creatinine release
D.
Cardiac dysrhythmias - ANSWER-A.
The most common cause for ATN in a normotensive patient who has experienced
crush injuries is rhabdomyolysis with resultant myoglobinuria. Rhabdomyolysis is
acute muscle destruction and is associated with myoglobinuria. Myoglobin released
from muscle cells may cause acute kidney injury by having a direct toxic effect on
tubule epithelial cells or inducing intratubular cast formation.
Test Taking Tip
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, The key points in this question are that she had a crush injury and that she was not
hypotensive. Hemorrhage or dysrhythmias significant enough to cause ATN
certainly would cause hypotension, so eliminate "Hemorrhage and Cardiac
Dysfunction." Creatinine is a normal waste product that normal kidneys easily
excrete, so eliminate option "Creatinine release." Rhabdomyolysis causes
myoglobin release, which is toxic to the renal tubules, especially in large amounts
as would occur in a crush injury. Choose the "Rhabdomyolysis" option.
A patient admitted with Goodpasture syndrome has developed acute tubular
necrosis. The patient's phosphorus level is 6.5 mg/dl. Control of the phosphorus is
important to avoid complications from which of the following?
A.
Hyponatremia
B.
Hypocalcemia
C.
Hypernatremia
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