NR571: Week 7- complex Renal Metabolic & nutritional disorders
UPDATED ACTUAL Questions and CORRECT Answers
Doris is an 86-year-old (weight: 48 kg) with a serum Answer & Rationale: No. Doris has less muscle mass, as a result of the normal
creatinine of 1.2 mg/dL. Her 21-year-old grandson is a aging process. Serum creatinine levels are decreased in patients with decreased
competitive bodybuilder (weight: 90 kg) with the same muscle mass and therefore are underestimated by the value reported. This
serum creatinine value. The normal range of serum underscores the importance of using the eGFR equation as a more accurate
creatinine reported from this laboratory is 0.7-1.2 mg/dL. measurement of GFR which is based on factors such as age, gender, and ethnicity.
Do they have the same renal function?
Patrice is a 71-year-old admitted to the hospital from a Answer & Rationale: When elevations in the BUN or creatinine are present, the
skilled nursing facility with altered mental status. The staff BUN/Cr ratio can help determine whether azotemia is due to a pre-renal, intrinsic,
reports that "she has not been interested in eating or or post-renal source. In normal individuals, the ratio ranges between 12 and 20. In
drinking much" over the last week. Physical exam reveals prerenal azotemia with hypoperfusion of the kidneys, the BUN/Cr ratio would be
orthostatic hypotension, mucous membranes, and poor elevated (>20). Used in the context of Patrice's clinical history, along with exam
skin turgor. Lab results are serum Cr is 2.3 mg/dL (0.7-1.2 findings consistent with dehydration, the BUN/Cr ratio (calculated as 58/2.3=25) is
mg/dL) and BUN is 58 (5-20). How would the initial strongly suggestive of a pre-renal etiology due to hypovolemia.
measurement of the BUN/Cr ratio help in determining the
cause of Patrice's acute kidney injury (AKI)?
Roger is an 82-year-old with cellulitis to the left lower Answer: Total CO2 content should be decreased
extremity. Over the last 24 hours, he has developed Rationale: Serum CO2 will be decreased with metabolic acidosis and represents
hypotension, fever, and metabolic acidosis. What do you the kidney's buffer response to a drop in the pH. (Bonus: In this case, acidosis is
expect to see on the serum chemistry panel, which likely a reflection of the accumulation of lactic acid in the blood secondary to
reflects Roger's kidney response in correcting the acid- hypotension and decreased organ perfusion.
base imbalance?
what are the 5 ways to assess kidney function? Urine examination (urinalysis and microscopy)
Serum chemistry (electrolytes and metabolic waste)
Acid-base balance (serum chloride and carbon dioxide)
Tubular function (urine concentration and dilution)
Glomerular filtration (filtration of functioning nephrons)
what is a urine dipstick used for in assessing kidney useful in differentiating urinary symptom etiology (dysuria, polyuria, hematuria,
function? etc.) when used in conjunction with the physical examination.
Urine microscopy, specifically when casts are visualized, is highly suggestive of
renal disease.
what are the 3 serum chemistry test used to assess kidney Blood urea Nitrogen (BUN)
function? Creatinine (Cr)
BUN/Cr Ration
What is BUN? BUN is a waste product derived from the breakdown of dietary proteins that are
removed by the kidneys.
It provides a rough index of glomerular function and is less reliable than
creatinine levels in estimating kidney function.
UPDATED ACTUAL Questions and CORRECT Answers
Doris is an 86-year-old (weight: 48 kg) with a serum Answer & Rationale: No. Doris has less muscle mass, as a result of the normal
creatinine of 1.2 mg/dL. Her 21-year-old grandson is a aging process. Serum creatinine levels are decreased in patients with decreased
competitive bodybuilder (weight: 90 kg) with the same muscle mass and therefore are underestimated by the value reported. This
serum creatinine value. The normal range of serum underscores the importance of using the eGFR equation as a more accurate
creatinine reported from this laboratory is 0.7-1.2 mg/dL. measurement of GFR which is based on factors such as age, gender, and ethnicity.
Do they have the same renal function?
Patrice is a 71-year-old admitted to the hospital from a Answer & Rationale: When elevations in the BUN or creatinine are present, the
skilled nursing facility with altered mental status. The staff BUN/Cr ratio can help determine whether azotemia is due to a pre-renal, intrinsic,
reports that "she has not been interested in eating or or post-renal source. In normal individuals, the ratio ranges between 12 and 20. In
drinking much" over the last week. Physical exam reveals prerenal azotemia with hypoperfusion of the kidneys, the BUN/Cr ratio would be
orthostatic hypotension, mucous membranes, and poor elevated (>20). Used in the context of Patrice's clinical history, along with exam
skin turgor. Lab results are serum Cr is 2.3 mg/dL (0.7-1.2 findings consistent with dehydration, the BUN/Cr ratio (calculated as 58/2.3=25) is
mg/dL) and BUN is 58 (5-20). How would the initial strongly suggestive of a pre-renal etiology due to hypovolemia.
measurement of the BUN/Cr ratio help in determining the
cause of Patrice's acute kidney injury (AKI)?
Roger is an 82-year-old with cellulitis to the left lower Answer: Total CO2 content should be decreased
extremity. Over the last 24 hours, he has developed Rationale: Serum CO2 will be decreased with metabolic acidosis and represents
hypotension, fever, and metabolic acidosis. What do you the kidney's buffer response to a drop in the pH. (Bonus: In this case, acidosis is
expect to see on the serum chemistry panel, which likely a reflection of the accumulation of lactic acid in the blood secondary to
reflects Roger's kidney response in correcting the acid- hypotension and decreased organ perfusion.
base imbalance?
what are the 5 ways to assess kidney function? Urine examination (urinalysis and microscopy)
Serum chemistry (electrolytes and metabolic waste)
Acid-base balance (serum chloride and carbon dioxide)
Tubular function (urine concentration and dilution)
Glomerular filtration (filtration of functioning nephrons)
what is a urine dipstick used for in assessing kidney useful in differentiating urinary symptom etiology (dysuria, polyuria, hematuria,
function? etc.) when used in conjunction with the physical examination.
Urine microscopy, specifically when casts are visualized, is highly suggestive of
renal disease.
what are the 3 serum chemistry test used to assess kidney Blood urea Nitrogen (BUN)
function? Creatinine (Cr)
BUN/Cr Ration
What is BUN? BUN is a waste product derived from the breakdown of dietary proteins that are
removed by the kidneys.
It provides a rough index of glomerular function and is less reliable than
creatinine levels in estimating kidney function.
