Current Diagnosis and Treatment Pediatrics:
Ch 24: Kidney & Urinary Tract Questions and
Correct Answers
What should be included in the history when renal disease is suspected?
✓ ~~~ Preceding acute or chronic illnesses, rashes or joint pain/swelling, growth delay
or failure to thrive, urinary symptoms, hematuria/proteinuria, pain, sudden weight
gain/loss or edema, drug/toxin exposure, perinatal history, family history of kidney
disease
What are important aspects of the physical examination for evaluating the kidney
and urinary tract?
✓ ~~~ Height, weight, growth percentiles, skin lesions, pallor, edema, skeletal
deformities, anomalies of ears/eyes/external genitalia, blood pressure measurement,
abdominal palpation and auscultation
What should be assessed during blood pressure measurement in a child?
✓ ~~~ Measured in a quiet setting, with a manual cuff of appropriate size, in the right
upper extremity, child seated with feet flat on the ground, cuff covering two-thirds of
the child's upper arm, assessment of peripheral pulses
What should be assessed during abdominal palpation and auscultation in a child?
✓ ~~~ Nephromegaly, abdominal masses, musculature, ascites, bruits
What is the purpose of laboratory evaluation of renal function?
✓ ~~~ To assess kidney function and detect abnormalities
What is serum analysis?
✓ ~~~ Measurement of various substances in the blood to evaluate kidney function
What substances are commonly measured in serum analysis for renal function?
✓ ~~~ Creatinine, blood urea nitrogen (BUN), electrolytes (sodium, potassium,
chloride), albumin
What is the significance of creatinine in serum analysis?
✓ ~~~ Indicates kidney function and can help diagnose kidney disease
What is the significance of blood urea nitrogen (BUN) in serum analysis?
, ✓ ~~~ Indicates kidney function and can help diagnose kidney disease
What is the significance of electrolytes (sodium, potassium, chloride) in serum
analysis?
✓ ~~~ Imbalances can indicate kidney dysfunction
What is the significance of albumin in serum analysis?
✓ ~~~ Low levels can indicate kidney damage or disease
What is urinalysis?
✓ ~~~ Examination of urine to assess kidney function and detect abnormalities
What are the components of a urinalysis?
✓ ~~~ Physical characteristics, chemical analysis, microscopic examination
What physical characteristics are assessed in urinalysis?
✓ ~~~ Color, clarity, odor, specific gravity
What chemical analysis is performed in urinalysis?
✓ ~~~ Measurement of substances such as glucose, protein, blood, pH
What microscopic examination is performed in urinalysis?
✓ ~~~ Detection of cells, casts, crystals, bacteria
What is a urine culture?
✓ ~~~ Laboratory test to identify and determine the sensitivity of bacteria in the urine
What is a renal ultrasound?
✓ ~~~ Imaging test that uses sound waves to visualize the kidneys and urinary tract
What is a renal biopsy?
✓ ~~~ Procedure to obtain a small sample of kidney tissue for microscopic
examination
What are the standard indicators of renal function?
✓ ~~~ Serum levels of urea nitrogen and creatinine.
What is the normal ratio of urea nitrogen to creatinine?
, ✓ ~~~ 10:1.
When may the urea nitrogen to creatinine ratio increase?
✓ ~~~ When renal perfusion or urine flow is decreased.
What can cause an increase in the urea nitrogen to creatinine ratio?
✓ ~~~ Urinary tract obstruction or dehydration.
Why is serum creatinine considered the most reliable single indicator of glomerular
function?
✓ ~~~ Because it is less affected by factors like nitrogen intake, catabolism, and
corticosteroid use.
What factors can affect the generation of creatinine?
✓ ~~~ Age, sex, malnutrition, chronic illness, and amputation.
How does serum creatinine level change over the first 1-2 weeks after birth?
✓ ~~~ It declines to reach a normal level for age.
What is serum cystatin C?
✓ ~~~ A cysteine protease inhibitor produced by all nucleated cells and released in
the blood.
How are levels of serum cystatin C affected?
✓ ~~~ They are not affected by sex, height, or muscle mass.
What is an additional indicator of glomerular function besides creatinine?
✓ ~~~ Serum cystatin C.
What are some limitations of cystatin C assays?
✓ ~~~ They are less widely available and less reliable in certain clinical settings.
What are some less precise but important indicators of possible renal disease?
✓ ~~~ Abnormalities of serum electrolytes, bicarbonate, pH, calcium, phosphorus,
magnesium, albumin, or complement.
What does GFR stand for?
✓ ~~~ Glomerular Filtration Rate.
What does GFR measure?
, ✓ ~~~ The rate at which blood is filtered by the glomeruli in the kidneys.
What does endogenous creatinine clearance (CCr) estimate?
✓ ~~~ Glomerular filtration rate (GFR)
What is the 'classic' approach for determining CCr?
✓ ~~~ A 24-hour urine collection
Why is it difficult to accurately obtain CCr in the pediatric population?
✓ ~~~ Especially in children who are not continent
What is the normal range for total daily creatinine excretion?
✓ ~~~ 15-25 mg/kg
Are normal values higher in males or females?
✓ ~~~ Higher in males, reflective of differences in muscle mass
What does the CCr formula require measurements of?
✓ ~~~ Plasma or serum creatinine (PCr), urine creatinine (UCr), and urine volume (V)
What is the formula for calculating CCr?
✓ ~~~ CCr = (UCr x V) / PCr
Why is correction for size needed in children?
✓ ~~~ Because accepted ranges of normal CCr are based on adult parameters
What is the standard body surface area used for correction in the formula?
✓ ~~~ 1.73 m2
At what age do children reach adult levels of GFR?
✓ ~~~ Approximately 2 years of age
What does GFR below 90 mL/min/1.73 m2 in children > 2 indicate?
✓ ~~~ Underlying kidney disease
When can equations to estimate GFR be used?
✓ ~~~ When the creatinine is stable and not in patients with acute kidney injury (AKI)
What is the 'Bedside Schwartz' equation used for?
