Pathophysiology: Chapter 40: Alterations of Renal and Urinary Tract Function in Children Flashcards
The functional kidney is associated with which embryonic organ?
a. Metanephros c. Pronephros
b. Mesonephros d. Endonephros
ANS: A
The functional kidney is associated with the metanephros. The kidney develops from three
sets of structures: the pronephros (nonfunctional by the end of the embryonic period),
mesonephros (nonfunctional), and metanephros (the functional kidney). Endonephros is
not relevant to this process.
When does urine formation and excretion begin?
a. At birth
b. By 3 months’ gestation
c. By 6 months’ gestation
d. By 8 months’ gestation
ANS: B
Urine formation and excretion begin by the third month of gestation.
Compared with an adult, an infant has a greater content of extracellular fluid, as well as a
greater rate of fluid exchange. What effect does this have on the fluid balance of a child
compared with that of an adult?
a. Edema development is less of a problem.
b. Overhydration is not difficult to manage.
c. Daily fluid requirements are greater.
d. The control of dehydration is more difficult.
ANS: D
An infant not only has a greater content of extracellular fluid, but infants also have a
greater rate of fluid exchange. The adult takes in and excretes approximately 2000 ml of
water daily, representing 5% of the total body fluid and 14% of the extracellular fluid. In
contrast, the infant’s daily exchange of 600 to 700 ml of water represents 290% of the total
body fluid or nearly 50% of the extracellular volume, making control of dehydration and
overhydration more difficult. This fact makes the other options incorrect.
What term is used to identify the condition that exists when the urethral meatus is located
on the undersurface of the penis?
a. Hypospadias c. Hyperspadias
b. Epispadias d. Chordee
ANS: A
Hypospadias is a congenital condition in which the urethral meatus is located on the
ventral side or undersurface of the penis. This is the only term used for this condition.
What initiates inflammation in acute poststreptococcal glomerulonephritis?
a. Lysosomal enzymes
b. Endotoxins from Streptococcus
c. Immune complexes
d. Immunoglobulin E (IgE)–mediated response
ANS: C
The immune complexes initiate inflammation and glomerular injury in acute
poststreptococcal glomerulonephritis. Antigen-antibody complexes are deposited in the
glomerulus, or the antigen may be trapped within the glomerulus and immune complexes
formed in situ. The other options are not involved in initiating inflammation in this
situation.
Acute glomerulonephritis (AGN) may be accompanied by a positive throat or skin culture
for which bacteria?
a. Staphylococcus aureus c. Pseudomonas aeruginosa
b. Streptococcus d. Haemophilus
ANS: B
AGN may be accompanied by a positive throat or skin culture for Streptococcus. AGN is
not associated with any of the other options.
What is the cause of smoky, brown-colored urine resulting from acute poststreptococcal glomerulonephritis? a. Presence of red blood cells b. Presence of urobilinogen c. Slough from the collecting tubules d. Protein in the urine
ANS: A
The urine is usually smoky brown or cola-colored because of the presence of red blood
cells. The other options are not correct statements regarding this condition.
In immunoglobulin G (IgG) nephropathies such as glomerulonephritis, IgG is deposited in
which location?
a. Juxtamedullary nephrons
b. Glomerulus basement membranes
c. Mesangium of the glomerular capillaries
d. Parietal epithelium
ANS: B
Glomerulonephritis develops with the deposition of antigen-antibody complexes (IgG,
immunoglobulin A [IgA], and C3 complement) in the glomerulus, or the antigen may be
trapped within the glomerulus and immune complexes formed in situ.
Immunofluorescence microscopy shows lumpy deposits of IgG and C3 complement on the
glomerular basement membrane (see Figure 39-5). When considering IgG nephropathies,
the only location of the IgG immunoglobulins is the correct option.
What is the pathophysiologic process responsible for the autoimmune disorder of
hemolytic-uremic syndrome (HUS)?
a. Immunoglobulin A (IgA) coats erythrocytes that are destroyed by the spleen, and
remnants are excreted through the kidneys.
b. Verotoxin from Escherichia coli is absorbed from the intestines and damages
erythrocytes and endothelial cells.
c. Endotoxins from E. coli block the erythropoietin produced by the kidneys, which
reduces the number of erythrocytes produced by the bone marrow.
d. Failure of the nephron to filter urea increases the blood urea nitrogen, which binds
to erythrocytes that are subsequently destroyed by the spleen.
ANS: B
In HUS, verotoxin from E. coli is absorbed from the intestines, the glomerular arterioles
become swollen, and these narrowed vessels damage erythrocytes as they pass through.
HUS is responsible for causing a cascade of effects, including lysis of glomerular capillary
endothelial cells. The other options are not relevant.
What is the first indication of nephrotic syndrome in children?
a. Periorbital edema c. Frothy urine
b. Scrotal or labial edema d. Ascites
ANS: A
Onset of nephritic syndrome is insidious, with periorbital edema as the first sign of the
disorder. None of the other options represent the first indication of nephritic syndrome in
children.
Bacteria gain access to the female urinary tract by which means?
a. Systemic blood that is filtered through the kidney
b. Bacteria traveling from the lymph adjacent to the bladder and kidneys
c. Bacteria ascending the urethra into the bladder
d. Colonization of the bladder when urine is static
.
ANS: C
Urinary tract infections (UTIs) in girls occur as a result of perineal bacteria, especially
Escherichia coli, ascending the urethra. None of the other options represent the means by
which bacteria gain access to the female urinary tract
What causes vesicoureteral reflux to occur in children?
a. Children do not ask for help in urinating in a timely manner, and urine is forced up
into the ureters.
b. The submucosal segment of a child’s ureter is short, making the antireflux
mechanism inefficient.
c. The trigone lying between the opening to the ureters and the urethra is
underdeveloped in children.
d. As the bladder fills in infants and children, it pulls the smooth lining of the
transitional epithelium away from the ureters, making the reflux valves ineffective.
ANS: B
Although reflux is considered abnormal at any age, the shortness of the submucosal
segment of the ureter during infancy and childhood renders the antireflux mechanism
relatively inefficient and delicate. The other options are not considered reasons for this
reflux.
What is the mechanism for developing Wilms tumor?
a. The development of a Wilms tumor involves tumor-suppressor genes located on
chromosome 11.
b. Development involves an autosomal dominant inherited disorder involving the Y
chromosome.
c. Wilms tumor is an autoimmune disorder.
d. The development of a Wilms tumor is a congenital anomaly.
ANS: A
Wilms tumor–suppressor genes WT1 and WT 2 are located on chromosome 11. The other
options are not considered relevant to the development of a Wilms tumor.
Which anomaly is often associated with Wilms tumor?
a. Renal anaplasia c. Anemia
b. Aniridia d. Hypothyroidism
ANS: B
Aniridia (lack of an iris in the eye) is an anomaly often associated with Wilms tumor.
Approximately 10% of children who have Wilms tumor also have a loss of other important
genes and therefore have a number of congenital anomalies. The other anomalies listed are
not associated with a Wilms tumor.
Which statement is false about the causes of enuresis?
a. A maturational lag may cause enuresis.
b. Enuresis may be related to increased light sleep.
c. Obstructive sleep apnea may be a symptom of enuresis.
d. Excessive nocturnal levels of vasopressin may cause enuresis.
ANS: D
Children who do not have the normal nocturnal elevation of vasopressin produce a higher
volume of urine with a lower osmolality. The other options are accurate statements
regarding enuresis.
