[PEDIA2] LE6 2026 Flashcards
A male child presents with repeated urinary tract infections and failure to gain weight. Micturating cystourethrogram (MCUG) shows dilation of the prostatic urethra and posterior urethral valves. What is the most likely diagnosis?
A. Vesicoureteral reflux
B. Posterior urethral valves
C. Urethral stricture
D. Bladder outlet obstruction
B. Posterior urethral valves
Rationale:
Posterior urethral valves are a common cause of urinary tract infections (UTIs) and failure to thrive in male infants.
They cause bladder outlet obstruction, leading to dilation of the prostatic urethra and hydronephrosis.
MCUG is typically used to diagnose posterior urethral valves.
A 6-month-old male has bilateral abdominal masses and hypertension. His older sister died as a neonate, and his mother had polyhydramnios during pregnancy. What is the most likely diagnosis?
A. Polycystic kidney disease
B. Hydronephrosis
C. Renal vein thrombosis
D. Acute tubular necrosis
A. Polycystic kidney disease
Rationale:
Polycystic kidney disease (PKD) can present in infancy with bilateral abdominal masses and hypertension.
The family history (sister dying as a neonate) and polyhydramnios during pregnancy are strong indicators of autosomal recessive PKD, which often presents in neonates or infants with renal failure and enlarged kidneys.
The most common intrinsic cause of acute kidney injury in childhood is:
A. Glomerulonephritis
B. Acute tubular necrosis
C. Interstitial nephritis
D. Renal artery thrombosis
B. Acute tubular necrosis
Rationale:
Acute tubular necrosis (ATN) is the most common intrinsic cause of acute kidney injury (AKI) in children.
It is often caused by ischemia or nephrotoxic agents (such as medications or infections).
ATN results in damage to the renal tubules, impairing their function and leading to acute kidney injury.
The classic electrolyte disturbance seen in renal tubular acidosis is:
A. Hyperkalemic metabolic acidosis
B. Hypokalemic metabolic acidosis
C. Hyperchloremic metabolic acidosis
D. Hypochloremic metabolic acidosis
C. Hyperchloremic metabolic acidosis
Rationale:
Renal tubular acidosis (RTA) results in hyperchloremic metabolic acidosis, which is due to a failure in renal acidification.
The kidneys cannot properly excrete hydrogen ions, leading to increased chloride in the blood to maintain electrochemical balance.
A newborn presents with gross hematuria noted when the diaper was changed. It was born at term and was further complicated by gestational diabetes. Physical examination reveals lethargy, dry mucous membranes, hypertension, and a right-sided flank mass. What is the most likely cause of hematuria?
A. Renal vein thrombosis
B. Polycystic kidney disease
C. Hydronephrosis
D. Urinary tract infection
A. Renal vein thrombosis
Rationale:
Renal vein thrombosis (RVT) is a common cause of gross hematuria in newborns and can be associated with gestational diabetes.
Abdominal mass, hypertension, and lethargy are typical features.
RVT can lead to kidney ischemia and hematuria due to impaired venous drainage.
Hemolytic uremic syndrome (HUS) is characterized by the triad of:
Microangiopathic hemolytic anemia, thrombocytopenia, and kidney dysfunction.
What is the evidence of renal injury in HUS?
A. Proteinuria
B. Hematuria
C. Hyperkalemia
D. Increased serum creatinine
B. Hematuria
Rationale:
Hemolytic uremic syndrome (HUS) often leads to kidney dysfunction, and hematuria is one of the early signs of renal injury in HUS.
Other renal manifestations may include proteinuria, increased creatinine, and oliguria, but hematuria is a key feature associated with kidney involvement in HUS.
A 12-year-old girl is diagnosed with nephrotic syndrome secondary to systemic lupus erythematosus (SLE). What is the most common type of secondary nephrotic syndrome in SLE?
A. Minimal change disease
B. Focal segmental glomerulosclerosis
C. Membranous nephropathy
D. IgA nephropathy
C. Membranous nephropathy
Rationale:
Membranous nephropathy is the most common form of secondary nephrotic syndrome in patients with systemic lupus erythematosus (SLE).
It is characterized by thickening of the glomerular basement membrane and is commonly associated with nephrotic-range proteinuria.
Alport syndrome is a progressive disorder involving the glomerular basement membrane (GBM). Which of the following is NOT a feature of Alport syndrome?
A. Sensorineural deafness
B. Hematuria
C. Proteinuria
D. Visual impairment
E. Renal failure
D. Visual impairment
Rationale:
Alport syndrome is characterized by sensorineural deafness, hematuria, proteinuria, and renal failure.
While visual impairment can occur in some patients, it is not a hallmark feature of Alport syndrome. The primary issues are related to the kidneys, ears, and eyes, but visual impairment is not as characteristic as the other listed features.
In a patient with post-streptococcal glomerulonephritis (PSGN), the most specific antibody marker is:
A. Anti-streptolysin O (ASO)
B. Anti-DNase B
C. Anti-hyaluronidase
D. Streptococcal antibody titer
B. Anti-DNase B
Rationale:
Anti-DNase B is the most specific antibody marker in post-streptococcal glomerulonephritis (PSGN).
Elevated anti-DNase B levels indicate recent streptococcal infection, which can trigger PSGN.
A 5-year-old patient has growth retardation secondary to chronic kidney disease. Which of the following is NOT recommended for management?
A. Increased caloric intake
B. Increased protein intake
C. Recombinant growth hormone
D. Vitamin D analogs
B. Increased protein intake
Rationale:
In chronic kidney disease (CKD), especially in growth retardation, it is not recommended to increase protein intake as it can worsen kidney function due to increased nitrogenous waste.
The management usually includes increased caloric intake, recombinant growth hormone for growth, and vitamin D analogs for bone health and calcium-phosphorus metabolism.
A 10-year-old boy presents with cola-colored urine, oliguria for 3 days, facial puffiness, edema, and hypertension. Urinalysis is positive for proteinuria and hematuria, and C3 levels are decreased. He had a skin infection 2 weeks prior. What is the most likely diagnosis?
A. Acute post-streptococcal glomerulonephritis
B. Nephrotic syndrome
C. IgA nephropathy
D. Henoch-Schönlein purpura
A. Acute post-streptococcal glomerulonephritis
Rationale:
The presentation of cola-colored urine, edema, hypertension, proteinuria, and hematuria with a history of a skin infection (likely impetigo) two weeks prior is classic for acute post-streptococcal glomerulonephritis.
The decreased C3 levels also support the diagnosis, as this is a key finding in PSGN.
Straining and dribbling of urine in a male child with recurrent urinary tract infections (UTIs) should raise suspicion for:
A. Vesicoureteral reflux
B. Posterior urethral valves
C. Urethral stricture
D. Bladder outlet obstruction
B. Posterior urethral valves
Rationale:
Posterior urethral valves are a common cause of straining and dribbling of urine in male children and can lead to recurrent UTIs.
This condition results in bladder outlet obstruction, leading to urinary retention and recurrent infections.
The most accurate diagnostic test for acute pyelonephritis in children is:
A. Urinalysis
B. Ultrasound
C. Dimercaptosuccinic acid (DMSA) scan
D. Voiding cystourethrogram (VCUG)
C. Dimercaptosuccinic acid (DMSA) scan
Rationale:
The DMSA scan is the most accurate test for diagnosing acute pyelonephritis in children. It detects renal cortical scarring and inflammation, which is characteristic of acute pyelonephritis.
Other tests like urinalysis or ultrasound may help, but the DMSA scan is the gold standard for acute kidney involvement.
A 16-year-old boy notices a painless mass in the left side of the scrotum. What is the most likely diagnosis?
A. Hydrocele
B. Epididymitis
C. Varicocele
D. Testicular torsion
C. Varicocele
Rationale:
Varicocele is a common cause of a painless scrotal mass in adolescent males.
It is characterized by dilated veins in the spermatic cord and is often described as a “bag of worms” upon palpation.
Varicoceles can cause infertility and are more prominent when standing.
A newborn delivered to a G2P1 mother with oligohydramnios and abdominal findings of the newborn showed a single umbilical artery. This condition is most commonly associated with:
A. Renal agenesis
B. Polycystic kidney disease
C. Neonatal lupus
D. Down syndrome
A. Renal agenesis
Rationale:
A single umbilical artery is commonly associated with renal agenesis or renal hypoplasia.
Oligohydramnios often results from renal agenesis, as the kidneys are not functioning properly to produce amniotic fluid.
While polycystic kidney disease and other conditions may also present with abnormal findings, renal agenesis is the most common association with a single umbilical artery.
A 10-year-old boy presents with gross hematuria, loin pain, and a recent history of diarrhea. On laboratory workup, urinalysis is unremarkable, and serum C3 levels are normal. What is the most likely diagnosis?
A. IgA nephropathy (Berger disease)
B. Hemolytic uremic syndrome (HUS)
C. Post-streptococcal glomerulonephritis (PSGN)
D. Alport syndrome
A. IgA nephropathy (Berger disease)
Rationale:
IgA nephropathy (Berger disease) typically presents with gross hematuria following an upper respiratory infection or gastrointestinal infection like diarrhea.
The normal serum C3 levels help differentiate IgA nephropathy from post-streptococcal glomerulonephritis (PSGN), which is associated with low C3 levels.
The unremarkable urinalysis is consistent with the diagnosis.
B. Renal biopsy
Rationale:
In APSGN, persistent low serum C3 levels, persistent hematuria, and elevated serum creatinine after 4 weeks suggest complicated PSGN or the possibility of a secondary renal disease.
Renal biopsy is the most appropriate next step to evaluate the kidney’s pathology and rule out other conditions, such as IgA nephropathy or focal segmental glomerulosclerosis.
Corticosteroids are not typically indicated for PSGN, and dialysis is only required if there is acute kidney failure.
Which of the following statements about acute osteomyelitis in children is CORRECT?
A. It is most commonly caused by viral infections.
B. It only affects flat bones.
C. Blood cultures are rarely positive.
D. It can result from either streptococcal pharyngitis or staphylococcal infections.
Wilms tumor is the most common malignant tumor of the genitourinary tract in children. What is the most common presenting sign?
A. Hematuria
B. Hypertension
C. Painful abdominal mass
D. Painless abdominal mass
D. Painless abdominal mass
Rationale:
The most common presenting sign of Wilms tumor in children is a painless abdominal mass.
Hematuria and hypertension can also occur but are less frequent than a palpable mass.
The mass is typically detected during routine examination or when parents notice abdominal enlargement in the child.
Which of the following statements about pyuria in children is INACCURATE?
A. Defined as urine output <0.3 mL/kg/hr
B. May be caused by acute tubular necrosis
C. Presence of ≥5 WBCs/high power field (hpf) is normal in girls
D. Post-renal causes should be ruled out in obstructive symptoms
C. Presence of ≥5 WBCs/hpf is normal in girls
Rationale:
Pyuria is defined as the presence of ≥5 WBCs/high power field (hpf) in the urine.
While pyuria can be caused by acute tubular necrosis, it is not considered normal in girls to have ≥5 WBCs/hpf without the presence of infection.
Post-renal causes should always be ruled out in cases of obstructive symptoms, as these may lead to urinary tract infections or other complications.
How is renal failure defined in children in terms of urine output?
A. Urine output <0.5 mL/kg/hour
B. Urine output <0.3 mL/kg/hour
C. Urine output <1 mL/kg/hour
D. Urine output <2 mL/kg/hour
B. Urine output <0.3 mL/kg/hour
Rationale:
Oliguria is defined as urine output of <0.3 mL/kg/hour in children.
This is one of the key indicators used in diagnosing acute renal failure or acute kidney injury (AKI) in pediatric patients.
Which of the following is the least commonly observed clinical feature in post-streptococcal glomerulonephritis (PSGN)?
A. Hematuria
B. Edema
C. Hypertension
D. Renal failure
D. Renal failure
Rationale:
The classic presentation of post-streptococcal glomerulonephritis (PSGN) includes hematuria, edema, and hypertension.
Renal failure is not commonly observed in PSGN, as the condition usually resolves with supportive care. Severe renal failure may occur in rare, complicated cases, but it is not a typical feature.
A 1-year-old child presents with recurrent urinary tract infections (UTIs). Renal ultrasound reveals bilaterally enlarged kidneys. What is the best next diagnostic test?
A. Renal biopsy
B. Voiding cystourethrogram (VCUG)
C. Urinary protein test
D. MRI of the kidneys
B. Voiding cystourethrogram (VCUG)
Rationale:
A VCUG is indicated in children with recurrent UTIs and bilateral kidney enlargement to assess for vesicoureteral reflux (VUR), a common cause of recurrent infections in children.
The test helps to evaluate if urine is refluxing back into the kidneys, leading to infections.