Pediatrics | Comprehensive Study Guide, Practice
Exam, Questions & Answers, Exam Prep Test Bank,
Pediatric Primary Care, Newborn Care, Growth &
Development, Immunization, Pediatric
Pharmacology, Childhood Disorders, Neonatal Care,
Clinical Decision-Making, Evidence-Based
Pediatrics, Detailed Rationales, Complete Review
Question 1: A 2-week-old male infant presents with poor feeding, lethargy, and
a high-pitched cry. On examination, he is jaundiced and has
hepatosplenomegaly. Laboratory studies reveal direct hyperbilirubinemia,
elevated liver transaminases, and thrombocytopenia. Which of the following is
the most likely diagnosis?
A. Biliary atresia
B. Neonatal hemochromatosis
C. Congenital cytomegalovirus infection
D. Galactosemia
CORRECT ANSWER: C. Congenital cytomegalovirus infection
Rationale:This presentation of sepsis-like symptoms, direct hyperbilirubinemia,
hepatosplenomegaly, and thrombocytopenia in a neonate is classic for congenital CMV
infection. Biliary atresia presents with persistent jaundice and acholic stools but not
typically with thrombocytopenia or significant transaminase elevation. Neonatal
hemochromatosis is characterized by severe liver failure and extrahepatic siderosis.
Galactosemia presents with jaundice, hepatomegaly, and failure to thrive after milk
ingestion, but thrombocytopenia is less characteristic.
Question 2: A 6-year-old girl is brought to the clinic for a school physical. She
has multiple café-au-lait macules (>6) measuring over 1.5 cm, axillary
freckling, and a positive family history. She is at increased risk for developing
which of the following neoplasms?
A. Pheochromocytoma
B. Optic glioma
C. Rhabdomyosarcoma
D. Neuroblastoma
CORRECT ANSWER: B. Optic glioma
Rationale:This child has neurofibromatosis type 1 (NF-1), diagnosed by the presence of
café-au-lait spots, axillary freckling, and family history. The most common central
nervous system tumor in NF-1 is the optic pathway glioma. Pheochromocytoma is also
associated but less frequently. Rhabdomyosarcoma and neuroblastoma are not primary
NF-1 tumors.
,Question 3: A 10-month-old infant with a history of recurrent sinopulmonary
infections and chronic diarrhea is found to have absent plasma cells and
markedly decreased immunoglobulins on serum electrophoresis. Which of the
following is the most likely underlying genetic defect?
A. Defect in the BTK gene
B. Mutation in the CFTR gene
C. Deletion in chromosome 22q11
D. Mutations in the ATM gene
CORRECT ANSWER: A. Defect in the BTK gene
Rationale:The presentation of recurrent infections, chronic diarrhea, and absent plasma
cells with panhypogammaglobulinemia is characteristic of X-linked
agammaglobulinemia (Bruton's disease), caused by a mutation in the BTK gene. CFTR
mutations cause cystic fibrosis. 22q11 deletion causes DiGeorge syndrome. ATM
mutations cause ataxia-telangiectasia.
Question 4: During a well-child visit, a 4-year-old boy's blood pressure is noted
to be 145/92 mmHg on two separate occasions. His physical examination is
normal except for a systolic ejection murmur. An echocardiogram reveals
coarctation of the aorta. Which of the following is the most appropriate initial
medical therapy?
A. Prostaglandin E1 infusion
B. Indomethacin
C. Propranolol
D. Furosemide
CORRECT ANSWER: C. Propranolol
Rationale:For a 4-year-old with coarctation of the aorta and hypertension, beta-
blockers such as propranolol are often used as initial medical therapy to help control
blood pressure while awaiting surgical intervention. Prostaglandin E1 is for ductal-
dependent lesions in neonates. Indomethacin is used to close a PDA. Furosemide may
be used for heart failure symptoms but is not primary therapy for coarctation.
Question 5: A 3-day-old term newborn is noted to have a scaphoid abdomen,
respiratory distress, and a nasogastric tube that fails to pass beyond 15 cm.
The most likely diagnosis is:
A. Tracheoesophageal fistula
B. Duodenal atresia
C. Congenital diaphragmatic hernia
D. Pyloric stenosis
CORRECT ANSWER: A. Tracheoesophageal fistula
Rationale:Failure to pass an NG tube beyond 15 cm suggests esophageal atresia. This is
commonly associated with a tracheoesophageal fistula. The scaphoid abdomen is due to
,air in the stomach and intestines via the fistula. Duodenal atresia presents with bilious
emesis and a double-bubble sign. CDH presents with respiratory distress and bowel
sounds in the chest. Pyloric stenosis presents at 2-6 weeks with projectile non-bilious
vomiting.
Question 6: An 8-year-old child presents with a 3-day history of cough, fever,
and conjunctivitis. On examination, he has an erythematous maculopapular
rash that started on his face and spread downward. He also has Koplik spots.
Which of the following is the most effective strategy to prevent transmission to
his susceptible sibling?
A. Administer oral acyclovir
B. Administer vitamin A
C. Administer the MMR vaccine within 72 hours of exposure
D. Administer immune globulin within 6 days of exposure
CORRECT ANSWER: D. Administer immune globulin within 6 days of exposure
Rationale:The child has measles. For susceptible household contacts, post-exposure
prophylaxis with immune globulin within 6 days of exposure is the most effective
strategy to prevent or attenuate disease. The MMR vaccine is effective if given within 72
hours of exposure, but immune globulin is preferred for high-risk contacts like infants or
immunocompromised individuals. Vitamin A is treatment for the patient, not
prophylaxis for contacts.
Question 7: A 16-year-old girl presents with fatigue, heat intolerance, and a 10-
pound weight loss over the past 2 months. Her mother has a history of Graves'
disease. On examination, she has a diffuse, non-tender goiter and fine tremors.
Which of the following laboratory findings is most consistent with her
diagnosis?
A. Elevated TSH and low free T4
B. Low TSH and elevated free T4
C. Normal TSH and low free T4
D. Elevated TSH and elevated free T4
CORRECT ANSWER: B. Low TSH and elevated free T4
Rationale:This presentation is consistent with hyperthyroidism, most likely Graves'
disease. The classic laboratory finding is a suppressed TSH with elevated free T4
and/or T3. This results from thyroid-stimulating immunoglobulins that mimic TSH.
Question 8: A 3-month-old infant is brought in for poor weight gain. She has a
history of frequent vomiting that is non-bilious and occurs shortly after feeds.
On physical examination, she is lethargic and has a palpable "olive" in the
right upper quadrant. Which of the following is the most appropriate initial
management?
, A. Administration of IV fluids and electrolyte correction
B. Pyloromyotomy
C. Nissen fundoplication
D. Nasogastric tube feeding
CORRECT ANSWER: A. Administration of IV fluids and electrolyte correction
Rationale:This is classic presentation of hypertrophic pyloric stenosis. The infant is
likely dehydrated and has a hypochloremic metabolic alkalosis. The most appropriate
initial management is to correct fluid and electrolyte imbalances (with IV fluids) before
proceeding with surgical pyloromyotomy.
Question 9: A 4-year-old boy with a history of recurrent otitis media presents
with sudden-onset, severe abdominal pain and vomiting. He appears toxic. On
examination, he has diffuse abdominal tenderness and guarding. His stool is
guaiac-positive. Which of the following is the most likely causative organism?
A. Salmonella
B. Shigella
C. Yersinia enterocolitica
D. Escherichia coli
CORRECT ANSWER: C. Yersinia enterocolitica
Rationale:Yersinia enterocolitica is a classic cause of mesenteric lymphadenitis, which
can mimic appendicitis. It can also cause a terminal ileitis. The presentation of
abdominal pain, vomiting, and a history of pharyngitis or otitis media is common. It is a
cause of pseudoappendicitis.
Question 10: A newborn is diagnosed with a congenital heart defect that is
characterized by a "boot-shaped" heart on chest X-ray and cyanosis. Which of
the following is the most likely diagnosis?
A. Truncus arteriosus
B. Transposition of the great arteries
C. Tetralogy of Fallot
D. Total anomalous pulmonary venous return
CORRECT ANSWER: C. Tetralogy of Fallot
Rationale:The "boot-shaped" heart (coeur en sabot) is a classic radiographic finding in
Tetralogy of Fallot, caused by right ventricular hypertrophy and an upturned cardiac
apex. It is the most common cyanotic congenital heart defect. Transposition of the great
arteries presents with an "egg-on-a-string" appearance.
Question 11: A 12-year-old boy has a history of prolonged bleeding after minor
dental procedures and frequent nosebleeds. His laboratory results show a
prolonged PTT, normal PT, normal platelet count, and normal bleeding time.
Which of the following factor deficiencies is most likely?