SPEX Pediatrics 2 — Questions and Answers
Question 1: A 6-week-old presents with projectile vomiting after every feeding. The vomitus is non-bilious and the infant appears hungry after vomiting. What is the most likely diagnosis?
- Pyloric stenosis (Correct answer)
- Intussusception
- Gastroesophageal reflux
- Hirschsprung disease
Correct answer: Pyloric stenosis
Pyloric stenosis classically presents at 3–6 weeks with non-bilious projectile vomiting and a palpable 'olive' mass in the right upper quadrant.
Question 2: Which vaccine is recommended at birth for all newborns in the US?
- Hepatitis A
- Hepatitis B (Correct answer)
- MMR
- Varicella
Correct answer: Hepatitis B
The hepatitis B vaccine is given at birth as the first dose to prevent perinatal transmission.
Question 3: A 2-year-old presents with a barking cough, inspiratory stridor, and low-grade fever. What is the most likely diagnosis?
- Epiglottitis
- Croup (laryngotracheobronchitis) (Correct answer)
- Foreign body aspiration
- Bacterial tracheitis
Correct answer: Croup (laryngotracheobronchitis)
Croup is caused by parainfluenza virus and produces the characteristic 'barking' cough and inspiratory stridor in children 6 months to 3 years.
Question 4: At what age should a healthy infant be able to sit without support?
- 3 months
- 6 months (Correct answer)
- 9 months
- 12 months
Correct answer: 6 months
Most infants achieve sitting without support by 6 months of age as a gross motor milestone.
Question 5: A child presents with a pruritic, honey-crusted lesion around the mouth. What is the first-line treatment?
- Oral amoxicillin
- Topical mupirocin (Correct answer)
- Oral fluconazole
- Topical hydrocortisone
Correct answer: Topical mupirocin
Localized impetigo is best treated with topical mupirocin, which targets S. aureus and Streptococcus pyogenes.
Question 6: Which electrolyte abnormality is most commonly associated with pyloric stenosis?
- Hyperkalemic metabolic acidosis
- Hypokalemic hypochloremic metabolic alkalosis (Correct answer)
- Hypernatremic metabolic acidosis
- Hyponatremic metabolic acidosis
Correct answer: Hypokalemic hypochloremic metabolic alkalosis
Repeated vomiting of gastric contents causes loss of HCl and K+, leading to hypokalemic hypochloremic metabolic alkalosis.
Question 7: A 4-year-old has a fever of 39°C, sore throat, and tonsillar exudates with tender anterior cervical lymphadenopathy. A rapid strep test is positive. What is the appropriate treatment?
- Amoxicillin for 10 days (Correct answer)
- Azithromycin for 5 days
- Cephalexin for 7 days
- No antibiotics; viral etiology
Correct answer: Amoxicillin for 10 days
Group A streptococcal pharyngitis is treated with amoxicillin for 10 days to eradicate infection and prevent rheumatic fever.
SPEX Pediatrics 2
A 6-week-old presents with projectile vomiting after every feeding.
The vomitus is non-bilious and the infant appears hungry after vomiting.
What is the most likely diagnosis?