NAPLEX Question of the Week: Pediatric Infections

This week's question focuses on a very special population of patients: Pediatrics.
NAPLEX Question of the Week: Pediatric Infections

AS is a 6-year-old male who presents to the ED with a 3-day history of dyspnea, productive cough, fatigue, and a fever of 100.4. Overall he appears stable and is saturating 99% O2 on room air.  He is taken for a chest x ray, and it shows consolidation in the lower left lobe. He has elevated WBC counts and blood/sputum cultures pending. He has no PMH (previously healthy) and NKDA. He is also up to date on all his childhood vaccinations. He is diagnosed with moderate CAP of suspected bacterial origin and is going to be treated as an outpatient. Which antibiotic regimen would be most reasonable for our patient?  

 

A. Amoxicillin 90 mg/kg/day PO divided BID plus doxycycline 10mg/kg PO divided BID

B. Azithromycin 5 mg/kg PO once daily x1 day, followed by 2.5 mg/kg PO once daily x 4 days 

C. Amoxicillin/clavulanate  45 mg/kg/day PO divided BID 

D. Amoxicillin 90 mg/kg/day PO divided BID and Azithromycin 10 mg/kg PO once daily x 1 day, followed by 5 mg/kg PO once daily x 4 days  

 

 

Correct answer with rationale:

The correct answer is D. 

In previously healthy, appropriately immunized infants, children, and adolescents with mild to moderate CAP (of suspected bacterial origin), the drug of choice is high dose amoxicillin (90 mg/kg/day) divided BID. The amoxicillin will cover Streptococcus pneumoniae which is the main pathogen of concern. However, because the child is > 2 years old you may choose to cover atypical pathogens such as Chlamydia pneumoniae and Mycoplasma pneumoniae. This is why the additional coverage with a macrolide such as azithromycin is reasonable (answer choice D).    Answer A is incorrect as doxycycline is not recommended in patients under the age of 8 by the FDA as well as the IDSA guidelines for treatment of CAP in pediatrics, even though it offers atypical coverage. Answer B is incorrect as the correct dose should be 10mg/kg PO X 1 dose, followed by 5mg/kg PO daily for 4 days. Answer C is incorrect as amoxicillin/clavulanate (Augmentin) while not a first-line therapy should be dosed at 90mg/kg/day divided q12h, not 45mg/kg/day divided q12h. 

If this patient were to be admitted, empiric therapy with a third-generation parenteral cephalosporin (ceftriaxone or cefotaxime) could also be used for hospitalized infants and children who are not fully immunized, in regions where local epidemiology of invasive pneumococcal strains show high-level penicillin resistance, or for infants and children with life- threatening infection, including those with empyema. Something else to keep in mind with ceftriaxone is that it should not be used in neonates < 28 days old due to risk of kernicterus.  In fully immunized patients in areas where low-level S. pneumoniae resistance is present, initial therapy with IV penicillin or ampicillin is reasonable.

Viral testing may be performed on most pediatric patients because viruses cause a significant proportion of CAP infections in children (especially those younger than 2 years old) as well as adults. There are many platforms available that will test for both viral and bacterial etiologies, including atypical pathogens but in mild outpatient cases often supportive care is given with no antibiotic therapy due to high likelihood of viral etiology. Finally, it is important to counsel pediatric patients and their parents on the importance of CAP prevention with guideline recommended vaccinations (pneumococcal, influenza, Haemophilus influenza type b, pertussis, varicella, measles, etc).  

Source for more information: Bradley JS, Byington CL, Shah SS, et al. Clinical Infectious Diseases. 2011; 53(7):e25-e76. 

Exam Competencies: Area 3 – Develop or Manage Treatment Plans (3.4 – Drug dosing or dosing adjustments; 3.11 – Evidence-based practice) Area 6 – Develop or Manage Practice or Medication-Use Systems to Ensure Safety and Quality (6.4 – Vulnerable populations, special populations, or risk prevention programs)

Congratulations to all of you who are finishing rotations and will be graduating soon. I just completed my first live board review of the season and would like to give a huge shout out to the wonderful students of Virginia Commonwealth University. You were fantastic! #GoRams

See everyone next week.

Dr. B