Neonatal infections

Question 1

Early onset sepsis vs late onset sepsis

Answer 1

• Early onset: Birth to 5 days
• Late onset: 5 days to 1 month

Question 1

Most common etiologies of early-onset sepsis

Answer 1

1. GBS
2. E. coli
3. H. influenzae
4. Listeria

Question 2

Risk factors for early onset sepsis

Answer 2

• Prolonged rupture of membranes
• Chorioamnionitis
• GBS + mother (even if treated)
• Maternal intrapartum fever or leukocytosis
• Preterm birth

Question 3

Asymptomatic infants with significant sepsis risk factors. . .

Answer 3

. . . should have a screening CBC and culture

Question 4

Initial workup for infants with suspected sepsis

Answer 4

• Immediately initiate ampicillin and gentamycin (do not delay for workup)
  
  • If CNS signs, add ceftriaxone
• Draw both blood AND CSF cultures
• If organ-specific signs/symptoms, appropriate imaging is indicated
• Suggestive of infection:​
  
  • ​<5,000 WBC
  • >40,000 WBC
  • Abs. PMN < 1,000
  • Band:PMN > 20%

Question 5

Most common etiologies of late-onset sepsis

Answer 5

• w/ associated meningitis: GBS or E. coli
• w/ associated osteomyelitis: GBS or S. aureus
• w/ associated arthritis: N. gonorrheae, S aureus, or gram negative rod
• w/ associated UTI: E. coli, Klebsiella, other gram negative rods

Question 6

A 13-month old child is noted to be at 25th percentile for weight, 10th percentile for height, and <5th percentile for head circumference. She was born at term. She was noted to have a small head at birth, to be developmentally delayed, and to have required cataract surgery shortly after birth. She currently takes phenobarbital for seizures. What is the most likely underlying diagnosis?

Answer 6

Congenital CMV infection syndrome:

• Microcephaly and developmental delay
• Cataracts
• Seizures (often with underlying periventricular calcifications)
• Hepatosplenomegaly w/ prolonged neonatal jaundice
• Purpura at birth

Question 7

If an infant has an infection within the first 6 days of life, it was almost certainly acquired from. . .

Answer 7

. . . the mother’s genitourinary tract

Question 8

If an infant has an infection within the between 1 week and 90 days of life, it was almost certainly acquired from. . .

Answer 8

. . . the caregiver’s environment

Question 9

Utility of CRP in the neonate

Answer 9

Since CBC and elevated WBC is not as useful of a finding in infants, the CRP is sometimes used as an adjunct when infection is suspected.

It is much more useful in the newborn than in adults.

Question 10

In any infant, GBS is the most common cause of neonatal sepsis up to the age of ___

Answer 10

In any infant, GBS is the most common cause of neonatal sepsis up to the age of 3 months

Question 11

Therapy of early onset neonatal sepsis vs late onset neonatal sepsis

Answer 11

• Early onset: ampicillin + gentamicin
• Late onset: vancomycin + ceftriaxone

Question 12

Likely etiology of neonatal conjuntavitis by time window

Answer 12

• First 6 to 12 hours of life: Chemical conjunctavitis – the result of the erythromycin prophylaxis or silver nitrate
• 2-5 days of life: N. gonorrheae
• 5-14 days of life: C. trachomatis

Question 13

If you are treating a baby for N. gonorrheae conjuncavitis, you should also. . .

Answer 13

. . . treat their parents to prevent reinfection

As with basically everything N. gonorrheae related, the same goes for C. trachomatis

Question 14

Oral erythromycin is used to treat chlamydial conjuctavitis or pneumonia in the newborn. What is a complication of oral erythromycin in a newborn?

Answer 14

Risk of hypertrophic pyloric stenosis

Remember the classic “olive-shaped” abdominal mass and non-bilious emesis