A 21-day-old girl is brought to the emergency department due to difficulty feeding. The neonate was born at term following an uncomplicated pregnancy and had been feeding well with a standard, cow's milk–based formula until 2 days ago. Since then, she has been sleepier, with a weak suck and fewer wet diapers. Today, she is increasingly fussy and is refusing to feed. Temperature is 35.1 C (95.2 F), blood pressure is 78/52 mm Hg, pulse is 150/min, and respirations are 62/min. The neonate is irritable and difficult to console. She has a full fontanelle and dry mucous membranes. Scleral icterus and jaundice of the face and chest is present. The lungs are clear, and no murmur is present. Abdominal examination is normal. Neurologic examination shows equal movement of all 4 extremities with mildly decreased muscle tone. Which of the following is the best next step in management of this neonate?
Neonatal sepsis | |
Etiology |
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Clinical features |
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Evaluation |
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Treatment |
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* Limited evaluation (without CSF studies) & outpatient management may be considered in well-appearing, febrile neonates age >21 days. ANC = absolute neutrophil count; CRP = c-reactive protein, CSF = cerebrospinal fluid. | |
This neonate (age ≤28 days) is irritable and hypothermic with a full fontanelle, findings concerning for neonatal sepsis with meningitis. Clinical manifestations of sepsis and/or meningitis in neonates are often subtle and nonspecific. They typically have temperature instability, causing either fever or hypothermia (<36 C [96.8 F]), as in this case. Unlike older children and adults, neonates with meningitis do not have nuchal rigidity or positive Kernig and Brudzinski signs. Instead, neonates are typically irritable, lethargic, and/or hypotonic (eg, weak suck, decreased muscle tone), often with a full fontanelle. Parents often express concern that the child is difficult to console and feeding poorly (which can result in fewer wet diapers). Jaundice (due to sepsis-associated cholestasis), respiratory distress, and seizure may also occur.
Because physical examination does not reliably distinguish among different types of serious neonatal bacterial infections (eg, meningitis, bacteremia, urinary tract infection), neonates with suspected infection urgently require a full evaluation. This includes a complete blood count with differential, urinalysis, cerebrospinal fluid (CSF) analysis, and cultures of all 3 fluids (blood, urine, CSF).
After cultures are obtained, neonates should immediately receive empiric antibiotics (eg, ampicillin and gentamicin). Antibiotic administration before obtaining cultures should be avoided when possible because antibiotics can sterilize cultures and make definitive diagnosis difficult. However, neonates who are critically ill (eg, septic shock, status epilepticus) or who cannot immediately undergo lumbar puncture should receive antibiotics prior to obtaining cultures.
(Choice B) Cerebral herniation due to infection does not occur in neonates due to their open fontanelles that relieve intracranial pressure. CT scan of the head is therefore not required before lumbar puncture in young infants.
(Choice C) Jaundice caused by hemolysis (eg, ABO incompatibility, spherocytosis) may warrant a peripheral smear and reticulocyte count for diagnosis. However, hypotonia and hypothermia would not be expected.
(Choice D) Switching to soy-based formula is the treatment for suspected galactosemia, which presents with lethargy, vomiting, and jaundice. Unlike this 21-day-old neonate, galactosemia symptoms develop within the first few days of life after introduction of dietary galactose (eg, breast milk).
(Choice E) Symptomatic congenital hypothyroidism causes poor feeding, hypothermia, jaundice, and lethargy. Acute symptom onset makes this diagnosis unlikely, and exclusion of infection is prioritized due to increased mortality with delayed treatment.
Educational objective:
Neonatal sepsis and meningitis present with nonspecific symptoms, including irritability, temperature instability (fever or hypothermia), poor feeding, and lethargy. In hemodynamically stable neonates with suspected sepsis, blood, urine, and cerebrospinal fluid, cultures should be obtained followed by administration of empiric antibiotics.