Pregnancy or weak sucking with lethargy in the first month of life

Specialty: Pediatrics.

• Difficulty feeding the newborn
• ineffective suction with drowsiness
• neonatal hypoactivity

Why it occurs

• Early or late neonatal sepsis (invasive systemic bacterial infection that depresses the central nervous system and decreases muscle tone and reflexes)
• Metabolic encephalopathy or inborn error of metabolism (defects of the urea cycle, organic acidemias or galactosemia that accumulate toxic metabolites producing lethargy and ineffective sucking after the start of dairy feeding)
• Congenital heart disease with low output or congestive heart failure (aortic coarctation, critical aortic stenosis, transposition of the great arteries that fatigue the infant when sucking)
• Severe hypernatremic dehydration due to ineffective breastfeeding (massive water loss produces lethargy and muscle weakness, aggravating the inability to suck)
• Severe congenital hypothyroidism (generalized slowing of metabolic and muscular functions of the newborn)
• Severe neonatal hyperbilirubinemia or kernicterus (cerebral toxicity due to indirect free bilirubin that causes initial lethargy and hypotonia)

Initial workup

Immediate emergency analysis: complete blood count, differential count, acute phase reactants (CRP, procalcitonin), capillary and venous blood glucose, capillary blood gas (to rule out severe metabolic acidosis), complete ionogram, blood ammonium, lactate and liver/renal profile. Paired blood cultures and urine cultures (if the infant is older than 7-10 days). Lumbar puncture for biochemical analysis and CSF culture (essential if sepsis/meningitis is suspected). Urgent Doppler echocardiogram if a pathological murmur is heard or there is suspicion of heart disease. Expanded emergency neonatal metabolic screening.

Standard management

• Ampicillin plus Cefotaxime or Gentamicin — neonatal broad-spectrum empirical antibiotic regimen for sepsis; ampicillin at a dose of 100-200 mg/kg/day IV divided every 6-12 hours; cefotaxime at a dose of 100-150 mg/kg/day IV divided every 8-12 hours, ideal for coverage of Gram-negative meningitis; gentamicin at a dose of 4-5 mg/kg IV every 24-36 hours
• 10% Glucosated Whey — immediate continuous intravenous infusion if associated hypoglycemia is documented; maintenance dose calculated based on weight and volume of fluids
• Hemodynamic support treatment with inotropes (Dopamine, Dobutamine) in neonatal intensive care if septic or cardiogenic shock is associated.