Infants newborn, kernicterus

Subsequent studies have shown (e.g. 5,6, Table I) that the liver of newborns is indeed deficient in enzymes needed not only for drug metabolism but also for the elimination of natural products. For example, because of the lack of UDP-glucuronyl transferase resulting in the inability to dispose of bilirubin, the newborn is at risk for brain damage by kernicterus. That PEP carboxykinase, the key catalyst of gluconeogenesis de novo is absent at 7 months and still at low titers 3 days after birth (Table I), probably contributes to the fact that transient hypoglycemia (which can also cause brain damage) represents a hazard to full term as well as premature infants. The immaturity of the hepatic enzyme composition imposes limitations on the choice of nutrients used to supplement or re-... 

Contraindications Sulfas should be avoided in newborns and infants less than 2 months old as well as pregnant women at term, due to the danger of kernicterus. Because sulfonamides condense with formaldehyde, they should not be given to patients receiving methenamine (see p. 327) for urinary tract infections. 

Sulfonamides are contraindicated in patients with known hypersensitivity or intolerance to any member of this drug femily. Sulfonamides are also contraindicated in pregnancy at term, for nursing mothers, and for infants less than 2 months old becanse they can promote kernicterus in the newborn by displacing bilirubin from plasma proteins. The sulfonamides, pyrimethamine, and trimethoprim are contraindicated in patients with documented blood dyscrasias. 

Cronin CM, Brown DR, Ahdab-Barmada M. Risk factors associated with kernicterus in the newborn infant importance of benzyl alcohol exposure. Am J Perinatol 1991 8(2) 80-5. 

Kernicterus can occur in small and premature babies, even after small doses of vitamin K, probably because of immature liver function. In its 1997 clinical practice guidelines, the Canadian Paediatric Society recommended that, in order to prevent haemorrhagic disease of the newborn, phytomenadione be given as a single intramuscular injection to all newborns within 6 hours of birth, in a dose of 1 mg for infants with a birth weight of more than 1500 g and half this dose for smaller infants. The dose is crucial, since overdosage carries a serious risk of kernicterus, especially in premature infants. There is only a remote possibility that this treatment might increase the risk of childhood cancer. 

There is no evidence that phylloquinone has any significant toxicity. However, the synthetic analogue menadione can undergo non-enzymic redox cycling, and injection of menadione in newborn infants has been implicated in the later development of leukaemia. For this reason it is generally advised that prophylactic vitamin K given at birth should be as phylloquinone by mouth rather than menadione by injection. Menadione may also cause haemolytic anaemia, hyperbilirubinaemia and kernicterus in the newborn. 

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