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IVA (isovaleric acidemia) is an inborn errors of organic acid
metabolism in which the organic acids derived from the amino acid
leucine cannot be fully catabolized because there is a block at
the third stage in the pathway from isovaleryl-CoA to 3-methylcrotonyl-CoA
(see diagram below). The organic acid intermediates that accumulate
(isovaleric acid, 3-OH-isovaleric acid) are toxic. The major initial
feature is metabolic acidosis and a "sweaty foot" odor.
History and Examination
The infant and parent(s) must be seen within the next day or
two following notification from the newborn screening program.
A METABOLIC PHYSICIAN MUST BE CONSULTED.
History
The infant may have a normal history. IVA may present after infancy
or in the first 14 days of life. The first symptoms include refusal
to feed, vomiting, drowsiness and seizures.
Examination
The infant may appear entirely healthy and well. Weight loss or
poor weight gain, as well as signs of dehydration, lethargy, hypothermia,
hepatomegaly, raised intracranial pressure or other neurological
features and a foul "sweaty feet" odor may be present.
ANY signs of illness must be treated as a medical emergency and
treated immediately.
Go to Acute illness protocol, IVA.
If the child appears well it is still essential
to refer to the metabolic center to ensure that the child and
family receive the necessary treatment and guidance to prevent
morbidity.
Contact the metabolic physician for markedly elevated C5
Discussion with parents for markedly
elevated C5
ENSURE THAT THE REPEAT NEWBORN SCREENING SAMPLE IS SENT TO THE
STATE LABORATORY AND THE RESULT OBTAINED ASAP
(Go to NNSGRC
for the state labs)
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