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PA (propionic academia) and MMA (methylmalonic academia) are
inborn errors of organic acid metabolism in which the organic
acids derived from the amino acids isoleucine, valine, threonine
and methionine and odd chain fatty acids cannot be fully metabolised
to succinyl-CoA (see diagram below). The organic acid intermediates
that accumulate are toxic. The major initial feature is metabolic
acidosis.
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. The majority of patients,
however, develop symptoms in the first days or weeks of life.
Poor feeding and vomiting can progress rapidly to coma and death.
Seizures occur in about 30% of affected infants. Since PA and
MMA are both autosomal recessive genetic disorders, there is a
25% chance that sibs of the identified infant may also have PA
or MMA. A family history of other children in the family becoming
seriously ill or having developmental delay is highly significant.
Examination
The infant may appear entirely healthy and well. If ill, the neonatal
signs are tachypnea, hypotonia, lethargy, dehydration and hypoglycemia.
ANY signs of illness must be treated as a medical emergency and
treated immediately. Go to Acute illness protocol, PA
or MMA.
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 C3
Discussion with parents for markedly
elevated C3
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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