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Alterations in Metabolic Status
Jan Bazner-Chandler
RN, MSN, CNS, CPNP
Developmental and Biologic Variances
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Most inborn errors of metabolism present in the
childhood years and, if untreated, results in early death.
Cognitive defects and neurologic symptoms (lethargy,
seizures, coma)
Short stature and failure to thrive
Feed problems and vomiting after feeding
Delayed tooth eruption
Hepatomegaly
Urine may have abnormal odor and color
Metabolic Disorders
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Inborn errors of metabolism
Maple syrup urine disease
Mineral disorders
Rickets
Wilson’ disease
Galactosemia
Neonatal Screening
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Over 30 inborn metabolic errors possible.
PKU, glactosemia, maple syrup disease included in most
newborn screening
Newborns are not routinely tested for the rare disorders
due to cost-to-benefit ratio.
Phenylketonuria
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PKU
First discovered in 1934
PKU is an autosomal recessive genetic defect found on chromosome
12
Child must receive the defective gene from both parents
1 in 60 people is an asymptomatic carrier
Symptoms 1 in 10,000 births
In turkey 23 in 10,000
Pathophysiology
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Phenylalanine is an essential amino acid found in all
protein food.
The accumulation of phenylalanine leads to severe
retardation.
With early identification of the defective gene
intervention can prevent retardation.
Diagnosis
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Heel stick done 24 to 48 hours after birth.
Infant must have an adequate intake of breast milk or
formula. (protein)
The drop of blood must be large enough to fill the
imprinted space on the filter paper.
Squeezing out more blood onto the paper creates a
layered effect that can produce a false-positive test result.
Treatment
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Focuses on preventing
excessive accumulation of
phenylalanine by restricting
protein intake.
Maintain levels below 0.9
mmol/L but maintain at0.2 to
allow for normal growth and
tissue repair.
Aspartame or NutraSweet
need to be avoided in diet.
Prognosis
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Teaching that reinforces the dietary regimen is critical to the successful
management of PKU
Family cohesion and adherence to the restricted diet positively
correlates with higher IQ levels.
Children at high risk for learning difficulties.
Diet generally discontinued around 10 years with full brain
development
Pregnant women with PKU deficiency at high risk for having a fetus
with mental retardation.