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Continuity Clinic Notebook:

Chapter 1: The Prenatal and Well Child Visit


Chapter 1 Index

A. General Information about the well child examination
--Prenatal Visit
--Well Child Check-up
--Neonatal Jaundice
--Breast Milk Jaundice
--Circumcision
--Diapers
--Pacifiers
--Birth Defects

 

Newborn Metabolic Screen

Conditions screened in newborn metabolic screen in Georgia: for results call: 404-727-0486

Name of Condition Frequency Criteria Treatment
1. Sickle Cell:
call: 721-9640 results
1:400 blacks Elevated Hgb S Prevent Sepsis:

po Pen V

2. Hypothyroidism 1:4,000 Low or nl T4; High TSH Replace L-thyroxine
3. PKU 1:10,000 Elevated phenylalanine Low phenylalanine diet
4. Tyrosinemia not reported Elevated tyrosine Restrict protein in diet

Give Vitamin C

5. Galactosemia 1:10,000 to 1:90,000 Elevated galactose Eliminate galactose and lactose in diet
6. Congenital Adrenal Hyperplasia 1: 15,000 to 1:3,000 in native Eskimos Elevated 17-OH progesterone Replace corticosteroids
7. Maple Syrup Urine Disease 1:90,000 to >1:200,000 Elevated leucine Diet low in leucine, isoleucine and valine
8. Homocystinuria 1:200,000 Elevated Methionine Methionine restricted diet; cystine replacement

Conditions for which also able to screen (not done in Georgia):

Condition Frequency Criteria Treatment
Biotinidase deficiency 1:70,000 Deficient/absent biotinide 10 mg biotin daily
Sickle cell - all children: Middle east; whites, Asia, Europe unknown Elevated Hgb S Prophylaxis

 

Cystic Fibrosis 1:2000 Immunoreactive trypsin 

false +:0.2%

false - 3.8%; DNA tests

Rx of CF
Duchenne's Muscular Dystrophy 1:11,000
(1:4000 males)
Creatine Kinase elevation Genetic Counseling
Others: MCAD, Organic Acidurias Tuberous Sclerosis      

Thyroid Abnormalities: other than sickle cell problems, most common problem seen:

T4 TSH Diagnosis
Normal normal Normal
Normal High* Hypothyroidism
Low High* Hypothyroidism
Low normal Thyroid Binding Globulin deficiency**
High low Hyperthyroidism

* If TSH is high, start Synthroid after drawing repeat TSH, free T4 – this is urgent!!!
**free T4 level will be normal.

Commonly asked questions and answers:

  1. Q: Which of the 8 conditions screened for will be affected by screening before 48 hours?
    A: a. Thyroid: Because of maternal surge at time of delivery the TSH and T4 will both be increased during the first 24 hours.
    b. MSUD - affected
    c. Homocystinuria - affected
    d. Not affected: galactosemia (if the deficient enzyme method used); PKU - although some with non-PKU hyperphenylalaninemia missed
     
  2. Q: Is 48 hours of age the most accurate time to do the metabolic screen?
    A: In the past, repeat metabolic screens were done at 4-6 weeks of age; the difference in return was minimal.  Thus, this is the time considered to be most important.
     
  3. Q: If the screen is not totally reliable before 48 hours of age, should we omit collecting the screen if child is discharged before that age?
    A: No.  Because of the answer to the first question above, all children should have a metabolic screen done before their discharge at any age.
     
  4. Q: What are the indications for collecting a second metabolic screen?
    A: Inadequate feeds, baby on antibiotics, sample collected prior to 48 hours of age.
     
  5. Q: If a second sample is needed, by what age should it be collected?
    A: By 7 days of age.
     
  6. Q: Which of the metabolic screen tests are affected by administration of antibiotics and why?
    A: Homocystinuria, MSUD, and tyrosinemia.  These 3 conditions are diagnosed by means of a bacterial inhibition assay - antibiotics kill the bacteria, so the test must be repeated. PKU used to be on the list, but recent studies show that untrue for this condition.
     
  7. Q: Which test is most likely to show a false negative result and why?
    A: Thyroid: - all T4 screening tests in premature infants should be repeated, because of physiological immaturity in prematures.
    - another reason is that small amounts of residual tissue can be lost in the first weeks of life, and hypothyroidism shows up later.
     
  8. Q: What is the most common reason to have a false positive or false negative results?
    A: Improperly collected specimens or improperly labeled specimens that get lost.
     
  9. Q: What are the only two conditions screened for in every state?
    A: Thyroid and PKU.

Updated 7/01

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Department of Pediatrics  |  Medical College of Georgia
Please email comments, suggestions or questions to:
John T.  Benjamin M.D., 
jbenj@mcg.edu

February 27, 2004