The Journal of the Arkansas Medical Society Med Journal April 2019 Final 2 | Page 13
AFMC: A CLOSER LOOK AT QUALIT Y
to determine the need for thyroid
hormone replacement. Thyroid
ultrasound and nuclear scan are
the two most commonly utilized
imaging modalities.
Patients with an initial TSH
level greater than 40 mIU/ml
on the NBS should have thyroid
hormone replacement initiated
with levothyroxine (L-T4). Treatment
should begin as soon as confirmatory
serum tests have been drawn, even
before results are available. 1,2 In a
recent survey of Arkansas primary
care providers (n=75), two-thirds
stated they prefer to wait for
confirmatory testing results before
beginning treatment because results
are usually available the same day.
Treatment goals are to normalize
TSH and Free T4 as soon as possible,
start treatment prior to three weeks
of life and keep TSH within the lower
half and Free T4 in the upper half of
the normal range. Children whose
levels were normalized by one to two
weeks scored higher on indices of
visual memory, attention and math
skills, compared to those who took
longer to normalize their levels. 3 An
L-T4 dose of 10-15 mcg/kg/day (max.
dose 50 mcg/day) is the recom-
mended initial oral replacement
dose. Individual differences and
co-morbidities should be considered
for initial dose selection. Frequent
clinical and biochemical assessments
are needed for optimal manage-
ment. Although normalization of TSH
may take up to four weeks, Free T4
level should become normal within
days of treatment. Measure TSH
and Free T4 in two weeks to ensure
good response to treatment and
timely adjustment of the medica-
tion dose. Avoid overtreatment as it
may result in sustained tachycardia,
jitteriness, impaired feeding, poor
weight gain, premature synostosis
and undue advancement of bone
age if not recognized early. Con-
sultation with a pediatric endocri-
nologist is strongly encouraged
to improve patients’ outcome.
Only tablet forms of L-T4 should
be used. No FDA-approved liquid
formulations are available in the
United States. There are concerns
for reliable dosing of suspension
forms prepared by individual
pharmacies. Iron, calcium, fiber and
soy products should be avoided
when administering L-T4 due to
interference with drug absorption.
L-T4 should be crushed and mixed
with small volume of breast milk,
formula or water, and given directly
into the infant’s mouth.
Inadequate thyroid hormone
replacement within the first
three years of life may result in
irreversible neurodevelopmental
outcomes. Highest risk factors for
developmental disability are severe
hypothyroidism at birth and delayed
diagnosis. NBS has largely eliminated
delays in timely diagnosis. However,
although rare, false negative results
in the NBS are still possible (i.e.,
preterm or multiple births). Serum
thyroid hormone measurement
should always be carried out if
clinical concerns exist, even if the
NBS was normal. Thyroid hormone is
essential for neuronal cell migration,
which peaks in the third trimester
and continues for three years of post-
natal life.
Children with CH must be
closely monitored for compliance
and age appropriate growth and
development at each visit. Poor
compliance alone is an independent
risk factor for worse outcome. Early
identification and timely intervention
are key to improving outcomes.
Ages and Stages Questionnaire
(ASQ) is a validated developmental
screening tool and superior to
surveillance alone. At-risk cases
(severe hypothyroidism at birth, TSH
elevation while on therapy) should
be more closely monitored. Use ASQ
to screen children’s gross-motor, fine-
motor, communication, personal-
social and problem-solving skills
from newborn until age 5. Hearing
tests should be carried out at birth
and as needed if speech delay is
suspected or diagnosed. 4 Targeted
training and personalized education
may be needed especially if
academic success and psychomotor
development is a concern. s
Drs. Wang and Tas are with
the Division of Endocrinology and
Diabetes, Arkansas Children’s Hospital
in Little Rock.
REFERENCES
1. Léger J, Olivieri A, Donaldson M, et
al. European society for paediatric
endocrinology consensus guidelines on
screening, diagnosis, and management
of congenital hypothyroidism. Horm Res
Paediatr. 2014. doi:10.1159/000358198
2. American Academy of Pediatrics S on E and
C on G, Rose SR, Section on Endocrinology
and Committee on Genetics, American
Thyroid Association L, et al. Update of
Newborn Screening and Therapy for
Congenital Hypothyroidism. Pediatrics. 2006.
doi:10.1542/peds.2006-0915
3. Selva KA, Harper A, Downs A, et.al.
Neurodevelopmental outcomes in
congenital hypothyroidism: Comparison
of initial T4 dose and time to reach target
T4 and TSH. J Pediatr. 2005. doi:10.1016/j.
jpeds.2005.07.024
4. Léger J. Congenital hypothyroidism: A
clinical update of long-term outcome
in young adults. Eur J Endocrinol. 2015.
doi:10.1530/EJE-14-0777
AFMC WORKS COLLABORATIVELY WITH PROVIDERS,
COMMUNITY GROUPS AND OTHER STAKEHOLDERS TO
PROMOTE THE QUALITY OF CARE IN ARKANSAS THROUGH
EDUCATION AND EVALUATION. FOR MORE INFORMATION
ABOUT AFMC QUALITY IMPROVEMENT PROJECTS,
CALL 1-877-375-5700 OR VISIT AFMC.ORG.
APRIL 2019
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