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Thyroid hormone is critical for normal growth and brain development,
and hypothyroidism in infancy is the leading cause of intellectual
Congenital hypothyroidism (CH), defined as deficiency of thyroid hormones
Congenital hypothyroidism is very important clinically since severe cases
will lead to irreversible mental handicap without prompt treatment.
The essential role of thyroid...
The essential role of thyroid hormones in brain development during
the first 24-36 months of age is well established; thus prompt
normalization of thyroid hormone levels is essential .
The incidence of CH diagnosed by neonatal screening varies per population,
ranging from 1 in 2000 to 1 in 3000 births and is comparatively higher
than the reported incidence prior to the era of screening.
Following clinical assessment, a good venous blood sample for
measurement of free thyroxine (fT4) and TSH is mandatory, since the result
reflects the presence and severity of congenital hypothyroidism.
Compared to venous serum, the concentrations in skin puncture serum
were higher for thyroid stimulating hormone (TSH) (86.7%). Capillary TSH
dried blood spot testing on the 3rd-5th day is the most sensitive method.
In our setup we could use only venous blood TSH levels rather than
capillary blood samples reason may be having expert nursing care to
collect the blood samples but not having sufficient infrastructure and
personnel to implement the same.
In our experience 4 babies out of 1500 had transient elevated TSH
levels which on follow up normalized within 3 weeks after birth without
treatment. There was no proved case of congenital hypothyroidism was seen
probable reasons may be use of common salt fortified with iodine for
cooking and staple diet being mainly fish.
In countries that can afford newborn screening, treatment within the
first 28 days of life - so-called 'early treatment' - has transformed the
outlook for children with CH so that severe growth retardation with mental
handicap(congenital hypothyroidism) is no longer seen.
It is described as primary when the gland itself is affected and
central when the defect lies in the hypothalamo-pituitary axis;
compensated when the hypothalamo-pituitary-thyroid axis is jeopardised but
still manages to maintain normal thyroxine (T4) levels and decompensated
when normal thyroid hormone levels cannot be maintained.
Van der Sluijs Veer et al. studied 95 toddlers with CH in whom L-
thyroxine treatment had been started at a median age of 9 days, with
normalization of the serum free T4 concentration within 2.1 days and of
the serum TSH level within 18.6 days.
Cord FT4 identifies only infants with severe CH. Cord TSH is more
sensitive than cord FT4 screening. Capillary TSH dried blood spot testing
on the 3rd-5th day is the most sensitive method.
In our experience it was found that serum thyrotropin values at 2nd and
3rd day were useful in screening and early treatment of congenital
Nikolina Zdraveska, Violeta Anastasovska and Mirjana Kocova.
Frequency of thyroid status monitoring in the first year of life and
predictors for more frequent monitoring in infants with congenital
hypothyroidism. J Pediatr Endocrinol Metab 2016; aop
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Deladoey J, Ruel J, Gigu?re Y, et al. Is the incidence of congenital
hypothyroidism really increasing? A 20-year retrospective population-based
study in Quebec. J Clin Endocrinol Metab 2011;96:2422-9.
Grosse SD, Van Vliet G. Prevention of intellectual disability through
screening for congenital hypothyroidism: how much and at what level? Arch
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Corbetta C, Weber G, Cortinovis F, Calebiro D, Passoni A, Vigone MC
et al. A 7-year experience with low blood TSH cutoff levels for neonatal
screening reveals an unsuspected frequency of congenital hypothyroidism
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Hardy JD, Zayed R, Doss I, Dhatt GS. Cord blood thyroxine and thyroid
stimulating hormone screening for congenital hypothyroidism: how useful
are they? J Pediatr Endocrinol Metab. 2008 Mar;21(3):245-9.
Hardy JD1, Zayed R, Doss I, Dhatt GS. Cord blood thyroxine and
thyroid stimulating hormone screening for congenital hypothyroidism: how
useful are they? J Pediatr Endocrinol Metab. 2008 Mar;21(3):245-9.
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