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Chagas and co-authors, Belo
Horizonte, MG, Brazil, called the attention to the fact that many
of children with congenital hypothyroidism, diagnosed at the
neonatal screening program as THYROID AGENESIS may, in fact, have
a cervical, normal positioned, hypoplastic thyroid gland. They
have examined six children with the diagnosis of thyroid agenesis
based on the absence of neck uptake of radionucleide. However, a
carefully conducted echographic study of the cervical region was
able to document a hypoplastic cervical thyroid gland. In two
(out of six) patients serum Tg was normally present in the
circulation. They concluded that a negative radioactive iodine or
pertechnetate neck scan is not sufficient for the diagnosis of
thyroid agenesis.
Pereira and co-workers, Curitiba, PR, Brazil, reported on the clinical and laboratory aspects of central congenital hypothyroidism due to isolated deficiency of TSH, a rare disorder. They were able to collect nine patients from five consanguineous families. The clinical features were short stature with a variable degree of hypothyroidism and mental retardation. All patients had low serum total T4 and low but detectable serum TSH. A modest but significant rise of serum TSH was observed in two patients after TRH stimulation. Secretion of the other pituitary hormones was not decreased. Serum prolactin was elevated in 6 children. They concluded that isolated deficiency of TSH has ample and diverse clinical features and that further studies concerning the molecular genetics of this syndrome should be conducted. Bazzara et al., Cordoba, Argentina, reported on 2 years of experience of Neonatal Screening of Congenital Hypothyroidism in the State of Cordoba, Argentina. A total of 21,078 neonates were screened by dry blood spots on filter paper that were assayed by a Delphia Neonatal hTSH method. Eleven congenital hypothyroid children were detected in these 2 years with a prevalence of 1/1916. This relatively high frequency may be due to additional mild iodine deficiency in the mountainous areas of Cordoba. Patients were started on L-T4 relatively late (mean 28±18 days). The etiological diagnosis was agenesis (3), ectopic thyroid (4) and dyshormonogenesis (4). The authors comment on the need to obtain a better integration between the laboratory and the public health system, in order to effect a more early start of treatment with L-T4. |
