HYPERTHYROIDISM IN CHILDREN AND ADOLESCENTS
Summary:
Introduction.
Hyperthyroidism is a state of hypermetabolism caused by an increase in
thyroid hormones. It is a condition more frequently described in adults,
since in prepubertal children it has a reported prevalence of 0.1/100 000
and in adolescents 1/100 000, being in all ages more frequent in women.
Patients and Methods.
They were developed in patients under 15 years of age with a diagnosis of
hyperthyroidism, monitored between July 1, 2004 and June 31, 2005.
The diagnosis of hyperthyroidism was based on the presence of
suppressed TSH. The etiologic study included measurement of TSH
receptor stimulating antibodies {Thyroid Stimulating Receptor Antibodies
(TRAb)) Normal value < t l% inhibition; Anti Thyroperoxidase (ATPO) and
Anti Thyroglobulin (ATG), I'^' uptake and thyroid ultrasonography.
Results.
Twenty-six patients were evaluated, 22 of which were women (84.6%) and
3 of the patients were Down syndrome carriers (11%). The diagnosis was
made at 9.8 ± 3.5 years (range 3.8 to 14.5). The duration of symptoms
before the start of treatment was 6.6 ± 10.6 months (median 3 months,
range 1 to 48 months). The most frequent symptoms were goiter (96.2%),
sweating (80.7%) and tachycardia (77%). The most frequent cause of HT
was Graves' disease (73% of cases); in 15.3% (4/26) the etiology
corresponded to Hashytoxicosis and in 11.5% of cases (3/26) the etiology
could not be concluded. Antithyroid drugs were the first line treatment in
23 patients, using PTU 78% (18 patients) and Tiamazol (Thyrozol®) 22% (5
patients). 62.5% of the patients became euthyroid at 6 months and 79.1%
at 12 months. 31.5% (6/19) of EG presented hypothyroidism at 6.3 ± 4
months of DAT use, requiring substitution with LT4. The r^' was indicated
in 4 children (16.6%): in one case it was the treatment of choice from the
beginning because the patient had significant hepatic involvement prior to
the start of therapy. Two patients received it because they presented
significant elevation of transaminases, and one girl abandoned treatment
due to family problems and was readmitted with thyroid storm symptoms.
Thyroidectomy was indicated in 2 patients (8.3%), both with GD; one for
giant goiter, with no response to DAT after 19 months of use and the
other for persisting hyperthyroidism after 25 months of DAT use.
Regarding treatment complications, 15% of the cases treated with
antithyroid drugs presented a significant increase in transaminases, which
required discontinuation of the drug and alternative therapy. No
alterations were recorded in the hemogram. There were no complications
derived from I'^' or thyroidectomy at the date of the study.
Discussion.
Thyroid hormones play a crucial role in the growth and development of
the child, participating in the myelination of the CNS, in growth, in puberty
and in the metabolism of the different organs, so that thyroid dysfunction
could cause irreversible damage during childhood^. All these symptoms
were present in varying degrees in our patients, as spontaneous
consultation or in a directed anamnesis. There is no known treatment to
correct the autoimmune disorder of GD since all therapies are aimed at
decreasing the hyperfunction of the thyroid gland. TADs inhibit the
synthesis of thyroid hormones by interfering with the oxidation and
binding of iodine to the thyroid cell. In conclusion we can say that HT in
children and adolescents is infrequent, however, the great variety of
clinical signs it presents should alert pediatricians to avoid delay in its
diagnosis and management, which can leave important sequelae in the
patient, especially at younger ages when it presents in a more severe form
and remission is slower.