[Tc99m-pertechnetate thyroid scintigraphy in newborns with congenital hypothyroidism].
BACKGROUND
Congenital hypothyroidism is one of the most frequent endocrine diseases of the newborn and requires an early diagnosis to avoid its deleterious effects on neurological and intellectual functions.


OBJECTIVE
To evaluate thyroid scintigraphy (TS) findings in newborns with congenital hypothyroidism (CH), detected in the national program of newborn screening, which is working in Chile since 1992.


METHODS
TS findings of 189 newborns with CH (68% female) were analyzed. Tc99m pertechnetate TS was performed at 19 +/- 11 days of life. The gland was classified as eutopic, ectopic or absence of contrast (AC). Eutopic glands were classified by visual and quantitative criteria as: normal, goiter and decreased contrast (DC). TS results were compared by gender and hormonal levels.


RESULTS
Forty seven percent of newborns had ectopy, 29.1% eutopy and 24.3% AC. Eutopic gland predominated in males (44.2% vs 22.7%) and ectopy was more frequent in girls (53.1% vs 32.8%, p < 0.05). Newborns with AC had the most severe hormonal alterations, without gender differences. Newborns with normal TS had less hormonal alterations than those with goiter.


CONCLUSIONS
TS allows an etiological classification of CH. Thyroid dysgenesis is the most frequent cause, most of which correspond to ectopy, especially in girls. Eutopic glands are present in one third of newborns with CH. Goiter predominates, especially in males.
Lobo
Gabriel
G
Unidad de Medicina Nuclear, CDT Hospital San Juan de Dios, Servicio de Pediatría, Hospital San Juan de Dios, Servicio de Salud Metropolitano Occidente, Ministerio de Salud, Chile. globo@machi.med.uchile.cl
Ladrón de Guevara
David
D
Arnello
Francisca
F
Pérez
Andrés
A
Vivanco
Ximena
X
Bruggendieck
Bernardo
B
Bustos
María Eliana
ME
Jiménez
César
C
Donoso
Gilda
G
Brantes
Jorge
J
Becerra
Carlos
C
D002677:Chile; D003409:Congenital Hypothyroidism; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000000981:diagnostic imaging*; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m; D013961:Thyroid Gland / Q000000981:diagnostic imaging*
D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m