TY - JOUR
T1 - Fetal sinus bradycardia is associated with congenital hypothyroidism
T2 - An infant with ectopic thyroid tissue
AU - Nakanomori, Aya
AU - Nagano, Nobuhiko
AU - Seimiya, Ayako
AU - Okahashi, Aya
AU - Morioka, Ichiro
N1 - Publisher Copyright:
© 2019 Tohoku University Medical Press.
PY - 2019/8
Y1 - 2019/8
N2 - Hypothyroidism is rarely included in the differential diagnosis for fetal sinus bradycardia. We report an infant with congenital hypothyroidism caused by ectopic thyroid tissue, who showed antenatal bradycardia. The baseline fetal heart rate was 100-110 bpm at 30 weeks of gestation, and fetal echocardiography revealed sinus bradycardia but no cardiac anomalies. Maternal thyroid function was normal (thyroidstimulating hormone [TSH] 2.03 µ IU/ml, free T3 2.65 pg/ml, and free T4 0.99 ng/dl) when measured at 31 weeks of gestation. Her serum anti SS-A and SS-B antibodies, anti-thyroglobulin, and microsomal antibodies were negative. A male infant without cardiac anomalies was delivered at 35 weeks and 4 days of gestation and admitted for prematurity and respiratory distress syndrome. The infant’s heart rate was 70-110 bpm (normal: 120-160 bpm) on admission. On 8 days of age, thyroid function tests revealed that the infant had severe hypothyroidism (TSH 903.3 µ IU/ml, free T3 1.05 pg/ml, and free T4 0.26 ng/dl). The prolonged jaundice assumed to be due to hypothyroidism. Oral levothyroxine sodium hydrate (10 µ g/kg/ day) was immediately started on day 8. After the treatment, the heart rate was gradually increased to 130-140 bpm as the infant’s thyroid function was improved (TSH 79.8 µ IU/ml, free T3 2.95 pg/dl, and free T4 1.66 ng/dl on day 22). The infant was diagnosed ectopic thyroid tissue because of the high thyroglobulin level (85.9 µ g/l). In conclusion, congenital hypothyroidism should be included in the differential diagnosis in cases of fetal bradycardia without cardiac anomalies or maternal autoimmune diseases.
AB - Hypothyroidism is rarely included in the differential diagnosis for fetal sinus bradycardia. We report an infant with congenital hypothyroidism caused by ectopic thyroid tissue, who showed antenatal bradycardia. The baseline fetal heart rate was 100-110 bpm at 30 weeks of gestation, and fetal echocardiography revealed sinus bradycardia but no cardiac anomalies. Maternal thyroid function was normal (thyroidstimulating hormone [TSH] 2.03 µ IU/ml, free T3 2.65 pg/ml, and free T4 0.99 ng/dl) when measured at 31 weeks of gestation. Her serum anti SS-A and SS-B antibodies, anti-thyroglobulin, and microsomal antibodies were negative. A male infant without cardiac anomalies was delivered at 35 weeks and 4 days of gestation and admitted for prematurity and respiratory distress syndrome. The infant’s heart rate was 70-110 bpm (normal: 120-160 bpm) on admission. On 8 days of age, thyroid function tests revealed that the infant had severe hypothyroidism (TSH 903.3 µ IU/ml, free T3 1.05 pg/ml, and free T4 0.26 ng/dl). The prolonged jaundice assumed to be due to hypothyroidism. Oral levothyroxine sodium hydrate (10 µ g/kg/ day) was immediately started on day 8. After the treatment, the heart rate was gradually increased to 130-140 bpm as the infant’s thyroid function was improved (TSH 79.8 µ IU/ml, free T3 2.95 pg/dl, and free T4 1.66 ng/dl on day 22). The infant was diagnosed ectopic thyroid tissue because of the high thyroglobulin level (85.9 µ g/l). In conclusion, congenital hypothyroidism should be included in the differential diagnosis in cases of fetal bradycardia without cardiac anomalies or maternal autoimmune diseases.
KW - Congenital hypothyroidism
KW - Ectopic thyroid tissufree
KW - Fetal bradycardia
KW - Levothyroxine sodium hydrate
KW - Maternal autoimmune disease
UR - http://www.scopus.com/inward/record.url?scp=85071635303&partnerID=8YFLogxK
U2 - 10.1620/tjem.248.307
DO - 10.1620/tjem.248.307
M3 - Article
C2 - 31462599
AN - SCOPUS:85071635303
SN - 0040-8727
VL - 248
SP - 307
EP - 311
JO - Tohoku Journal of Experimental Medicine
JF - Tohoku Journal of Experimental Medicine
IS - 4
ER -