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![Treatment
• PROPYL THIOURACIL - blocks the oxidation of iodine in the thyroid gland :
prevents synthesis of T4 and T3
• Dose 150-400mg initially (4-6 weeks) and maintain with 50-150mg
• METHIMAZOLE - blocks the organification of iodine : decreases thyroid
harmone production
• Dose 5-15mg daily
In one report of 77 newborns of euthyroid mothers treated with PTU or methimazole, there were no significant differences in TSH
concentrations measured in cord blood at birth [15]. However, compared with control neonates who were not exposed in utero to thionamides,
mean cord TSH levels were higher in neonates exposed to PTU but not methimazole
Low thyroid function at birth is found in approximately one-half of neonates whose mothers received PTU or methimazole during pregnancy
and who had serum T4 concentrations within the normal (nonpregnant) range [4]. In spite of these observations, two studies reported that the
intelligence quotient (IQ) scores of children who were exposed to thionamides in utero (but were euthyroid at birth) were normal](https://image.slidesharecdn.com/presentation7-240214115508-bd851409/75/Presentation-7-pptx-13-2048.jpg)
![During lactation
• Very little PTU and methimazole is excreted in breast milk safe for mothers
to breast feed while taking doses to PTU at or below 150mg/day and
methimazole 15mg/day
• High doses of antithyroid drug : thyroid function should be checked in
umbilical cord blood and at regular interval in the neonate.
• PTU associated hepatotoxicity , we consider methimazole. If the dose
exceeds :20mg daily then the infants should be assessed after one and
three months.
in a study of 139 mothers taking up to 20 mg methimazole daily, thyroid function, growth, and development of their breastfed
infants were normal [56]. Similar results were seen in a study of mothers taking PTU [57]. There has yet to be a report of
agranulocytosis or liver disease in an infant who was nursed by a woman taking PTU or methimazole.](https://image.slidesharecdn.com/presentation7-240214115508-bd851409/75/Presentation-7-pptx-17-2048.jpg)
![Postpartum
• Measure TFT six weeks postpartum then every six weeks if an adjustment
dose is needed or every 4 months if TFT remain normal
• Postpartum hyperthyroidism maybe due to a relapse of Graves’ disease or
due to postpartum thyroiditis
in a study of 150 women with Graves' disease in remission after antithyroid drug therapy [59]. Of the 25 women who had a
subsequent pregnancy, 21 (84 percent) experienced a relapse, compared with 70 of 125 (56 percent) who did not have a pregnancy.
The risk of relapse appeared to be related to the postpartum period rather than the pregnancy itself as 20 of the 21 relapses
occurred four to eight months postpartum](https://image.slidesharecdn.com/presentation7-240214115508-bd851409/75/Presentation-7-pptx-18-2048.jpg)
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Presentation 7.pptx
- 1. Hyperthyroidism in pregnancy Moderator: Dr. Aravind Presenter : Keerthana
- 2. Objectives • Physiological changesin pregnancy • Incidence • Clinical features • Pathogenesis • Diagnosis • Treatment • Adverse effect • Therapies not recommended
- 3. Physiological changes ofthyroid during pregnancy • TBG - increase ( hepatic synthesis is increased ) • TT4 AND TT3 - Increased to compensate for the rise • FT3 - decreased • FT4 - are altered less by pregnancy but do fall a little in 1st and 2nd trimesters • TSH - decreases in 1st trimester , increase in 2nd and 3rd trimester
- 5. Incidence • 1 in500 pregnancies • 50% family history of autoimmune thyroid disease • Most cases encountered in pregnancy have already been diagnosed and will already be on treatment • If thyrotoxicosis occurs for the first time in pregnancy it usually presents late in 1st or early in 2nd trimester
- 6. Clinical features Discriminatory features: Weight loss Exophthalmos Tremors Lid lag Persistent tachycardia
- 7. Pathogenesis 95% : Graves’disease (Autoimmune disorder caused by TSH stimulating harmone) More rarely Toxic multinodular goitre Toxic adenoma GTT Subacute thyroiditis Iodine, amiodarone or lithium therapy Choriocarcinoma Molar pregnancy
- 8. Screening for maternalthyroid antibodies • Graves’ disease- with Fetal or neonatal hyperthyroidism in previous pregnancy • Active Graves’ disease being treated • Euthyroid or have undergone ablative therapy and have Fetal tachycardia or IUGR • Chronic thyroiditis without goitre • Fetal goitre on ultrasound • Screening for neonatal thyroid antibodies
- 9. Diagnosis • Overt -raised FT4 or FT3 , decreased TSH • Subclinical - decreased TSH , normal FT3 and FT4
- 10. Treatment of hypothyroidismis not required in • Transient subclinical hyperthyroidism- in first trimester as it is considered to be a normal physiological finding • hCG mediated overt hyperthyroidism : as it is transient and mild • Hyperemesis gravidarum associated hyperthyroidism
- 11. Effect of thyrotoxicosison pregnancy • Exacerbations : may occur in 1st trimester • Improvement and a lower requirement for antithyroid treatment during 2nd and 3rd trimester
- 12. Aim of treatment •Control the thyrotoxicosis • Maintain optimal control with the lowest dose of antithyroid medication • Monitoring • The women should be clinically euthyroid • FT4 at the upper end of normal range • TFT every 4 week till TSH and FT4 are within normal, every trimester thereafter.
- 13. Treatment • PROPYL THIOURACIL- blocks the oxidation of iodine in the thyroid gland : prevents synthesis of T4 and T3 • Dose 150-400mg initially (4-6 weeks) and maintain with 50-150mg • METHIMAZOLE - blocks the organification of iodine : decreases thyroid harmone production • Dose 5-15mg daily In one report of 77 newborns of euthyroid mothers treated with PTU or methimazole, there were no significant differences in TSH concentrations measured in cord blood at birth [15]. However, compared with control neonates who were not exposed in utero to thionamides, mean cord TSH levels were higher in neonates exposed to PTU but not methimazole Low thyroid function at birth is found in approximately one-half of neonates whose mothers received PTU or methimazole during pregnancy and who had serum T4 concentrations within the normal (nonpregnant) range [4]. In spite of these observations, two studies reported that the intelligence quotient (IQ) scores of children who were exposed to thionamides in utero (but were euthyroid at birth) were normal
- 14. • Pre treatmentevaluation - neutrophil count less than 1000cells or elevated liver transaminase ( more than 5 fold ) prior to initiating PTU • Diagnosed before pregnancy : • Surgery but has complication if hypocalcemia and hypothyroidism • If already on treatment with methimazole then after careful monitoring of TFT tests weekly then monthly then the drug to be discontinued if normal TSH AND TRab are negative • Switch to PTU before trying to conceive
- 15. • Diagnosed duringpregnancy : PTU can be continued or switched back to methimazole at 16 weeks. Risk is can cause Fetal hypothyroidism but the pro is it is less metabolised in the liver hence less hepatotoxicity • Diagnosed after first trimester : symptomatic moderate to severe hyperthyroidism should take methimazole • Initial dosing • PTU 50mg two to three times daily • Methimazole 5 to 10 mg daily • Carbimazole 5 to 15mg daily
- 16. Adverse effects • PTUassociated liver failure • If tolerated and no adverse side effect then switch to methimazole in second trimester • Carbimazole rarely can cause neutropenia and agranulocytosis and aplasia cutis • Thionamide intolerance is present then surgery can be considered as radioiodine therapy is contraindicated in pregnancy only when there is increased risk of spontaneous abortion or premature delivery. • Prior to thyroidectomy she needs to be treated with beta blockers and pottassium iodide solution as it lowers the serum thyroid harmone concentration acutely and decreased thyroid gland vascularity
- 17. During lactation • Verylittle PTU and methimazole is excreted in breast milk safe for mothers to breast feed while taking doses to PTU at or below 150mg/day and methimazole 15mg/day • High doses of antithyroid drug : thyroid function should be checked in umbilical cord blood and at regular interval in the neonate. • PTU associated hepatotoxicity , we consider methimazole. If the dose exceeds :20mg daily then the infants should be assessed after one and three months. in a study of 139 mothers taking up to 20 mg methimazole daily, thyroid function, growth, and development of their breastfed infants were normal [56]. Similar results were seen in a study of mothers taking PTU [57]. There has yet to be a report of agranulocytosis or liver disease in an infant who was nursed by a woman taking PTU or methimazole.
- 18. Postpartum • Measure TFTsix weeks postpartum then every six weeks if an adjustment dose is needed or every 4 months if TFT remain normal • Postpartum hyperthyroidism maybe due to a relapse of Graves’ disease or due to postpartum thyroiditis in a study of 150 women with Graves' disease in remission after antithyroid drug therapy [59]. Of the 25 women who had a subsequent pregnancy, 21 (84 percent) experienced a relapse, compared with 70 of 125 (56 percent) who did not have a pregnancy. The risk of relapse appeared to be related to the postpartum period rather than the pregnancy itself as 20 of the 21 relapses occurred four to eight months postpartum
- 19. Beta blockers In earlymanagement of thyrotoxicosis. Beta blockers in pregnant women with moderate to severe hyperthyroidism and hyperandergenic symptoms Metoprolol 25 to 50mg daily Propranolol 20mg three to four times daily Labetalol 100mg BD They need to be tapered and discontinued within 2 to 6 weeks For pregnant women with moderate to severe hyperthyroidism due to Graves’ disease, toxic adenoma or toxic multinodular goitre thionamide remains the first choice of treatment. Thionamide
- 20. Therapies not recommended •Radio iodine- absolutely contraindicated. However studies shows that if dome in first trimester before 8 to 10 weeks does not cause Fetal hypothyroidism or congenital anomalies. Spontaneous pregnancy loss was reported in a few cases. • Thyroxine - little T4 crosses the placenta making it even more difficult to determine the minimal dose of thionamide