Hypothyroidism

Published on 31/05/2015 by admin

Filed under Obstetrics & Gynecology

Last modified 22/04/2025

Print this page

This article have been viewed 1736 times

Chapter 31 Hypothyroidism

INTRODUCTION

Description: Reduced or inadequate circulating levels of thyroid hormone. Women are 5 to 10 times more likely than men to suffer from hypothyroidism. Menstrual disturbances may be the first indication of this abnormality. Some women develop a transient (3 to 4 months) hypothyroid state (painless subacute thyroiditis) after giving birth.

Prevalence: Five to 10 of 1000 general population, 6% to 10% of women older than age 65.

Predominant Age: Older than age 40.

Genetics: No genetic pattern for idiopathic type, may be associated with type II autoimmune polyglandular syndrome (HLA-DR3, HLA-DR4).

ETIOLOGY AND PATHOGENESIS

Causes: Idiopathic or autoimmune (most common when goiter is present)—after ablative medical or surgical therapy. Postpartum thyroiditis (silent)—abnormalities of thyroid-stimulating hormone (TSH) or thyrotropin-releasing hormone (TRH) production or release.

Risk Factors: Age, other autoimmune disease, ablative therapy, pituitary failure.

MANAGEMENT AND THERAPY

Nonpharmacologic

General Measures: Evaluation, education about need for continuing therapy.

Specific Measures: Thyroid replacement mediation.

Diet: High-bulk diet to avoid constipation.

Activity: No restriction.

Patient Education: Education regarding need for compliance with medication and follow-up; American College of Obstetricians and Gynecologists Patient Education Pamphlet AP128 (Thyroid Disease).

Drug(s) of Choice

Levothyroxine (Synthroid, Levothroid) 50 to 100 microgram PO daily, increase by 25 microgram/day every 4 to 6 weeks until TSH is in normal range.

Contraindications: Adrenocorticoid insufficiency (uncorrected), thyrotoxic heart disease.

Precautions: The initial dose should be reduced in elderly patients.

Interactions: The dose of insulin, oral hypoglycemics, and anticoagulants may need to be adjusted after thyroid therapy is initiated. Other possible interactions may be seen with oral contraceptives, estrogen and cholestyramine. Ferrous sulfate may decrease the absorption of thyroid replacement medications.

FOLLOW-UP

Patient Monitoring: Thyroid status should be checked every 6 weeks until stable, then every 6 months. Because of the prevalence of hypothyroidism in older women, a baseline assessment should be obtained at age 45 and periodic screening (biannually) is recommended in patients older than age 60.

Prevention/Avoidance: None.

Possible Complications: Life threatening—coma (myxedema coma) and hypothermia. (Treatment is with intravenous thyroid hormone replacement and steroid therapy. Supportive therapy [oxygen, assisted ventilation, fluid replacement] and intensive-care nursing may be indicated.) Others—treatment-induced congestive heart failure, increased susceptibility to infection, megacolon, organic psychosis with paranoia, infertility and amenorrhea, or osteoporosis resulting from overtreatment.

Expected Outcome: With treatment, return to normal function. Relapse will occur if therapy is discontinued.

MISCELLANEOUS

Pregnancy Considerations: Medication may need to be adjusted. TSH levels should be checked monthly during the first trimester. TSH levels should be checked at 6 weeks postpartum. Women who develop postpartum thyroiditis have a 30% chance of developing hypothyroidism in the future. Any goiter during pregnancy is abnormal.

ICD-9-CM Codes: Based on cause.

Grozinsky-Glasberg S, Fraser A, Nahshoni E, et al. Thyroxine-triiodothyronine combination therapy versus thyroxine monotherapy for clinical hypothyroidism: meta-analysis of randomized controlled trials. J Clin Endocrinol Metab. 2006;91:2592.

American College of Obstetricians and Gynecologists. Thyroid Disease in Pregnancy. ACOG Practice Bulletin 37. Washington, DC: ACOG, 2002.

Bach-Huynh TG, Jonklaas J. Thyroid medications during pregnancy. Ther Drug Monit. 2006;28:431.

Barzel US. Hypothyroidism: diagnosis and management. Clin Geriatr Med. 1995;11:239.

Boelaert K, Franklyn JA. Thyroid hormone in health and disease. J Endocrinol. 2005;187:1.

Casey BM. Subclinical hypothyroidism and pregnancy. Obstet Gynecol Surv. 2006;61:415. quiz 423.

Casey BM, Leveno KJ. Thyroid disease in pregnancy. Obstet Gynecol. 2006;108:1283.

Davis LE, Leveno KJ, Cunningham FG. Hypothyroidism complicating pregnancy. Obstet Gynecol. 1988;72:108.

Hypothyroidism in the pregnant woman. Drug Ther Bull. 2006;44:53.

Lao TT. Thyroid disorders in pregnancy. Curr Opin Obstet Gynecol. 2005;17:123.

Lazarus JH. Thyroid disorders associated with pregnancy: etiology, diagnosis, and management. Treat Endocrinol. 2005;4:31.

Lazarus JH, Premawardhana LD. Screening for thyroid disease in pregnancy. J Clin Pathol. 2005;58:449.

Mandel SJ, Larsen PR, Seely EW, Brent GA. Increased need for thyroxine during pregnancy in women with primary hypothyroidism. N Engl J Med. 1990;323:91.

Pearce EN, Farwell AP, Braverman LE. Thyroiditis. N Engl J Med 348 2003 2646 Erratum in: N Engl J Med. 2003;349:620.

Redmond GP. Thyroid dysfunction and women’s reproductive health. Thyroid. 2004;14(Suppl 1):S5.

Schindler AE. Thyroid function and postmenopause. Gynecol Endocrinol. 2003;17:79.

Soldin OP. Thyroid function testing in pregnancy and thyroid disease: trimester-specific reference intervals. Ther Drug Monit. 2006;28:8.

Wartofsky L, Van Nostrand D, Burman KD. Overt and “subclinical” hypothyroidism in women. Obstet Gynecol Surv. 2006;61:535.

Related

Netters Obstetrics and Gynecology