Source: Jonklaas J, Talbert RL.
Thyroid Disorders. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR,
Wells BG, Posey LM, eds. Pharmacotherapy:
A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7991868.
Accessed June 22, 2012.
- Overactive thyroid
- Clinical and biochemical syndrome resulting from increased
thyroid hormone production.
- TSH-secreting pituitary adenomas
- Graves’ disease
- Trophoblastic diseases
- Thyroid autonomy
- Toxic adenoma
- Multinodular goiter
- Subacute thyroiditis
- Painless thyroiditis
- Ectopic thyroid tissue
- Struma ovarii
- Exogenous thyroid hormone sources
- Thyrotoxicosis results when tissues exposed to excessive
levels of thyroxine (T4), triiodothyronine (T3),
- TSH-secreting pituitary tumors release active hormone unresponsive
to normal feedback control.
- In Graves’ disease, hyperthyroidism results from
action of thyroid-stimulating antibodies (TSAb).
- Autonomous thyroid nodule (toxic adenoma) is thyroid mass
whose function is independent of pituitary control.
- In multinodular goiters, follicles with autonomous function
generate more thyroid hormone than required.
- Painful subacute thyroiditisoften
develops after viral illness.
- Painless thyroiditis may have underlying autoimmune cause.
- Amiodarone may induce thyrotoxicosis and may also cause destructive
thyroiditis with loss of thyroglobulin and thyroid hormones.
- In National Health and Nutrition Examination Survey III:
- 0.7% of those surveyed had subclinical hyperthyroidism
and 0.5% had clinically significant hyperthyroidism.
- Prevalence of suppressed TSH peaked for people aged 20–39,
declined in those 40–79, and increased again in those 80
- Abnormal TSH levels were more common among women than men.
- Emotional lability
- Easy fatigability
- Heat intolerance
- Weight loss with increased appetite
- Increased frequency of bowel movements
- Proximal muscle weakness
- Scanty or irregular menses in women
- Thyroid enlargement
- Pretibial myxedema
- Warm, smooth, moist skin and unusually fine hair
- Lid lag
- Resting tachycardia, widened pulse pressure, and systolic
- Gynecomastia in men
- Fine tremor of protruded tongue and outstretched hands
- Hyperactive deep tendon reflexes
- Thyroid storm:
- Decompensated thyrotoxicosis
- High fever (often above 39.4°C [103°F])
- TSH, total T4, free T4, T3 resin
uptake, free thyroxine index, 24-hour radioactive iodine uptake
- Thyroid scan shows areas of autonomously functioning thyroid
tissue in multinodular goiters.
- General anxiety disorder, panic disorder, mania
- Other hypermetabolic states (e.g., cancer, pheochromocytoma)
- Subclinical hyperthyroidism
- Eliminate excess thyroid hormone.
- Minimize symptoms and long-term consequences.
- Provide individualized therapy based on:
type and severity
- Patient age and sex
- Existence of nonthyroid conditions
- Response to previous therapy
- Consider thyroidectomy if on antithyroid drug treatment
- Large gland (>80 g)
- Severe ophthalmopathy
- Lack of remission
- Thioureas (propylthiouracil [PTU], methimazole)
- Usual initial doses:
- PTU 300–600
mg daily, usually in 3 or 4 divided doses
- Methimazole 30–60 mg daily in 3 divided doses
- Improvement observed within 4–8 weeks, then start
tapering regimen to maintenance doses (e.g., PTU 50–300
mg, methimazole 5–30 mg).
- Change dosages approximately once monthly ...