Recommendation for Hypothyroidism Screening
Hypothyroidism



Approximately 1-6% of the population has hypothyroidism
More than half of the cases of hypothyroidism are undiagnosed
Treatable with a thyroid hormone replacement medication
Who should go for screening?



Routine screen for neonates
Anyone with unexplained symptoms as listed in when to seek medical advice
Anyone with risk factors
♦ Age over 40 years
♦ Female
♦ Family history of thyroid disease
♦ History of autoimmune disease such as rheumatoid arthritis or type 1 diabetes
♦ History of thyroid surgery or radioactive iodine treatment
♦ Elevated triglycerides or cholesterol
When to seek medical advice








Unexplained fatigue, weakness, slow movement, constipation
Cold intolerance
Hair loss and/or dry skin
Menorrhagia, impaired fertility
Carpal tunnel syndrome
Myalgias and arthralgias
Memory impairment, hearing loss, hoarseness
Weight gain, edema of the face and extremities
Screening
A blood sample is drawn and a TSH level is measured. With specific reason, a free T4 level
may also be measured.
Lab findings include:
● high TSH in primary hypothyroidism or low TSH in secondary or tertiary hypothyroidism
● low freeT4
Other lab findings may include:
● high AST, CPK, cholesterol and triglycerides, prolactin levels
● low sodium, blood glucose levels
● mild anemia
Prevention
● Rarely preventable as most common causes are idiopathic, of autoimmune origin, or due to
treatment of hyperthyroidism
● Less common causes, including drugs (lithium and amiodarone) or an iodine deficiency, may
be preventable in theory but difficult to avoid in practice
● Complications can be prevented by routine screening of neonates and those with risk factors
Treatment
● Levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid)
-initial dose: 25-50 mcg QD, low starting doses are especially important in patients with
cardiac disease
-usual maintenance dose: 75-150 mcg QD
-available tablet strengths: 25, 50, 75, 88, 100, 112, 125, 150, 175, 200, 300 mcg
● Monitoring- measure TSH level in 6 weeks after initiation of or change in drug therapy as the
T½ of T4 (levothyroxine) is 1 week
Useful Sites and Resources



www.vh.org
www.Mayoclinic.com
www.thyroid.org
References
1. www.vh.org/Providers/ClinRef/FPHandbook/Chapter06/13-6.html
2. www.Mayoclinic.com/findinformation/diseasesandconditions/invoke.cfm?id=D500353
3. www.thyroid.org/resources/patients/brochures/hypothyroidism.html