E03.0-5/E03.8-9
DESCRIPTION
Hypothyroidism causes general slowing of metabolism, which results in symptoms that include fatigue, slow movement and speech, hoarse voice, weight gain, constipation, cold intolerance, depression and impaired memory. Physical signs may include bradycardia, dry, coarse skin, hair loss and delayed relaxation of deep tendon reflexes.
Common causes of primary hypothyroidism are:
- thyroiditis
- post surgery
- amiodarone
- radio-active iodine
Secondary hypothyroidism (< 1% of cases) may be due to any cause of anterior hypopituitarism.
DIAGNOSIS
- Check TSH concentration. If elevated, check T4 concentration.
- If TSH is elevated, and T4 is low, diagnose hypothyroidism.
MEDICINE TREATMENT
- Levothyroxine, oral, 100 mcg daily, preferably on an empty stomach.
- If there is a risk of ischaemic heart disease, start at 25 mcg daily and increase by 25 mcg every 4 weeks.
- In the elderly, start at 50 mcg daily, increased by 25 mcg at 4 week intervals, according to response.
- Check TSH and T4 after 2–3 months and adjust dose if required.
- Once stable, check TSH andT4 annually.
REFERRAL
- Suspected hypopituitarism.
- Hypothyroidism in pregnancy.