Why Am I So Tired? : Hypothyroidism

Sarah is a 32 year-old software engineer who presents with a one year history of fatigue, difficulty losing weight, dry skin, cold intolerance and difficulty concentrating. She has been busy working long hours and initially attributed her symptoms to long work hours and stress. Her mother has a history of hypothyroidism.

At her routine follow-up with her family physician, Sarah mentioned her symptoms, and her physician noted slight enlargement of her thyroid gland. The results of her blood tests were as follows:

Thyroid stimulating hormone (TSH): 15.6 mIU/L (N 0.32-400 mIU/L) Free thyroxine (Free T4): 7 pmol/L (N 9-19 pmol/L)

The combination of signs and symptoms along with bloodwork showing an elevated TSH and low Free T4 confirmed the diagnosis of hypothyroidism, almost certainly due to Hashimoto’s thyroiditis, the most common cause of hypothyroidism and typically more common in women than men and often associated with a family history of thyroid disease.

Sarah is started on thyroid hormone replacement therapy with a high quality brand preparation of levothyroxine (Synthroid®). Her pharmacist instructs her to take the medication on an empty stomach every morning. Within about 6 weeks, all of Sarah’s symptoms have resolved and she has returned to feeling perfectly normal. Repeat bloodwork done 8 weeks after initiating treatment revealed a normal TSH.

Sarah will benefit from regular follow-up with her family physician, with TSH testing at least once yearly or if symptoms return. Her pharmacist can help with ongoing reminders about how to properly take her medication.