Case Studies

 Case 5.3 Primary autoimmune hypothyroidism

A 36-year-old woman presented with a 1-year history of 20-kg weight gain, generalized fatigue, thinning hair and tingling in her hands at night. Her husband had also commented that she had developed a deeper, croaky voice. Her periods had become irregular and lighter than previously. On examination she was overweight with generally dry skin and thin, rather coarse hair. She was bradycardic with a pulse of 60. She had evidence of bilateral carpal tunnel syndrome and was felt to have slow relaxing reflexes. Investigation confirmed the clinical diagnosis of primary hypothyroidism, her serum thyroid-stimulating hormone (TSH) was significantly elevated at 28U/ml (normal <4) and her total serum thyroxine was low at 19µmol/l. Antibodies to thyroid peroxidase were present at high titre, consistent with primary autoimmune hypothyroidism.

She was treated with oral thyroxine at 100µg daily. Her TSH and serum thyroxine returned to the normal range and her skin, hair, voice and hands returned slowly to normal over the next year. Her weight however remained 15kg heavier than before she developed myxoedema.

She agreed to take part in a family study of autoimmue disease. The prevalence of autoantibodies and autoimmune disease are summarised in Fig. C5.1.