[The paradox of TSH elevation in Sheehan's syndrome]

A 59-year-old woman was examined because of weight gain, increasing fatigue and secondary amenorrhoea, which occurred after a complicated delivery at age 18. The finding of an increased TSH concentration was initially considered as primary hypothyroidism and substitution therapy was commenced. Because of the concomitant secondary amenorrhoea the patient was referred for additional endocrinological investigations.

Biochemical analysis confirmed the increase in TSH concentrations, and revealed a gonadotropin deficiency, a decrease in IGF-I concentration and a free urinary cortisol concentration at the lower end of the normal range. Dynamic testing of pituitary function (insulin tolerance test) confirmed a severe growth hormone deficiency and partial secondary adrenal insufficiency. An MRI study of the pituitary showed an empty sella with some remaining pituitary tissue at the bottom of the sella.

The laboratory findings of pituitary insufficiency with an empty sella on MRI scan suggested Sheehan's syndrome despite an increase in thyrotropin level. Pituitary replacement therapy was started with hydrocortone, combined estrogens and progesterone in addition to levothyroxin, which considerably improved clinical symptoms.

A history of secondary amenorrhoea after a complicated delivery including significant bleeding or septic complications suggest Sheehan's syndrome, which can result in partial or complete panhypopituitarism. In such circumstances the pituitary hormone levels are usually reduced. TSH concentrations, however, may be increased.