Peripartum hypopituitarism and lymphocytic hypophysitis.

The classical cause of postpartum hypopituitarism is Sheehan's syndrome, in which an obstetric catastrophe is associated with hypotension. However, with improvements in obstetric care, the most common cause now may be lymphocytic hypophysitis. Five women with postpartum hypopituitarism, whose symptoms occurred during or immediately after pregnancy, had detailed endocrine and pituitary imaging for the duration of follow-up. Two presented with visual symptoms, and three with non-specific illnesses related to varying deficiencies of anterior pituitary hormones. Four were unable to lactate, and four were initially amenorrhoeic. Initially, four of the five women had enlarged pituitary glands on magnetic resonance imaging. Four have to some extent recovered pituitary function. One patient had associated thyroiditis: in two cases antinuclear antibodies became positive during follow-up, and in one of these dsDNA antibody was also detected. In no case were pituitary antibodies detected. None had complicated pregnancies or deliveries, and the two who had caesarean sections had no episodes of hypotension. The presentation of secondary hypothyroidism combined with ACTH deficiency in four of the five women strongly suggests lymphocytic hypophysitis. This diagnosis should be considered in postpartum women with general malaise and persistent amenorrhoea, as well as in women who develop visual impairment in the last trimester of pregnancy without antecedent pituitary disease. A conservative policy of management of the pituitary enlargement should be pursued as this resolves.