Possible Hypopituitarism


Question

I have a 29 year old female with secondary amenorrhea for 4 years.It appears to be hypothalamic amenorrhea by workup. However, her F T4 and Ft3 were low with a TSH of 1.78. I suspect central hypothyroidism. Her Mri showed a possible microadenoma,. Could a Microadenoma be responsible for selective hypogonadism and hypothyroidism? Alan Terlinsky MD

Response

Thank you for your enquiry. Your patient has amenorrhoea with hormonal features of secondary hypogonadism and hypopituitary hypothyroidism; the pituitary MRI may indicate a microadenoma. It would be helpful to know the dimensions of the putative pituitary lesion and also whether there is any evidence of hyperprolactinaemia. It would be unusual for a small intrasellar lesion to cause overt hypothyroidism but the gonadotrophin-ovarian axis is more vulnerable. Is there any other clinical factor which might predispose to a sick euthyroid picture and

thus simulate secondary hypothyroidism? Weight related amenorrhoea, which may persist after weight regain in a significant proportion of

patients, will give a picture of gonadotrophin deficiency and may be associated with secondary and reversible thyroid function changes -

worth exploring this aspect. On present evidence I would suggest a full dynamic pituitary function test (insulin or glucagon) for ACTH/cortisol and GH secretion. I would be pleased to advise further with some additional information as indicated above. Prof John Monson