Endocrine Abstracts

A 68-year-old previously well man was referred to the endocrinology department in April 2007 with generalised tiredness and dizziness following a recent viral upper respiratory illness. He had no symptoms to suggest pituitary dysfunction. He was normotensive and lacked clinical features of hypopituitarism or dysthyroidism. Visual fields were normal to confrontation. Testicular volumes were normal. Initial baseline pituitary function tests (reference ranges in brackets): FT₄ 5.8 pmol/l (9–24), FT₃ 4.3 pmol/l (2.5–5.7), TSH 0.18 mIU/l (0.2–4); LH 0.6 IU/l (2–10), FSH 1.7 IU/l (2–12), testosterone 0.9 nmol/l (8–30); random cortisol 97 nmol/l; prolactin 248 mIU/l (0–500). Full blood count, renal function and liver function tests were normal. He was seen in clinic urgently and commenced on levothyroxine 50 mcg and hydrocortisone 25 mg daily in divided doses. Symptoms improved markedly after initiating treatment. A glucagon stimulation test 10 days later demonstrated subnormal cortisol response with a basal cortisol of 350 nmol/l and peak cortisol of 457 nmol/l at 180 min. Peak GH response was 3.3 mcg/l.

MRI of the pituitary gland was normal. Two months later his random testosterone levels had spontaneously improved to 8.8 nmol/l. Levothyroxine and hydrocortisone were discontinued. On repeat glucagon stimulation testing, basal cortisol was 270 nmol/l peaking at 180 min to 523 nmol/l. Other pituitary tests showed FT₄ 9.6 pmol/l and TSH 3.65 mIU/l; LH 2.5 IU/l, FSH 3.3 IU/l, prolactin 188 mIU/l, IGF-1 13.3 nmol/l (9–25) and 0900 a.m. testosterone was now 17.1 nmol/l. He remains well and symptom free without any replacement treatment. Anterior pituitary function remains normal.

Transient hypopituitarism is rare, especially following a viral illness. Only one such case has been reported previously. Follow-up reassessment of pituitary function has allowed us to successfully withdraw replacement therapy, demonstrating that hypopituitarism infrequently may be reversible.