Endocrine Abstracts

A 78-year-old female presented with acute onset of severe headache and vomiting. Sub arachnoid haemorrhage was suspected but a CT brain scan was ‘normal’ and CSF bilirubin absent.

Three months later she complained of lethargy and a thyroid function test suggested secondary hypothyroidism. Further investigations confirmed partial hypopituitarism (growth hormone preserved) and review of the previous CT scan suggested the presence of a pituitary mass. This was confirmed on MR scanning and interpreted as infarction of a pituitary adenoma. The optic chiasm was not compromised and visual fields were normal with visual acuities 6/6 right and left. She remained well treated with hydrocortisone and thyroxine for 15 months before developing thirst, polydipsia and polyuria. Mild central diabetes insipidus was confirmed and MR scanning demonstrated an enlarged pituitary with thickened stalk in close contact with the optic chiasm. Visual field testing was normal but visual acuities were 6/12 right and left. CSF contained 2.89 g/l of protein with a relative lymphocytosis. Lymphocytic hypophysitis was considered as the diagnosis. Two months later she complained of deterioration of vision and was found to have bitemporal hemianopia with visual acuities 6/8 right and 6/24 left. Repeat MR scanning demonstrated gross pituitary enlargement and chiasmal compression. Treatment with intravenous methylprednisolone 500 mg daily for 3 days (pending neurosurgical intervention) returned visual fields to normal and visual acuities to 6/6 right and 6/7.5 left. A repeat MR scan confirmed shrinkage of the pituitary mass. Transphenoidal exploration 2 days later found a shrunken fibrous pituitary gland. Histology revealed changes consistent with lymphocytic hypophysitis.

This case demonstrates the vagaries of lymphocytic hypophysitis with acute development of severe endocrine and visual deficits occurring many months apart.