# Bilateral Sixth Nerve Palsy: A Rare Presentation of Primary Hypophysitis

## TL;DR

A 32-year-old woman with bilateral sixth nerve palsy and hypopituitarism was found to have hypophysitis, which improved with steroid treatment.

## Contribution

This paper reports a rare case of bilateral sixth nerve palsy as a presentation of primary hypophysitis.

## Key findings

- MRI showed symmetric pituitary gland expansion and cavernous sinus invasion.
- Treatment with IV methylprednisolone led to pituitary lesion reduction and partial to complete nerve palsy remission.
- Bilateral sixth nerve palsy is a rare manifestation of hypophysitis.

## Abstract

Cranial nerve palsy is common in pituitary disease and depends on the extension of the lesion into the cavernous sinuses. Bilateral cranial nerve palsy was described in pituitary adenomas with apoplexy and in only one case in hypophysitis. We present a case of a 32-year-old female manifesting with headache, diplopia, bilateral sixth nerve palsy, and hypopituitarism. Magnetic resonance imaging (MRI) revealed symmetric expansion of the pituitary gland, with bilateral cavernous sinus invasion and thickening of the pituitary stalk. Hypophysitis was suspected, and after treatment with IV methylprednisolone boluses, a decrease in the pituitary lesion was observed, with complete remission of sixth nerve palsy in the right eye and partial improvement in the left eye. In this case, we report an infrequent form of presentation of hypophysitis, and highlight that steroids are the first line of treatment.