Teaching Case

A 56-year-old lady presented with 6-8 weeks history of frontal headache associated with, photophobia, double vision and an episode of transient loss of consciousness. Bloods show deranged electrolytes, hyperprolactinaemia, hypothyroidism and growth hormone deficiency.

On examination, all cranial nerves intact, no weakness in upper or lower limbs, no cerebellar signs.

MRI Brain confirmed bulky pituitary and stalk with extension into the hypothalamic region.

Enlarged adenohypophysis of the pituitary with suprasellar extension into the pituitary stalk was noted. There was also abutment of the chiasma and extension along the pituitary stalk behind the chiasma into the hypothalamus, the infundibular recess and the mammillary bodies.

Post-contrast enhancement pattern confirmed hypophysitis.

Hypophysitis, a rare condition, is characterised by the inflammation of the pituitary gland or pituitary stalk, usually resulting in hypopituitarism [1]. The most common symptoms of hypophysitis are a headache with or without nausea and visual disturbances. Patients may also develop symptoms and signs of endocrine insufficiencies such as diabetes insipidus, hypothyroidism, hyperprolactinaemia and growth hormone deficiency. Other non-endocrine symptoms such as cranial nerve palsies, cavernous sinus involvement and weight gain have been reported [2].

Hypophysitis can be classified according to the anatomic location of pituitary involvement or primary and secondary causes. In primary hypophysitis, the idiopathic inflammatory process is confined to the gland. Primary hypophysitis can be further classified by their histopathology forms, with lymphocytic hypophysitis being the commonest, followed by granulomatous hypophysitis. Secondary causes are due to specific aetiologies including drugs and systemic diseases, such as sarcoidosis, systemic lupus erythematous and Erdheim-Chester Disease [3].

Investigations of patients with hypophysitis include routine baseline blood such as full blood count, urea and electrolytes, liver and bone profile and early morning pituitary-related hormone profile. Anti-diuretic hormone should be measured in patients with suspected diabetes insipidus. Thyroid function test, prolactin and growth hormone levels are useful to guide diagnosis.

Gadolinium-enhanced pituitary MRI is the preferred radiological choice of investigation. MRI findings may show homogeneously enhancing pituitary gland, absence of posterior pituitary bright spot, diffuse enlargement of glands or dural thickening, midline stalk and parasellar mucosal thickening or normal sellar size [4]. The patient had CT brain as her initial investigation which was suspicious for hypophysitis. This initial imaging-guided her requesting physician in further investigations such as blood tests and further imaging especially pituitary MRI, which is the preferred choice of investigation.

Biopsy of the pituitary gland for histology assessment is a definitive method to confirm hypophysitis. This patient had her biopsy which confirmed granulomatous hypophysitis secondary to Granulomatosis with Polyangiitis. She was then started on levothyroxine for hypothyroidism and hydrocortisone.

Various treatments for hypophysitis such as immunosuppressive agent, surgery, radiotherapy and conservative options are available. Management of hypophysitis is mainly aimed at treating pituitary hormone deficiencies according to recommendations and to reduce inflammation or enlargement of the gland [1]. Mass reduction by pituitary surgery, one of the most common therapies, may be effective but patients may experience partial or significant loss of pituitary function. Glucocorticoids are useful as an inflammatory agent to reduce the size of the mass but are associated with recurrence and adverse side effects [5].

Learning points

Imaging plays an important role in guiding clinicians in managing a patient with hypophysitis including further blood investigations looking for thyroid function, prolactin level and treatment and follow-up. This condition can be easily misdiagnosed as pituitary adenoma or infection. It is important to recognise the symptoms and have a high index of suspicion when patients present with these symptoms and to not delay treatment. 

Written informed patient consent for publication has been obtained.