Prolactinoma and Hyperprolactinaemia

If the hyperprolactinaemia occurs in the presence of a drug known to elevate prolactin, for example risperidone, discuss whether it is possible to withdraw this with the patient.

Any interfering agents should be withdrawn for at least six weeks prior to retesting prolactin on at least two occasions.

Psychotropic agents must be withdrawn under close psychiatric supervision only whereas other agents, for example contraceptive pills, may be stopped abruptly.

If serum levels normalise after drug withdrawal, the patient should be reassured that no further investigation or treatment should be necessary.

If the patient requires resumption of treatment, estrogen or testosterone therapy may be considered for symptom control.

Severe symptoms, for example galactorrhoea, may necessitate switching to an alternative psychotropic agent under supervision.

Dopamine agonists should be used with extreme caution in this instance.

If the prolactin does not normalise on drug withdrawal, or if the agent cannot be stopped for other reasons, proceed to MRI scan and management as below.

This is performed to rule out a large non functioning pituitary tumour particularly in patients using interfering medications, or to assess the pre-treatment size of a prolactinoma.

Ensure that thyroid function is normal and assess whether the patient has PCOS before treating elevated prolactin.

Other abnormalities of pituitary function, for example hypopituitarism or elevation of IGF-I, will require formal assessment and treatment as appropriate.

If the patient does not complain of galactorrhoea and is menstruating regularly or is post menopausal, no treatment may be necessary.

Very low doses, for example cabergoline 0.25mg once or twice a week, should be enough to control symptoms in the majority of cases with microprolactinomas.

Warn patients of possible psychiatric, fibrotic and gastrointestinal side effects and advise them to take medication during the main meal of the day.

Aim to use the minimum dose to achieve regular menses and control galactorrhoea. Absolute normalisation of prolactin may not be necessary. 

Treatment should be started after the MRI scan is performed since tumour shrinkage may be rapid.

Baseline chest radiograph, electrocardiogram, echocardiogram and renal function should all be performed within three months of starting ergot derived dopamine agonists in view of recent guidance. Further monitoring tends to be on an annual basis, though should depend on the cumulative dose exposure, underlying conditions and results of previous screens.

Clinical review after three months is mandatory to review the scans with the patient, ensure resolution of symptoms and to recheck serum prolactin.

With a confirmed microadenoma, aim to withdraw treatment every two years or at the time of natural menopause if the patient is well controlled. 

Treatment should resume if the patient develops amenorrhoea, or if there was a large initial lesion on MRI scan and the prolactin rises dramatically post treatment cessation. 

Generally, there is no indication to repeat MRI scans if the initial pre-treatment MRI was normal or showed a microadenoma.

If visual fields are abnormal on examination, or a macroadenoma is suspected, this must be performed at baseline and repeated during treatment to confirm response. With non functioning pituitary adenomas, serum prolactin will fall but tumour shrinkage will not be observed and so surgery should be considered.

If visual loss is confirmed or the optic chiasm compromised on the MRI scan, higher doses of dopamine agonists may be used for urgent decompression of the optic pathway.

Warn patients of possible psychiatric, fibrotic and gastrointestinal side effects and advise them to take medication during the main meal of the day.

Serum prolactin levels are expected to fall smoothly but dramatically in response to dopamine agonist therapy.

A very rapid response, for example complete normalisation within a week, may indicate that the prolactin is elevated due to disinhibition from a non functioning tumour. In this case, there will be no visual field or MRI response and urgent surgery should in stead be considered.

Clinical review with repeat visual fields and serum prolactin at six weeks.

If serum prolactin levels have not responded, consider alternative dopamine agonist.

If prolactin has responded dramatically, but there is no improvement in vision arrange a repeat MRI scan and consider urgent surgery.

If prolactin is falling, and the patient is clinically improving, continue treatment, consider dose reduction and arrange routine rescanning (timing depends on initial clinical and MRI features and clinical response).

Baseline chest radiograph, electrocardiogram, echocardiogram and renal function should all be performed within three months of starting ergot derived dopamine agonists in view of recent guidance. Further monitoring depends on initial results, underlying conditions, and cumulative dose exposure, but is generally repeated on an annual basis.

Aim to use the minimum dose necessary to restore vision and to control tumour size and symptoms, rather than aiming for a 'normal' serum prolactin.

Retest baseline pituitary function at three months.

Menses will usually be restored in female patients. However, with long standing macroprolactinomas, gonadotropin function may not return. Testosterone replacement is thus frequently required in male patients despite good control of serum prolactin.

Patients with sight threatening macroadenomas should be seen at six weeks, then three, six and 12 months, then annually lifelong for monitoring of their treatment, tumour size and pituitary function.

Aim to reduce doses wherever possible while maintaining disease control.

Attempt to withdraw treatment every two years if the patient is well controlled.

Consider conventional radiotherapy if ongoing dopamine agonist requirements are high, dopamine agonists are not tolerated, or ifi the tumour is not well controlled on scanning.