How are prolactinomas diagnosed?
The diagnosis may be suspected from the symptoms. Women tend to be diagnosed earlier than men because a change in the woman's periods is an early symptom and is easily noticed. Some prolactinomas are diagnosed by chance if you have tests for another reason. If a prolactinoma is suspected, you may be offered several tests.
A blood sample to check the level of prolactin in the blood. A very high prolactin level usually means that a prolactinoma is present. However, there are other causes of raised prolactin levels. For example, some medicines may cause high prolactin levels. These include:
- The anti-sickness medicines metoclopramide and domperidone.
- Antidepressants of the selective serotonin reuptake inhibitor (SSRI) type.
- Some medicines used to treat schizophrenia or bipolar disorder.
Other blood tests may be done at the same time. It is important to test the thyroid gland and to check kidney function, as both these can affect prolactin levels. Further tests may be needed to see if the tumour is causing a lack of other hormones made by the pituitary gland.
Eye tests will assess if the tumour is pressing on the optic nerve - this includes a test of visual fields.
A magnetic resonance imaging (MRI) scan or a computed tomography (CT) scan can show the size of the tumour. A bone density scan may be advised for some patients, to check whether they are at risk of 'thinning' of the bones (osteoporosis), which is a possible complication.
Further reading and references
Molitch ME; Endotext. Prolactinoma Management. April 2015.
Molitch ME; Diagnosis and Treatment of Pituitary Adenomas: A Review. JAMA. 2017 Feb 7317(5):516-524. doi: 10.1001/jama.2016.19699.
Brue T, Castinetti F; The risks of overlooking the diagnosis of secreting pituitary adenomas. Orphanet J Rare Dis. 2016 Oct 611(1):135.
Position statement on the use of dopamine agonists in endocrine disorders; Society for Endocrinology (Feb 2009 - reviewed Nov 2011)
I was originally diagnosed last May with Prolactinoma that stemmed from not getting my period for over 6 months with off and on again headaches. My prolactin level at that time was 200ng. ...katienellie
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