In practice, it is important to exclude both hypothyroidism and the ingestion of drugs that either deplete central dopamine or block dopamine receptors as causes of hyperprolactinaemia. Having excluded these two causes, three diagnostic possibilities remain: the patient may have:
ΓÇó A microadenoma
ΓÇó A macroadenoma
ΓÇó No tumour at all.
If hypothyroidism and the ingestion of drugs have been ruled out, and patients with hyperprolactinaemia do not harbour an identifiable tumour, they are described as having idiopathic hyperprolactinaemia.
