[Unusual causes of hyperprolactinaemia]

Pituitary adenoma is the main cause of hyperprolactinaemia; however, physicians should be aware that the pituitary is not always to blame. There are many other physiological and pathological causes for hyperprolactinaemia, and the contribution of stress, medication and the presence of macroprolactin should not be overlooked. We describe three patients - a 19-year-old female, a 28-year-old female and a 20-year-old male - in whom hyperprolactinaemia was due to medication use, physical stimulation of the nipple and a combination of macroprolactianaemia with a microadenoma, respectively. The first two case reports show that conducting a thorough patient history can prevent unnecessary imaging and laboratory costs. The third case illustrates that macroprolactinaemia and true hyperprolactinaemia may coexist. While early screening for macroprolactinaemia in an asymptomatic patient can save money, finding macroprolactinaemia in a symptomatic patient still warrants further workup.