If untreated, the resulting adult could be extremely tall. This is called gigantism. Overproduction of growth hormone in adults can lead to a condition called acromegaly. Symptoms include headaches, visual problems, and an increase in shoe or glove size, as well as some changes in facial features, such as increased prominence of the jaw. These changes can be very gradual.
Treatment is usually by one or more of surgery, radiotherapy and drug treatment.
For further details, please see our leaflet on ' Acromegaly '. Prolactin Overproduction of prolactin is called hyperprolactinaemia and can be due to one of several causes. Certain medications can cause it, especially anti-sickness tablets or tranquillisers. If your thyroid gland is underactive it could be the culprit. Thirdly, it could be due to a benign tumour which is itself producing prolactin.