CAUSES OF ELEVATED PLASMA PROLACTIN

Physiological

• Stress

• Pregnancy

• Lactation

• Nipple stimulation

Drugs

Dopamine antagonists

• Antipsychotics (phenothiazines and
butyrophenones) Antidepressants

• Antiemetics (e.g. metoclooramide, demperidone)

• Methyldopa

Estrogens

Oral contraceptive pill

Pathological

• Common

Disconnection hyperprolactinaemia (e.g. non-
functioning pituitary marcoadenoma).

• Primary hypothyroidism

• Prolactinoma

• Polycystic ovary

Uncommon

• Hypothalamic disease

• Pituitary tumour secreting prolactin and growth
hormone

• Renal failure

CLINICAL FEATURES

1 . Galactorrhoea and hypogonadism.

2. Unexplained infertility.

3. In women there is secondary amenorrhoea, oligomenorrhea, or menorrhagia, and anovulation with infertility.

4. In men there is decreased libido, erectile impotence reduced shaving frequency and

INVESTIGATION

1. Plasma prolactin level.

• Normal upper level is 500 mU/L.

• In pregnancy and lactation prolactin levels may reach 20000 mU/L.

• In non-pregnant and non-lactating patients’ levels of 500-1000 mU/L are likely to be induced by stress or drugs.

• Levels between 1000-5000 mU/1 are likely to be due to drugs or macroprolactinomas.

• The levels above 5000 mU/l are highly suggestive of prolactinoma.

• Unless the prolactin falls after withdrawal of relevant drug therapy, serum prolactin level > 1000/mU/L is a possible indication of MRI  of the hypothalamus and pituitary gland.

2. MRI of the pituitary. MRI can detect all macroadenomas and about 70% of microadenomas also.

3. FSH, LH, TSH, and T4