20/05/2017
Previously, we saw a brief introduction about galactorrhoea, the following are the causes of galactorrhoea
-MEDICATIONS
These are a common cause of galactorrhea.These agents can block dopamine and histamine receptors, deplete dopamine stores, inhibit dopamine release, and stimulate lactotrophs. Estrogen in oral contraceptives can cause galactorrhea by suppressing the hypothalamic secretion of prolactin inhibitory factor and by direct stimulation of the pituitary lactotrophs. Galactorrhea also may develop following estrogen withdrawal because of the absence of the inhibitory effect on prolactin action at the breast
-PITUITARY TUMORS
Pituitary tumors, the most common pathologic cause of galactorrhea, can result in hyperprolactinemia by producing prolactin or blocking the passage of dopamine from the hypothalamus to the pituitary gland. Prolactinomas are the most common type of pituitary tumor and are associated with galactorrhea, amenorrhea, and marked hyperprolactinemia. The serum level of prolactin usually correlates with the size of the tumor.
A minority of patients have gigantism/acromegaly with elevated levels of prolactin and growth hormone. Macroprolactinomas are associated more often with visual field defects, headache, neurologic deficits, and loss of anterior pituitary hormones.8
-HYPOTHALAMIC AND PITUITARY STALK LESIONS
Hypothalamic lesions such as craniopharyngioma, primary hypothalamic tumor, meta-static tumor, histiocytosis X, tuberculosis, sarcoidosis and empty sella syndrome, and pituitary stalk lesions—traumatic or secondary to the mass effects of sellar tumors—are infrequent but significant causes of galactorrhea. These lesions destroy dopamine-producing neurons in the hypothalamus and block the passage of dopamine from the hypothalamus to the pituitary gland.
-THYROID DISORDERS
In patients with primary hypothyroidism, there is increased production of thyrotropin-releasing hormone, which may stimulate prolactin release. Hyperprolactinemia also may result from decreased hypothalamic dopamine secretion and decreased metabolic clearance of prolactin. Occasionally, galactorrhea may result from thyrotoxicosis, possibly because of an increase in estrogen-binding globulin or alterations in estrogen metabolism that change the free estrogen level
-CHRONIC RENAL FAILURE
Approximately 30 percent of patients with chronic renal failure have elevated prolactin levels, possibly because of decreased renal clearance of prolactin. Although galactorrhea in these patients is rare, it can result from the elevated prolactin levels.
-NEUROGENIC CAUSES
Neurogenic stimulation may repress the secretion of hypothalamic prolactin inhibitory factor, which results in hyperprolactinemia and galactorrhea. Galactorrhea may be caused by prolonged, intensive breast stimulation, such as from suckling, self-manipulation, or stimulation during sexual activity. Galactorrhea caused by breast stimulation is more common in parous women but has been reported in virgins, postmenopausal women, and men
*Neurogenic causes of galactorrhea include chest surgery, burns, and herpes zoster that affects the chest wall. Stimuli are thought to pass along the intercostal nerves to the posterior column of the spinal cord, to the mesencephalon, and finally to the hypothalamus, where the secretion of prolactin inhibitory factor is reduced. Galactorrhea may develop as a complication of spinal cord injury. Chronic emotional stress may be a neurogenic cause of galactorrhea.
-NEONATAL GALACTORRHEA
High levels of estrogens in the placental-fetal circulation can result in gynecomastia in newborn infants. Enlargement of the breasts, which may be associated with secretion of milk (so-called “witch’s milk”), often is transient but may last longer in breastfed infants.
-IDIOPATHIC (UNKNOWN ) CAUSES
Idiopathic galactorrhea is a diagnosis of exclusion. Galactorrhea is considered idiopathic if no cause is found after a thorough history, physical examination, and laboratory evaluation. The patient’s breast tissue may have increased sensitivity to normal circulating prolactin levels.
In our next article, we shall look at the management of galactorrhoea, thanks alot
