endocrine and metabolic disorders
Prolactinoma
Diagnosis of Prolactinoma
Prolactin levels Thyroxine (T4) and thyroid-stimulating hormone (TSH) levels CT or MRI Diagnosis of galactorrhea due to a prolactin-secreting pituitary adenoma is based on elevated prolactin levels (typically > 5 times normal, sometimes much higher.) Decrease in lesion size in response to drug treatment may confirm the diagnosis when prolactin levels are elevated to an equivocal range. In general, prolactin levels correlate with the size of a pituitary tumor and can be used to follow patients over time. With a nonfunctioning pituitary mass, prolactin levels are not usually elevated > 3 to 4 times normal. A trial ofdopamineagonist therapy can help distinguish between prolactin-secreting and nonfunctioning lesions; in both types of lesion, prolactin levels decrease after treatment, but prolactin-secreting lesions decrease in size, whereas nonfunctioning lesions do not. levels may be low in men. Primary hypothyroidism is easily ruled out by absence of elevated TSH. In the setting of a known pituitary tumor, TSH and free thyroxine levels should be measured to evaluate for Diagnosis . MRI with contrast is the method of choice in identifying microadenomas. High-resolution CT may be used when MRI is contraindicated or unavailable. Visual field examination is indicated in all patients with macroadenomas and in any patient who elects surveillance only. 