Cause:
- Neoplasms: polyendocrine adenomas including FSH-, LH-, and/or TSH-producing ones, which rarely secrete intact hormone (Nejm 1991;324:822) unlike (Nejm 1980;302:210) ACTH-, HGH-, and prolactin-producing ones (Galactorrhea/Amenorrhea Syndrome (Prolactinoma)); craniopharyngiomas; metastases especially from lung; neurofibromas
- Trauma
- Granulomas: Hans-Christian disease, sarcoid (often causes just prolactinemia) (Ann IM 1972;76:545), tuberculosis
- Vascular: carotid aneurysm, postpartum infarction (Sheehan's syndrome), diabetic vascular disease, prepartum in diabetics (Ann IM 1971;74:357)
- Late cmplc of extracranial head and neck tumor or brain (Nejm 1993;328:87) irradiation
- Congenital
Pathophys:Order of most frequent hormonal defects w pituitary tumor: growth hormone > gonadotropins > TSH > ACTH. Prolactin may be autonomously produced by some pituitary tumors which cause hypopituitarism.
Sx:Hypogonadism with amenorrhea w or w/o lactation; hypothyroidism; adrenal insufficiency; headaches; bitemporal visual field losses
Si:Findings of above
r/o "EMPTY SELLA SYNDROME" (Ann IM 1986;105:238), an incidental pickup of an enlarged sella on skull xray, usually but not always w normal pituitary function; HYPOTHALAMIC DYSFUNCTION, seen with weight loss, esp in anorexia nervosa
Lab:
Chem:Serum levels of HGH, T3T4, TSH after TRH, testosterone or estradiol, LH, FSH, ACTH, and cortisol all low
Hem:Anemia (Nejm 1971;284:479)
Xray:MRI, or CT if MRI not available, shows pituitary mass; w calcification in craniopharyngioma
Rx:
See Table 5.3 (Nejm 1991;324:1555)
- Replacement hormones: L-thyroxine, glucocorticoids, testosterone/estrogen, and recombinant growth hormone (Nejm 1989;321:1797), at least in children and perhaps in adults to preserve bone density (Ann IM 1996;883:932)
- Surgical resection via transsphenoidal approach for documented adenomas; cmplc: diabetes insipidus
- Radiation in some cases after surgery if residual tumor on MRI
- of galactorrhea/amenorrhea prolactinomas (Galactorrhea/Amenorrhea Syndrome (Prolactinoma))