Anterior Pituitary Deficiency Syndromes
- 90% of cases are caused by destruction of the anterior pituitary
- In general, more than 75% of the anterior pituitary tissue must be destroyed to produce symptoms of hormone deficiency.
- Panhypopituitarism results, a syndrome of multiple simultaneous endocrine deficiencies (thyroid, adrenal, gonadal).
- Causes of pituitary destruction:
- Replacement/compression of normal pituitary by non-functioning anterior pituitary tumors (tend to be large at discovery)
- Sheehan's syndrome (postpartum pituitary necrosis)
- Infarction of hypertrophic pituitary due to obstetric hemorrhage or shock. The pituitary is normally hypertrophic in pregnancy; the increase in pituitary size increases its metabolic requirements and also increases pressure in the sella turcica. Thus the pituitary is susceptable to decreases in blood pressure related to problems during delivery.
- Also can occur with DIC, sickle cell anemia, cavernous sinus thrombosis and other vascular disorders.
- Symptoms may require years to develop after the initial damage.
- Empty Sella Syndrome (uncommon)
- Compression of the pituitary by herniated arachnoid, infarction of an anterior pituitary adenoma, or infarction with Sheehan's syndrome may lead to pituitary destruction.
- The initial cause of the problem may not be clear, and may have occured much earlier. The syndrome's name comes from the radiologic finding of no pituitary in the sella turcica when the symptomatic patient is worked up.
- Hypothalamic tumors, usually gliomas or craniopharyngiomas, are a rare cause of pituitary destruction.
Last modified: 1/16/97; Author: J. Harrison