This is the deficient secretion of one or more pitutiary hormones because of pituitary or hypothalamic disease.
A patient and physician should become suspicious of subnormal pituitary function when a patient has a known pituitary tumor or a symptom that known to be caused by inadequate production of a pituitary hormone. Damage to the anterior pituitary can occur suddenly or slowly and can affect one or multiple hormones. Thus there are a few factors that become important in understanding the symptoms:
1. The rate of onset of the disease affecting the pituitary cells will determine when a patient may notice the problem. For example a condition like pituitary apoplexy is a sudden event which can lead to death in the short term if not treated adequately. In contrast, radiation therapy to the pituitary can create symptoms very slowly over a period of years.
2. The severity of the hormone deficiency can make some symptoms more or less obvious to a patient. Partial deficiencies of some hormones may have no symptoms as compared to complete deficiency.
3. The number of pituitary cells affected can create different clusters of symptoms. If all the pituitary hormones are deficient it is called panhypopituitarism.
The hormones that can be affected are
for normal body functions the base amount of ACTH secretion needs to be adequate to maintain the serum cortisol in the normal range and increase in times of stress to raise serum cortisol levels appropriately.
The TSH concentration is no longer helpful in TSH deficiency since it will artificially appear in the normal range. T4 and T3 levels will need to be used. Symptoms of hypothyroidism will be present.
Gonadotropins (LH and FSH)
In men the testosterone levels are important in this diagnosis. In premenopausal females the menstrual cycle is the best measurement. In post menopausal females the LH and FSH are useful.
This is a difficult diagnosis to make and specialized testing is needed.
Testing for low prolactin levels is unncessary since there is no use for prolactin other than breast feeding. Also, there is no reliable way to determine what a low level should be. Finally, there is no treatment for this condition.