The pituitary gland was very small and there were few remnants of both the anterior and the posterior pituitary. The eponym Simmonds syndrome is used infrequently for acquired hypopituitarism, especially when cachexia (general ill health and malnutrition) predominates. Most of the classic causes of hypopituitarism were described in the 20th century; the early 21st century saw the recognition of how common hypopituitarism could be in previous head injury victims.Until the 1950s, the diagnosis of pituitary disease remained based on clinical features and visual field examination, sometimes aided by pneumoencephalography and X-ray tomography. Nevertheless, the field of pituitary surgery developed during this time. The major breakthrough in diagnosis came with the discovery of radioimmunoassay by Rosalyn Yalow and Solomon Berson in the late 1950s. This allowed the direct measurement of the hormones of the pituitary, which as a result of their low concentrations in blood had previously been hard to measure. Stimulation tests were developed in the 1960s, and in 1973 the triple bolus test was introduced, a test that combined stimulation testing with insulin, GnRH and TRH. Imaging of the pituitary, and therefore identification of tumors and other structural causes, improved radically with the introduction of computed tomography in the late 1970s and magnetic resonance imaging in the 1980s.
Hormone replacement
Most pituitary hormones can be replaced indirectly by administering the products of the effector glands: hydrocortisone (cortisol) for adrenal insufficiency, levothyroxine for hypothyroidism, testosterone for male hypogonadism, and estradiol for female hypogonadism (usually with a progestogen to inhibit unwanted effects on the uterus). Growth hormone is available in synthetic form, but needs to be administered parenterally (by injection). Antidiuretic hormone can be replaced by desmopressin (DDAVP) tablets or nose spray. Generally, the lowest dose of the replacement medication is used to restore wellbeing and correct the deranged results, as excessive doses would cause side-effects or complications. Those requiring hydrocortisone are usually instructed to increase their dose in physically stressful events such as injury, hospitalization and dental work as these are times when the normal supplementary dose may be inadequate, putting the patient at risk of adrenal crisis.Long-term follow up by specialists in endocrinology is generally needed for people with known hypopituitarism. Apart from ensuring the right treatment is being used and at the right doses, this also provides an opportunity to deal with new symptoms and to address complications of treatment.Difficult situations arise in deficiencies of the hypothalamus-pituitary-gonadal axis in people (both men and women) who experience infertility; infertility in hypopituitarism may be treated with subcutaneous infusions of FSH, human chorionic gonadotropin–which mimics the action of LH–and occasionally GnRH. Prognosis
Several studies have shown that hypopituitarism is associated with an increased risk of cardiovascular disease and some also an increased risk of death of about 50% to 150% the normal population.