Question: What is the difference between panhypopituitarism vs. hypopituitarism?

Answer: The terms are often used interchangeably. Strictly speaking, panhypopituitarism refers to loss of all pituitary function, both anterior and posterior pituitary function. However, some use this term to refer to loss of anterior pituitary function without diabetes insipidus (function of the posterior pituitary gland). Panhypopituitarism would involve loss to the pituitary hormones that control adrenal cortisol production, thyroid gland production, gonadal function (testosterone production in men, menstrual cycles in women and fertility in both men and women), growth hormone production, and in the case of loss of posterior pituitary function, diabetes insipidus resulting in frequent urination [particularly at night] and excessive thirst. The term hypopituitarism can refer to complete or partial loss of pituitary function. This may mean the need for 1, 2, 3 or more pituitary hormone deficiencies. In summary: the need for a particular hormone replacement or several hormone replacements defines the function of the pituitary gland. My preference is to describe a patient’s condition as partial hypopituitarism, with statement of which hormones require replacement or panhypopituitarism with or without diabetes insipidus.

By Dr. Mary Lee Vance MD (Winter, 2012)