Endocrinological diagnosis and replacement therapy for hypopituitarism

Hypopituitarism is a rare condition characterized by deficiency of one or more anterior pituitary hormones due to a pituitary and/or hypothalamic disorder.1 Pituitary adenoma is the most common cause of acquired hypopituitarism in adults, followed by surgical treatment and radiation therapy of pituitary tumors, whereas inflammatory/infiltrative, vascular, and infectious diseases are rare.2 Clinical features are mainly related to the cause and acuity of the underlying disease and to severity and type of the hormone deficiencies. Signs and symptoms of hypopituitarism are usually insidious and unspecific, frequently resulting in a diagnostic delay, although acute debut may occur. In patients at high risk of hypopituitarism (e.g., patients with pituitary adenoma and after pituitary irradiation), pituitary function should be regularly assessed, and hormonal replacement therapy initiated when needed. In patients with pituitary tumors, and after radiation therapy, pituitary dysfunction usually develops in a sequential pattern with the somatotropic axis being first affected, followed by the gonadal, thyrotropic, and corticotropic axes.2 When this order of pituitary hormone loss is different, other underlying causes should be suspected, especially when diabetes insipidus is also present. Hypopituitarism is associated with excess mortality, mainly due to cardiovascular diseases.3–5 Patients with hypopituitarism require lifelong replacement therapy with regular monitoring to avoid under- or overreplacement.