• The pituitary is formed of two anatomically and embryologically distinct lobes:
◦ anterior pituitary: which secretes growth hormone (GH), gonadotropins (luteinizing hormone (LH) and follicle-stimulating hormone (FSH)), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), and prolactin
◦ posterior pituitary: which secretes vasopressin and oxytocin.
• Hypopituitarism is deficiency of one or more pituitary hormones. Some hormones, e.g. GH (LH/FSH), are more likely to present with isolated deficiencies, while others, e.g. TSH, ACTH, are more often found as part of multiple pituitary hormone deficiency (MPHD).
• Deficiencies may be congenital (including genetic) or acquired; secondary to tumour, trauma, infiltration, infection, or irradiation.
• GH deficiency:
◦ diagnosed using a combination of clinical, radiological, and biochemical assessment (including GH stimulation testing)
◦ treatment is with GH (including if necessary into adulthood).
• LH/FSH deficiency:
◦ If acquired, often one of the first anterior pituitary hormones to be lost.
◦ Congenital forms:
■ present with cryptorchidism and/or micropenis in males
■ may occur in isolation, or in association with anosmia (Kallmann and CHARGE syndromes).
◦ Treatment: sex steroid therapy to induce secondary sexual characteristics, and recombinant FSH/LH to induce fertility potential.
• ACTH deficiency:
◦ Unlike primary adrenal problems, hyperpigmentation does not occur.
◦ Although mineralocorticoid production is preserved, hyponatraemia may still occur.
◦ Treatment is with hydrocortisone.
• TSH deficiency:
◦ TSH may be low, normal, or raised (but inappropriate for free thyroxine level).
◦ Treatment is with thyroxine.
• Vasopressin deficiency:
◦ produces cranial diabetes insipidus
◦ treatment is with DDAVP (orally or nasally).
• Prolactin and oxytocin deficiency rarely produce clinical problems.
Machine-Learning Prediction of Postoperative Pituitary Hormonal Outcomes in Nonfunctioning Pituitary Adenomas: A Multicenter Study
