Pituitary Disorders Flashcards
What is the most common cause of pituitary malfunction?
Adenoma
What does it mean when a pituitary tumour is said to be non functioning?
The tumour cells themselves do not produce any hormone
How is a pituitary tumour diagnosed?
1) MRI
2) Assessment of visual field
3) Assessment of endocrine function
What hormones are usually the first to be affected in hypopituitarism?
GH and LH/FSH
What is panhypopituitarism?
Deficiency of all anterior pituitary hormones
What are a few symptoms of GH deficiency in adults?
Decrease in tolerance to exercise, decreased muscle strength, increased body fat and reduced sense of well being
What can gonadotropin deficiency result in?
Loss of libido, infertility, oligomenorrhea or amenorrhea, impotence
What could cause ADH deficiency?
Hypothalamic tumour or pituitary tumour that has extended up into the hypthalamus
Cranial radiotheraphy, pituitary surgery, autoimmune, meningitis
What does insufficient ADH release lead to?
Excess excretion of dilute urine resulting in dehydration and increased thirst
What is diabetes insipidus?
A disease in which the secretion of or response to the pituitary hormone vasopressin is impaired, resulting in the production of very large quantities of dilute urine, often with dehydration and insatiable thirst.
What are the three main conditions caused by excess pituitary hormone production?
Prolactin excess, GH excess and ACTH excess
What is the normal function of prolactin?
Initiate and maintain lactation
What is prolactin release regulated by?
Prolactin released hormone (stimulates) and dopamine (inhibits)
What are some symptoms of hyperprolactinaemia?
Galactorrhea (unexplained milk production)
Gynecomastia (hard breast tissue)
Hypogonadism (diminished activity of ovaries/testes)
Amenorrhea
Erectile dysfunction
What is hypogonadism?
Decreased sex hormone production
Why does hyperprolactinaemia lead to decreased sex hormone production?
Hyperprolactinaemia -> higher dopamine level in hypothalamus -> inhibition of GnTH -> decreased FSH and LH from anterior pituitary
What is the most common cause of hyperprolactinaemia?
Prolactinoma - pituitary adenoma that secretes prolactin
Aside from an adenoma, what else could cause hyperprolactinaemia?
Pregnancy, suckling, stress, exercise, antidepressants, antipsychotics
What is used to treat hyperprolactinaemia?
Cabergoline - dopamine receptor agonist
What changes in physical appearance can be associated with GH excess?
Broad nose, coarse facial features, thick lips, a prominent supraorbital ridge, enlarged hands and feet, greasy skin
How can GH excess be treated?
Surgery, radiation therapy and drug therapy
Eg antagonists of the GH receptor - pegvisomant
