Hyper secretion of Anterior Pituitary Hormones Flashcards
Hyper secretion tends to be due to
isolated pituitary tumours
Ectopic
Hyper secretion tends to be associated with
visual field defects e.g. bitemporal hemianopia
Excess ACTH TSH LH/FSH GH Prolactin
ACTH - Cushing's TSH - thyrotoxicosis LH/FSH - precocious puberty GH - acromegaly/ gigantism Prolactin - hyperprolactinaemia
Signs and symptoms of acromegaly
Increased growth of:
cartilage, periosteal bone, fibrous tissue, connective tissue, internal organs (cardiomegaly, splenomegaly, hepatomegaly), enlarged supraorbital ridges, hand, nose and feet, mandible
Metabolic effects: increased GH –> increased glucose production –> increased insulin production –> insulin resistance and symptoms of DM
Others: Thickening of lips Hyperhidrosis Hypertension (increased stress on CVS) Headaches Macroglossia --> obstructive sleep apnoea Barrel chest Kyphosis Carpal Tunnel syndrome - increased cartilaginous growth puts pressure on nerves
A tumour secreting GH and prolactin can cause
acromegaly and hyperprolactinaemia
Diagnosis of acromegaly
give glucose. Normally after glucose is injected, GH should decrease.
(remember after insulin induced hypoglycaemia, GH rises)
In acromegalics, GH rises after glucose injected.
Look for an increase in IGF-1
Treatment options for acromegaly
Surgery - transphenoidal hypophysectomy
Radiotherapy
Chemotherapy – SS analogue e.g. octreotide
or DA agonist e.g. cabergoline or bromocriptine
Disadvantage of radiotherapy
Over a long period of time you can become hypopituitary
clinical uses of octreotide
Just before surgery to make the pituitary tumour smaller
Long term in people whose acromegaly isn’t controlled by other means
Treatment of other neuroendocrine disorders e.g. carcinoid tumours
Physiological and pathological causes of hyperprolactinaemia
Physiological - breastfeeding and pregnancy
Pathological - prolactinoma
Effect of increased prolactin on LH and FSH
Increased prolactin causes decreased GnRH pulsatility and decreased LH and FSH
Clinical feature of hyperprolactinaemia
Women - galactorrhea
decreased libido
secondary amenorrhoea/ oligomenorrhoea
infertility screen
Men - galactorrhea (rare because less oestrogen)
decreased libido
erectile dysfunction
infertility screen
Diagnosis of hyperprolactinaemia
Signs and symptoms
blood test for high prolactin
Treatment of hyperprolactinaemia
DA agonists (DA inhibits prolactin)
Cabergoline
Bromocriptine
Side effects of treatment for hyperprolactinaemia
Nausea/vom/abdominal cramps
Postural hypotension
Dyskinesias
Psychomotor excitation
