Hypersecretion of APG hormones Flashcards
Hyperpituitarism?
Symptoms associated with excess production of adenohypophysial hromones
What are some causes or hyperpituitarism?
Isolated pituitary tumours
BUT
could be ectopic (from non-endocrine tissue) in origin
What is hyperpituitarism often associated with?
Visual field & CN defects e.g. bitemporal hemianopia
Excess ACTH (corticotrophin) can result in……
Cushing’s Disease
Excess TSH (thyrotrophin) can result in……
Thyrotoxicosis
Excess gonadotrophins (LH/FSH) can result in……
Precocious puberty in children
Excess prolactin can result in……
Hyperprolactinaemia
Excess GH can result in……
Gigantism (in children)
Acromegaly (in adults)
Physiological causes of hyperprolactinaemia?
Pregnancy
Breastfeeding
Pathological causes of hyperprolactinaemia?
Prolactinoma (often microadnenomas) - most common functioning pituitary tumour
High prolactin suppresses GnRH pulsatility
Signs/symptoms of hyperprolactinaemia in women?
x Galactorrhoea (milk production)
x 2o amenorrhoea (or oligomenorrhoea)
x loss of libido
x infertility
Signs/symptoms of hyperprolactinaemia in men?
x galactorrhoae UNCOMMON (as do not have appropriate steroid for it)
x loss of libido
x erectile dysfunction
x infertility
What is different about prolactin to the other APG hormones?
Has an INHIBITORY regulation
via. Dopamine
How is prolactin inhibited?
Dopamine from hypothalmic dopaminergic neurones
BINDS to
D2 receptors on the lactotrophs to switch OFF prolactin secretion
What is the 1st line treatment for hyperprolactinaemia?
D2 receptor agonists (oral!)
Examples of the 1st line treatment for hyperprolactinaemia?
Bromocriptine
Cabergoline
How does the 1st line treatment for hyperprolactinaemia work?
- Decreases prolactin secretion
2. Reduces tumour size
Side-effects of the 1st line treatment for hyperprolactinaemia work?
x Impulse control disorder - dopamine receptors found elsewhere as well
x Nausea & vomiting
x Postural hypotension
x Dyskinesias (impairment of voluntary movement)
x Depression (exhaustion of dopamine stores)
x pathological gambling
Why does excress GH (somatotrophs) present differently in children & adults?
In adults, the growth plates have fused so cannot grow in height
BUT
in children this has not happened yet
Why does excess GH usually result in the 2 conditions?
Usually due to benign GH secreting pituitary adenoma
Why is acromegaly associated w. increased morbidity and mortality?
Insidious onset (gradual but harmful on onset) - signs/symptoms progress gradually so can remain undiagnosed hence untreated results in increased…..
What complications are normally seen in those w. acromegaly when they die?
CVS disease - 60%
Respiratory complications - 25%
Cancer - 15% e.g. bowel cancer
Whats grows in acromegaly?
x Periosteal bone x Cartilage x Fibrous tissue x Connective tissue x Internal organs (cardiomegaly, splenomegaly, hepatomegaly etc)
Clinical features of acromegaly?
x Hyperhidorsis (excess sweating)
x Headache
x Face enlargement (e.g. supraorbital ridges)
x Macroglossia (enlarged tongue) - which can cause sleep apnoea
x Prognathism (mandible grows, protruding the lower jaw)
x Carpal tunnel syndrome (median nerve compression)
x Barrel chest
x Kyphosis (spinal disorder)
