Anterior pituitary - hypersecretion Flashcards
What is the most common cause of hypersecretion of pituitary hormones?
Pituitary tumour
Describe how pituitary tumours can lead to bitemporal hemianopia
Temporal aspects of light hit nasal aspects of retina, fibres from nasal aspect meet at optic chiasm, compression by tumour –> bitemporal hemianopia
What pathology is caused by an excess of ACTH?
Cushing’s
What pathology is caused by an excess of TSH?
Thyrotoxicosis
What pathology is caused by an excess of LH/FSH?
Precocious puberty
What pathology is caused by an excess of prolactin?
hyperprolactinaemia
What pathology is caused by an excess of GH?
Gigantism/ acromegaly
Recall the pathologies associates with excess GH in adults and children
Adults: acromegaly
Children: gigantism
Describe the onset of acromegaly
Insidious
Recall 5 things that grow excessively in acromegaly
- Periosteal bone
- Cartilage
- Fibrous tissue
- Connective tissue
- Internal organs (heart/spleen/liver)
Recall the 11 clinical features associated with acromegaly. Which of these are the main two?
HYPERHIDOSIS HEADACHE Facial changes Prognathism Carpal tunnel Barrel chest Kyphosis Diabetes Hypertension Cardiomyopathy Increased cancer risk
Recall the facial changes associated with acromegaly
Enlargement of:
- supraorbital ridges
- Nose
- lips
- Tongue
Recall and explain 2 methods of diagnosing acromegaly
- Measure IGF-1 (not pulsatile, elevated in acromegaly)
2. Oral glucose test (acromegaly -> failure to suppress GH)
What is the first-line treatment for acromegaly?
Surgery to remove adenohypophysial tumour
Recall 2 options for medical treatment of acromegaly, and give an example of each
Somatostatin analogues (octreotide) DA agonists (cabergoline)
Recall 3 side effects of cabergoline
Nausea
Diarrhoea
Gall stones
What is cabergoline’s main clinical use?
Pre-operative tumour reduction
Why is octreotide known as “endocrine cyanide”?
Inhibits many peptides (not GH specific)
Describe the effect of hyperprolactinaemia on GnRH
Suppresses GnRH pulsatility
Recall 4 symptoms of hyperprolactinaemia in women
Galactorrhoea
Amenorrhoea
Loss of libido
Infertility
Recall 4 symptoms of hyperprolactinaemia in men
Loss of libido
Erectile dysfunction
Infertility
Recall the hormone-receptor interaction controlling prolactin secretion
Dopamine - D2 receptors on lactotrophs –> inhibition of prolactin release
What is the first-line treatment for hyperprolactinaemia? Name 2 examples
D2 receptor agonist: cabergoline, bromocriptine
Recall 5 side-effects of cabergoline
- Pathological gambling
- Dyskinesia
- Postural hypotension
- Depression
- Nausea and vomiting
