Therapeutics of pituitary disease Flashcards
Hormones made by pituitary
Anterior: ACTH, TSH, GH, LH/FSH, prolactin
Posterior: ADH, Oxytocin
Main effects of pituitary tumour
- hormone hypersecretion
- effects of the physical mass: compression on pituitary tissue –> hyposecretion, compression of neighbouring structures (CN, optic chiasm, hypothalamic damage)
Compression of optic chiasm by pituitary tumour
loss of temporal vision (temporal hemianopia)
Management of a non-functioning pituitary adenoma
- if compressing CN’s/optic chiasm - transphenoidal surgery)
- if not -surveillance
Complication of pituitary surgery
- hormone deficiency (hard to remove only the tumour)
- CSF leak
- hormone deficiency
Types of function pituitary tumours
- prolactinoma (medical treatment 1st line)
- Cushings (ACTH), TSHoma, Acromegaly (GH), Gonadotrophinoma - 1st line surgical treatment, then medical, then radiotherapy
Treatment of prolactinoma
1st line - dopamine agonists
- carbergoline (best), bromocriptine
- dopamine inhibits prolactin synthesis
- if treatment fails (prolactin levels do not normalise or tumour doesn’t shrink) - swap to other medication, surgery
Acromegaly
Growth hormone excess -> excess IGF-1 –>
- sweating, headaches, large hands/feet
- macroglossia, nerve entrapment (CTS)
- hypertension, DM, hyperlipidaemia, hypertrophic cardiomyopathy and obstructive sleep apnoea
Management of acromegaly
- transphenoidal hypophysectomy
2. medical - somatostatin anologues, GH receptor antagonists and dopamine agonists
Somatostatin analogues for acromegaly
- natural somatostatin causes cell proliferation and GH synthesis
- analogues have a longer half life –> tumour shrinkage and IGF-1 normalisation
- ocreotide, lanreotide, pasireotide
- s/e - gallstones, abdo cramps, diarrhoea, hair loss, hyperglycaemia,
GH receptor antagonist for acromegaly
- pegvisomant
- competitive antagonist of GH for GH receptor - doesn’t inhibit GH synthesis
- normalises IGF-1 and improves glucose control, but does not shrink tumour
Dopamine agonists for acromegaly
- e.g. bromocriptine
- reduces GH synthesis
- efficacy tends to wear off with prolonged use
Cushing’s disease
pituitary adenoma secreting ACTH causing excess cortisol
- round plethoric face, weigh gain, thin skin, easy bruising, striae, mood disturbance, hypertension, DM, infections
Management of Cushing’s disease
- surgery (high recurrence)
2. medical management - etomidate (inhibits steroidogenesis), mifepristone (glucocorticoid receptor antagonist)
Hypopituitarism
normally due to large tumour compressing part of gland - replace missing hormones
