Pituitary tumours (non-functioning) Flashcards
Define non-functioning pituitary adenoma.
A tumour with no hypersecretion of hormone.
What are most common pituitary adenomas? (functioning and non-functioning)
- Prolactinomas (35%)
- Somatotroph adenomas (20%)
- Corticotroph adenomas (10-12%)
- Gonadotroph adenomas (20%)
- Null cell adenomas (10%)
- Thyrotroph adenomas (1-2%)
Give 3 neoplastic and non-neoplastic causes of bitemporal hemianopia.
NEOPLASTIC
- Pituitary macroadenoma
- Meningioma e.g. suprasellar
- Cranipharyngioma
- Chiasmatic glioma
NON-NEOPLASTIC
- Aneurysm or ectatic carotid artery
- Epidermoid cyst
- Sarcoid
- Dermoid cyst
Describe the optic pathways.
NB the right side of something is processed with the left half of each retina etc.
Describe some visual field defects caused by lesions in different parts of the visual pathway.
How common are non-functioning pituitary tumours?
Non-functioning pituitary adenomas account for 15% of all pituitary adenomas
3rd most common intra-cranial neoplasm in adults
Small pituitary tumours (<4 mm) are common and often found incidentally
Do non-functioning pituitary tumours produce any hormones?
They usually make at least one of the pituitary hormones even though they are called non-functioning
However the tumours appear non functioning because
- FSH and LH excess usually do not cause specific symptoms
- only parts/subunits of the hormone are produced which are not active
- they are secreted into blood in small amounts so blood levels are usually normal
What are the signs and symptoms of CNFPAs?
- Usually asymptomatic so present late - rarely produce LH and FSH
Stretching of the dura around pituitary →
- Headaches - mass effect
- Imbalance, urinary incontinence - may cause dural stretch or cavernous sinus invasion
Compression of optic chiasm →
- double vision, visual field defects (18-78%) - 3rd, 4th, 6th cranial nerve palsies
- facial pain and paraesthesias - V1 and V2 branch of CN5 palsy
Depletion of hormone due to compression of normal functioning pituitary →
- hypopituitarism - gonadotrophs/somatotrophs are most susceptible to local pressure damage from pituitary adenoma
- hypogonadism, GH deficiency, hypothyroidism, adrenal insufficiency
- no hyperkalaemia as mineralocorticoid pathway is intact
CAN PRESENT WITH PITUITARY APOPLEXY
What are the signs and symptoms of pituitary apoplexy?
- Severe headache
- Sudden onset
- Nausea
- Vomiting
- Fever
- Meningismus
- Altered GCS
- Visual disturbances
- Hypopituitarism
Precipitating factors: head injury, anticoagulant therapy, dopamine agonists, radiotherapy, dynamic endocrine tests
May be asymptomatic
What investigations would you do for pituitary adenoma (nf)?
Pituitary MRI pre- and post-gadolinium enhancement - better than CT; shows tumour invasion into cavernous and sphenoid sinus and any mass effect.
Ophthalmic evaluation - Humphrey 30-2 test.
Routine blood tests - hormones, metabolic panel, FBC.
- Hyponatraemia - in adrenal insufficiency and hypothyroidism
- Anaemia - in hypogonadism, hypothyroid or adrenal insufficiency
- Lipid panel - hyperlipidaemia in hypogonadism
Hormone tests:
- Prolactin - elevated in prolactinoma or stalk compression
- IGF-1 - low or normal in GH deficiency
- LH/FSH
- testosterone, estradiol
- TSH, free thyroxine
- morning cortisol
- ACTH
How do you manage CNFPAs? (not on Sofia)
Microadenoma → observation
Macrodenoma →
- Observation OR
- Surgery - trans-sphenoidal
- +/- Radiotherapy - if residual tumour after surgery; via gamma knife
- +/- Somatostatin analogues/DA - if residual tumour or recurrence after surgery and radiotherapy
- Hormone replacement - as shown by CPFT
What is a normal prolactin level?
<600
If prolactin is >6000 what is the diagnosis?
Prolactinoma is the only cause of such high prolactin
Describe how a CPFT is carried out.
- Fast patient overnight
- Ensure good IV access
- Weight pt. and calculate dose of insulin required (0.15units/kg i.e. 70kg woman = 10.5units)
- Mix and IV. Inject the following (patient may vomit on injection):
- Insulin 0.15 units/kg
- TRH 200mcg
- LHRH/GnRH 100mcg
- Take bloods at 0, 30 and 60 minutes of glucose, cortisol, GH, LH, FSH, TSH, prolactin and T4
- Take bloods at 90 and 120 minutes of glucose, cortisol and GH
What is the diagnosis?
Functioning pituitary adenoma
Management:
- URGENT hydrocortisone replacement (fludrocortisone is not necessary as adrenals should still be able to make aldosterone as it is independent of the HPA)
-
Total therapy (ordered):
- Hydrocortisone replacement
- Thyroxine replacement
- Oestrogen replacement
- GH replacement
- (Cabergoline or Bromocriptine – if prolactinoma is the cause of the failure –> shrinks tumour)
- Dopamine agonists
What is the diagnosis?
Disconnection hyperprolactinaemia (non-functioning pituitary adenoma).
- Adenoma presses on pituitary stalk
- Dopamine prevented from reaching anterior pituitary
- No -ve inhibition on prolactin release
- Hyperprolactinaemia
