Pituitary tumours Flashcards
Describe non-functioning adenomas
a pituitary tumour with no hypersecretion of hormone
Associated with MEN-1
Accounts for 14-54% of pituitary adenomas
Micro-adenoma: tumour size <1 cm
Macro-adenoma: tumour size ≥1 cm
What do functioning pituitary tumours result in
ACTH → Cushing’s
TSH → thyrotoxicosis
Gonadotrophins → precocious puberty
Prolactin → hyperprolactinaemia
GH → gigantism/acromegaly
Symptoms of pituitary tumours
SOL → headaches, visual loss, seizures
Non functioning → Pituitary Failure or Hypopituitarism
- Reduction of Gonadotrophins (FSH, LH) → ↓Testosterone, ↓ Libido, Impotence, Infertility
- Hypothyroidism
- Adrenal insufficiency
- Diabetes insipidus
If large pituitary tumour → Prolactin (due to compression of pituitary stalk – ‘stalk effect’) → Galactorrhoea, amenorrhoea
Signs of pituitary tumours
Bitemporal hemianopia
Cranial nerve palsies
RICP → papilloedema, focal neurology, Cushing’s
Investigations for pituitary tumours
Field assessment: ?bitemporal hemianopia
CPFT (Combined Pituitary Function Test) “Triple Test”
Pituitary hormone: prolactin, TFTs, cortisol/glucose, GH
MRI: ?pituitary adenoma
Describe CPFT (Combined Pituitary Function Test) “Triple Test”
GnRH/LHRH + TRH + insulin (hypoglycaemic stress)
- Insulin → hypoglycaemic stress
- CRH ↑ → ACTH ↑→ Cortisol ↑
- GHRH ↑ → GH ↑ - TRH
- TSH ↑ + prolactin ↑ → T4 ↑ - GnRH/LHRH
- LH, FSH ↑ - Fast patient overnight
- Ensure good IV access
- Weight pt. and calculate dose of insulin required
- Mix and IV Inject the following (patient may vomit on injection):
i. Insulin 0.15U/kg
ii. TRH 200mcg
iii. 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
- Replacement: hydrocortison
Management for a large prolactinoma that is causing pituitary failure
Macro: Trans-sphenoidal resection
+ replacement
1. Hydrocortisone (URGENT)
2. Thyroxine replacement
3. Oestrogen replacement
4. GH replacement (if young and growing)
How would you differentiate between a prolactinoma and non-functioning pituitary adenoma
Prolactinoma - prolactin levels >6000
NFPA - prolactin is raised, but not >6000
This is due to the adenoma pressing on the pituitary stalk and preventing dopamine from reaching the anterior pituitary → no -ve inhibition on prolactin release → secondary hyperprolactinaemia
What are the contraindications to the combined pituitary function test
Epilepsy
Cardiac disease
Untreated hypothyroidism
What are the causes of prolactinaemia
<1000: stress-induced, recent breast/vaginal exam, hypothyroidism, PCOR
1000-5000: antipsychotics, PCOS, microadenoma, NFPA, breastfeedng
>5000: macroadenoma
What is the management for a microadenoma
Micro: dopamine agonist (bromocriptine, cabergolin)
Management for non-functioning pituitary tumours
Miro-adenoma → Active surveillance
Surgical resection (transsphenoidal)
Post-op radiotherapy
+
Hormone replacement
- Hydrocortisone replacement (fludrocortisone not required)
- Thyroxine replacement
- Oestrogen replacement
- GH replacement
- Cabergoline or Bromocriptine – brings down prolactin and allows women to ovulate and men to be fertile
When is surgical resection of pituitary tumours first line
Pituitary apoplexy
Clinically non-functional pituitary macro-adenomas that abut the optic chiasm, and those with mass effect such as visual field defect
Other neurological deficits related to compression from the tumour
Tumours that demonstrate progressive increase in size
Most pituitary macroadenomas, with consideration of size at presentation and likelihood for growth and clinical impact if growth occurs.
Refractory headaches not attributable to other headache syndromes
Endocrine dysfunction related to compression from the tumour, including hypopituitarism or stalk effect causing hyperprolactinaemia.
