Pituitary disease

Question 1

Produces what hormones

Answer 1

Anterior = TSH, GH, ACTH, FSH, LH, Prolactin
Posterior = ADL and oxytocin

Question 2

Loss of which signal results in congenital pituitary aplasia

Answer 2

Prop-1 and Pit-1

Question 3

What hypothalamic hormones control pituitary secretion?

Answer 3

TRH = TSH
GnRH = FSH and LH
GHRH = GH
CRH = ACTH
Dopamine = suppresses prolactin

Question 4

? Prolactinoma

Answer 4

Present with galactorrhoea and breast tenderness and amenorrhoea

Test = prolactin levels
MRI pituitary

Treatment = dopamine agonist - bromocriptune or caberoline to normalise prolaticne
Withdraw treatment at 2-4yrs if prolactin normal and tumour decreasing in size
40% recur

Question 5

? Corticotropin disorder?

Answer 5

Deficiency suspected:

• Insulin tolerance test
• short synacthen test

Overactivity suspected:

• 24hr urinary free cortisol (high)
• Midnight salivary cortisol (high)
• Dexamethasone suppression test (doesn’t decrease)

Question 6

? Somatotroph disorder?

Answer 6

Deficiency suspected:

• Insulin tolerance test
• glucagon or arginine/GNRH stimulation test

Overactivity suspected:

• Elevated IGF-1
• OGTT (detectable GH)

Question 7

Posterior pituitary disorder

Answer 7

Water deprivation test

Expect sOSM >300 –> uOSM 500-600

Question 8

Craniopharyngioma and the pituitary

Answer 8

Most common hypothalamic lesion

Causes Diabetes insipidus, anterior pituitary insufficiency and hyperphagia

Question 9

Pituitary masses

Answer 9

Determine endocrine function and seek evidence of mass effect

Usually monoclonal and slow growing:

• 40% non-functional
• 30% prolactinomas
• 15% secrete GH
• 10% ACTH
• < 5% TSH and LH

Surgery is prime treatment

Question 10

Genetic Syndromes causing familial pituitary tumours

Answer 10

1. MEN1 = menin gene
   - -> pituitary, parathyroid and pancreas tumours
2. p27 mutations
   - -> parathyroid and pituitary
3. AIP mutations
   - -> young onset GH secreting tumours
4. PPKAR1A mutations –> carney syndrome
   - -> freckles, myxomas, testicular, adrenal and pituitary adenomas or hyperplasia

Question 11

Cushing’s Disease

Answer 11

ACTH secreting pituitary adenomas

Hypercortisolism and hyperpigmentation

DIAGNOSIS IS HARD:

• Hypercortisolism on urinary cortisol, midnight salivary cortisol or dexamethasone suppression test +
• Raised or normal ACTH
• MRI brain
• Petrosal sinus sampling

Treatment = surgery
If fails = ketaconazole or mityrapone

Question 12

Causes of endogenous cushing’s syndrome

Answer 12

Cushings disease +++

Ectopic ACTH
Adrenal adenoma
Adrenal carcinoma

Question 13

Acromegaly

Answer 13

Raised IGF-1 and clinical features of disease - acral overgrowth, DM, OA, OSA and vascular disease

Treatment = surgery
If surgery fails –> dopamine agonist –> somatostatin analogue - octreotide –> radiotherapy

Most commonly associated with thyroid cancer
Need colonscopy from 40yrs to screen for bowel cancer
Monitor for DM and CVD

Question 14

Pituitary insufficiency

Answer 14

Replace:

• STEROIDS - dexamethasone
• Thyroxine
• Testosterone or HRT

Associated with increased incidence of IHD and stroke

Question 15

Pituitary apoplexy

Answer 15

Usually due to sudden haemorrhage into pituitary following childbirth or trauma

Frontal headache and neuropraxia common

NEED STEROIDS

Question 16

Pregnancy and pituitary tumours

Answer 16

Pregnancy –> increased size of pituitary

Must consider surgery prior to pregnancy

If prolactinoma = cease bromocriptine during pregnancy +/- surgery and give bromocriptine if visual fields become compromised

Question 17

Problem with short synacthen test post pituitary resection?

Answer 17

SST = The administration of synthetic ACTH with measurement of a baseline cortisol and a serum cortisol one hour post (normal >500 nmol/L)

False negative if adrenals have not atrophied
Typically performed 4-6 weeks after surgery