Pituitary Disease

Question 1

What is the hypothalamus

Answer 1

• coordinating centre for endocrine centre
• inputs from upper cortical parts, autonomic function, environ cues, peripheral endocrine feedback
• delivers signals to pituitary via stalk = hormone release influencing target organ
• ant. pituitary connected via portal system so high levels of hormones reaching pituitary
• anterior and posterior pituitary

Question 2

Pituitary gland anatomy

Answer 2

• outside dura
• in sella turcica
• below optic chiasm
• anterior and posterior gland
• behind eyes
• accessed through sphenoid bones

Question 3

Anterior pituitary

Answer 3

• rich blood supply (capillary plexus) with high releasing hormones
• ACTH
• TSH
• GH
• LH/FSH
• PRL

Question 4

Posterior pituitary

Answer 4

• inferior hypophyseal artery supplies
• drains into inf hypophyseal veins into systemic circ
• ADH
• oxytocin

Question 5

Hormone excess and deficiency syndromes

Answer 5

GH = acromegaly, deficiency
PRL = hypogonadism, failed lactation
FSH/LH = rare, hypogonadism
ACTH = cushing's, adrenal insufficiency
TSH = hyperthyroidism, hypothyroidism
ADH = SIADH, diabetes insipidus

Question 6

Effect of pituitary tumours

Answer 6

• tumour = releases more hormone = excess

- non functioning tumour = presses on working structures of pituitary = don’t produce enough = deficiency

Question 7

Hormone hypersecretion

Answer 7

• prolactinoma = amenorrhoea/galactorrhoea
• acromegaly
• cushing’s
• thyrotoxicosis (2ndry) (excess TSH) (v. rare)

Question 8

Symptoms from pituitary mass

Answer 8

• headaches
• vision loss
• pituitary gland hyposecretion
• pituitary apoplexy

Question 9

How to classify pituitary tumours

Answer 9

Microadenoma = <1cm
Macroadenoma = 1cm or more

Question 10

Prolactinoma = symptoms, signs, invest, management

Answer 10

• commonest functioning pituitary adenoma
• SYMP = amennorhoea, galactorrhoea, ED, sight loss as chiasmal compression
• SIGNS = galactorrhoea, hypogonadism, bitemporal hemianopia
• INVEST = prolactin, TFT, LH, FSH, testosterone, MRI pituitary
• MANAGEMENT = dopamine agonist as prl release inhibition (bromocriptine, cabergoline)

Question 11

Other causes of hyperprolactinaemia

Answer 11

• lactation/pregnancy
• drugs = antacids, anti-psychotics, anti-emetics (block dopamine)
• stress
• seziures
• stalk compression
• macroprolactin (produce larger form of prolactin so seems as if elevated but actually normal levels and no physiological effect)

Question 12

GH excess 2 types

Answer 12

• gigantism = before puberty, before closure of growth plate

- acromegaly = after puberty, after completion of linear growth

Question 13

Acromegaly symptoms

Answer 13

• triad = headaches, sweating, arthralgia
  + increased ring/shoe signs, weakness, diabetes, carpal tunnel, atherosclerosis, increased risk of cancer as IGF-1 excess = colorectal cancer

Question 14

Acromegaly signs

Answer 14

• spade hands
• prominent supraorb ridge
• prognathism (large and forward facing jaw)
• bitemporal hemianopia
• hypertension
• wide spaced teeth

Question 15

Investigations for acromegaly

Answer 15

• OGTT as GH should suppress with glucose, fast patient and check levels, then 75g glucose, GH should fall but if failure to suppress GH = positive
• , IGF-1 (non diagnostic, response to treatment test)
• MRI pituitary

Question 16

Treatment for acromegaly

Answer 16

• octreotide (somatostatin analogue, injection 1 a month)
• pegvisomont (GH receptor antagonist, if octreotide not responsive)
• trans phenoidal surgery

Question 17

Cushing’s syndrome 2 types and causes

Answer 17

ACTH dependent 75%
- corticotroph adenoma (Cushing's)
- ectopic cushings (ACTH/CRH tumours)
ACTH independent (25%)
- adrenal carcinoma
- adrenal adenoma
- exogenous steroids (cushingoid appearance)

Question 18

Symptoms of Cushing’s

Answer 18

CHO/Protien/Fat Met
- central obesity/moon faces, fat pads
- osteoporosis
- diabetes
- hypertriglycaemia
- peripheral wasting of fat/muscle
SEX HORMONES
- amenorrhoea/infertility
- excess hair growth
- impotence
SALT AND WATER RETENTION
- HTN and oedema

IMPAIRED IMMUNITY
NEUROCOGNITIVE CHANGES

Question 19

Signs of Cushing’s

Answer 19

plethoric face
purple stretch marks
thin skin
moon face
central obesity

Question 20

Cushing’s screening tests

Answer 20

• disrupted circadian rhythm = should be midnight serum/salivary cortisol low, day curve, morning cortisol surge (not diagnostic)
• 24 hour urine free cortisol = increased load?
• MAIN ONE, SCREENING = low dose dexamethasone suppression test, 1mg, should suppress adrenals for 24-48 hours completely, if Cushing’s failure of suppression, measure cortisol and ACTH

Question 21

Cushing’s management

Answer 21

• trans-sphenoidal surgery
• ketoconazole = anti-fungal, stops steroid pathway and adrenolytic
• metyrapone = side effects but adrenolytic preventing excess cortisol, good to get fitter prior to surgery

Question 22

Hypopituitarism define

Answer 22

• loss of all or some pituitary hormones, usually anterior

Question 23

Causes of hypopituitarism

Answer 23

Adenoma
Irradiation
Infarction (sheehan’s)(post childbirth)
- infiltration (sarcoid, TB)

Question 24

Symptoms of hypopituitarism

Answer 24

Loss of libido
Weakness
Amenorrhoea
Impotence
Depression
Hypothyroidism

Question 25

Signs of hypopituitarism

Answer 25

Pallor
Hypothyroid
Absent pubic/axillary hair
testicular atrophy
visual field defect
postural hypotension

Question 26

Investigations of hypopituitarism

Answer 26

insulin stress test
low T4 test
MRI pituitary

Question 27

Treatment of hypopituitarism

Answer 27

HRT = hydrocortisone then T4 then testosterone

- ovulation induction

Question 28

Pituitary Apoplexy

Answer 28

• abrupt acute haemorrhagic infarction of pituitary adenoma
• presents = acute headache, meningism, visual impairment, ophthalmoplegia, low GCS
• glucocorticoid replacement!! as adrenal insufficiency
• then surgical decompression