Pituitary Disorders

Question 1

Describe the clinical presentation of pituitary tumours

Answer 1

Mass effect of tumour on local structures
Abnormality in pituitary function - visual loss, headache
hypo- or hyper-secretion

Question 2

What is the mass effect of pituitary tumour on local structures?

Answer 2

Optic chiasm - Visual field loss due to pressure on optic chiasm
III, IV (eye movement)
Upward growth - grows superiorily - visual loss
Pituitary tumour can lead to loss of vision at the sides
Va, b nerve (pain) pain and double vision - lateral growth of pituitary tumour
internal carotid artery (blood supply) VI nerve (lateral eye movement)

Question 3

Describe the hypothalamic control of the posterior pituitary

Answer 3

positive control- measure in the blood
GH + 
LH / FSH + = gonadotrophins 
TSH + 
ACTH +

negative control
Prolactin - -> hypothalamus inhibits this

If you have disinhibtory smth, prolactin goes up the rest go women

Question 4

What results from gonadotropin deficiency

Answer 4

Loss of secondary sexual characteristics in adults

Loss of periods an early sign in women

Question 5

What resulte from TSH and ACTH deficiency?

Answer 5

Late feature of pituitary tumours

TSH deficiency – low thyroid hormones cold, weight gain, tiredness, slow pulse low T4 and non-elevated TSH

ACTH deficiency – low cortisol tired, dizzy, low BP, low sodium HPA axis most important Can be life threatening

Can have large or small tumours - large can cause pressure - compress talk etc

Question 6

Which pituitary hormones are common/rare to be in excess?

Answer 6

Common
Prolactin
GH
ACTH - adrenal hypertrophy

Rare
TSH LH/FSH

Question 7

Describe he biochemical assessment o pituitary disease

Answer 7

Basal blood test sufficient: Thyroid axis: fT4, TSH
Gonadal axis: LH, FSH - fsh high early in period
testosterone - men
oestradiol - women
Prolactin axis: serum prolactin

Dynamic blood test may be needed
HPA axis: 0900 cortisol
GH axis: GH / IGF-1 - growth in pulsing manner,

Question 8

What are teh stimulation test and the suppression test

Answer 8

Stimulation test - suspected hormone deficiency

Suppression test - suspected hormone excess

Question 9

Describe the dynamic assessment of the HPA axis

Answer 9

Adrenal axis
Deficiency
• Direct stimulation of adrenals by ACTH (synACTHen)
• Response to hypoglycaemic stress - mobilise glycogen stores (insulin stress test)
Excess
• Suppress ACTH axis with steroids (dexamethasone) - eg for Cushing’s
Glucose switches of growth hormone - eg if you eat sugar but GH high - prolonged GH

Question 10

Describe the dynamic assessment of the GH axis

Answer 10

GH axis
Deficiency
• Response to hypoglycamic stress (insulin stress test)
Excess
• Suppress GH axis with glucose load (glucose tolerance test)

Question 11

How is pituitary disease assessed radiological?

Answer 11

MRI

Question 12

How are visual fields assessed?

Answer 12

If you have a lesion by right eye - light cannot get to left side of brain - blind right eye
If you get a tumour on right side near Brian - lose left side o both eyes
If you get a chiasmal lesion - by temporal hemianopsia - lease outer halves of vision in each eye

Question 13

What is bi-temporal hemi-anopia?

Answer 13

Loss of vision of left side of left eye and right side of right eye (peripheral vision)
Highly suggestive if pituitary tumour

Question 14

What is prolactinoma?

Answer 14

Prolactin-secreting pituitary tumour
Prolactin normally <400
Large tumour = macro-adenoma (> 1cm)
Small tumour = micro-adenoma (< 1cm)
The larger the tumour, the higher the prolactin
Prolactinomas are treated with tablets not an operation - 2 tablets of dopamine - dopamine shrinks it
Even if the tumour is very large causing visual problems
Never send a patient for surgery until prolactin levels known

Question 15

What is macro-prolatinoma?

Answer 15

Prolactin >4000?

Tumour will shrink with dopamine agonist Remember dopamine inhibits prolactin

Question 16

What is hyperprolactinaemia?

Answer 16

Prolactin directly inhibits LH secretion

Question 17

What are the symptoms of hyperprolatinaemia in women?

Answer 17

Menstrual disturbance Fertility problems Galactorrhoea - milky discharge
In micro-prolactinomas serum prolactin is not that high

Question 18

What are symptoms of hyperprolactinaemia in men/

Answer 18

Men present later than women (no periods)
Usually larger tumours (macro-adenomas)
Symptoms of low testosterone are non-specific
May present with mass symptoms such as visual loss

Question 19

What will lead to prolactin disinhibition

Answer 19

Prolactin is under tonic inhibitory control by dopamine

Anything blocking stalk will lead to prolactin disinhibition

Question 20

What are different causes of high prolactin?

Answer 20

If prolactin < 5,000 the high prolactin might be due to disinhibition (‘stalk effect’) rather than active prolactin secretion
If prolactin > 5,000 the high prolactin is likely to be due to active prolactin secretion (prolactinoma)
This is important as prolactinomas are treated medically but non functioning pituitary tumours are treated surgically

Question 21

What is non-functioning pituitary adenoma?

Answer 21

No secretion of biologically active hormones
Mass effect - visual problems or headache
May secrete inactive hormones (e.g ACTH or LH / FSH)
Clinical features from are due to mass effect or symptoms of low pituitary hormones
‘hypopituitary’ bloods with disinhibition hyperprolactinaemia

Question 22

Describe the treatment of prolactinoma

Answer 22

Dopamine agonists stimulate D2 receptor
Bromocriptine and cabergoline very effective at reducing prolactin
Remember dopamine antagonists can cause high prolactin
Anti-sickness, anti-psychotic drugs
Always check medication in a patient with high prolactin level
And make sure patient is not pregnant!

Question 23

What is acromegaly?

Answer 23

‘Large extremities’
Te l l -tale sign is large hands and feet
GH-secreting pituitary tumour
Leading to gradual changes in features over years
Important for medical students to learn about this
The diagnosis is made by any doctor in any clinical setting

Question 24

What are long term complications of untreated acromegaly?

Answer 24

Premature cardiovascular death
Increased risk of colonic tumours
Probably increased risk of thyroid cancer
Disfiguring body changes that may be irreversible
Hypertension and diabetes
Unpleasant symptoms

Question 25

What are biochemical tests to confirm acromegaly

Answer 25

Oral Glucose Tolerance Test (OGTT) with GH response Failure to suppress GH < 1 ug/L Elevated IGF-1 level (age related reference range) Growth Hormone Day Curve (GHDC) – elevated mean GH Better to think of acromegaly and be wrong than not to consider it

Question 26

What are treatments of acromegaly?

Answer 26

Surgical removal of tumour through the nose Very specialist surgery Safe in the right hands Tumours in cavernous sinus need additional treatment

Question 27

What are additional treatments for acromegaly?

Answer 27

Medical treatment ``` 1. Reduce GH secretion Dopamine agonist • Cabergoline • Bromocriptine Somatostatin analogues (SSA) • Octreotide • Lanreotide • Pasireotide ``` 2. Block GH receptor • Pegvisomant

Question 28

How can radiotherapy be used to treat (acromegaly??)

Answer 28

External beam - Multiple short bursts over several weeks Gamma knife - High concentration over single time

Question 29

What is a pet scan?

Answer 29

-a new imaging techniques

Question 30

What is cushings disease?

Answer 30

``` ACTH-secreting pituitary tumour A very interesting condition Classical change in appearance • Round pink face with round abdomen • Skinny and weak arms and legs • Thin skin and easy bruising • Red stretch marks (‘striae’) on abdomen • High blood pressure and diabetes • Osteoporosis (thin bones) ```

Question 31

What is the difference between cushings disease and Cushing’s syndrome?

Answer 31

Cushing’s disease is due to a pituitary tumour Cushing’s syndrome may be caused by other pathologies Adrenal tumour, ectopic ACTH, steroid medication Harvey Cushing was a famous neurosurgeon He described the condition and made up the treatment So it’s allowed to be his disease when pituitary!

Question 32

What is diabetes insipidus

Answer 32

Not to be confused with diabetes mellitus sugar diabetes (‘sweet’) ‘Diabetes’ is the Greek word for ‘Siphon’ Diabetes insipidus Large quantities of pale (insipid) urine Extreme thirst due to fluid loss The posterior pituitary gland secretes vasopressin (ADH) Anti-Diuretic Hormone Lack of ADH - lose water ‘Diuresis’ means increased urine ‘Anti-diuresis’ means the opposite

Question 33

What is the action of vasopressin?

Answer 33

It’s ADH Aquaporins and all that Look uo

Question 34

What is the difference between cardinal DI and neprogenic DI?

Answer 34

Cranial DI is vasopressin deficiency pituitary disease Nephrogenic DI is vasopressin resistance kidney disease Diabetes insipidus is unusual in standard pituitary tumours Standard pituitary tumours just affect anterior pitutiary ``` Types of pathology that cause cranial DI • Inflammation • Infiltration • Malignancy • Infection ```

Question 35

What are consequences of untreated DI?

Answer 35

Severe dehydration Very high sodium levels ‘hypernatraemia’ Reduced consciousness, coma and death Cranial DI responds brilliantly to synthetic vasopressin Desmopressin nasal spray, tablets or injection Very important to understand this condition

Question 36

What is pituitary apoplexy?

Answer 36

‘Apoplexy’ is the old-fashioned word for stroke Sudden vascular event in a pituitary tumour Bleeding within tumour ‘haemorrhage’ Blood supply cut off ‘infarction’

Question 37

Describe the clinical presentation of pituitary apoplexy?

Answer 37

Sudden onset headache Double vision Visual field loss Cranial nerve palsy Hypopituitarism cortisol deficiency most dangerous Apoplexy needs prompt diagnosis and treatment