16. Pituitary Disorders

Question 1

What is the clinical presentation of pituitary tumours?

Answer 1

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

Question 2

Why is there visual field loss in upwards growth of pituitary tumour?

Answer 2

Pressure on optic chiasm

Causes bitemporal hemi-anopia (tunnel vision)

Question 3

What does lateral growth of pituitary tumour cause?

Answer 3

Pain and double vision

Question 4

What is the order of hormone secretion lost from a pituitary tumour?

Answer 4

Growth hormone
Gonadotropin hormone
TSH and ACTH

Question 5

What does a gonadotropin deficiency cause?

Answer 5

Delayed puberty in children
Loss of secondary sexual characteristics in adults
Loss of periods an early sign in women

Question 6

What does TSH deficiency cause?

Answer 6

Low thyroid hormones
Weight gain
Tiredness 
Slow pulse 
Low T4 and non-elevated TSH

Question 7

What does a ACTH deficiency cause?

Answer 7

Low cortisol
Tired
Dizzy
Low BP
Low sodium
Can be life-threatening

Question 8

What are the most common abnormalities in pituitary function and hormone excess?

Answer 8

Prolactin
GH
ACTH

Question 9

How do you do a biochemical assessment of pituitary diseases in thyroid, gonadal and prolactin axes?

Answer 9

Basal blood test sufficient
Thyroid axis - fT4, TSH
Gonadal axis - LH, FSH, testosterone, oestradiol
Prolactin axis - serum prolactin

Question 10

How do you do a biochemical assessment of pituitary disease in the HPA and GH axes?

Answer 10

Dynamic blood test
HPA axis - cortisol at 9am
GH axis - GH/IGF-1

Question 11

If a deficiency is suspected in the adrenal axis what would you do?

Answer 11

Synacthen test - direct stimulation of adrenals by ACTH

Insulin stress test - response to hypoglycaemic stress

Question 12

If an excess in the adrenal axis is suspected what do you do?

Answer 12

Dexamethasone suppression test - suppress ACTH axis with steroids

Question 13

If a deficiency is suspected in GH axis what do you do?

Answer 13

Insulin stress test - response too hypoglycaemic stress

Question 14

If an excess in GH axis is suspected what do you do?

Answer 14

Glucose tolerance test - suppress GH axis with glucose load

Question 15

What is a prolactinoma?

Answer 15

Prolactin-secreting pituitary tumour

The larger the tumour, the higher the prolactin

Question 16

How are prolactinomas treated?

Answer 16

With tablets, never operation

Question 17

What are symptoms of hyperprolactinaemia in women?

Answer 17

Menstrual disturbance
Fertility problems
Galactorrhoea - milk discharge from nipple

Question 18

What are the symptoms of hyerprolactinaemia in men?

Answer 18

Present later than women
Usually larger tumours
Symptoms of low testosterone are non-specific
May present with mass symptoms such as visual loss

Question 19

How are high prolactin and pituitary mass connected?

Answer 19

Prolactin is under tonic inhibitory control by dopamine
Anything blocking stalk will lead to prolactin disinhibition
If prolactin <5000 high prolactin may be due to disinhibition
If prolactin >5000 high prolactin likely to be due to active prolactin secretion

Question 20

What are non-functioning pituitary adenomas?

Answer 20

No secretion of biologically active hormones
May secrete inactive hormones (ACTH or LH/FSH)
Clinical features due to mass effect or symptoms of low pituitary hormones

Question 21

What is the treatment of prolactinoma?

Answer 21

Dopamine agonists stimulate D2 receptor
Bromocriptine and cabergoline reduce prolactin

Dopamine antagonists can cause high prolactin, such as drugs for anti-sickness or anti-psychotic

Question 22

What is acromegaly caused by?

Answer 22

GH secreting pituitary tumour

Leading to gradual changed in features over years

Question 23

What are the long-term complications of untreated acromegaly?

Answer 23

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

Question 24

What are the biochemical tests to confirm acromegaly?

Answer 24

Oral glucose tolerance test with GH response
Failure to suppress GH
Elevated IGF-1 level
Growth hormone day curve - elevated mean GH

Question 25

What is the treatment of acromegaly?

Answer 25

Surgical removal of tumour
Tumours in cavernous sinus need additional treatment
Reduce GH secretion via dopamine agonists and somatostatin analogues
Block GH receptor

Question 26

What is Cushing’s disease?

Answer 26

ACTH-secreting pituitary tumour

Question 27

What are the symptoms of Cushing’s disease?

Answer 27

Round pink face with round abdomen
Skinny and weak arms and legs
Thin skin and easy bruising
Red stretch marks on abdomen
High BP and diabetes
Osteoporosis

Question 28

What is diabetes insipidus?

Answer 28

Lack of ADH

Causes extreme thirst and large quantities of pale (insipid) urine

Question 29

What is the difference between cranial DI and nephrogenic DI?

Answer 29

Cranial is ADH deficiency pituitary disease

Nephrogenic is ADH resistance kidney disease

Question 30

What are the types of pathology that cause cranial DI?

Answer 30

Inflammation
Infiltration
Malignancy
Infection

Question 31

What are the consequences of untreated DI?

Answer 31

Severe dehydration
Very high sodium levels
Can lead to reduced consciousness, coma and death

Question 32

What is pituitary apoplexy?

Answer 32

Sudden vascular even in pituitary tumour (type of stroke)
Bleeding within tumour - haemorrhage
Blood supply cut off - infarction

Question 33

What is the clinical presentation of pituitary apoplexy?

Answer 33

Sudden onset headache
Double vision
Visual field loss
Cranial nerve palsy
Hypopituitarism