Clinical abnormalities of glands

Question 1

What is a primary hormone over/under secretion caused by?

Answer 1

A problem with the specific gland

Question 2

What is a secondary hormone over/under secretion caused by?

Answer 2

a problem with the pituitary gland (no/too much hormone is produced to tell the specific gland to produce another hormone)

Question 3

Can a tumour/nodules be present in the gland or pituitary without affecting hormone secretion?

Answer 3

Yes

Question 4

Abnormalities in which three glands can be diagnosed simply with a static test?

Answer 4

Thyroid
Sex glands
Prolactin over-secretion

Question 5

What is tested for in a static test for those with suspected primary hyperthyroidism? What levels? Why?

Answer 5

T3 and T4 will be elevated
TSH will be suppressed

Negative feedback form high levels of T3/T4 prevents the pituitary from producing more TSH

Question 6

When are stimulation tests used?

Answer 6

To test for hormonal UNDER-SECRETION when static tests are not enough

Question 7

When are suppression tests used?

Answer 7

To test for hormonal OVER-SECRETION when static tests are not enough

Question 8

How is a stimulation test used to test for adrenal insufficiency?

Answer 8

ACTH is given, cortisol levels are expected to rise because the adrenal gland is stimulated by ACTH to secrete cortisol

Question 9

What is the insulin stress test? What does it test for?

Answer 9

Insulin is given, which lowers the blood sugar. Low glucose levels cause a stressful situation for the body because glucose is needed for the brain to function, so hormone secretion e.g. cortisol, growth hormone, rises. If tis does not happen, there is a problem with the pituitary gland.

Question 10

Why is glucagon stimulation sometimes used instead of the insulin stress test?

Answer 10

It is less sensitive, but is used in patients with heart problems etc. who may not be able to cope with the insulin stress test.

Question 11

How is steroid production tested using a suppression test?

Answer 11

Exogenous steroids are given, which should switch off internal cortisol/steroid production through suppression of ACTH by negative feedback. If not, then the gland is producing too much steroid.

Question 12

How is a suppression test used to test for GH production?

Answer 12

Glucose is given and GH secretion is tested. Glucose should switch off GH production.

Question 13

what is gland over-secretion usually caused by?

Answer 13

Benign tumours

Question 14

What can gland under-secretion be caused by?

Answer 14

Gland destruction due to;

• inflammation (including autoimmune conditions)
• infarction (obstruction of blood supply)
• tumours/nodules with normal hormone production that block secretions
• other

Question 15

What is prolactin over secretion usually caused by?

Answer 15

A pituitary tumour secreting prolactin (prolactinoma)

Usually benign

Question 16

What control is prolactin usually under?

Answer 16

Inhibitory

Dopamine is secreted by the hypothalamus to prevent prolactin secretion

Question 17

What are the clinical presentations of prolactin over-secretion?

Answer 17

Galactorrhea (breast milk production)
Amenorrhoea
Headaches and visual field problems
Sexual dysfunction because less FSH and LH

Question 18

How is prolactin over-secretion diagnosed?

Answer 18

Static test and MRI to confirm the tumour

Question 19

What else can cause prolactin levels to mildly increase?

Answer 19

Sexual intercourse
nipple stimulation
stress
drugs 
non-functioning pituitary tumour which compresses the hypothalamus and interferes with inhibitory effect

Question 20

Do prolactinomas usually require surgery?

Answer 20

No, can usually be treated medically

Question 21

What does growth hormone over secretion cause?

Answer 21

Excessive growth spurts, increased size of feet and hands, gigantism

In adults, skin, soft tissue and skeleton are effected giving an acromegalic face and wide hands/feet and increased sweating

Question 22

How is GH over-secretion diagnosed?

Answer 22

Suppression tests; glucose is given followed by GH measurements at different time points.
Glucose should suppress GH production and plasma levels of the hormone should fall.
Imaging is needed to confirm the presence of a pituitary tumour

Question 23

What is the treatment for GH over-secretion?

Answer 23

Surgical removal of tumour

Radiotherapy and medical therapy if not all the tumour is removed

Question 24

What are the symptoms of cushing’s syndrome?

Answer 24

Causes growth arrest in children
Typical facial appearance is round (moon like), acne, excess hair.
Fat redistribution and truncal obesity with thin extremities
Thin skin, easy bruising, striae (stripes) on abdomen

Question 25

What causes Cushing’s syndrome?

Answer 25

Pituitary secreting ACTH tumour (Cushing’s disease)
Adrenal tumour secreting cortisol (ACTH will be low because of negative feedbacK)
Cancer producing ACTH

Question 26

How is Cushing’s syndrome diagnosed?

Answer 26

Dexamethasone suppression test confirms the failure to suppress cortisol production
To differentiate between adrenal and pituitary Cushing’s, a static ACTH is carried out. If ACTH is suppressed, it is adrenal. If it is high, it is pituitary (or a cancer producing ACTH)

Question 27

What is the treatment for pituitary or adrenal Cushing’s?

Answer 27

Surgery, radiotherapy and medical treatment

Question 28

What is the treatment for cancer causing Cushing’s?

Answer 28

Treat the original cancer