16 Pituitary Disorders

Question 1

What is the most common cause of pituitary malfunction?

Answer 1

Adenoma (benign tumour)

Question 2

Why would a ‘non-functioning adenoma’ result in inadequate production of pituitary hormones?

Answer 2

Physical pressure- growing tumour on glandular tissues.

Question 3

What symptoms may an adenoma cause, other than inadequate production of pituitary hormones?

Answer 3

Headaches (pressure on surrounding structures in vicinity of tumour), visual problems (compression of optic nerve), vomiting+nausea

Question 4

How would a clinician investigate a suspected pituitary tumour?

Answer 4

1. MRI scan: delineate anatomy, size, location of mass
2. Hormone levels in blood/ Staining sections from tumour biopsy w/. antibodies of relevant hormone: to assess endocrine function

Question 5

What is hypopituitarism?

Answer 5

Insufficient hormone production

Question 6

Apart from pituitary adenoma, what else may cause hypopituitarism?

Answer 6

Radiation therapy, Inflammatory disease, head injury.

Question 7

How does hypopituitarism due to adenoma usually progress?

Answer 7

Progressive loss of anterior pituitary function- first GH and LH/FSH

Question 8

What is panhypopituitarism?

Answer 8

Deficiency of all anterior pituitary hormones

Question 9

Under which circumstances would ADH and oxytocin secretion be affected?

Answer 9

1- Tumour affects hypothalamic function

2- Inflammatory process involved

Question 10

What are some of the symptoms of Growth Hormone Deficiency?

Answer 10

1- Decreased exercise tolerance
2- Decreased muscle strength
3- Increased body fat
4- Reduced sense of ‘well being’

Question 11

Why is a combination of direct and indirect measurements required to to diagnose a GH deficiency?

Answer 11

Difficult to diagnose as GH secretion= PULSATILE

Question 12

What are 2 possible reasons for GH deficiency in children?

Answer 12

1- Gene mutation

2-Autoimmune inflammation

Question 13

How prevalent are GH deficiencies at birth?

Answer 13

1 in 3800 live births

Question 14

How might a severe GH deficiency affect a baby prenatally?

Answer 14

(little effect on fatal growth)
Hypoglycaemia
Jaundice

Question 15

How would a GH deficiency present in a patient from the age of 1 year-teens?

Answer 15

Poor Growth

Short Stature

Question 16

How might a Gonadotropin Deficiency present?

Answer 16

Women:Lack of libido, infertility, oligomenorrhoea/amenorrhoea

Men: Lack of libido, impotence

Question 17

What may cause ADH deficiency?

Answer 17

Hypothalamic/pituitary tumour, cranial radiopathy, pituitary surgery, autoimmune infiltration, infection (e.g. meningitis)

Question 18

How does an ADH deficiency present?

Answer 18

• Excess excretion- dilute urine

- Increased thirst sensation (polydipsia)

Question 19

What is Diabetes Insipidus?

Answer 19

Cranial form of ADH deficiency.

Question 20

What is the normal physiological function of Prolactin?

Answer 20

Initiate and maintain lactation.

Question 21

How is Prolactin secretion regulated?

Answer 21

Secreted by lacrotropes in anterior pituitary, regulated by:
Stimulator=Prolactin Releasing Hormone
Inhibitor= Dopamine (dominates)

Question 22

How does hyperprolactinaemia present?

Answer 22

1, Galactorrhoea (unexplained milk production)
2, Gynecomastia (hard breast tissue)
3, Hypogonadism
4, Amenorrhea
5, Erectile dysfunction

Question 23

Why does hyperprolactinaemia cause hypogonadism?

Answer 23

Higher dopamine levels- Inhibit GnRH secretion and therefore FSH and LH secretion from anterior posterior.

Question 24

What’s the most common cause of prolactinoma?

Answer 24

Pituitary adenoma- secretes prolactin

Question 25

Apart from a pituitary adenoma what other causes are there for hyperprolactinaemia?

Answer 25

Pregnancy, suckling, stress, exercise, drugs (e.g. antipsychotics, antidepressants)

Question 26

How is hyperprolactinaemia treated?

Answer 26

1. Dopamine receptor agonist (e.g. cabergoline) | 2. (rare cases) Trans-sphenoidal surgery/ radiotherapy used

Question 27

What else may increase in production and release if GH production increases?

Answer 27

IGF-1 production

Question 28

How long might GH and IGF-1 overproduction take to present symptoms in a patient?

Answer 28

6+ years

Question 29

How might a patient with GH excess present?

Answer 29

Broad nose, coarse facial features, which lips, prominent supraorbital ridge, enlargement of hand and feet, greasy skin (excessive sweating), deepening of voice

Question 30

Why would the voice deepen in a patient with GH excess?

Answer 30

Hypertrophy of soft tissues in upper airways

Question 31

What does excess GH in children result in?

Answer 31

Excess GH before fusion of epiphyseal plates in long bones : GIGANTISM

Question 32

What is acromegaly?

Answer 32

Excess GH in adults

Question 33

What complications might a patient have if they have an excess of Growth Hormone?

Answer 33

(GH antagonises actions of insulin) Diabetes mellitus +other metabolic complications

Question 34

What are the treatment options for patients with acromegaly?

Answer 34

1- Surgery to remove adenoma 2- Radiation therapy 3- Drug therapy ( e.g. dopamine receptor agonists -some efficacy) (Somatostatin analogs- suppress GH secretion) (GH receptor antagonists)

Question 35

Why does somatostatin have limited use even though it limits GH secretion?

Answer 35

Very short half-life

Question 36

What is Cushing's syndrome?

Answer 36

Excess endogenous secretion of ACTH (adrenocorticotropic hormone- regulates levels of cortisol) from anterior pituitary gland