CBL

Question 1

name two embryological pouches from which the pituitary develops from

Answer 1

downwards from the diencephalon and upwards from an extension of the oral cavity (Rathke’s pouch)

Question 2

Structure of the anterior pituitary

Answer 2

The anterior pituitary contains glandular cells that secrete a variety of hormones into the circulation; this is controlled by the hypothalamus

Question 3

Structure of the posterior pituitary

Answer 3

The posterior pituitary does not contain glandular cells; instead, it contains axons and terminals of neurons whose cell bodies are located in the hypothalamus

Question 4

Location of the pituitary gland

Answer 4

The pituitary gland lies at the base of the skull in a portion of the sphenoid bone within the pituitary fossa, which is bounded by the anterior clinoid process and the posterior clinoid process

Together, this forms the sella turcica (Turkish saddle)

A diaphragm of dura covers the pituitary fossa, with a hole in it to allow the pituitary stalk to pass through

Within the fossa, the pituitary is surrounded by dura, the diaphragma sella

The pituitary gland sits on the other side of the sphenoid bone of the sphenoid air sinus; this is a common surgical route for pituitary surgery (trans-sphenoidal surgery)

Question 5

Cushing’s Syndrome possible treatments?

Answer 5

• Excision of causative pituitary adenoma,
  generally by transsphenoidal surgery - 80%
  success
• radiotherapy - highly effective in pituitary
  Cushing’s, takes time to work
• Medical treatment - not highly effective,
  hazardous, adrenal enzyme inhibitors e.g.,
  ketoconazole
• adrenalectomy - avoid, Nelson’s syndrome risk

Question 6

Effect of low dose dexamethasone test on patient with Cushing’s syndrome?

Answer 6

Low dose will not suppress patients with cushing’s syndrome, but will suppress healthy subjects

Question 7

What two conditions does a high dose dexamethasone test differentiate between?

Answer 7

High dose is used to differentiate between Cushing’s disease (will be suppressed) and Ectopic ACTH production/adrenal abnormalities (will not be suppressed).

Question 8

Percentage break down of most common causes of Cushing’s syndrome?

Answer 8

 70% ACTH secreting pituitary tumor (Cushing’s disease)
 20% adrenal cause e.g adenoma or carcinoma (rarer)
 10% ectopic ACTH secretion e.g bronchial
carcinoid

Question 9

Acromegaly Treatment?

Answer 9

Primary treatment: Transsphenoidal resection of
pituitary tumour, success 80%
 Medical treatment: Octreotide - long acting
analogue of somatostatin, now available as
monthly depot injection
 Dopamine agonists - useful if cosecrete prolactin
mainly
 Radiotherapy: for failed surgery, slow effect

Question 10

What would you test if acromegaly was suspected?

Answer 10

 Best single test: IGF-1 (somatomedin C)
 Additional test: Growth hormone – glucose
suppression test
 Pituitary MRI - usually visible tumour
 rare causes: ectopic GHRH secretion, ectopic GH
secretion

Question 11

Clinical signs of acromegaly?

Answer 11

Increased ring, shoe and hat size, facial changes
enlargement of nose and jaw, prognathism, increased gap between teeth, increased tongue and soft tissues, cartilaginous overgrowth (arthritis)

Question 12

Medical conditions assosciated/caused by acromegaly?

Answer 12

hypertension, cardiomegaly, diabetes

mellitus, mass effects of tumour

Question 13

Symptoms prolactinoma in men?

Answer 13

Excess prolactin in men causes hypogonadism
reduced libido, occas impotence. Often not
diagnosed until tumour is large often with visual
change

Question 14

Symptoms prolactinoma in pre menopausal women?

Answer 14

Excess prolactin in pre-menopausal women
causes amenorrhoea, infertility and sometimes
galactorrhoea. Tend to be diagnosed early

Question 15

Symptoms prolactinoma in post menopausal women?

Answer 15

Mass effect only.