Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MEH > 8.2 Pituitary Disorders > Flashcards

8.2 Pituitary Disorders Flashcards

1
Q

What is the best way of viewing the pituitary gland?

A

MRI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the presenting symptoms of pituitary tumours?

A

visual loss
headache (dura stretching)
abnormality in pituitary function (hyper/hypo secretion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What local structures are affected by the mass increase caused by pituitary tumours?

A 
internal carotid artery 
VI nerve (optic chasm)
optic chasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why do some patients experience visual field loss due to a pituitary tumour?

A

when there is upwards (superior growth of the pituitary tumour, there is disturbance of the optic chasm.The increased pressure on the optic chasm results in vision field loss.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is bitemporal semi-anopia?

A

tunnel vision, poor peripheral vision to the right and the left. Occurs when there is increased pressure on the optic chasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What occurs when there is sideways (lateral) growth of a pituitary tumour?

A

Pain and double vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how can pituitary tumours result in hypopituitarism?

A

swelling of the tumour may stop the hormones released from the hypothalamus descending to the pituitary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is hypopituitarism?

A

Hypopituitarism is the decreased (hypo) secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In what order do hormones become deficient in hypopituitarism?

A

GH
LH/FSH (gonadotropin)
TSH/ACTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What occurs if a patient is deficient in growth hormone?

A

Short stature in children (pituitary dwarfism)

Reduced quality of life in adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what occurs if patients are deficient in gonadotropin?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What occurs in patients with TSH and ACTH deficiency?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What hormones are commonly seen in hormone excess cause by an abnormality of pituitary function?

A

Common: Prolactin, growth hormone, adrenocorticotropin hormone

Rare : Thyroid stimulating hormone, gonadotropic hormones.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are pituitary diseases assessed?

A 
Biochemical assessment. 
Thyroid axis = fT4, TSH
Gonadal axis = LH, FSH
- oestradiol - women
- testosterone - men
Prolactin axis = serum prolactin
HPA axis = 09:00 cortisol
GH axis = GH / IGF-1
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why are cortisol levels measure at 9am?

A

Cortisol is high in the morning, low in the

night. So measured at 9:00 as that’s when it should be at its highest.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

when is a stimulation test conducted?

A

when there is suspected hormone deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when is a suppression test done?

A

when there is suspected hormone excess.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what assessments are conducted if there is a suspected deficiency of the adrenal axis?

A

Deficiency
• Direct stimulation of adrenals by ACTH (synACTHen)
• Response to hypoglycaemic stress (insulin stress test)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what assessments are conducted if there is a suspected excess of adrenal axis?

A

Suppress ACTH axis with steroids (dexamethasone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what assessments are conducted if there is a suspected growth hormone acid deficiency?

A

Response to hypoglycamic stress (insulin stress test)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what assessments are conducted if there is a suspected excess of GH axis?

A

Suppress GH axis with glucose load (glucose tolerance test)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a prolactinoma?

A

Prolactin-secreting pituitary tumour. The larger the tumour, the higher the prolactin

23
Q

what is a macro-adenoma?

A

A large tumour that is larger than 1cm

24
Q

what is a micro-adenoma?

A

A smaller tumour that is smaller than 1cm

25
Q

How are prolactinomas treated?

A

with medication, not with an operation. All pituitary macro adenomas must test prolactin levels before surgery, as cannot operate on a prolactinoma.

26
Q

What medication is used to treat macro-prolactinomas?

A

Dopamine ( prolactin inhibiting hormone PIH ) inhibits prolactin secretion and therefore tumour will shrink against dopamine agonist.
Bromocriptine and cabergoline very effective at reducing prolactin

27
Q

What is hyperprolactinaemia?

A

The presence of abnormally high levels of prolactin in the blood. Normal levels are less than 500 mIU/L [20 ng/mL or µg/L] for women, and less than 450 mIU/L for men.

28
Q

What are the symptoms of hyperprolactinaemia in women?

A

As prolactin inhibits LH there are fertility problems and menstrual disturbance.
Prolactin stimulates lactation, therefore galactorrhoea is experienced in hyperprolactinaemia.

29
Q

What are the symptoms of hyperprolactinaemias in men?

A

men present later than women as they do not menstruate.
Symptoms of low testosterone (due to inhibition of LH) are non-specific. As pituitary adenomas in men are usually large tumours (macro-adenomas), male patients may present with mass symptoms such as peripheral vision loss.

30
Q

How will prolactin secretion by the anterior pituitary gland be affected if the pituitary stalk (infundibulum) is blocked?

A

As prolactin is under tonic inhibitory control by dopamine. If the pituitary stalk is blocked, dopamine cannot descend from the hypothalamus and results in prolactin disinhibition. This can lead to hyperprolactinaemia

31
Q

How do serum prolactin levels indicate whether hyperprolactinaemia is caused by disinhibition or prolactinaemia?

A

If prolactin < 5,000miU/L the high prolactin might be due to disinhibition (‘stalk effect’) rather than active prolactin secretion
If prolactin > 5,000miU/L the high prolactin is likely to be due to active prolactin secretion (prolactinoma)

32
Q

Why is it important to test prolactin serum levels before operating on a pituitary macro adenoma?

A

This is important as prolactinomas are treated medically but non functioning
pituitary tumours are treated surgically

33
Q

What is a non-functioning pituitary adenoma?

A

A pituitary tumour that has no secretion of biologically active hormones. May secrete inactive hormones (ACTH/LH/FSH). Symptoms caused by mass effect or due to low pituitary hormones.

34
Q

Describe typical blood results of a patient with non-functioning pituitary adenoma.

A

Typical of disinhibition prolactinaemia:
Low T4 levels due to low TSH secretion.
Very high prolactin levels (1,200) due to disinhibition. This results in very low testosterone, LH and FSH levels.
09:00 Cortisol levels are also very low due to low ACTH release from the anterior pituitary gland.
GH and IGF-1 levels are low.

35
Q

Why do anti-sickness and anti-psychotic drugs often cause hyperprolactinaemia?

A

As these medications are dopamine antagonists and therefore cause prolactin to be disinhibited.

36
Q

what is acromegaly?

A

Increased GH levels win adults. May be due to GH-secreting pituitary tumour.
Sign is large hands and feet.

37
Q

What are long-term complications of untreated acromegaly?

A

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

38
Q

What biochemical tests are used to confirm acromegaly?

A

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

39
Q

How is acromegaly treated?

A
  1. Surgery
    - Usually caused by a pituitary tumour. Surgical removal of this tumour through trans-sphenoidal hypophysectomy
  2. Medication
    - Reduce GH secretion. Dopamine agonist and somatostatin analogues
    - Block GH receptor
  3. Radiotherapy
    - External beam
    - gamma knife
40
Q

What imaging techniques are used to view a pituitary tumour

A 
MRI (transverse plane)
PET scan (used radioactive drug to show activity of cells)
41
Q

What is Cushing disease?

A

ACTH-secreting pituitary tumour

42
Q

How does bushings disease change your appearance?

A
  • 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)
  • Fat pad buffalo hump
43
Q

what is Cushings syndrome?

A

A condition caused by oversecretion of glucocorticoid hormones from the adrenals, resulting in a redistribution of body fat and other effects.
Results due to adrenal tumour, ectopic ACTH, steroid medication. NOT due to pituitary tumour (Cushings disease)

44
Q

What are the symptoms of Cushings syndrome?

A

similar to Cushings disease (puffy face, fat accumulation around the torso, fat loss from legs and arms, and easy bruising)

45
Q

What is diabetes insipidus?

A

A condition resulting from decreased release of ADH from the posterior pituitary gland caused by the hypothalamus not secreting vasopressin. Results in large quantities of pale (insipid) urine and extreme thirst due to fluid loss

46
Q

What is cranial DI?

A

Cranial diabetes insipidus is a vasopressin deficiency pituitary disease

47
Q

What is nephrogenic DI?

A

Nephrogenic Diabetes Insipidus is vasopressin resistance kidney disease

48
Q

where do pituitary tumours normally affect?

A

Standard pituitary tumours just affect anterior pitutiary. Hence rarely see diabetes insipidus as posterior pituitary tumour rarely seen.

49
Q

What pathology causes cranial diabetes mellitus?

A
  • Inflammation
  • Infiltration
  • Malignancy
  • Infection
50
Q

What are the consequences of untreated diabetes insipidus?

A

Severe dehydration
Very high sodium levels ‘hypernatraemia’
Reduced consciousness, coma and death

51
Q

How is cranial diabetes insipidus treated?

A

Cranial DI responds brilliantly to synthetic vasopressin

Desmopressin nasal spray, tablets or injection

52
Q

What does apoplexy mean?

A

Stroke

53
Q

What is a pituitary apoplexy?

A

Stroke of the pituitary. Sudden vascular event in a pituitary tumour, may be infarct or haemorrhage.

54
Q

what are the clinical presentations of pituitary apoplexy?

A 
Sudden onset headache
Double vision
Cranial nerve palsy
Visual field loss
Hypopituitarism (cortisol deficiency most dangerous)

MEH (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions