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5. Endocrinology > 11. Anterior Pituitary gland disorders > Flashcards

11. Anterior Pituitary gland disorders Flashcards

1
Q

Define hypopituitarism.

A

Disorders caused by complete / partial loss of pituitary gland hormone secretion + production

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2
Q

What is panhypopituitarism?

A

When all of the pituitary hormones are underproduced

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3
Q

Give the 7 causes of hypopituitarism.

A
  1. Tumours
    • Pituitary adenomas
    • Brain
    • Body
  2. Traumatic injury
    • Shock, stroke -> ischaemia -> infarction
    • E.g. Sheehan’s syndrome
  3. Vascular
    • Haemorrahges
    • E.g. Pituitary apoplexy
  4. Radiation
  5. Infections
    • AI e.g. autoimmune hypophystitis
    • Brain e.g. meningitis
    • Abnormal brain cells e.g. haemochromtosis
  6. Congenital (defect in transcription factors)
    • PROP1 gene mutation -> hormone deficiency
    • PIT1 gene mutation -> GH, PRL + TSH deficiencies
  7. Hypothalamic dysfunctions
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4
Q

What are the 3 types of pituitary dysfunctions?

A
  1. Tumour mass effects
  2. Hormone excess
  3. Hormone deficiency
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5
Q

What is a benign pituitary adenoma?

A

Benign tumour of the anterior pituitary cells

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6
Q

What happens in a pituitary adenoma?

A

In pituitary adenomas, 1 of the types of cells mutates and becomes neoplastic, meaning that it starts dividing uncontrollably.

Over time, it forms a tumor.

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7
Q

Give 3 potential consequences of a pituitary adenoma.

A
  1. Pressure on local structures e.g. optic chiasm.
  2. Hypo-pituitarism
  3. Functioning tumour e.g. Cushing’s, gigantism, prolactinoma.
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8
Q

Name the 2 types of pituitary adenomas.

A
  1. Non-functioning / silent
  2. Functioning
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9
Q

How can pituitary adenomas be classified according to their size?

A
  1. Microadenomas - smaller than 1cm
  2. Macroadenomas - larger than 1cm
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10
Q

Give 4 local effects/signs + symptoms of pituitary adenoma.

A
  1. Headaches - due to increased ICP
  2. Temporal visual field defects - bitemporal hemianopia.
  3. Cranial nerve palsy and temporal lobe epilepsy.
  4. CSF rhinorrhoea (drainage of CSF through the nose)
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11
Q

What is a craniopharyngioma?

A

A rare type of brain tumour (suprasellar neoplasm) derived from the cells of Rathke’s pouch, a structure that normally develops into the anterior pituitary gland during fetal development.
I.E. derived from pituitary gland embryonic tissue.

Can result from benign cysts and calcification of Rathke’s pouch.

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12
Q

Give 4 signs of Craniopharyngioma.

A
  1. Raised ICP.
  2. Vision affected.
  3. Growth failure.
  4. Puberty affected.
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13
Q

Name 3 examples of functioning pituitary adenomas.

A
  1. Prolactinoma - Prolactin
  2. Acromegaly and Gigantism - GH
  3. Cushing disease - ACTH
  4. TSHoma / thyrotropinoma - TSH
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14
Q

What is the most common type of functioning pituitary adenoma?

A

Prolactinoma

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15
Q

What is the most frequent subtype of non-functional pituitary adenoma?

A

Gonadotroph derived adenomas

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16
Q

How is a pituitary adenoma diagnosed?

A
  1. Measuring relevant pituitary hormone levels
  2. MRI
    - To image the pituitary gland to see if there’s a tumor and estimate its size.
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17
Q

Treatment of a pituitary adenoma

A

Prolactinomas:
Medication - dopamine agonist (inhibits prolactin secretion)
E.g. Bromocriptine / Cabergoline

Somatotrophic + Corticotrophic adenomas:
Transsphenoidal surgical resection
(which is when the tumor is removed through the nose and the sphenoidal sinus)

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18
Q

What is the affect of hypopituitarism on testosterone and FSH/LH levels?

A
  • Testosterone will be low.
  • FSH/LH will be low.
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19
Q

What is the affect of hypopituitarism on TSH and T4 levels?

A
  • TSH will be low.
  • T4 will be low.
20
Q

What is the affect of hypopituitarism on oestradiol and FSH/LH levels?

A
  • FSH/LH are low.
  • Oestradiol is low.
21
Q

What is the affect of hypopituitarism on cortisol and ACTH levels?

A
  • ACTH is low.
  • Cortisol is low.
22
Q

Define hyperprolactinaemia.

A

A disorder caused by high blood levels of the pituitary hormone, prolactin

23
Q

Give 7 causes of hyperprolactinaemia.

A
  1. Prolactinoma / lactotroph adenoma
  2. Pregnancy (physiologic hyperprolactinaemia)
  3. Damage to hypothalamic-pituitary stalk
  4. Disorders affecting the hypothalamus
  5. Primary hypothyroidism
  6. Medications - dopamine antagonists, oestrogens
  7. Renal failure
24
Q

Define prolactinoma.

A

A benign tumor, or adenoma, of the pituitary gland that secretes excess prolactin

25
Q

What can prolactinomas be categorised into?

A
  1. Microprolactinoma - less than 10 mm in diameter
  2. Macroprolactinoma - greater than 10 mm
26
Q

Give 3 causes of prolactinoma.

A
  1. Pituitary adenoma.
  2. Anti-dopaminergic drugs.
  3. Mutation in the lactotroph cells of the anterior pituitary that allows the cells to divide uncontrollably.
27
Q

What would happen to serum prolactin levels if something was to impact on the pituitary stalk and block dopamine release?

A

Prolactin levels would increase.

28
Q

Give 6 signs of prolactinoma.

A
  1. Infertility
    - Females: No menstrual cycles -> no ovulation -> infertile
    - Males: Impaired genital activity -> hypogonadism
  2. Golactorrhoea
    - Spontaneous secretion + flow of breast milk -> a milky nipple discharge
  3. Amenorrhoea
    - Complete lack of menstruation
  4. Loss of libido
  5. Visual field defects
    - Compress the optic nerves as they cross at the optic chiasm
  6. Headaches
    - Compress surrounding structures like the meninges
29
Q

Give 2 signs of prolactinoma in biologically-male individuals.

A
  1. Gynecomastia (breast enlargement)
  2. Erectile dysfunction
30
Q

Give 4 signs of prolactinoma in biologically-female individuals.

A
  1. Increased risk of fractures and osteoporosis
    - Due to decreased oestrogen levels -> decreased prevention of osteoclast differentiation - more bone breakdown
  2. Vaginal dryness
  3. Golactorrhoea
    - Spontaneous secretion + flow of breast milk -> a milky nipple discharge
  4. Amenorrhoea
    - Complete lack of menstruation
31
Q

Describe the investigations for suspected prolactinoma.

A
  1. Prolactin levels
  2. CT head
32
Q

Describe the treatment for prolactinoma.

A

Medication - dopamine agonist (inhibits prolactin secretion)
E.g. Bromocriptine / Cabergoline / Quinagolide

Surgery
- Only considered for individuals with macro-prolactinomas or in individuals who fail medical therapy.

Radiation therapy
- If complete resection of the prolactinoma is not possible
- If prolactin levels remain elevated after surgery

33
Q

Give 3 complications of prolactinoma.

A
  1. Infertility
  2. Sight loss
  3. Raised intracranial pressure (ICP)
34
Q

What investigation would you do on someone presenting with difficulty getting pregnant, golactorrhoea, amenorrhoea, loss of libido and headaches?

A

You would measure serum prolactin.

These are symptoms of prolactinoma.

35
Q

Define acromegaly.

A

Hypersecretion of Growth Hormone in adulthood after epiphyseal plates closea

36
Q

What can cause acromegaly?

A

A benign pituitary adenoma producing excess GH.

37
Q

Give 5 symptoms of acromegaly.

A
  1. Change in appearance (maxillofacial changes)
    - Large tongue (macroglossia)
    - Spaces between teeth (interdental separation)
    - Forehead and brow protrusion
    - Jaw protrusion (prognathism)
  2. Increase in size of hands and feet (acral enlargement)
    - Spade-like hands
    - Sweaty hands and oily skin
  3. Organomegaly
    - Heart, kidneys, vocal chords
  4. Deep voice
  5. Excessive sweating
  6. Arthralgias
    - Joint pain
  7. Headache
  8. Hypogonadal symptoms
    - Amenorrhoea, weight gain, tiredness
  9. Vision problems
    - Bitemporal hemianopia
38
Q

What 5 co-morbidities / complications are associated with acromegaly?

A
  1. Arthritis.
  2. Cerebrovascular events and headaches
  3. Hypertension and heart disease.
  4. Sleep apnea.
  5. T2 DM.
39
Q

What investigations might you do on someone who you suspect has acromegaly?

A
  1. Plasma GH levels can exclude acromegaly - not diagnostic!
  2. Serum IGF-1 levels raised (blood test)
  3. Oral glucose tolerance test - diagnostic!
  4. MRI of pituitary.
40
Q

What test is diagnostic for acromegaly?

A

Oral glucose tolerance test (OGTT)
- Failure of glucose to suppress serum GH
- 75 hm OGTT

41
Q

Criteria for acromegaly diagnosis

A

Acromegaly excluded if:
random GH <0.4 ng/ml and normal IGF-I

If either abnormal proceed to:
75 gm Glucose tolerance test (GTT)

Acromegaly excluded if:
IGF-I normal
and
GTT nadir GH <1 ng/ml

42
Q

Describe the treatment for acromegaly.

A
  1. Trans-sphenoidal surgical resection.
  2. Radiotherapy.
  3. Medical therapy: somatostatin analogues, dopamine agonists, GH antagonists
43
Q

Give 3 advantages of using dopamine agonists in the treatment of acromegaly.

A
  1. No hypopituitarism.
  2. Oral administration.
  3. Rapid onset.
44
Q

Give 2 disadvantages of using dopamine agonists in the treatment of acromegaly.

A
  1. Can be ineffective.
  2. Risk of side effects.
45
Q

Give 3 potential complications of trans-sphenoidal surgical resection for the treatment of acromegaly.

A
  1. Hypopituitarism.
  2. Diabetes insipidus.
  3. Haemorrhage.
  4. CNS injury.
  5. Meningitis.
46
Q

What are the 3 classes of drugs used as medical therapy to treat acromegaly? Give an example of each.

A
  1. Dopamine agonist - Cabergoline
    - For tumours that also release prolactin
  2. Somatostatin analogue - Octreotide
    - Stop GH production
  3. Growth Hormone receptor antagonist - pegvisomant
    - Block GH binding to receptors
47
Q

What is the difference between acromegaly and gigantism?

A

Gigantism - GH hypersecretion before epiphyseal plates close in childhood

Acromegaly - GH hypersecretion after closure of epiphyseal plates in adulthood

5. Endocrinology (20 decks)

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