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Endocrinology > Pituitary Tumours > Flashcards

Pituitary Tumours Flashcards

1
Q

Samatotroph tumours?

A

Acromegaly

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2
Q

Lactotroph tumours?

A

Prolactinoma

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3
Q

Thyrotroph tumours ( v rare )

A

TSHoma

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4
Q

Gonadotroph tumours? ( v rare )

A

GONADOTROPHINOMA -

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5
Q

Corticotroph tumours?

A

Cushings disease / corticotroph adenoma

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6
Q

How can we classify pituitary tumours with size?

A

Check with radiological MRI

  • Microadenoma (<1cm)
  • Macroadenoma (>1cm)

Can be sellar or suprasella

Can be compressing cavernous sinus or not

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7
Q

How can we classify pituitary tumours with function?

A

Excess secretion of a specific pituitary hormone
eg prolactinoma

No excess secretion of pituitary hormone (Non Functioning Adenoma)

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8
Q

Are there many malignant pituitary tumours?

A

Pituitary carcinoma is very rare

Pituitary adenomas can have a benign history but displayer malignant behaviour

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9
Q

What does hyperprolactinaemia do to kisspeptin nuerones?

A

Inhibits –> decrease downstream GnRH/LH/FSH/T/Oest

–> Oligo-amenorrhoea/Low libido/Infertility/Osteoporosis

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10
Q

Serum prolactin is x to tumour size?

A

Proportional

  • commonest functioning type pit adenoma. Usually serum prolcactin is >5000 mU/L
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11
Q

What is the presentation of prolactinoma?

A
  • Menstrual disturbance
  • Erectile dysfunction
  • Reduced libido
  • Galactorrhoea
  • Subfertility
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12
Q

What causes an elevated prolactin physiology?

A

During pregnancy/breastfeeding
Stress: exercise, seizure, venepuncture * pain of needle
Nipple/chest wall stimulation

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13
Q

What are the pathological causes of an elevated prolactin?

A
  • Primary hypothyroidism
  • Polycystic ovarian syndrome
  • Chronic renal failure
  • PRL can also be up in non functioning pit adenomas e.g. hypopituitary, can be up in acromegaly
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14
Q

What Iatrogenic causes are there for an elevated prolactin?

A
  • Antipsychotics
  • Selective serotonin re-uptake inhibitors
  • Anti-emetics
  • High dose oestrogen
  • Opiates
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15
Q

How does macroprolactin raise serum levels?

in this case reassure patients as there will be no clinical symptoms

A

Monomeric prolactin is an active molecule however it is sticky

An antigen antibody complex of monomeric prolactin and igG can form
This reduces its bioactivity
needs alternative method to confirm
Limited bioavailability and bioactivity

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16
Q

How to reduce the effect of venepuncture stress when testing serum prolactin?

A

Exclude by a cannulated prolactin series
Sequential serum [prolactin] measurement 20 mins apart with an indwelling cannula to minimise venepuncture stress

  • if prolactin is fine with each blood test following then it is not elevated
17
Q

How to treat prolactinoma?

A

first line treatment medical:

  • dopamine receptor agonist mainstay of treatment:
  • Cabergoline
  • Safe in pregnancy

Microprolactinomas will need smaller doses than macroprolactinomas

18
Q

How do dopamine receptor agonists reduce prolactin and shrink prolactinomas?

A

Dopamine released from HYPOTHALMIC DOPAMINERGIC NEURONES bind to D2 receptors on a lactotroph and acts as a agonist so prolactin cannot be released

19
Q

What are the symptoms of acromegaly?

A 
Sweatiness
Headache
Coarsening of facial features
Macroglossia
Prominent nose
Large jaw - prognathism
Increased hand and feet size
Snoring & obstructive sleep apnoea
Hypertension
Impaired glucose tolerance/diabetes mellitus
20
Q

How do diagnose acromegaly?

A

Elevated serum IGF-1
- Failed suppression of GH following oral glucose tolerance test
Prolactin can be raised ( co secretion of GH and prolactin )
One confirmed GH excess, pituitary MRI to visualise tumour

21
Q

What are the risks if acromegaly is not treated?;

A

Increased cardiovascular risk in untreated acromegaly

22
Q

What is the treatment of acromrglay?

A
  • First-line treatment is surgical – trans-sphenoidal pituitary surgery
  • Aim to normalise serum GH and IGF-1
    Can use medical treatment prior to surgery to shrink tumour or if surgical resection incomplete
  • Somatostatin analogues eg octreotide – ‘endocrine cyanide’
  • Dopamine agonists eg cabergoline (GH secreting pituitary tumours frequently express D2 receptors)
    Radiotherapy (slow)
23
Q

What is pituitary dependent Cushings disease/

A

Primary adenoma causing an excess of ACTH and hence more cortisol

24
Q

How to investigate cushings disease?

A

Elevation of 24h urine free cortisol - increased cortisol secretion

Elevation of late night cortisol – salivary or blood test – to check for loss of diurnal rhythm

Failure to suppress cortisol after oral dexamethasone (exogenous glucocorticoid) – increased cortisol secretion

25
Q

WHat are npn-functioning pituitary adenomas?

A

Can present with hypopituitarism
Serum prolactin can be raised

often present with visual dsiturbances
Trans-sphenoidal surgery needed for larger tumours, particularly if visual disturbance

Endocrinology (22 decks)

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