Pituitary tumours Flashcards

1
Q

Which endocrine cells secrete growth hormone?

A

Somatrophs

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2
Q

Lactotrophs release which hormone?

A

Prolactin

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3
Q

Which endocrine cells secrete thyroid stimulating hormone?

A

Thyrotrophs

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4
Q

Which hormones are secreted by the gonadotrophs?

A
Luteinising hormone (LH)
Follicle stimulating hormone (FSH)
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5
Q

Which cells secrete ACTH?

A

Corticotrophs

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6
Q

Acromegaly is related to which endocrine cell?

A

Somatotrophs

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7
Q

A tumour of the lactotrophs is referred to as?

A

Prolactinoma

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8
Q

A TSHoma is of what cell?

A

Thyrotrophs

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9
Q

What is a gonadotrophinoma?

A

Tumour of gonadotrophs

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10
Q

Which endocrine cells can be associated with Cushing’s disease?

A

Corticotroph adenoma

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11
Q

What is the classification of a microadenoma?

A

<1Omm (1cm)

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12
Q

What is the classification of a macroadenoma?

A

> 1cm (10mm)

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13
Q

What are the two types of a pituitary tumour in terms of function?

A

Excess secretion of a specific pituitary hormone

No excess secretion of pituitary hormone (non-functioning adenoma)

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14
Q

How is the mitotic index of a pituitary adenoma measured?

A

ki67 index benign is <3%

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15
Q

What mitotic index classifies a pituitary adenoma as benign?

A

<3%

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16
Q

Which hormone inhibits the pulsatile action of kisspeptin neurones?

A

Prolactin

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17
Q

What parameter of serum prolactin is associated with a prolactinoma?

A

> 5000mu/L

serum prolactin is proportional to tumour size

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18
Q

What are the clinical presentations of a prolactinoma?

A
menstrual disturbance
erectile dysfunction
Reduced libido
Galactorrhoea
Subfertility
19
Q

What are the physiological causes of an elevated prolactin?

A

Pregnancy/breast feeding
Stress; exercise, seizure, venepuncture (stress induced can lead to an increase in prolactin levels)
Nipple/chest wall stimulation

20
Q

What are the pathological causes of elevated prolactin?

A
Primary hypothyroidism (Due to increased TRH release)
Polycystic ovarian syndrome 
Chronic renal failure
21
Q

What are the latrogenic causes of elevated serum prolactin?

A
Antipsychotics
Selective serotonin re-uptake inhibitors
Anti-emetics
High dose oestrogen 
opiates
22
Q

What is macroprolactin?

A

A polymeric form of prolactin

An antigen-antibody complex of monomeric prolactin and IgG (normally <5% of circulating prolactin)

23
Q

How is the majority of prolactin transported within the serum?

A

Monomeric prolactin that is biologically active

24
Q

What are the two possible outcomes of an elevation of serum prolactin yet there are no clinical consistent features?

A

Macroprolactin

Stress of venipuncture

25
Q

How can a stress of venepuncture be excluded from true elevation in serum prolactin?

A

Exclude by a cannulated prolactin series

Sequential serum prolactin measurement 20 minutes apart with an indwelling cannula to minimise venepuncture stress.

26
Q

How is a true pathological elevation of serum prolactin diagnosed?

A

Conduct pituitary MRI

27
Q

What is the first line of treatment in regards to prolactinomas?

A

Dopamine receptor agonists (cabergoline or bromocriptine)

28
Q

What is the aim with using cabergoline?

A

Normalise serum prolactin and shrink prolactinoma

29
Q

How do dopamine receptor agonists work?

A

Bind to D2 receptors on lacotrophs therefore exerting an inhibitory effect on prolactin release

30
Q

What are the symptoms associated with 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
31
Q

Which factor is released from the liver upon stimulation of growth hormone?

A

IGF-1

and IGF-2

32
Q

How can acromegaly be diagnosed?

A

Elevated serum IGF-1

Failed suppression of GH following oral glucose load (OGTT) - paraxodical rise

33
Q

What is the main risk that is increased in patients with acromegaly?

A

Increased cardiovascular risk

34
Q

What is the first line of treatment in patients with acromegaly?

A

Trans-sphenoidal pituitary surgery

35
Q

What pharmacological treatments can be prescribed for acromegaly?

A

Somatosatin analogues (octreotide)

Dopamine agonists (cabergoline) -GH secreting pituitary tumours frequently express D2 receptors.

36
Q

What are the clinical features Cushing’s syndrome?

A
Mental changes (depression) 
Osteoporosis
Impaired glucose tolerance (diabetes)
High blood pressure
Proximal myopathy 
Red cheeks
Fat pads
Thin skin 
Easy bruising
Moon face
Purple striae
Pendulous abdomen
Poor wound healing
37
Q

What is the most common cause of Cushing’s syndrome?

A

Oral corticosteroids

38
Q

What are the four causes of Cushing’s disease?

A

Oral consumption of corticosteroids
Pituitary dependent Cushing’s disease (pituitary adenoma)
Ectopic ACTH (lung cancer)
Adrenal adenoma or carcinoma

39
Q

What are ACTH dependent forms of Cushing’s disease?

A
Corticotroph adenoma 
Ectopic ACTH (lung cancer)
40
Q

What are the ACTH independent causes of Cushing’s syndrome?

A

Oral corticosteroids

Adrenal adenoma or carcinoma

41
Q

What is Cushing’s syndrome?

A

An excess cortisol

42
Q

What is Cushing’s disease?

A

Due to corticotroph adenoma secreting ACTH

43
Q

How is Cushing’s disease investigated?

A

Elevation of 24h urine free cortisol - increased cortisol secretion

Elevation of late light cortisol - salivary or blood test - loss of diurnal rhythm

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

44
Q

What are the clinical features often presented alongside a non-functioning pituitary adenoma?

A

Bitemporal hemianopia