Pathology of the Pituitary Gland Flashcards

1
Q

What are the size classifications of pituitary tumours?

A

less/equal 1cm = microadenoma

>1cm = macroadenoma

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2
Q

What 2 structures can a non-functioning pituitary adenoma or a pituitary tumour compress?

A

Optic chiasma

Cranial Nerves 3,4,6

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3
Q

What cells are a pituitary adenoma derived form?

A

Cells from anterior pituitary

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4
Q

How are pituitary adenomas classified?

A

Cell type or hormone produced

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5
Q

What is the most common functional pituitary adenoma?

A

Prolactinoma

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6
Q

What are the other kinds of functional pituitary adenomas and what are their effects?

A

Growth hormone secreting adenoma - GH causes increase in IGF which stimulates growth of bone, cartilage and connective tissue giving gigantism or acromegaly

ACTH secreting adenoma - Leads to hypercortisolism, Cushing’s disease

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7
Q

What % of pituitary tumours are pituitary carcinoma?

A

<1%

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8
Q

List some causes of panhypopituitarism.

A
1y or metastatic tumours 
traumatic brain injury 
subarachnoid haemorrhage 
surgery or radiation 
granulomatous inflammation 
infarction/ haemorrhage (Sheehans syndrome)
Hypothalamic lesions
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9
Q

Define panhypopituitarism.

A

Decreased secretion of all of the pituitary hormones.

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10
Q

What is a carinopharyngioma derived from?

A

Remants of Rathke’s pouch (makes anterior pituitary)

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11
Q

List 5 things about carinopharyngiomas.

A
Slow growing, often cystic, may calcify 
Some arise within the sella but most suprasellar 
Bimodal incidence (5-15, 60-70s)
Headaches and visual disturbances 
Excellent prognosis - benign tumour
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12
Q

What are the 2 kinds of diabetes insipidus?

A

Central or nephrogenic

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13
Q

What is central diabetes insipidus?

A

ADH deficiency

Can be caused by trauma (including surgery), tumours and inflammatory disorders of hypothalamus and pituitary

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14
Q

What is nephrogenic diabetes insipidus?

A

Renal resistance to ADH effects

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15
Q

What does SIADH secretion mean?

A

Syndrome of Inappropriate ADH secretion

Ectopic production of ADH - paraneoplastic syndrome

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16
Q

With Acromagaly, which cancer are you at increased risk of?

A

Colon cancer

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17
Q

How do non-functioning pituitary adenomas arise?

A

Sporadic or associated with MEN1

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18
Q

Give some causes of prolactinoma.

A

Physiological: pregnancy, breast feeding, stress, sleep
Drugs (dopamin antagonists, anti-psychotics, antidepressants, oestrogen, coccaine)
hypothyroidism (2y prolactinoma)
Pituitary stalk lesion

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19
Q

How does a prolactinoma arise in a female?

A
Early presentation 
Galatorrhoea 
Menstrual irregularity 
Ammenorrhoea
Infertility
20
Q

How does a prolactinoma present in a male?

A
Late presentation 
Galactorrhoea 
visualy field abnormality 
headache 
impotence or ED 
Ant Pit malfunction
21
Q

What investigations are required for a suspected prolactinoma?

A

Serum prolactin
MRI
Visual field (bitemporal hemianopia)
Pituitary function tests (several hormones)

22
Q

How is a prolactinoma treated?

A

Dopamine agonists - Cabergoline, Metaclopramide - prolactin normaisation and tumour shrinkage

23
Q

What treatment is required for acromegaly?

A
Pituitary surgery 
Retest GTT – if still>1mcg then needs drugs:
Somatostain analogues: Octreotide 
Dopamine agonists: Cabergoline 
GH antagonist: Pegvisomant
24
Q

How does acromegaly present?

A

Thickened skin and enlarged jaw and facial aspects
Sweating
Sleep apnoea/ snoring
Visual disturbance
Headaches – increased blood flow and tumour expansion

25
What causes acromegaly?
Anterior pituitary gland produces excess growth hormone
26
What is the definitive test for acromegaly?
glucose tolerance test: suppression test of GH – paradoxical rise in GH occurs: normal GH suppresses to 1mcg/l
27
What blood test can be useful in the aiding the diagnosis of acromegaly?
IGF1
28
What can panhypopituitarism lead to?
``` GH -- growth failure TSH -- hypothyroidism LH/FSH -- hypogonadism ACTH -- Hypoadrenal (ife-threatening) ADH -- Diabetes Insipidus ```
29
Give some symptoms and signs of panhypopituitarism.
``` Menstraul irregularities Infertility/ impotence Gynaecomastia (M) Loss of facial hair (M) Loss of axillary and pubic hair hypothyroid faces abdo obesity dry skin and hair growth retardation (children) ```
30
What drugs can be given for panhypopituitarism?
``` Thyroxine Hydorcortisone ADH GH (rarely given) OCP Testosterone for males (Sustanon, testogel) ```
31
What are the risks of testosterone replacement?
Prostate enlargment (not cancer) Polycythemia Hepatitis (oral tabs only)
32
What can cause diabetes insipidus?
Familial – isolated or DIDMOAD Acquired (idiopathic, RTA, surgery, skull #) Rare (tumour, Sarcoid, meningitis, ext radiation)
33
What are the symptoms of DI?
Polyuria Polydipsia Signs of dehydration (sometimes) Blurred vision (rarely)
34
What are the symptoms of Cushing's disease?
``` Weight gain (central) HTN Alopecia Easily bruised Back pain Conjunctival oedema (chemosis) proximal myopathy thin skin striae facial plethora acne amenorrhoea altered psyche ```
35
What causes primary Cushing's disease?
Adrenal adenoma Pituitary adenoma Ectopic ACTH (usually carcinoma - lung)
36
Name 3 causes of secondary Cushing's disease?
Steroid meds Alcohol – pseudocushing’s Depression
37
What screening tests are used for Cushing's disease?
Dexamethasone 1mg overnight 24hr urinary free cortisol Morning & midnight cortisol
38
What test is used to provide a definitve diagnosis of Cushing's disease?
Low dose dexamethasone
39
When Cushing's disease is caused by a pituitary adenoma, is it likely to be a micro or macro adenoma?
microadenoma
40
When Acromegaly is caused by a pituitary adenoma, is it likely to be a micro or macro adenoma?
Macroadenoma
41
A pituitary adenoma = 1cm is known as what?
Mesoadenoma
42
What test is used to differentiate between the causes of Cushing's disease?
Short synacthen test
43
What are the 4 endocrine causes of HTN?
Phaechromocytoma Cushing's Conn's syndrome Acromegaly
44
Chronic suppression of pituitary ACTH production and adrenal atrophy leads to what?
unable to respond to stress (illness/surgery) need extra steroid when ill CANNOT stop steroid suddenly - gradual
45
What treatment can be used for the different types of Cushing's disease?
Pituitary: hypophysectomy and external radiotherapy if recurrence Adrenal: adrenalectomy Ectopic: remove source or bilateral adrenalectomy Metyrapone – if other Tx fails or while waiting for radio to work