pituitary Flashcards
1
Q
where is the pituitary gland found
A
pituitary fossa of the sphenoid bone / sella turcica
2
Q
what does the pituitary gland lie immediately inferior to
A
optic chiasm
3
Q
what effect does a pituitary tumour have on the visual field
A
bitemporal hemianopia
4
Q
how is the hypothalamus attached to the pituitary gland
A
pituitary stalk (infundibulum)
5
Q
what embrylogical structure is the anterior pituitary derived from
A
Rathke’s Pouch
6
Q
what are the 3 sections of the anterior pituitary
A
pars distalis
pars tuberalis
pars intermedia
7
Q
what is another name for the anterior pituitary
A
adenohypophysis
8
Q
what are the 3 cell types in the anterior pituitary
A
acidophils
basophils
chromophobes
9
Q
how is the anterior pituitary organised into cells
A
“islands, cords of cells”
10
Q
what is prolactin under tonic inhibition from
A
hypothalamic dopamine
11
Q
what do basophils produce
A
corticotrophs - ACTH
thyrotrophs - TSH
gonadotrophs - FSH/LH
12
Q
paired hormone concept refers to what
A
the pituitary released hormones (central) that are linked to peripheral hormones
13
Q
what is another name for the posterior pituitary
A
neurohypophysis
14
Q
what makes up the posterior pituitary
A
pars nervosa
15
Q
the posterior pituitary is an extension of what
A
the brain - modified glial cells and axonal processes
16
Q
what cells make up the posterior pituitary
A
non-myelinated axons of neurosecretory neurones
17
Q
what hormones does the posterior pituitary gland release
A
ADH/vasopressin
OT/oxytocin
18
Q
where are ADH and OT synthesised
A
hypothalamus
19
Q
what are the 2 routes of access to the pituitary fossa
A
transcranial (under frontal bone)
transphenoidal (via nasal cavities and sphenoid sinus)
20
Q
what structures are at risk in pituitary gland surgery
A
optic chiasm/CN II CN III, IV, V VI cavernous sinus ICA dura mater
21
Q
what would happen if the following was damaged in pituitary gland surgery:
optic chiasm
A
bitemporal hemianopia
22
Q
what would happen if the following was damaged in pituitary gland surgery:
CN III
A
problems with several eye movements
dilated pupil
23
Q
what would happen if the following was damaged in pituitary gland surgery:
CN IV
A
medial deviation of the eye
SO damage
24
Q
what would happen if the following was damaged in pituitary gland surgery:
CN V
A
sensory symptoms on face
problems chewing food
25
what would happen if the following was damaged in pituitary gland surgery:
CN VI
problems with abduction of eye
| LR damage
26
what would happen if the following was damaged in pituitary gland surgery:
cavernous sinus
venous haemorrhage
27
what would happen if the following was damaged in pituitary gland surgery:
ICA
haemorrhage
28
what would happen if the following was damaged in pituitary gland surgery:
dura mater
CSF leak
29
what are some examples of anterior pituitary hyperfunction
adenoma
| carcinoma
30
what are some examples of anterior pituitary hypofunction
```
surgery
radiation
haemorrhage
ischaemic necrosis (Sheehan syndrome)
tumours extending into sella
inflammatory (sarcoid)
```
31
what are some examples of posterior pituitary hypofunction
DI - lack of ADH secretion
32
what are some examples of posterior pituitary hyperfunction
SIADH
| ectopic secretion of ADH by tumours/paraneoplastic/primary disorder in pituitary
33
what are some examples of posterior pituitary hyperfunction
SIADH
| ectopic secretion of ADH by tumours/paraneoplastic/primary disorder in pituitary
34
do pituitary adenomas more often occur anterior or posterior
anterior
35
what % of intracranial tumours are pituitary adenomas
10% - relatively common
36
what can cause a pituitary adenoma
MEN1 or sporadic
37
what problems can a non-functional pituitary adenoma cause
hypofunction - hypoadrenalinism, hypothyroidism, hypogonadism, DI, GH deficiency
38
what local effects can a pituitary tumour cause
```
headache
bitemporal hemianopia
compression on CN II III IV V VI
atrophy of surrounding tissue
disturbance of hypothalamic centres of temperature
sleep and appetite affected
infarction --> panhypopituitarism
erosion through floor of sella --> CSF rhinorrhoea
```
39
what is the most common functional pituitary adenoma
prolactinoma
40
what is the 2nd most common functional pituitary adenoma
GH secreting
41
what would an ACTH secreting pituitary adenoma cause
cushings disease --> bilateral adrenocortical hyperplasia
| usually a microadenoma
42
are pituitary carcinomas common or rare
rare (< 1% pituitary tumours)
43
are pituitary carcinomas usually non-functional or functional
functional - prolactin or ACTH
44
do pituitary carcinomas metastasise late or early
late after many recurrences
45
do prolactinomas present earlier in males or females
females
46
what are some s/s of prolactinoma in females
```
galactorrhoea
menstrual irregularity/amenorrhoea
infertility
decreased libido
vaginal dryness
weight gain
```
47
what are some s/s of prolactinoma in males
```
impotence
visual field abnormality
headache
decreased facial hair
galactorrhoea
infertility
decreased libido
```
48
how does increased prolactin cause hypogonadism, infertility and osteoporosis
inhibits secretion of GnRH therefore decreased LH/FSH/Testosterone/oestrogen
49
what size is a microadenoma and what is a macroadenoma
microadenoma < 1cm
| macroadenoma >1cm
50
what investigations are done in suspected prolactinoma
```
(pregnancy test)
serum prolactin conc
MRI pituitary
visual fields
pituitary function tests to see other hormones affected
U+Es
```
51
what is the first line treatment in a prolactinoma
dopamine agonist
52
what are 3 examples of dopamine agonists and what has the least side effects
Bromocriptine
Quinagoldine
Cabergoline (least side effects)
53
what do dopamine agonists do in prolactinomas
restore menstrual cycle and decrease tumour size
54
what are some side effects of dopamine agonists
N+V
low mood
postural hypotension
fibrosis of heart valves
55
which of the dopamine agonists cannot be used in pregnancy
bromocriptine
56
what is the treatment in prolactinoma if the person is dopamine agonist intolerant
surgery
57
what does a GH secreting pituitary adenoma cause
acromegaly
58
are men or women more prone to getting a GH secreting pituitary adenoma
men
59
why does a GH secreting pituitary adenoma cause acromegaly
GH stimulates IGF-1 which causes growth of bone, cartilage and connective tissue
60
what are some common phrases that go with acromegaly
"rings and shoes dont fit anymore"
"wonky jaw"
"put on weight (muscle) but now look haggard"
61
what else is a cause of acromegaly
hyperplasia e.g. via ectopic GHRH form carcinoid tumour (rare)
62
what are some s/s acromegaly
```
snoring/sleep apnoea
headache
thickened soft tissues - skin, large jaw, large hands, sweaty
hypertension
wide nose
big supraorbital ridges
macroglossia
wide spaced teeth
acanthosis nigricans
amenorrhoea/reduced libido
arthralgia/back ache
DM
local pituitary effects
colon cancer/polyps
cardiac failure/early CV death
```
63
what investigations are done in suspected GH secreting pituitary adenoma
IGF-1
GTT suppression test
MRI pituitary fossa
look at old photos
64
blood glucose, Ca, phosphate in acromegaly
raised
65
what would be normal results of a GTT supression test
GH suppresses to < 0.4 ug/L after glucose
66
what would be results of a GTT suppression test that indicate acromegaly
GH unchanged/no suppression/paradoxical rise/remains > 1ug
67
what is the treatment for a GH secreting pituitary adenoma
surgery
radiotherapy if unsuitable for surgery
drugs
68
what might give false positives in a GTT
```
puberty
pregnancy
hepatic and renal disease
anorexia
DM
```
69
what is considered clinically safe levels of GH in follow up of GHSPA
GH < 0.4 (post GTT) or < 2 random
70
why should random GH measurement not be relied on
normal secretion is pulsatile
71
what effect do stress, sleep, puberty and pregnancy have on GH secretion
increase
72
what should be surveillanced after a GHSPA
cancer - colon/tubulovillous
| CV risk factors
73
as a follow up what should people with GHSPA get yearly
GH
IGF-1
+/- OGTT
visual fields
74
what is the first line drug treatment for acromegaly
somatostatin analogues
75
give 3 examples of somatostatin analogues
sandostatin LAR
lanreotide
octreotide
76
what do somatostatin analogues do
reduce GH in most patients and tumour shrinkage in 30-50% of cases in 6-12 weeks - although reexpansion once stopped
77
what drug is used to relieve headache post op within 1 hour
somatostatin analogue
78
what are some side effects of somatostatin analogues
```
local stinging
flatulence
diarrhoea
abdominal pain
gall stones
impaired glucose tolerance
```
79
what other drugs can be used in the treatment of acromegaly
dopamine agonists
| GH antagonists
80
what is an example of a dopamine agonist
cabergoline
81
when would cabergoline (dopamine agonist) be preferred
tumour that co-secretes GH and prolactin
82
what is an example of a GH antagonist
Pegvisomant
83
how is pegvisomant administered
SC
84
how does pegvisomant work
binds to GH receptor and blocks GH activity
85
does pegvisomant reduce tumour size
no - may see small increase in some
86
does pegvisomant decrease IGF-1
yes
| GH may rise
87
where are craniopharyngiomas found
between pituitary and 3rd ventricle floor
88
what are craniopharyngiomas derived from
pituitary embryonic tissue - remnants of rathke's pouch
89
what % of intracranial tumours are craniopharyngiomas
1-5%
90
are craniopharyngiomas slow or fast growing
slow
91
how might you describe a craniopharyngioma
may be solid/cystic/calcific/full of debris
92
are most craniopharyngiomas suprasellar or within sella
suprasellar
93
craniopharyngiomas have a bimodal incidence
| what are the 2 most common age ranges
5-15 years
| 50-60 years
94
what is the most common childhood intracranial tumour
craniopharyngioma
95
what is the prognosis like of a craniopharyngioma if it is < 5cm
excellent
96
what may develop following radiation treatment
SCC
97
what are some s/s of a craniopharyngioma
```
growth retardation in children - > 50% present with this
headache / visual disturbance
N+V
DI
behavioural changes
early/delayed puberty/oligo/amenorrhoea
impotence
reduced libido
reduced fertility
appetite/weight changes
sleep disturbance
```
98
does pituitary hypofunction usually affect one or multiple hormones
usually panhypopituitarism
99
what are some s/s of anterior panhypopituitarism
```
menstrual irregularites/infertility/impotence
gynaecomastia
decreased strength
abdominal obesity
loss of facial/axillary/pubic hair
dry skin and hair
erectile dysfunction
hypothyroid
growth retardation
osteoporosis
decreased libido
decreased CO and exercise ability
```
100
what is an example of posterior hypopituitarism
diabetes insipidus
101
what can cause panhypopituitarism
tumour
secondary mets (lung breast)
local brain tumour - astrocytoma, meningioma, glioma
granulomatous disease e.g. TB, sarcoidosis, histiocytosis
vascular disease (polyarteriitis)
trauma
hypothalamic disease (syphillis, meningitis)
sheehan syndrome
infection
craniopharyngioma
irradiation of pituitary
infiltration - haemochromocytosis, amyloid
kallmans
102
how do you check pituitary steroid hormone production
synacthen stimulation test - cortisol
| insulin tolerance test (cortisol and GH)
103
when would you do a prolonged glucagon test instead of an insulin tolerance test
epilepsy
heart disease
adrenal failure
104
what is a normal cortisol following insulin tolerance test
> 500
105
what is a normal GH following insulin tolerance test
> 7 ug/L
106
apart from checking pituitary hormones in panhypopituitarism what else would you want to do
MRI for hypothalamic or pituitary tumour
107
what is the treatment of panhypopituitarism
replace lost hormones
108
how would hypothyroidism as a result of panhypopituitarism be treated
thyroxine
109
how would secondary adrenal failure as a result of panhypopituitarism be treated
hydrocortisone
110
how would DI as a result of panhypopituitarism be treated
desmospray
111
how would GH be replaced
nightly SC
112
how would sex steroids be replaced
HRT/oestrogen/progesterone
| testosterone
113
how can testosterone be given
IM injections, skin gel or tablets
114
what are 3 side effects of testosterone replacement
prostate enlargement (monitor PRE and PSA)
polycynthaemia (monitor FBC)
hepatitis (only oral tablets)
115
what is the problem in diabetes insipidus
no ADH secretion to act on kidneys to cause water retention so lots of pure water is lost in urine
116
what is Na like in DI
high
117
what are some s/s of hypernatraemia
```
irritability
lethargy
cognitive dysfunction
tachycardia
abnormal skin turgor
dry axilla
```
118
what are the 2 groups of causes of DI
central and nephrogenic
119
what is a nephrogenic cause of DI
renal resistance to ADH
120
what are some central causes of DI
familial (DIDMOAD) - DI, DM, optic atropy, deaf
ADH deficiency
trauma/surgery
tumours
inflammatory disorders of pituitary/hypothalamus
sarcoidosis
meningitis
121
how is DI diagnosed
water deprivation test
122
what is another test that should be done when someone presents with the symptoms of DI
serum glucose to exclude DM
123
describe a water deprivation test
NBM for 8-12 hours
| check urine and serum osmolalities for 8 hours then 4 hours after giving IM DDAVP
124
describe the results of a water deprivation test
Ur/serum osmol ratio > 2 = normal
otherwise - DI
if it improves after DDAVP = cranial DI
125
what is the treatment of central DI
desmospray
| desmopressin (oral or IM) in emergency or post pituitary surgery
126
what are the s/s of DI
similar to DM
polyuria
polydipsia
dehydration
127
what is the treatment of nephrogenic DI
bendroflumethiazide
| NSAIDs
128
how do NSAIDs help in nephrogenic DI
lower urine vol and serum Na by inhibiting prostaglandin synthase - prostaglandins locally inhibit action of ADH
129
in hormone replacement should hydrocortisone or levothyroxine be given first
steroid first - thyroid may ppt as adrenal crisis
130
what is a pituitary apoplexy
rapid pituitary enlargement from bleed into a tumour which may cause mass effects and hypopituitarism --> CV collapse and death
