Adrenal Tutorial Flashcards
1
Q
from top to bottom list the layers of the adrenal glands
A
connective tissue cortex: zona glomerulosa zona fasciculata zonareticularis =bottom of cortex medulla
2
Q
what controls the zona glomerulosa
A
renin-angiotensin system
3
Q
what controls the zona fasciculata
A
ACTH
4
Q
what controls the zona reticularis
A
ACTH
5
Q
what controls the medulla
A
sympathetic NS control
6
Q
what is produced by the zona glomerulosa
A
mineralocorticoid (aldosterone)
7
Q
what is produced by the zona fasciculata
A
glucocorticoids- cortisol, cortisone, corticosterone
8
Q
what is produced by the zona reticularis
A
sex hormones - dehydroepiandrosterone (DHEA)
9
Q
what is produced by the medulla
A
catecholamines- adrenaline, nor-adrenaline
10
Q
what is all steroid hormone derived from
A
cholesterol
11
Q
what cells in the medulla make the catecholamines
A
chromaffin cells
12
Q
what do the chromaffin cells make the catecholamines from
A
tyrosine
13
Q
do catecholamines have a long or short half life
A
short
14
Q
what stimulates the synthesis and release of aldosterone
A
angiotensin II
15
Q
what does aldosterone do
A
increased NaCl retention and reabsorbtion within the kidney
due to osmosis water is also reabsorbed
blood volume and pressure in increased
causes loss of potassium in urine due to Na+ K +ATP ase
16
Q
how else does angiotension II cause water reabsorption
A
working with ADH
17
Q
describe the renin angiotensin cycle
A
(decreased NaCl, ECF volume, blood pressure)
increased renin + angiotensin = angiotensin 1 + ACE = angiotensin II acts on zona glomerulosa to make aldosterone
18
Q
what is conns syndrome
A
where a tumour present in the cells of the zona glomerulosa secretes excess amounts of aldosterone
19
Q
what is the biochem of conns
A
increased NaCl
increased H2O
decreased K+
20
Q
what are the symptoms of conns
A
hypertension
hypokalaemia
21
Q
does adrenal hyperplasia affect one or both adrenal glands usually
A
bilaterally
22
Q
are adrenal hyperplasia and conns primary or secondary aldosteronism
A
primary
23
Q
what are the symptoms of adrenal hyperplasia
A
sames as conns- hypertension and hypokalaemia
24
Q
how do you diagnose primary aldosteronism
A
aldosterone to renin ratio
if ratio is above 750 then carry out a saline suppression test - if aldosterone doesnt drop by 50% then primary aldosteronism
25
describe a saline suppression test
2 litres of saline is administered to patient over the course of 4 hours, if aldosterone levels fail to decrease by 50% then will confirm primary aldosteronism
26
what is the best treatment for unilateral primary aldosteronism
unilateral conns
| surgery best for decreasing blood pressure
27
what is the best treatment for bilateral primary aldosteronism
aldosterone receptor antagonist e.g. spirinolactone- reduces reabsorption of NaCl and H20
28
what are the side effects of spironolactone
nausea, rashes, gynaecomastia
| can use eplerenone instead
29
how do angiotensin II and ACTH stimulate the adrenal glands to produce hormones
cause increase growth of the cells stimulating them to produce hormones
30
what are the functions of glucocorticoids (esp cortisol)
maintain plasma glucose levels
when stressed provide fuel from carbs, fats and proteins (increases lipolysis leading to increased plasma fatty acids. increase proteolysis causing increased plasma amino acids)
increases responsiveness of adrenoreceptors to adrenaline- prevents shock
anti inflammatory and immunosuppressive role
increased hepatic gluconeogenesis and decreased glucose uptake in all tissues expect the brain (both cause increased plasma glucose)
31
what are the signs of cortisol excess
```
muscle wasting
central obesity
cardiac output and blood flow increased (hypertension)
plethoric 'moon' face (due to fat redistribution)
conjunctival oedema
cataracts
easy bruising
skin infections
poor wound healing
buffalo hump
proximal myopathy, proximal muscle wasting (increased proteolysis)
thin skin
purpura
red/ purple striae
back pain (muscle weakness and central obesity)
polydipsia and polyuria
bone pain
euphoria
severe depression
psychosis
insomnia
```
32
what effect does ecess cortisol have on the immune system
decreased macrophage and cytokine activity
33
how does cortisol excess affect bone
reduced osteoblast activity and decreased calcium absorption- bone pain, kyphosis, osteoporosis
34
how does excess cortisol effect the skin
decreased collagen formation
35
describe the regulation of cortisol
(stress illness / diurnal rhythm) hypothalamus secretes corticotrophin releasing hormone- ant pituitary - ACTH - adrenals - cortisol (neg feeback on ant pituitary and hypothalamus)
36
what are the types of cushings
ACTH dependent or independent
37
what is the most common cause of cushings
ACTH dependent due to adenoma in the pituitary gland that produces ACTH
38
what are the types of ACTH dependent cushings
adenoma in pituitary gland that produces ACTH
Ectopic cancers that secrete ACTH - lung, thymus, pancreas
39
what other symptoms might a pituitary tumour produce
headaches and visual field impairment
40
what are the types of ACTH independent cushings
adrenal adenoma (most common)
adrenal carcinoma
nodular hyperplasia
41
in ACTH independent cushings is ACTH high or low
low
42
why is there oversection of sex hormones in cushings
as the zona reticularis is also stimulated by ACTH
43
what is seen in hypersecretion of DHEA
women: acne, amenorrhea, frontal balding, facial hair growth
men: lack of libido and impotence
44
what is the definitive test for cushings
low dose dexamethasone test
45
what is dexamethasone
very potent glucocorticoid
46
what result in a LLDT would show no cushings
<50 nmol/litre
47
what result in a LLDT would show cushings
>100 nmol/litre suspicious of cushings
48
what can determine between pituitary, adrenal and ectopic cushings
high dose dexamethasone test
49
how does a HDDT distinguish in cushings
pituitary- suppressed by 50%
adrenal and ectopic -not supressed
50
what are the ACTH levels like in pituitary, adrenal and ectopic cushings
pituitary- <300
adrenal- <1
ectopic- >300
51
what does untreated cushing lead to
death due to complications from hypertension, diabetes mellitus, cardiovascular disease
52
what is the medical therapy for cushings
metyrapone- a 11beta- hydroxylase blocker that stops the synthesis of cortisol
ketoconazole works in same way and is synergistic with metyrapone
53
why do you need to reduce cortisol levels before surgery
as immune response still impaired
54
how are anterior pituitary tumour usually removed
trans-sphenoidal removal
55
what ca be done if surgery doesnt help cushings (pituitary)
radiotherapy
56
what is the surgical treatment for adrenal cushings
bilateral adrenalectomy
57
what cells make up the medulla of the adrenal glands
chromaffin cells
58
what controls the release of catecholamines from the medulla
sympathetic nervous system
59
what is the effect of adrenaline
increases rate and strength of heart, vasoconstrictor effect on peripheral vessels- increases blood pressure
vasodilation of the skeletal muscle- delivers more oxygen and glucose
60
adrenaline acts on B1 receptors on the .... to have the effect of...
heart
increased force and rate
61
adrenaline acts on alpha 1 receptors on .... to have the effect of...
blood vessels
vasoconstriction
62
adrenaline acts on B2 receptors on .... to have the effect of...
skeletal muscle
vasodilation
63
adrenaline acts on alpha 2 receptors on the .... to have the effect of...
islet beta cells
decreased insulin secretion
64
how does adrenaline affect metabolism and via what receptors
alpha and beta 1
increases gluconeogenesis and glycogenolysis
65
what are the symptoms of hypersecretion of adrenaline
classic triad: HPX, sweating, headaches
```
arrhythmias
tachycardia/ bradycardia
pallor
excessive flushing
postural hypertension
anxiety
polydipsia
polyuria
constipation
paralytic ileus of the bowel
```
66
what is a phaeochromocytoma
rare catecholamine secreting tumour that arises from sympathetic paraganglia cells
67
what are paraganglia cells
collections of adrenaline secreting chromaffin cells
68
where are phaeochromocytoma found
medulla of adrenals or sympathic chain
69
what are paragangliomas
phaeochromocytomas found at the oartic bifurcation
70
what is the 10% tumour
```
10% extra adrenal
10% malignant
10% bilateral
10% in children
10% hereditary syndrome
```
71
what hereditary conditions are associated with phaeochromocytoma
MEN 2 (usually bilateral in this condition)
72
what tumours do you get in MEN 2
thyroid, parathyroid, neuro endocrine (phaeochromocytoma)
73
what can be used diagnose phaeochromocytoma
24hr urinary catecholamines and metabolites
CT/MRI
131 iodine MIBG (labelled with beta and gamma particles)
74
what is the treatment for phaeochromocytoma
complete alpha and beta blockade (atenolol, phenoxybenzamine) before surgery to prevent arrhythmias and CV complications
if malignant then chemo + 131 iodine MIBG
75
what can cause adrenal hypofunction
primary- addisons disease (automimme attack on adrenal glands)
secondary- pituitary problem, lack of ACTH
iatrogenic- steroids might cause adrenal glands to atrophy
76
how does an addisonian crisis present
high potassium, low sodium, dehydration, low glucose, abdo pain. weakness, vomiting
77
what is the treatment for an addisonian crisis
immediate
glucose
IV fluids
steroid replacement
78
what can help distinguish primary and secondary addisons
increased skin pigmentation- caused by ACTH being converted to melatonin, cant be a secondary (pituitary) cause
79
in addisons what causes the low sodium and high potassium
lack of aldosterone
80
in addisons what causes the low glucose
lack of glucocorticoids
81
what antibodies in addisons disease
anti-adrenal antibodies
82
what can determine whether the adrenal glands are working or not
synACTHen test- measure cortisol produced by adrenals in response to synthetic ACTH, should be more than 500 at 30 mins
83
what is congenital adrenal hyperplasia
where adrenal glands lack the enzymes needed for making steroids
- can present as acute salt loss crisis or ambiguous genitalia in early childhood, or in hirsutism in late childhood/adulthood
- treatment is steroids
84
what is the hormone replacement given for adrenal insufficiency
hydrocortisone - replaces glucocorticoids
| fludrocortisone- given to replace aldosterone (no required in all cases)
85
what are the sick day rules for adrenal insufficiency and patient education points
if have period of illness then always double your dosage
dont suddenyl stop as this causes adrenal crisis even when well
carry identification that you are on steroids
86
what would postural hypotension raise concerns of
adrenal insufficiency
