Basic Principles Flashcards
1
Q
what is ACTH?
A
adrenocorticotrophic hormone
2
Q
what gland produces adrenocorticotrophic hormone (ACTH)?
A
anterior pituitary
3
Q
what is the function of adrenocorticotrophic hormone (ACTH)?
A
stimulates the adrenal cortex to synthesise and release cortisol
4
Q
what does anti-diuretic hormone (ADH) do to the concentration of urine?
A
increases the concentration
5
Q
what type of target cells are involved in endocrine signalling?
A
distant target cell
6
Q
what type of target cells are involved in autocrine signalling?
A
acting on itself
7
Q
what type of target cells are involved in paracrine signalling?
A
surrounding (local) cells
8
Q
what are the 3 main classes of hormones?
A
- (glyco)proteins and peptides
- steroids
- tyrosine and tryptophan derivatives
9
Q
what molecule are steroids derived from?
A
cholesterol
10
Q
what type of hormone is oxytocin?
A
protein/peptide
11
Q
what type of hormone is cortisol?
A
steroid
12
Q
what type of hormone is aldosterone?
A
steroid
13
Q
what type of hormone is adrenaline or epinephrine?
A
tyrosine/tryptophan derivatives
14
Q
what type of hormones are the thyroid hormones?
A
tyrosine derivatives
15
Q
what type of hormone is insulin?
A
protein/peptide
16
Q
what type of hormone is testosterone?
A
steroid
17
Q
are amines pre-synthesised and stored or synthesised on demand?
A
pre-synthesised and stored
18
Q
where are amines stored?
A
intracellular vesicles
19
Q
what is the exocytosis of vesicles concentrated with amine hormones dependent on?
A
Ca2+ influx caused by a stimuli
calcium dependent exocytosis
20
Q
are peptide/protein hormones pre-synthesised and stored or synthesised on demand?
A
pre-synthesised and stored
21
Q
where are proteinpeptide hormones stored?
A
intracellular vesicles
22
Q
what is the exocytosis of vesicles concentrated with protein/peptide hormones dependent on?
A
Ca2+ influx caused by a stimuli
calcium dependent exocytosis
23
Q
are peptide hormones hydrophilic or hydrophobic?
A
hydrophilic
24
Q
are amine hormones hydrophilic or hydrophobic?
A
hydrophilic
25
how are amine hormones transported in the plasma?
free
26
how are protein/peptide hormones transported in the plasma?
free
27
in the first stage of production of a steroid hormone, what is cholesterol converted into?
pregnenolone
28
what is the rate limiting step in the production of a steroid hormone from cholesterol?
conversion of cholesterol to pregnenolone
29
where does the conversion of cholesterol to pregnenolone occur?
mitochondrial membrane
30
where are steroid hormones stored?
they aren't stored within the cell, as soon as they are made they are released directly into the blood stream
31
why is there a slow time frame of steroid hormone action?
because it depends on synthesis and release of a new hormone and not just release of a pre-existing hormone
32
how are steroid hormones transported in the plasma?
bound to a carrier protein
33
what are the 2 functions of a carrier protein in the transportation of hormone?
1. increase amount transported in blood
| 2. prevent rapid excretion by preventing filtration at the kidney
34
what amine hormones needs to be transported in the bloodstream bound to a carrier protein because it is relatively insoluble in plasma?
thyroid hormones
35
what is the important carrier protein specific to cortisol?
cortisol-binding globulin
36
apart from cortisol, what hormone does cortisol-binding globulin also transport?
some aldosterone
37
what is the important carrier protein specific to thyroxine (T4)?
thyroxine-binding globuline
38
apart from thyroxine, what hormone does thyroxine-binding globulin also transport?
some triiodothyronine (T3)
39
what is the important carrier protein specific to testosterone and estradiol?
sex steroid-binding globulin
40
when are the levels of cortisol in the body highest and when are they lowest?
highest- 9/10am
lowest- 12am
(diurnal rhythm)
41
when are the levels of testosterone in the body highest?
first thing in the morning
42
what are the 3 main types of hormone receptor?
1. g-protein coupled
2. receptor kinases
3. nuclear receptors
43
what type of hormones activate g-protein coupled receptors?
amines and some proteins/peptides
44
what type of hormones activate receptor kinases?
proteins/peptides
45
what are the 3 subclasses of nuclear receptors?
```
class 1
class 2
hybrid class
```
46
what is the difference between class 1 and class 2 nuclear receptor?
```
class 1- in the absence of hormone, located within the cytoplasm, move to nucleus once activated by hormone
class 2- always present in the nucleus, hormone has to diffuse into nucleus to have it's effect
```
47
what are class 1 nuclear receptors bound to when in the cytoplasm?
inhibitory heat shock proteins
48
what type of hormones activate class 1 nuclear receptors?
mainly steroids
49
what type of substance activate class 2 nuclear receptors?
lipids
50
what type of receptor does insulin signal via?
tyrosine kinase receptor
51
once the receptor steroid complex (class 1 nuclear receptor) moves to the nucleus, it forms a dimer. what does this dimer bind to within the DNA?
hormone response elements
52
what endogenous substance might make urine red or red/brown?
haemoglobin
| myoglobin
53
what endogenous substance might make urine smokey red?
intact RBC
54
what endogenous substance might make urine yellow and frothy when shaken?
bilirubin
55
what inborn error of metabolism makes urine brown-black on standing?
alkaptonuria
| due to homogentisic acid
56
what does leucocyte presence in urine indicate?
UTI
57
what does urobilinogen presence in urine indicate?
a normal finding
| increased urobilinogen might indicate liver abnormalities or excessive destruction of RBCs (eg haemolytic anaemia)
58
what is the normal pH of urine?
5-6
| 5.5 average
59
when are pH values for urine at their lowest?
after overnight fast
60
when are pH values of urine at their highest?
after meals
61
what may a strongly acidic urine pH indicate?
uncontrolled diabetes
starvation
dehydration
62
what may an alkaline urine pH of >8 indicate?
stale sample
| UTI
63
what does specific gravity of urine assess?
the concentration and diluting power of the kidneys
64
what does the presence of bilirubin in urine indicate?
hepatic or biliary disease
65
what does the presence of nitrites in urine suggest?
UTI
66
what type of bacteria causing UTIs cause the presence of nitrites in urine and why?
gram negatives
| convert dietary nitrates into nitries
67
what main 5 diagnoses does the persistent presence of protein in urine suggest?
```
renal disease
UTI
hypertension
pre-eclampsia
congestive heart failure
```
68
what does the presence of blood in urine suggest?
serious renal or urological disease
| UTI
69
what does the presence of ketones in urine suggest?
starvation
| uncontrolled diabetes
70
what are the 5 main causes of glucose in urine?
```
uncontrolled diabetes
stress
cushings syndrome
post-general anaesthetic
acute pancreatitis
```
(because of either increased blood glucose levels or reduced renal glucose absorption)
71
if not tested within one hour of collection, where should urine be stored?
refrigerator
72
where should the urine reagent strips be stored?
a cool, dry place
| do not put in refrigerator
73
are acinar cells the exocrine or endocrine part of the pancreas?
exocrine
74
what cells secrete insulin?
pancreatic beta cells
| found in pancreatic islets
75
what cells secrete glucagon?
pancreatic alpha cells
| found in pancreatic islets
76
compare glucagon and insulin in terms of effect on hepatic glucose output? (gluconeogenesis)
insulin decreases gluconeogenesis
glucagon increases gluconeogenesis
77
what secretes somatostatin?
pancreatic delta cells
| found in pancreatic islets
78
what organelle synthesise preproinsulin? (the larger single chain preprohormone of insulin)
rough endoplasmic reticulum
79
what type of insulin was used before human insulin?
bovine insuline
80
what transporter does glucose enter pancreatic B cells via?
GLUT 2
81
once inside a pancreatic B cell, what enzyme phosphorylates the glucose?
glucokinase
82
once inside a pancreatic B cell, what does glucokinase convert glucose into?
glucose-6-phosphate
83
what happens to the pancreatic beta cell intracellular ATP concetration as the metabolism of glucose increases?
ATP concentration increases
84
how many molecules of ATP are produced after oxidative phosphorylation of one glucose molecule?
36
85
what does ATP within the pancreatic beta cell do to the ATP-sensitive K+ channels? and what does this cause?
ATP inhibits the ATP-sensitive K+ channels
prevents K+ efflux
therefore cause depolarisation of the beta cell membrane
86
inhibition of K+ efflux within the pancreatic beta cell cause depolarisation of the beta cell membrane, what does this result in?
opening of voltage-gated Ca2+ channels
87
what does an increase of intracellular calcium within the pancreatic beta cell cause?
fusion of the secretory vesicles with the cell membrane (exocytosis)
--> release of insulin into the bloodstream
88
how many stages of insulin release are there after glucose is administered orally?
2 stages
| biphasic
89
compare the 2 stages of insulin release?
1st stage: insulin granules immediately available for release from readily releasable pool
2nd stage: reserve pool must undergo preparation reactions to become mobilised and then release
90
what is the target for sulphonylurea drugs? (in diabetes)
| and how does it work?
the sulphonylurea subunit of the ATP-sensitive K channel
| inhibits the ATP-sensitive K channel to cause depolarisation
91
how many proteins make up the ATP-sensitive K channel?
2
92
what cells must be functioning in order for sulphonylureas to be useful in the treatment of diabetes?
pancreatic B cells
| working beta cells, but defective ATP-sensitive K channels
93
what is the function of diazoxide on ATP-sensitive K channels within pancreatic B cells?
stimulates the ATP-sensitive K channels causing repolarisation and inhibits insulin secretion
94
what is MODY?
maturity-onset diabetes of the young
| familial form of early-onset type 2 diabetes
95
what enzyme do mutations causing MODY affect?
glucokinase
96
what do MODY mutations do to the blood glucose threshold for insulin secretion?
increase the blood glucose threshold for insulin secretion
| glucose sensing defect
97
why can MODYs be treated with sulphonylurea?
because they have working beta cells
98
what is the primary problem in type 2 diabetes?
reduced insulin sensitivity in tissues
99
what are the 3 amino acids that can be phosphorylated and why?
serine
threonine
tyrosine
because they have an OH group
100
what charge is introduce into the protein structure when serine, threonine or tyrosine are phosphorylated?
a large negative charge
101
what are the subunits of an insulin receptor?
2 extracellular alpha subunits
| 2 transmembrane beta subunits
102
what are the insulin-binding domains on the insulin receptor?
the 2 extracellular alpha subunits
103
what are the subunits of the insulin receptor linked by?
disulfide bonds
104
what does binding of insulin to the alpha subunits cause?
autophosphorylation of the beta subunits thus activating the catalytic activity of the receptor
105
glucose enters cells via what transporter?
GLUT 4
106
in which type of diabetes can ketoacidosis occur?
type 1 diabetes
107
where are ketone bodies formed?
liver mitochondria
108
what type of oxidation converts acetyl Co-A into ketone bodies?
beta-oxidation
109
when is acetyl coA converted to ketone bodies?
when there is no oxaolacetate to allow acetyl CoA to enter the TCA
110
why might oxaloacetate be unavailable for the TCA cycle?
during times of starving oxaloacetate is used for gluconeogenesis and is not generated through glycolysis
111
what is broken down into acetyl CoA?
fatty acids
112
why does ketoacidosis occur in type 1 diabetes?
when insulin isn't injected, cells fail to receive enough glucose and therefore switch to fat breakdown.
fatty acids are broken down into acetyl CoA which can't go through the TCA cycle so form ketone bodies
--> ketoacidosis
113
why is there no ketoacidosis normally in type 2 diabetes?
the high concentrations of insulin in inhibit lipase (the enzyme which breaks down triglycerides into glycerol and free fatty acids)
--> no excessive breakdown of fat resources
114
what does insulin do to the activity of hexokinase?
increases the activity of hexokinase
115
what does glucagon do to the activity of phosphofructokinase?
decreases the activity of phosphofructokinase
116
what are the 3 ketone bodies?
acetone
acetoacetic acid
beta-hydroxybutyric acid
117
compare the half lives of steroid hormones to tyrosine derivative hormones?
steroid hormones have a longer half life
118
how many transmembrane domains are there in a G-protein coupled receptor?
7 transmembrane domains
119
what are the 5 hormones secreted from the anterior pituitary?
- growth hormone (GH)
- luteninsing hormone/follicle stimulating hormone (LH/FSH)
- adrenocorticotrophic hormone (ACTH)
- thyroid stimulating hormone (TSH)
- prolactin (PRL)
120
what are the 2 hormones secreted from the posterior pituitary gland?
- ADH
| - oxytocin
121
what does normal TSH usually indicate about thyroid function?
normal thyroid function
122
what does raised TSH usually indicate about thyroid function?
hypothyroid
123
what does low TSH usually indicate about thyroid function?
hyperthyroid
124
when might TSH not be a reliable marker of thyroid status?
```
when there is pituitary dysfunction
eg
secondary hypothyroidism
(low TSH causing hypothyroid)
or
TSHoma
(high TSH causing hyperthyroid)
```
125
what is released by the hypothalamus to stimulate the anterior pituitary to secrete ACTH?
CRH
| corticotrophin-releasing hormone
126
what 2 hormones does cortisol have negative feedback upon?
CRH
(corticotrophin-releasing hormone)
ACTH
(adrenocorticotrophic hormone)
127
when is the best time to measure cortisol?
9am
128
why are cortisol levels highest in the morning?
prepares body for physiological demands of the day
129
what hormone released by the hypothalamus acts as a positive stimulatory hormone on the pituitary gland, causing it to release growth hormone?
-GHRH
| growth hormone releasing hormone
130
growth hormone acts on the liver to produce what hormone?
insulin-like growth factor 1
| IGF-1
131
what is a surrogate marker used to estimate GH activity?
IGF-1
| insulin-like growth factor 1
132
when GH is at high concentrations, what will the surrogate marker IGF-1 be?
raised
133
when GH is at low concentrations, what will the surrogate marker IGF-1 be?
might be normal
| other things cause the production of IGF-1
134
can IGF-1 measurement indicate GH hypersecretion or hyposecretion?
hypersecretion
| when IGF-1 is high, GF is high; when IGF-1 is normal, GF might be normal or low- unable to tell
135
when should you measure testosterone?
9am
136
dopamine (produced by the hypothalamus) has what effect on the anterior pituitary gland in terms of prolactin secretion?
dopamine inhibits prolactin secretion
137
what autocrine/paracrine effect does prolactin have on target breast tissue?
positive feedback
138
what receptor mediates the effects or prolactin?
prolacin receptor (PRLR)
139
what effect does vasopressin have on blood vessels?
constriction
140
what effect does vasopressin have on the kidneys?
increases fluid reabsorption
141
what overall effect does vasopressin have on the blood pressure?
increases arterial pressure
142
what is cortisol deficiency caused by?
adrenal insufficiency due to
-primary adrenal failure
or
-pituitary disease (secondary hypoadrenalism)
143
in UK what is the most common cause of primary adrenal failure?
autoimmune (addison's disease)
144
what is addison's disease caused by?
primary adrenal failure caused by autoimmune destruction of the adrenal cortex
145
what is cushings syndrome?
cortisol excess for any reason
146
what is cushings disease?
cortisol excess due to pituitary problem
147
what are the 4 main causes of cortisol excess? (cushings syndrome)
- pituitary origin
- adrenal origin
- ectopic ACTH
- exogenous steoirds
148
if there is a hormone excess, should you do a suppression or stimulation test?
suppression test
149
if there is a hormone deficiency should you do a suppression or stimulation test?
stimulation test
150
how do you undertake dynamic testing of a deficiency in cortisol production?
stimulation test
-synacthen test
(synthetic ACTH)
151
how do you undertake dynamic testing of an excess in cortisol production?
suppression test
| -using dexamethasone
152
are the 4 causes of cushings syndrome ATCH- dependent or independent?
- pituitary cause: ATCH- dependent
- adrenal cause: ATCH-independent
- ectopic cause: ATCH- dependent
- exogenous steroids:@ ATCH- independent
153
if there is a failure of cortisol suppression on low dose dexamethasone suppression testing, what does this indicate?
cushings syndrome
154
if there is a failure of cortisol suppression on low dose dexamethasone suppression testing, and the ATCH is low, what is the likely origin of cushings syndrome?
adrenal cause
155
if there is a failure of cortisol suppression on low dose dexamethasone suppression testing, and the ATCH is high, what is the likely origin of cushings syndrome?
pituitary, or ectopic aCTH
156
compare hormones released from posterior and anterior pituitary in terms of where they are synthesiseed?
hormones released from anterior pituitary are synthesised in the anterior pituitary gland
hormones released from the posterior pituitary are synthesised in the hypothalamus
157
what hormone produced from the hormone causes the release of LH/FSH within the pituitary?
GnRH
| gonadotrophin releasing hormone
158
what does an insulin stress test measure?
the increase in growth hormone and cortisol
159
what do stress hormones do to the blood sugar?
increase
160
what is a synacthen test?
when you inject ACTH to measure cortisol response
| stimulation test
161
is an insulin stress test a suppression or stimulation test?
stimulation test
162
what is a water deprivation test?
deprive patient of water for 8 hours and the measure concentration of urine
(it should have doubled by 2)
163
what hormone is a water deprivation test testing?
ADH
164
is a water deprivation test a stimulation or suppression test?
stimulation
165
what are the 5 physiological causes of raised prolactin?
```
breast feeding
pregnancy
stress
sleep
nipple stimulation
```
166
what are the 3 pathological causes of raised prolactin?
hypothyroidism (low DA)
stalk lesions
prolactinoma
167
what is the first line treatment for raised prolactin?
dopamine agonists
168
what do dopamine agonists do to prolactinomas?
make them shrink
169
is a glucose tolerance test for testing GH a stimulation or suppression test?
suppression test
170
compare the GH response in a patient with acromegaly to a normal response after a glucose tolerance test?
normal GH should decrease
| acromegaly: GH will not be suppressed
171
what medications can be used in the treatment of acromegaly?
somatostatin analogues
(dopamine analogues,
GH antagonist)
172
what are the 3 short term side effects of somatostatin analogues?
flactulence
diarrhoea
abdo pain
173
what are the 2 long term side effects of somatostatin analogues?
gastritis
| gallstones
174
how do you do a suppression test for cushings?
dexamethasone
| exogenous steroid
175
compare normal response to exogenous dexamethasone to a cushings response?
normal: cortisol levels decrease
cushings: cortisol levels remain high
176
what is mineralocorticoid activity?
the retention of sodium in exchange for potassium or hydrogen ions
177
what is the main steroid with mineralocorticoid activity?
aldosterone
178
what organ makes renin?
kidneys
179
what is the function of renin?
converts angiotensinogen to angiotensin I
180
what happens to the rate of renin secretion if there is low blood pressure?
low blood pressure within the kidney causes increased rate of renin secretion
181
what happens to the concentration of the urine when there is increased ADH secretion?
increased concentration of urine
182
what happens to the concentration of the urine when there is decreased ADH secretion?
decreased concentration of urine (dilute)
183
does concentrated urine have a low or high osmolality?
high osmolality
184
does dilute urine have a low or high osmolality?
low osmolality
185
what are the 2 possible causes of low serum sodium? (ie in terms of water or sodium)
too much water
| too little sodium
186
what are the 2 possible causes of high serum sodium? (ie in terms of water or sodium)
too much sodium
| too little water
187
what are the 2 main reasons for too much water? (in terms of excretion and intake)
decreased excretion
| increased intake
188
what condition causes increased intake of water which could cause decreased serum sodium?
compulsive water drinking
189
what does syndrome of inappropriate anti-diuresis (SIAD) do to the rate of water excretion?
decreases the rate of water excretion
190
what are the 2 main reasons for too little sodium? (in terms of excretion and intake)
```
decreased intake (rare)
increased excretion
```
191
what 3 organs are the main areas within the body wear sodium is lost?
kidneys
gut
skin
192
what is addison's disease?
adrenal insufficiency
193
why might there be increased sodium loss from the kidneys in addison's disease?
insufficient aldosterone is produced and so not enough sodium can be retained
194
what are the 2 major reasons for sodium loss from the skin?
sweating
| burns
195
what are the 2 main causes for too little water? (in terms of excretion and intake)
decreased water intake
| increased water excretion
196
what is the name for disruption of water balance axis causing inappropriately increased water excretion?
diabetes insipidus
197
what goes wrong in diabetes insipidus?
- problem with ADH secretion (central diabetes insipidus)
| - problem with ADH action on the kidneys (nephrogenic diabetes insipidus)
198
what is the main cause of too much sodium? (in terms of excretion or intake)
increased intake
199
what are the 3 main causes of increased sodium intake which can lead to increased serum sodium?
IV medications given as sodium salts
near-drowning in sea
high-salt infant feeds
200
a low BP which falls on standing points to the likelihood that what salt is low?
sodium
201
why might a patient with addison's disease get symptoms of dizziness?
due to hypotension from too little water
202
why might a patient with addison's disease have excess pigmentation?
the adrenal glands are insufficient and so the lack of aldosterone/cortisol negative feedback causes the ACTH levels to greatly increase.
ACTH is degraded by proteases causing a release of melanocyte stimulating hormone which causes pigmentation
203
when there is too much water due to inappropriate ADH secretion (SAID) what are the serum sodium levels and the volume status?
low serum sodium level
unremarkable volume status
204
what investigation is used to look for Addison's disease?
serum cortisol
205
what does non-osmotic stimuli for ADH release do to the serum sodium?
decreases serum sodium
206
what is the problem (sodium or water) when there is hypovolaemia and hyponatraemia?
too little sodium
207
when is hypervolaemia most often seen?
oedema
208
what is pseudohyponatraemia?
when total sodium is low but serum osmolality is normal
209
what are trophic hormones?
hormones which act on other endocrine glands
210
what are non-trophic hormones?
hormones which act on target cells directly
211
what are the 4 trophic hormones produced by the anterior pituitary?
ACTH
TSH
FSH
LH
212
what are the 2 non-trophic hormones produced by the anterior pituitary?
GH
| prolactin
213
what are the 3 main cell type within the anterior pituitary gland?
acidophils
basophils
chromophobes
214
what cells within the anterior pituitary gland produce growth hormone? and what type of cell is this?
somatotrophs
a type of acidophil
215
what cells within the anterior pituitary gland produce prolactin? and what type of cell is this?
mammotrophs
a type of acidophil
216
what cells within the anterior pituitary gland produce adrenocorticotrophic hormone? and what type of cell is this?
corticotrophs
a type of basophil
217
what cells within the anterior pituitary gland produce thyroid stimulating hormone? and what type of cell is this?
thyrotrophs
a type of basophil
218
what cells within the anterior pituitary gland produce FSH/LH? and what type of cell is this?
gonadotrophs
a type of basophil
219
what are the 2 main reasons for hyperfunction of the anterior pituitary gland?
adenoma
| carcinoma
220
what are the 5 main reasons for hypofunction of the anterior pituitary gland?
- surgery/radiation
- sudden haemorrhage into gland
- ischaemic necrosis
- tumours extending into sella
- inflammatory conditions
221
what is the most common functional pituitary adenoma?
prolactinoma
222
what is panhypopituitarism?
pituitary hypofunction of all the anterior pituitary hormones
(not just individual ones)
223
what are craniopharyngiomas derived from?
remnants of rathke's pouch
| the pouch from which the anteiror pituitary was derived
224
craniopharyngiomas have a bimodal incidence, when are they prevalent?
- 5-15 years
| - 60- 75 to years
225
what is the rare but serious complication of craniopharyngioma?
squamous cell carcinoma
| esp following radiation
226
what are the 2 main causes for central diabetes insipidus?
ADH deficiency
| trauma/surgery
227
what is the main cause of nephrogenic diabetes insipidus?
renal resistance to ADH
228
what type of hormones are produced from the adrenal cortex?
steroid hormones
229
what type of hormones are produced from the adrenal medulla?
catecholamine hormones
230
what are the 3 zones of the cortex?
zona glomerulosa
zona fasciculata
zona reticularis
231
what are the main hormones secreted by the zona glomerulosa of the adrenal cortex?
mineralocorticoids
| eg aldosterone
232
what are the main hormones secreted by the zona fasciculata of the adrenal cortex?
glucocorticoids
| eg cortisol
233
what are the main hormones secreted by the zona reticularis of the adrenal cortex?
androgens
234
what is the adrenal medulla innervated by?
pre-synaptic fibres from the sympathetic nervous system
235
what cells within the medulla secrete catecholamines?
chromaffin cells
236
what are the 3 main reasons for hyperfunction of the adrenal gland? (primary)
hyperplasia
adenoma
carcinoma
237
what are the 3 main causes of acute hypofunction of the adrenal gland? (primary)
- waterhouse-friderichsen
- rapid withdrawal of steroid treatment
- adrenal haemorrhage
238
what is the main cause of chronic hypofunction of adrenal gland? (primary)
addison's disease
239
acquired adrenocortical hyperplasia can be ACTH driven or independent. Is diffuse hyperplasia ACTH driven or independent?
ACTH driven
240
acquired adrenocortical hyperplasia can be ACTH driven or independent. Is nodular hyperplasia usually ACTH driven or independent?
ACTH independent
241
what syndrome describes the effects of primary hyperaldosteronism?
conn's syndrome
242
what are the 2 main causes of secondary hyperaldosteronism?
- increased renin
| - decreased renal perfusion (ie hypovolaemia)
243
what are the 2 adrenal medullary tumours?
phaeochromocytoma
| neuroblastoma
244
when are neuroblastomas diagnosed?
within 18 months usually
otherwise diagnosed in infancy
245
where do neuroblastomas arise?
adrenal medulla
| sympathetic chain
246
what are phaeochromocytoma cells derived from?
chromaffin cells of the adrenal medulla
247
what hormones do phaeochromocytomas secrete?
carecholamines
248
what do phaeochromocytomas do to blood pressure?
cause it to drastically increase
249
what is the 10% phaeochromocytoma rule? (7)
```
10% are extra-adrenal
10% are bilateral
10% malignant
10% are not associated with hypertension
10% are associated with hyperglycaemia
10% in children
10% familial (more like 25% now)
```
250
are phaeochromocytomas part of MEN 1 or MEN 2?
MEN 2
251
what are the 7 main contents of the cavernous system?
- carotid artery
- cavernous sinus
- oculomotor nerve
- trochlear nerve
- opthalmic branch of trigeminal nerve
- maxillary branch of trigeminal nerve
- abducens nerve
252
what system regulates the aldosterone levels within the body?
the renin-angiotensin system
253
what doses of corticosteroids are use in the suppression of inflammation? (physiological, supraphysiological or subphysiological)
supraphysiological
254
what doses of corticosteroid are used in the suppression of immune system? (physiological, supraphysiological or subphysiological)
supraphysiological
255
what doses of corticosteroids are used in steroid replacement treatment? (physiological, supraphysiological or subphysiological)
physiological
256
what are the 4 main causes of primary adrenal insufficiency?
Addison's (autoimmune)
congenital adrenal hyperplasia
adrenal malignancy
adrenal TB
257
compare Na and K levels in a patient with Addison's disease to normal levels?
Na reduced
| K increased
258
what stimulation test can be used in the diagnosis of primary adrenal insufficiency?
short synacthen test
| ACTH IV/IM and measure plasma cortisol
259
when treating primary adrenal insufficiency what drugs are used as cortisol and aldosterone replacement?
hydrocortison to replace cortisol
| fludrocortisone to replace aldosterone
260
why do you not need to give fludrocortisone to a patient with secondary adrenal insufficiency?
because aldosterone production will be preserved due to renin-angiotensin system
261
what is the most common cause of secondary adrenal insufficiency?
exogenous steroid use
262
compare the clinical features of secondary adrenal insufficiency to Addison's?
similar except in secondary adrenal insufficiency the aldosterone production is intact, and the skin remains pale (no excessive ACTH)
263
what are the 3 main causes of ACTH dependent cushing's syndrome?
pituitary adenoma (cushings disease)
ectopic ACTH
ectopic CRH
264
what are the 3 main causes of ACTH independent cushing's syndrome?
adrenal adenoma
adrenal carcinoma
nodular hyperplasia
265
what are the 3 main screening tests used in cushings syndrome?
- overnight dexamethasone suppression test
- 24 hour urinary free-cortisol
- late night salivary cortisol
266
what is the definitive test for cushing's syndrome?
low dose dexamethasone suppression test over 2 days
| and repeat to confirm
267
why can prolonged high dose steroid therapy cause secondary adrenal deficiency?
chronic suppression of pituitary ACTH production and adrenal atrophy
268
what is the most common cause of cushing's syndrome?
iatrogenic (due to high dose steroid therapy)
269
what is the most common cause of primary aldosteronism?
bilateral adrenal hyperplasia
270
what causes conn's syndrome?
an adrenal adenoma
| unilateral
271
what suppression test can be used for the diagnosis of primary aldosteronism?
saline suppression test
272
what is the treatment of a conn's adenoma causing aldosteronism?
surgery
273
what is the treatment of bilateral adrenal hyperplasia?
use mineralocorticoid receptor antagonists eg spironolactone or eplerenone
274
what is the most common cause of congenital adrenal hyperplasia?
21a hydroxylase deficiency
| an enzyme defect within the steroid pathway
275
what type of inheritence is 21a hydroxylase deficiency? (which leads to congenital adrenal hyperplasia)
autosomal recessive
276
what are the 2 variants of 21a hydroxylase deficiency?
classical
| non-classical
277
compare classical and non-classical variants of 21a hydroxylase deficiency in terms of the extent of deficiency?
classical: complete deficiency
| non-classical
278
how do you diagnose 21a hydroxylase deficiency?
basal or stimulated 17-OH progesterone level
279
in 17 hydroxylase deficiency, what is the only cortex hormone which can still be made?
aldosterone
280
in 21a hydroxylase deficiency, what is the only cortex hormone which can still be made?
testosterone (through DHEA)
281
what is the name for a extra-adrenal phaeochromocytoma?
paraganglioma
| within the sympathetic chain
282
blocking sympathetic system is how some phaeochromocytomas are managed, which should be blocked first alpha or beta receptors?
alpha before beta
283
compare MEN 1 and MEN 2 in terms of type of genes affected?
MEN1: tumour suppressor gene is inactivated
MEN2: ongogene is activated into proto-oncogene
284
what type of inheritance is von hippel lindau syndrome?
autosomal dominant
285
what gene is mutated in von hippel lindau syndrome?
von hippel lindau tumour suppressor gene
286
what type of receptor does growth hormone signal via?
cytokine receptor
287
what type of receptor does calcium signal via?
g-protein coupled receptor
288
which facial nerve (trochlear or abducens) is involved in lateral gaze?
abducens
289
which facial nerve (trochlear or abducens) is involved in medial gaze?
trochlear
290
what receptor do TZDs work on?
PPARgama
291
what is the iodine uptake of acute thyroiditis on scan?
reduced/no uptake
292
compare macroprolacitinomas and microprolactinomas in terms of size?
macro over 1cm
| micro under 1cm
293
what syndrome is usually present if there is metastatic disease to the pituitary gland/.
diabetes insipidus
294
why must you always give hydrocortisone before thyroxine in panhypopituitarism? (ie in a non-functioning tumour)
to prevent an addisonian crisis
295
what is the classic symptom triad of a phaeochromocytoma?
headaches
sweating
palpitations
