Pituitary Flashcards
1
Q
Gold standard test for Growth hormone deficiency
A
Insulin tolerance test
2
Q
Normal subjects response to insulin induced hypoglycemia
A
Peak Gh secretions more than 5 ug/L
3
Q
Definition of severe GHD
A
Peak Gh response to hypoglycemia of less than 3 IG/L
4
Q
Direct precursor of testosterone
A
Androstenedione
5
Q
Chiari frommel syndrome
A
Post partum galactorrhea
Amenorrhea
Utero ovarian aropthy
6
Q
Inhibitors of prolactin
A
Dopamine
Endothelin
Calcitonin
Tgf B2
7
Q
Gold standard test for GHD
A
GH deficiency
8
Q
GH replacement dose
A
0.2-0.3 mg/day
9
Q
When to treat with growth hormone
A
Clinical features if hyposomatotropism
Evoked GH <3 ug/L
IGF 1 low
10
Q
How to monitor response to GH
A
Measure IGF levels after 1 month
Toteate dose to normalize IGF levels after 1 month
Stop if no clinical reaoinse aft
11
Q
Adrenal insufficency dx
Serum cortisol morning levels
A
<3 ug/dL suggests acth deficiency
>18 ug/dL normal acth reserve
12
Q
Normal acth values in am
A
8-25 ng/L
13
Q
Dynamic testing for acth
A
Hypothalamic ITR
Pituitary CRH or AVP
Adrebal ACTH
14
Q
How to do insulin tolerance test for ACTH reserve
A
Insulin 0.1-0.15 U/kg IV after an overnight fast
Achieve symptomatic hypoglycemia and glood glucose less than 40
Normal reaponse:
Cortisol more than 20 ug/dL
Venous samples collect 0.,15,30,45,60,90,120
Glucose acth and cortisol
15
Q
Recommended dose hydrocortisone adrenal steroid replacement
A
15-20 ug/day
16
Q
Half lifr cortisol
A
Less than 2 hrs
17
Q
How to test for gonadotropin
A
Single bolus of GnRH 25-100 ug
Evoke LG and FSG within 20-30 mins
18
Q
GH hormone therapy effect on lipids
A
Improved HDL and chole ratio
No change in Tg
19
Q
Range of morning plasma ACTHlevels
A
8 to 25 ng/L
20
Q
Cortisol values as a normal response to hupoglycemia
A
Higher than 20 ug/dL
21
Q
Mechanism of action Metyrapone
A
Blocks 11 B hydroxylase
22
Q
An activin binding protein (gnrh) which inhibits activin action by inhibiting activin binding to its receptor
A
Follistatin
23
Q
Autoimmune inflammatory condition occuring during or shortly after parturition
A
Lymphocytic hypophysis
24
Q
What is ipilimumab?
A
Antibody that blocks the cytotoxic T lymphocyte antigen 4 which is also expressed by the pituitary
25
RX lymphophtcytic hypophysis
Replace pit deficits spontaneous resolution of inflammatory mass followed
26
Lab findings in lymphophtcytic hypoglycemia hysis
ESR elevated
| (+) abx to 49 kda cytosolic protein in 70%
27
Characteristic for abscess on Mri
Isointense central cavity with surrounding ring enhancement
28
Pituitary mass
(+) vimentiun
S100 protei.
Glial fibrillat acidic protein
Pituicytoma
29
Most common carcinoma that metastasizes to pituitary
Breast
Then
Lung, prostate, renal
30
Features of ipilimumab induced hypophysitis
```
Central hypothyroidism in 100
AI In 50-84
Hyponat up to 5O%
Low prolactin
Low testosterone
```
31
Inability to nurse and
| Post partum amenorrhea
Sheehans syndrome
| Pituitary necrosis due to vasopasn due to hupovolemic shock
32
Gene locus MEN 4
CDKN 1B
33
Female to male ratio of microprolactinpmas
20:1
34
PRL levels steongly suggestive of a MICROPROLACTINOMA
> 200 ug/L
Pathognomonic >500
35
The most common potuitary tumors associated with men 1
Prolactinomas
36
% pf patients with acromegaly with elevated PRL
50%
37
AE of dopamine agonists
Heart valve regurgitation
38
Management of patients with prolactinomas planning pregnancies
MACROADENOMA ?
DC bromocriptine
Periodic visual field examinations
Post partum MRI after 6 weeks
MICROADENOMA
Surgery before pregnancy
Ensure bromocriptine sensitivity before pregnancy
Monitoring visual fields expectantly if need bromocriptine resumption
High dose steroids for threatened vision/ adenoma hemprrhage occurs
39
Anti hypertensives that cause hyperprolactinemia
“LVR”
Labetalol
Verapamil
Reserpine
40
What are the physiologic causes of hyperprolactinemia?
```
Exercise
Coitus
Stress
Sleep
Suckling
Pregnancy
```
ECSSSP
41
Reason why prolactin is moderately elevated in patients with chronic renal failure and those on HD
Mean 28
Decreased glomerular filtratoon rate
This may cause sexual dysfunction
42
Weight of the adult pituitary
600 mg (rang 400-900)
43
5 distinct hormone secreting cell types in the mature anterior pituitary gland
```
Corticotroph cells
Somatotroph cells
Thyrotroph cells
Gonadotroph cells
Lactotroph cells
```
44
Blood supply of hypothalamus
Superior hypophyseal arteries (branch of ICA)
45
Blood supply of anterior pituitary gland
Long and short hupophyseal portal arteries (from infundibar plexuses and stalk)
46
Blood supply of posterior pituitary
Inferior hypophyseal arteries
47
Rathke’s pouch formation
4-5th week gestation
48
Where is the pituitary formed from?
Anterior - rathke’s puth
| Posterior neural ectoderm assoc with 3rd ventricle development
49
Required tor the initial pouch invagination for pituitary morphoenesis
BMP4
50
When does the anterior pituitary under major cell differentiation?
12 wks
51
When are corticotrophs identifiables
6 wks
Somatotroph- 8 wks
Thyrotroph- 12 weeks
Lactotroph-24 weeks
52
Directs corticotroph cell commitment
Tpit protein
53
Determines subsequent developemebt if POUF1F1 and gonadotroph cell lineages
PROP1
54
Major determinant of pituitary cell lineage
PROP1
55
Corticotrop cell devt occurs earliest and is independent of PROP1 determined lineages. What is a prerequisite for POMC expression
T pit protein
56
Effect of VIP and serotonin pn prolactin secretion
Stimulates PRL
57
Share a common a subunit expression under developmental control of Gata2
TSH
| Gonadotropin expressing cells
58
Transfeiption factors
| Detemines gonadotroph development
SP1 and DAX1
59
Effect of opiates on PRL
Acutely induce PRL release
60
Effect of cyproheptadine on PRL
Attenuatea noctirnal prl secretion
61
Side effects of pituitary irradiation
- hypopituitarism
- second brain tumors
- cerebrovascular doseases
- visual damage
- brain necrosis
62
To minimize visual damage what is recommended dose od radiation
Less than 200 rads
63
Second brain tumors reported after pituitary irradiation
Glioma
64
3 phases of post op diabetes insipidus
1. Transient disorder
2. Interphase 6-11
3. 3rd phase return to DI
65
Rathke’s pouch is where thne ___ is derived
Anterior and intermiediate lobes of the pituitary
66
Parasellar masses
Locally invasive
From midline notochord remnants
Mucin rich matrix
Chordomas
67
Critical neuroectodermal sugnal
Dorsal gradient of pituitary devt
Needed for initial puch invagination
BMP4
68
Pituitary stem cell progeniyors that express this marker can regenerate in times of stress
Sox 1 and sox 2
69
Rieger syndrome
| Mutation in eye umbilicL cord defect in...
Pitx2
70
Sequence of hormone loss
| Pituitary compression
GFLTA
Radiation
GFLAT
71
Stimulates PRL secretion
TEVS
TRH
Estrogen
VIP
Serotonin
72
Inhibits prolactin
```
DECT
dopamine
Endothelin 1
Calciyonin
TGF B
```
73
Anti psychotic drug with minimal effect on PRL levels so you may shift to this to rule out drug induced hyperprolactinemia (short of stopping the meds)
Olanzapine
74
Hallmarks of pathologic prolactinemia
Galactorrhea
| Reporxuctive dysfunxction
75
Chiari frommel syndrome
Pathologic hyper prolactinemia
Post partim galactorrhe
Amenorrhea
Ureteo ovarian atrophy
76
Time frim discontinuation of nursing continued milk production is abnormal
6 months
77
How come 50% of patients with actomegaly have galactorrhea despite normal prolactin levels
Human GH is a potent lactogen
78
The most frequent cause of galactorrhea
Normoprolactinemic galactorrhea
79
PRL deficiency with central hypothyroidism
Immunoglubulin superfamily member 1 defficiency syndrome
80
Side effect CRH stimulation test
| Table
Flushing
81
Side effect metyrapone test
Nausea insomnia adrenal crisis
82
Effect of norepinephrine to GH secretion
A adrenergic increases release
| B adrenergic inhibits
83
These substances account for GH release during exercise and stress
Endorphins and enkephalins
84
These STIF teceptor subtypes mediate GH secretion
2 and 5
85
Effect of ghrelin
Binds growth hormone secretagogue receptor to release GHRH and pituitary GH
86
70% of GH secretion in its diurnal rhythm occurs when
Slow wave sleep
87
The signature property of GH
Protein anabolism, reducing urea synthesis and urea secretion
88
Effect of GH on glucose metabolism
Insulin like effects: enhanced glucose uptake in cells
Whole body: suppresses glu oxidation while enhancing hepatic glu production
89
Critical factor for corticotroph cell differentiation
Tpit
90
Where are corticotrophs clustered
Central medial pituitary wedge
91
Weight of pituitary gland
600 mg
92
GH uses
Osteoporosis
| HIV cachexia
93
Melanocortin receptor for melanocyte stimulation
MCR1
Mcr2 adrenals
Mcr 3 Nd 4 leptin
94
MOA metyrapone
Inhibits adrenal 11 B hydroxylase
95
Most common endocrine deficit encountered with ipilimumab induced hypophysitis
Secondary adrenal insuffiency
96
Median onset of ipilimumab induced hupophysitis
CTLA4
97
Isolated in prolactinomas
PTTG
98
MEN1 gene
Chromosome 11q13
99
MEN 4 gene
CDKN1B
100
Mutations seen in patients with gigantism
AIP mutations
101
Rx DI
Vasopressin
Desmopressin
Chlorpropamide
Indomethacin
Not recomended:
Carbamazepine
Clofibrate
102
Natriuretic agents for DI
Thiazide
Amiloride
Indapamide
103
Target bp alpha blockadr
<120/80 seared
| >90 sbp standing
104
Losnsger duration of alpha blockade needed
Cathecholamine cardiomyopathy
| Cathecholamine induced vasculitis
105
When to start alpha blockade
7-10 days pre op
106
When to start beta blocked
2-3 days pre op
107
Target HR beta blockade
60-80 bpm
108
Anaesthesia to use in pheo
Propofol
Etomidate
Barbiturates
109
Inhibits aldosterone
Heparin
ANP
Dopamine
“HAD”
110
MC cause of hyperaldosteronism
Bilateral idopathic hyperplasia
111
When to test hyperaldo
```
Hypertension and hypokalemia
Resi hrn
Icidentaloma and htn
Onset of HTN at young age <20
Sever htn >150/100
Whenever considering secondary HTN
```
112
Positive result for hyperaldosteronism screening
PAC> 15
Renin < 1
20 ratio
113
High renin high aldo
Renovascular disease
114
Diff liddle from AME
Give amiloride /traimtene (corrects liddle)
115
How to diagnose SAME
24 h urine cortisol and cortisone
Increase ratio in the 24h urine
116
Age risk foctors fot DM
Unite age over 40
| Williams 45
117
prevalence of DM
8. 8% IDF
| 7. 2% Unite
118
Criteria for diagnosis of atypical pituitary adenomas
```
Invasion
Rapid growth
Recurrenc
Diameter more than 4 cn
Resistance to medical therapy
Carcinoma, if extracranial metastasis
```
119
WHO 2004 diagnosis attpical adrenocorticotrophic hormone
```
Aggressive invasive
Pleomorphic
Increased mitotic activity
Ki 67 >3%
P53 immunoreactivity
```
120
Genes assic wifh familial pituitary tumor syndromes
Men1
Men4
Carney complex
Familial isolated pit adenomas
121
Used to treat aggresisve pituitrytumors that failed to respond to other therapy or if with evidence of carcinoma
Temozolomide
122
Interferes with drug efficacy of temozolomide
O MGMT
123
Radiation Dose for irradiation pituitary mass
Max 5000 rads
| 180 rad 5-6 weeks
124
Indications for pituitary ireadiation
```
P242
Adjuvant to surgical therapy
1) pit adenoma
2) craniopharyngioma
3) nelson syndrome
4) nonadenomatous sellar mass
5) tumor recurrence
6) hormone hypersecretion recurrence
```
125
Second brain tumors implicated post pituitary irradiation
Gliomas
| Astrocytonas
126
Acromegaly treatment which emgances insulin sensitivity hence suited for patients with co existing diabetes
Pegvisomant
127
Marker of responsiveness to pegvisomant
IGF-1
| Because action is on peripheral receptor and levels of GH rise as IGF1 negative feedback is lost
128
Monitoring of patients on pegvisomant
Hepatic transaminases every 6 mos
| Monitoring tumor growth
