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Year 2- ENDO mine > hyposecretion of anterior pituitary hormones > Flashcards

hyposecretion of anterior pituitary hormones Flashcards

1
Q

what does hyposecretion of anterior pituitary hormones mean?

A

inadequate anterior pituitary function

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2
Q

what are the 5 main anterior pituitary hormones

A 
FSH/LH
prolactin 
GH
TSH 
ACTH
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3
Q

define hypopituitarism

A

DECREASED PRODUCTION OF ALL ANTERIOR PITUITARY HORMONES (PANHYPOPITUITARISM) or of specific hormones

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4
Q

what 2 can hypopituitarism be classified into

A

congenital defects

acquired

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5
Q

classifying endocrine gland diseases into primary and secondary

A

Disorder results in
SECONDARY
endocrine gland disease= defect in the anterior pituitary gland

Disorder results in
PRIMARY endocrine
gland disease = defect in the actual gland such as the endocrine gland

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6
Q

what is congenital panhypopituitarism?

A

Deficient in GH and at least 1 more anterior pituitary hormone

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7
Q

what is congenital panhypopituitarism due to?

A

Rare
Usually due to mutations of transcription factor genes needed for normal anterior pituitary development
eg PROP1 mutation

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8
Q

what does congenital panhypopituitarism result in?

How can it be diagnosed?

A

Short stature

Hypoplastic anterior pituitary gland on MRI

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9
Q

what can lead to ACQUIRED PANHYPOPITUITARISM

A

Tumours
hypothalamic - craniopharyngiomas
pituitary – adenomas, metastases, cysts
Radiation
hypothalamic/pituitary damage
GH most vulnerable, TSH relatively resistant
Infection eg meningitis
Traumatic brain injury
Infiltrative disease – often involves pituitary stalk
eg neurosarcoidosis
Inflammatory (hypophysitis)
Pituitary apoplexy
haemorrhage (or less commonly infarction)
Peri-partum infarction (Sheehan’s syndrome)

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10
Q

what are symptoms of PANHYPOPITUITARISM due to deficient hormones?
FSH/LH
ACTH
TSH

A 
Occasionally called Simmond’s disease 
Symptoms due to deficient hormones 
FSH/LH= Secondary hypogonadism
Reduced libido
Secondary amenorrhoea
Erectile dysfunction
ACTH= Secondary hypoadrenalism (cortisol 			deficiency) Fatigue
TSH	 = Secondary hypothyroidism, Fatigue
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11
Q

what is sheehan’s syndrome specifically?

A

SPECIFIC IN WOMEN
Specifically describes post-partum hypopituitarism secondary to hypotension (post partum haemorrhage - PPH)
Less common in developed countries
Anterior pituitary enlarges in pregnancy (lactotroph hyperplasia), so when there is a haemorrhage and great loss of blood, there is not enough blood supplying the newly enlarged pituitary gland- so it eventually dies off.
PPH leads to pituitary infarction

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12
Q

what is the presentation of sheehan’s syndrome?

A

Lethargy, anorexia, weight loss – TSH/ACTH/(GH) deficiency
Failure of lactation – PRL deficiency
Failure to resume menses post-delivery
Posterior pituitary usually not affected

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13
Q

what is pituitary apoplexy?

A

Similar to sheehan’s but not specific to women.
Intra-pituitary haemorrhage or (less commonly) infarction
Often dramatic presentation in patients with pre-existing pituitary tumours (adenomas)
May be first presentation of a pituitary adenoma
Can be precipitated by anti-coagulants
Rapid presentation

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14
Q

what is the presentation of pituitary apoplexy?

A

SEVERE sudden onset headache
Visual field defect – compressed optic chiasm, bitemporal hemianopia
Cavernous sinus involvement may lead to diplopia (IV, VI) (=double vision), ptosis (III) (droopy eyelids)

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15
Q

biochemical diagnosis for hypopituitarism

  • basal plasma conc
  • what are the cons?
A

Basal plasma concentrations of pituitary or target endocrine gland hormones

	- interpretation may be limited
   		- undetectable cortisol – what time of 	day?
   		- T4 – circulating t1/2 6 days
 		- FSH/LH – cyclical
	- GH/ACTH - pulsatile
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16
Q

biochemical diagnosis for hypopituitarism

-stimulated (dynamic) pituitary function tests

A
  1. Stimulated (‘Dynamic’) Pituitary Function Tests
    • ACTH & GH = ‘stress’ hormones
    • Hypoglycaemia (<2.2mM) = ‘stress’
    • Insulin-induced hypoglycaemia stimulates
      GH release
      ACTH release (cortisol measured)
    • TRH stimulates TSH release
    • GnRH stimulates FSH & LH release
17
Q

biochemical diagnosis for hypopituitarism

-radiological diagnosis

A

Pituitary MRI
May reveal specific pituitary pathology
eg haemorrhage (apoplexy), adenoma

Empty sella – thin rim of pituitary tissue

18
Q

HORMONE REPLACEMENT THERAPY IN HYPOPITUITARISM

  • ACTH
  • TSH
  • FSH/LH (f)
  • FSH/LH (m)
  • GH
A
  • hydrocortisone
  • thyroxine
  • HRT
  • Testosterone
  • GH
19
Q

what does growth hormone (somatotrophin) deficiency lead to?
-in adults and children

A

in children results in short stature (=2 SDs < mean height for children of that age and sex)

in adults, effects less clear

20
Q

what are other causes of short stature

A

Genetic: Down’s syndrome, Turner’s syndrome, Prader Willi syndrome
Emotional Deprivation
Systemic disease: Cystic Fibrosis, Rheumatoid arthritis
Malnutrition
Malabsorption: Coeliac disease
Endocrine Disorders: Cushing’s syndrome, Hypothyroidism, GH deficiency, poorly controlled T1DM
Skeletal dysplasias: Achondroplasia, osteogenesis imperfecta

21
Q

whats the growth axis for GHRH- draw

A

SS+ GHRH
somatotrophin
(liver)
IGFII and IGFI

22
Q

what leads to prader willi syndrome?

A

GH deficiency secondary to hypothalamic dysfunction

23
Q

what leads to pituitary dwarfism?

A

childhood GH deficiency

-lack of GH produced released

24
Q

what leads to laron dwarfism

A

Mutation in GH receptor (in liver)

IGF-1 treatment in childhood can increase height

25
Q

causes of acquired GH deficiency in adults

A

TRAUMA
PITUITARY TUMOUR
PITUITARY SURGERY
CRANIAL RADIOTHERAPY

26
Q

what can be used to diagnose GH deficiency?

A

Random GH little use – pulsatile
PROVOCATIVE CHALLENGE
(i.e. STIMULATION) TEST

27
Q

what are GH provocation tests?

A

GHRH + ARGININE (i.v.) (in combination more effective than each alone)
INSULIN (i.v.) – via hypoglycaemia
GLUCAGON (i.m.) (causing over vomiting, leading to stress)
EXERCISE (e.g. 10 min step climbing; when appropriate)

Measure plasma GH at specific time-points (before and after)

28
Q

why is there GH secretion in response to hypoglycaemia?

A

GH are stress hormones
Hypoglycaemia leads to stress in the body
So a lot of GH is released.

29
Q

examples of growth hormone therapy/treatment

A 
Preparation:
Human recombinant GH
 (approved name: SOMATOTROPIN)
Administration:
Daily, subcutaneous injection
Monitor clinical response &amp;
   adjust dose to IGF-1
30
Q

what are the signs and symptoms of GH deficiency in adults?

A

Reduced lean mass, increased adiposity, increased waist:hip ratio

Reduced muscle strength & bulk reduced exercise performance

Decreased plasma HDL-cholesterol & raised LDL-cholesterol

Impaired ‘psychological well being’ and reduced quality of life

31
Q

what are the potential benefits of GH therapy in adults?

A

Improved body composition – decreased waist circumference, less visceral fat

Improved muscle strength and exercise capacity

More favourable lipid profile - higher HDL-cholesterol, lower LDL-cholesterol

Increased bone mineral density

Improved psychological well being and quality of life

32
Q

what are the potential risks of GH therapy in adults?

A

Increased susceptibility to cancer
– no data to support this currently

Expensive – NICE estimated cost of lifelong GH treatment in adult = £42K

33
Q

what is achondroplasia due to?

A 
ACHONDROPLASIA
Mutation in Fibroblast Growth 
    Factor Receptor 3 (FGF3)
Abnormality in growth plate 
    chondrocytes  - impaired 
    linear growth  
Average size trunk
Short arms and legs

Year 2- ENDO mine (19 decks)

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