Hyposecretion of anterior pituitary hormones Flashcards

1
Q

What are the anterior pituitary hormones

A
Growth hormone
Prolactin
Thyroid stimulating hormone
Follicle stimulating hormone/ Liutenising hormone
Adrenocorticotrophin hormone
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2
Q

What is the difference between a primary and secondary endocrine gland disease

A

primary - disorder in the endocrine gland that releases the primary hormone (thyroid, gonads, adrenal cortex)

Secondary - disorder in the anterior pituitary gland

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3
Q

What is hypopituitarism

A

Decreased production of ALL anterior pituitary hormones (panyhypopituitarism) OR of a specific hormone
Either congenital or acquired

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4
Q

Describe congenital panhypopituitarism

A

Rare
Usually due to mutations of transcription factor genes needed for normal anterior pituitary development e.g. PROP1 mutation
Deficient in GH and at least 1 other APH

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5
Q

What may indicate congenital panhypopituitarism

A

Hypoplastic APG on MRI

Short stature

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6
Q

What are some examples of causes of acquired panhypopituitarism

A

Tumours
Radiation (damage where GH is most vulnerable and TSH is resistant)
Infection (meningitis)
Traumatic brain injury
Infiltrative disease (often involves pituitary stalk, neurosarcoidosis)
Inflammatory (hypophysitis)
Pituitary apoplexy (haemorrhage, infarction)
Peri-partum infarction (sheehan’s)

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7
Q

Give examples of tumours that may cause acquire panhypopituitarism

A

Hypothalamic - craniopharyngioma

Pituitary - adenoma, metastases, cysts

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8
Q

What is another name for panhypopituitarism

A

Simmond’s disease

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9
Q

What are the symptoms of panhypopituitarism if TSH is deficient

A

(Secondary hypothyroidism)

Fatigue

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10
Q

What are the symptoms of panhypopituitarism if ACTH is deficient

A

(Secondary hypoadrenalism)

Fatigue

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11
Q

What are the symptoms of panhypopituitarism if FSH/LH is deficient

A

(Secondary hypogonadism)
Reduced libido
Secondary amenorrhoea
Erectile dysfunction

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12
Q

Describe Sheehan’s syndrome

A

Post-partum hypopituitarism, secondary to hypotension (usually post partum haemorrhage)
Anterior pituitary enlarges in pregnancy (lactotroph hyperplasia)
Leads to pituitary infarction
Less common in developed countries

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13
Q

Describe the presentation of Sheehan’s syndrome

A
Lethargy 
Anorexia
Weight loss
Failure of lactation
Failure to resume menses
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14
Q

What is pituitary apoplexy

A

Intra-Pituitary haemorrhage or infarction
Dramatic presentation in patients with pre-existing pituitary tumours (adenomas)
Can be precipitated by anti-coagulants

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15
Q

What are the symptoms of pituitary apoplexy

A

Severe sudden onset headache
Visual field defect (compressed optic chasm -> bitemporal hemianopia)
Cavernous sinus involvement may lead to diplopia (IV, VI), ptosis (III)

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16
Q

How do you diagnose hypopituitarism biochemically

A

Basal plasma concentrations of pituitary or target endocrine gland hormones
Stimulated pituitary function tests

17
Q

Why may diagnosis of hypopituitarism via basal plasma concentrations of hormones be difficult

A
Interpretation may be limited
Undetectable cortisol (conc. varies during the day) 
T4 half life is 6 days
FSH/LH is cyclical
GH/ACTH - pulsatile
18
Q

Describe the diagnosis of hypopituitarism via stimulated pituitary function tests (ACTH, GH, TSH, FSH + LSH)

A

ACTH and GH Are stress hormones
Insulin-induced hypoglycaemia will stimulate the release of GH and ACTH
TRH stimulates TSH release
GnRH stimulates FSH and LH release

19
Q

How do you diagnose hypopituitarism radiologically

A

Pituitary MRI
May reveal specific pituitary pathology e.g. haemorrhage (apoplexy), adenoma
Empty sella - thin rim of pituitary tissue

20
Q

Describe hormone replacement therapy when GH is deficient + what you check

A

Give GH

check IGF1 and growth chart in children

21
Q

How does GH deficiency present in children and adults

A

children - results in short stature

Adults - effects of GH replacement less clear

22
Q

What are some causes of short stature

A

Genetic (Downs, turners, PDW)
Emotional deprivation
Systemic disease (CF, rheumatoid arthritis)
Malnutrition
Malabsorption (coeliac)
Endocrine disorders (Cushings, hypothyroidism, GH deficiency, uncontrolled T1DM)
Skeleteal dysplasias (achondroplasia, osteogenesis imperfecta)

23
Q

Describe prader will syndrome

A

GH deficiency secondary to hypothalamic dysfunction

24
Q

Describe Achondroplasia

A

Dwarfism
Mutation in fibroblast growth factor receptor FGF3
Abnormality in growth plate chondrocytes - impaired linear growth
Average sized trunks
Short arms and legs

25
Q

What is pituitary dwarfism

A

Childhood GH deficiency

26
Q

What is Laron dwarfism

A

High incidence in a specific village in Ecuador
Mutation in GH receptor
IGF-1 treatment in childhood can increase their height

27
Q

How do you diagnose short stature

A

Mid parental height

Based on father and mother

28
Q

How is GH deficiency diagnosed

A

Random GH is of little use (pulsatile)

Provocative challenge test

29
Q

What is the provocative test and what can be used for it

A

Measures plasma GH at specific time points

GHRH and arginine (via IV)
Insulin (via IV)
Glucagon (intramuscular)
Exercise (10 min step climbing)

30
Q

Draw a graph for growth hormone secretion in response to hypoglycaemia

A

In normal people after insulin is given, GH increases rapidly then decreases
In GH deficient people the GH increases very little gradually and reaches its maximum much later

31
Q

How is GH therapy prepared

A

Human recombinant GH

32
Q

How is GH therapy administered

A

Daily subcutaneous injection

Monitor the clinical response and adjust dose to IGF-1

33
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

34
Q

What are the benefits of GH therapy in adults

A

Decreased waist circumference, less visceral fat
Improved muscle strength and exercise capacity
High HDL and low LDL
Increased bone mineral density
Improved psychological well being

35
Q

What are the risks of GH therapy in adults

A

Increase susceptibility to cancer

Expensive (£42K) for lifelong treatment