Hyposecretion of APG hormones Flashcards by Rama Jha

5 hormones released from adenohypophysis?

FSH/LH
Prolactin
ACTH
TH
GH

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What determines the disorder category?

The level at which the defect lies

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Primary endocrine gland disease?

Lies in the ENDOCRINE GLAND

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Secondary endocrine gland disease?

Defect is in the ANTERIOR PITUITARY HORMONE

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Hypopituitarism?

Decreased production of SPECIFIC hormones

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Panhypopituitarism?

Decreased production of ALL anterior pituitary hormones

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2 types of causes?

Congenital (rare)

Acquired

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Cause of congenital panhypopituitarism?

Rare

Cause: mutations of TFs genes needed for normal anterior pituitary development (PROP1 mutation)

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Presentations of congenital panhypopituitarism?

Deficient in GH and at least ONE MORE anterior pituitary hormone

Short stature
Hypoplastic APG on MRI

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Cause of acquired panhypopituitarism?

x Tumours
x Radiation
x Infection
x Traumatic brain injury
x Infiltrative disease
x Inflammatory
x Pituitary apoplexy
x Sheehan's Syndrome (peri-partum infarction)

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Acquired panhypopituitarism:

Tumours, Radiation, Infection, Infiltrative disease, Pituitary apoplexy?

Tumours - hypothalamic (craniopharyngiomas) & pituitary (adenomas, metastases, cysts)

Radiation - hypothalamic/pituitary damage (GH most vulnerable, TSH least!)

Infection - meningitis

I.D - often invovles pituitary stalk (neurosarcoidosis)

P.A - haemorrhage (less commonly infarction)

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Causes of panhypopituitarism?

Simmond’s Disease

Symptoms due to deficient hormones

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FSH/LH on panhypopituitarism?

2o hypogonadism

Reduced libido
2o amenorrhoea (F)
Erectile dysfunction (M)

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ACTH on panhypopituitarism?

2o hypoadrenalism (cortisol deficiency)
Fatigue

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TSH on panhypopituitarism?

2o hypothyroisism

Fatigue

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What is Sheehan’s Syndrome?

Post-partum Hypopituitarism

2o to hypotension (PPH - post partum haemorrhage)

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What causes Sheehan’s Syndrome?

Anterior pituitary englarges in pregnancy (due to lactotroph hyperplasia)

SO the hypotension from loss of blood from giving birth = pituitary becomes under perfused = infarction

(Posterior PG usually NOT affected)

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Easy presentations of Sheehan’s Syndrome to notice?

Failure of lactation - PRL deficiency

Failure to resume menses post-delivery

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Hard presentations of Sheehan’s Syndrome to notice?

Lethargy
Anorexia
Weight loss (TSH, ACTH, GH) deficiency

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What is pituitary apoplexy?

Intra-pituitary haemorrhage (or less commonly infarction)

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What type of patients can present with pituitary apoplexy?

Dramatic presentation in patients w. pre-existing pituitary tumours (adenomas)

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What can be used for pituitary apoplexy?

Precipitated by anti-coagulants

Symptoms of pituitary apoplexy?

SEVERE sudden onset headache

Visual field defect - compressed optic chiasm (above PG)
x Bitemporal hemianopia

Cavernous sinus
x Diplopia - double vision (CNIV & VI)
x Ptosis - drooping upper eyelid (CNIII)

Type of biochemical diagnosis for hypopituitarism which is limited?

Basal plasma [ ] of pituitary OR target endocrine gland hormones

Why is this type of biochemical diagnosis limited?

Cortisol - undetectable as [ ] varies throughout the day T4 - has a LONG half-life (6 days) so many take a while to fall FSH/LH - cyclical GH/ACTH - pulsatile

What is the alternative biochemical diagnosis method for hypopituitarism?

Stimulated pituitary function tests

Methods used for the alternative biochemical diagnosis method for ACTH & GH hypopituitarism?

ACTH & GH - 'stress' hormones with 'stress' defined as HYPOGLYCAEMIA So an insulin-induced hypogylcaemis stimulates GH and ACTH (cortisol measured) release

Methods used for the alternative biochemical diagnosis method for TSH hypopituitarism?

TRH (in injection) stimulated TSH release

Methods used for the alternative biochemical diagnosis method for FSH & LH hypopituitarism?

GnRH stimulated FSH & LH release

What is the radiological diagnosis for hypopituitarism?

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

Why can an CT scan not be used for hypopituitarism diagonsis?

Can only see blood in fossa

HRT for ACTH?

Deficient Hormone: ACTH Replacement: Hydrocortisone (cannot replace w. ACTH as pulsatile) Check: Serum cortisol

HRT for TSH?

Deficient Hormone: TSH Replacement: Thyroxine Check: Serum free T4

HRT for Women LH/FSH?

Deficient Hormone: LH/FSH Replacement: HRT (E2 progestagen) Check: Symptom improvement, withdrawal bleeds

HRT for Men LH/FSH?

Deficient Hormone: LH/FSH Replacement: Testosterone Check: Symptom improvement, serum testosterone

HRT for GH?

Deficient Hormone: GH Replacement: GH Check: IGF1, growth chart (children)

Effects of GH (somatotrophin) deficiency in children and adults?

Children - short stature Adults - effects less clear

7 causes of short stature?

x Genetic - Down's/Turner's/Prader Willi Syndrome x Emotional deprivation x Systemic disease - CF, rheumatoid arthritis x Malnutrition x Malabsorption - coeliac disease (go gluten-free diet!) x Endocrine disorders - Cushing's syndrome, Hypothyroidism, GH deficiency, poorly controlled T1DM x Skeletal dysplasias

3 points of short stature causation in children on the GROWTH AXIS?

Hypothalamus - Prader-Willi Syndrome Anterior pituitary hormone (lack of GH) - Pituitary Dwarfism GH receptor defect - Laron Dwarfism

Prader Willi Syndrome?

GH deficiency 2o to hypothalamic dysfunction

Dwarfism?

ACHONDROPLASIA (skeletal abnormality - endocrine system is FINE) Mutation in FGF3 Abnormality in growth plate chondrocytes - impaired linear growth

Presentation of dwarfism?

Average size trunk Short arms & legs

Pituitary dwarfism?

Childhood GH deficiency

Laron dwarfism?

Mutation in GH receptors

What can be used to treat laron dwarfism?

Treated with IGF-1 in childhood - can increase height

How can you diagnose short stature?

Mid-parental height - predicted height mapped out and then followed

3 causes of ACQUIRED GH deficiency in adults?

In adults, hypothalamus OR APG is normally affected x Trauma x Pituitary Tumour/Surgery x Cranial Radiotherapy

How can you diagnose GH deficiency in adults?

Cannot measure GH as pulsatile in nature Provocative challenge i.e. STIMULATION TEST

4 GH provocation tests?

GHRH + arginine [i.v.] (arginine stimulated GH production) Insulin [i.v.] - via. hypoglycaemia (if deficient, very low GH response - should normally increase) Glucagon [i.m.] - drives up GH and ACTH (as induces vomiting which is a stress-factor) Exercise

What is used as GH therpary?

Human recombinant GH (somatotropin)

How is GH therapy administrated and monitored?

Daily, subcutaneous injection Monitor respone to IGF-1 (what liver makes in response to GH)

Symptoms of GH deficiency in adults?

x Reduced lean mass x Increase adiposity x Increase waist: hip x Reduced muscle strength & bulk (so reduced exercise performance [ONE of the PROVOCATION TESTS!!!!] x Decreased HDL and Increased LDL x Affects mental health - affecting quality of life

Benefits of GH therapy in adults?

(literally opp. of the symptoms!)

Potential risks of GH therpay in adults?

Increases susceptibility to cancer Expensive! (£42k)