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Flashcards in Hyposecretion of anterior pituitary hormones Deck (43)
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1
Q

What are examples of anterior pituitary hormones?

A
FSH/LH
Prolactin
Growth Hormone
TSH
ACTH
2
Q

What is hypopituitarism/panhypopituitarism?

A

Decreased production of ALL adenohypophysial hormones - can be specific however

3
Q

What usually causes congenital panhypopituitarism?

A

Mutations of transcription factor genes needed for normal pituitary development eg PROP1 mutation

4
Q

What is the outcome of congenital panhypopituitarism?

A

Deficiency of GH and at least 1 other pituitary hormone

5
Q

What are signs of congenital panhypopituitarism?

A
Abnormal slowing of growth
Delayed puberty
Excessive thirst and excessive urination
Less frequent menstrual periods
Low blood sugar (hypoglycemia)
Prolonged jaundice in infants
Sensitivity to cold
Poor appetite
Weight loss or weight gain
Unusually dry skin
Nausea or dizziness Fatigue or drowsiness
Small penis in males
6
Q

What investigations would you do for congenital panhypopituitarism?

A

Look for a hypoplastic (underdeveloped) adenohypophysis on an MRI

7
Q

In what different ways can you acquire panhypopituitarism?

A

Tumours (hypothalamic or pituitary)
Radiation (GH most vulnerable while TSH is relatively resistant)
Infection
Traumatic brain injury
Infiltrative disease (neurosarcoidosis)
Pituitary apoplexy
Peri-partum infaction (sheehans syndrome)

8
Q

What symptoms are caused by a FSH/LH deficiency?

A

Reduced libido
Secondary amenorrhoea
Erectile dysfunction

9
Q

What symptoms are caused by an ACTH deficiency?

A

weight loss, lack of appetite (anorexia), muscle weakness, nausea and vomiting, and low blood pressure (hypotension). Low blood levels of sugar and dilutional hyponatremia (low blood sodium levels) may occur

10
Q

What symptoms are caused by a TSH deficiency?

A

fatigue, lethargy, cold intolerance, and weight gain
(brittle fingernails; coarsening and thinning hair; puffy eyes; pale, dry skin; weakness; and constipation. Hoarseness; menstrual disorders; puffy hands, face and feet; thickening of the skin; thinning of eyebrows; increased cholesterol levels; muscle and/or joint aches and stiffness; slowed speech; and decreased hearing are symptoms usually expressed later in the course of the disease)

11
Q

What are the presentations of panhypopituitarism and what is it also called?

A

Secondary hypogonadism
Secondary hypoadrenalism
Secondary hypothyroidism
Also called Simmond’s disease

12
Q

What is sheehan’s syndrome?

A

Post partum hypopituitarism secondary to hypotension due to post partum haemorrhage where due to the already enlarged anterior pituitary that happens in pregnancy and from the hypotension from loss of blood leads to the pituitary becoming underperfused by the small superior hypophyseal artery that supplies all the blood and then infarcts

13
Q

How does Sheehan’s Syndrome present?

A

Hard to notice - lethargy, anorexia, weight loss (TSH, ACTH, GH deficiency)
Easy to notice - failure of lactation (prolactin deficiency), failure to resume menstrual cycles post delivery
Normally hard to see sheehans syndrome because lots of the symptoms are normal signs post pregnancy

14
Q

What is a pituitary aploplexy

A

An intra pituitary haemorrhage/infarction

15
Q

What are the symptoms of a pituitary apoplexy?

A

Severe sudden onset headache, bitemporal hemianopia, diplopia, pitosis

16
Q

What is diplopia?

A

Double vision

17
Q

What is ptosis?

A

Drooping upper eyelid

18
Q

How can you biochemically diagnose hypopituitarism?

A

Basal plasma conc of hormones: cortisol is low, T4/tyroxine, FSH/LH, GH/ACTH
Stimulated pituitary function tests: ACTH/GH are stress hormones, insulin induced hypoglycaemia stimulates GH/ACTH release. TRH stimulates TSH release and GnRH stimulates FSH and LH release

19
Q

What is stress biochemically defined as in the body?

A

Hypoglycaemia <2.2mM glucose

20
Q

How can you radiologically diagnose hypopituitarism?

A

Pituitary MRI can show things like an ‘empty sella’ where there is only a thin rim of pituitary tissue

21
Q

If someone is deficient in ACTH what do you treat with to replace the hormone and how do you check?

A

Replacement: hydrocortisone
Check: Serum cortisol

22
Q

If someone is deficient in TSH what do you treat with to replace the hormone and how do you check?

A

Replacement: Thyroxine
Check: Serum free T4

23
Q

If a woman is deficient in LH/FSH what do you treat with to replace the hormone and how do you check?

A

Replacement: HRT (E2 plus progestagen)
Check: Symptom improvement, withdrawal bleeds

24
Q

If a man is deficient in LH/FSH what do you treat with to replace the hormone and how do you check?

A

Replacement: Testosterone
Check: Symptom improvement, serum testosterone

25
Q

If someone is deficient in GH what do you treat with to replace the hormone and how do you check?

A

Replacement: GH
Check: IGF2, growth chart (children)

26
Q

What are causes of growth hormone deficiency

A
Genetic eg prader-willi
Emotional deprivation
Systemic disease
Malnutrition
Malabsorption eg coeliac disease
Endocrine disorders eg cushings, GH deficiency
Skeletal dysplasia eg achondroplasia
27
Q

What is the definition of short stature in children?

A

<2 SD from the mean

28
Q

What is the definition of short stature in adults?

A

Less clear definition

29
Q

What mutation causes achondroplasia?

A

Mutation on fibroblast growth factor receptor 3 (FGF3)

30
Q

What abnormalities happen in achondroplasia?

A

Abnormalities in growth plate chondrocytes that impairs linear growth resulting in an average sized trunk and short arms/legs

31
Q

What causes short stature in pituitary dwarfism?

A

Childhood GH deficiency

32
Q

What causes short stature in prader willi syndrome?

A

GH deficiency secondary to hypothalamic dysfunction

33
Q

What causes short stature in Laron dwarfism?

A

High local incidence, mutation in GH receptor treated with IGF-1 in childhood

34
Q

How is short stature diagnosed?

A

Predicted height calculated according to parents heights and other factors, then the child’s length (later height) is mapped against its weight and followed. If they fall below the lowest line, they often need referring to a paediatrician

35
Q

What are causes of acquired GH deficiency in adults?

A

Trauma
Pituitary tumour/surgery
Cranial radiotherapy

36
Q

How can you diagnose acquired GH deficiency in adults?

A

Provocative challenge - a stimulation test
GHRH + Arginine (IV), Insulin (IV), glucagon (IM), exercise (10mins).
Plasma GH is then measured at specific time points after.

37
Q

The NICE cut off for hormonal replacement therapy for GH ?

A

3mcg/L

38
Q

How is growth hormone therapy prepared and administered?

A

Human recombinant GH is administered daily, as a subcutaneous injection that monitors clinical responses and adjusts dose to IGF-1

39
Q

What is the absorption and distribution of growth hormone therapy?

A

Maximal concentration in plasma in 2-6 hours

40
Q

What is the half life of GHRT

A

20 mins

41
Q

What is the duration of action of GHRT?

A

Lasts well beyond clearance with peak IGF1 levels at approx 20 hours

42
Q

What are GH deficiency symptoms

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.

43
Q

What are the risks of GHRT

A

Increased susceptibility to cancer although no currently supported data.
Expensive.