Hyposecretion of anterior pituitary hormones

Question 1

Name 6 hormones secreted by the anterior pituitary.

Answer 1

FSH

LH

Prolactin

GH

TSH

ACTH

Question 2

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

Answer 2

secondary is caused by anterior pituitary disorder

primary caused by endocrine gland disorder.

Question 3

Outline the endocrine chain of command.

Answer 3

hypothalamus –> anterior pituitary –> endocrine gland.

Question 4

Define hypopituitarism.

Answer 4

Decreased production of all anterior pituitary hormones or some specific hormones.

congential/acquired

Question 5

What causes congenital panhypopituitarism?

Answer 5

•Usually due to mutations of transcription factor genes needed for normal anterior pituitary development

e.g. PROP 1 mutation.

Question 6

What is the result of congenital panhypopituitarism?

Answer 6

Deficiency of GH and at least one more APT hormone –> short stature

Question 7

How is congenital panhypopituitarism diagnosed?

Answer 7

hypoplastic anterior pituitary gland on MRI

Question 8

Name potential causes of acquired panhypopituitarism.

Answer 8

Tumours

• hypothalamic (craniopharyngiomas)
• pituitary )adenomas, metastases, cysts)

Radiation

-hypothalamic/pituitary damage (GH most vulnerable, TSH resistant)

Infection.

Traumatic brain injury

Infiltrative disease

Inflammatory (hypophysitis)

Pituitary apoplexy

• haemorrhage or infarction.
• pre-oartum infarction (Sheehan’s syndrome)

Question 9

Give another name for Panhypopituitarism.

Answer 9

Simmond’s disease.

Question 10

What causes the symptoms of panhypopituitarism. Give some examples.

Answer 10

Symptoms due to deficient hormones.

e.g. FSH/LH - secondary hypogonadism, reduced libido, secondary amenorrhea, erectile dysfunction.

ACTH - secondary hypoadrenalism (cortisol deficiency), fatigue.

TSH - secondary hypothyroidism, fatigue.

Question 11

Explain Sheehan’s syndrome.

Answer 11

Describes post-partum hypopituitarism secondary to hypotension post partum haemorrhage.

Anterior pituitary enlarges in pregnenacy (lactotroph hyperplasia).

PPH –> pituitary infarction.

Question 12

Give 4 ways Sheehan’s syndrome presents.

Answer 12

Lethargy, anorexia, weight loss - due to TSH/ATCH/GH deficiency.

Failure of lactation - PRL deficiency.

Failure to resume menses post delivery.

Posterior pituitary usually not affected.

Question 13

What is pituitary apoplexy.

Answer 13

•Intra-pituitary haemorrhage or (less commonly) infarction

Question 14

Give 2 things that may cause pituitary apoplexy.

Answer 14

Anti-coagulants.

Pituitary adenoma (can be the first presentation)

Answer 15

Label pituitary diagram.

Question 16

Give 3 potential symtpoms of pituitary apoplexy.

Answer 16

Severe, sudden headache.

Visual field defect (compressed optic chiasm)

Diplopia (IV, VI) and ptosis (III) with cavernous isnus involvement.

Question 17

Outline the limitations of using basal plasma concentrations to diagnose hypopituitarism.

Answer 17

Limited interpretation:

cortisol present.at low levels + fluctuates throughout day.

T4 has a hald life of 6 days in the blood: may last after function.

FSH/LH are cyclical.

GH/ACTH are pulsatile.

Question 18

Outline how stimulated pituitary function tests work.

Answer 18

Induce stress then measure stress hormone levels (ACTH and GH).

Induce hypoglycaemia (>2.2mM) = ‘stress’ –> GH and ACTH release (measure cortisol).

TRH stimulates TSH

GnRH stimulates FSH and LH.

Question 19

How can hypopituitarism be diagnosed radailogically.

Answer 19

Pituitary MRI.

Can reveal specific pituitary pathology.

Question 20

Fill table showing deficient hormones, their replacements, and how to check.

Answer 20

Question 21

What is an indicator of somatotrophin deficiency.

Answer 21

Short stature in children (2 SDs below mean height)

Less clear in adults.

Question 22

GIve 7 causes of short stature in childre.

Answer 22

°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

Question 23

Label growth axis diagram

Answer 23

Question 24

What causes Prader Willi Syndrome.

Answer 24

GH deficiency secondary to impaired hypothalamic function.

Question 25

What causes dwarfism (Achondroplasia)?

expand.

Answer 25

•Mutation in Fibroblast Growth

Factor Receptor 3 (FGF3)

•Abnormality in growth plate

chondrocytes - impaired

linear growth

Question 26

Define pituitary dwarfism.

Answer 26

Childhood GH deficiency.

Question 27

What is Laron dwarfism?

Answer 27

GH receptor mutation.

IGF-1 treatment in childhood can increase height.

Question 28

What is mid parental height?

Answer 28

Predicted adult height based on mother’s and father’s height.

Question 29

Give 4 causes of acquired GH deficiency in adults.

Answer 29

Trauma

Pituitary tumour

Pituitary surgery

Cranial radiotherapy.

Question 30

How is GH deficiency in adults diagnosed?

Answer 30

Provocative challenge (random test = useless since GH is pulsatile).

e.g. GHRH + Arginine together

Insulin (cause hypoglycaemia)

Exercise.

Question 31

diagram to show GH response to stimulus.

Answer 31