Hypopituitarism 2 Flashcards
What is primary disease?
If the gland itself fails
What is secondary disease?
No signals from hypothalamus or anterior pituitary
What Primary hypoadrenalism?
Compared to secondary?
Destruction of adrenal cortex
Cortisol falls ACTH rises
Pituitary tumour damaging corticotrophs, can’t make ACTH, cortisol falls
What can cause hypogonadism ( men + women )
( primary hypogonadism )
Mumps = testes Chemo = ovaries
Congenital causes of hypopituitarism?
Rare
Mutations of Tfactor genes for normal A Pit development
Deficient in GH and at least 1 more pit hormone
Acquired causes of hypothyroidism:?
Adenoma = gland tumour or metastases Radiation Infection - meningitis Trauma Surgery Hypophysitis Pituitary apoplexy Peri-partum infarction. (Sheehan's syndrome)
What is panhypopituitarism?
Total loss of anterior and posterior pituitary function
some dysfunction especially inflammation or surgery may cause posterior issues too
Risk of radiotherapy induced hypopituitarism?
Pit + hypothalamus sensitive to radiation
depends on dose delivered to the axis
GH and gonadotrophins most sensitive
Prolactin can increase after radiation (lose dopamine)
Risk persists up to 10 years after due to the nature of chemo
What are the presentations of hypopituitarism?
( FSH/LH )
- Reduced libido
- Secondary amenorrhoea
- Erectile dysfunction
- Reduced pubic hair
( ACTH )
- Fatigue
( TSH )
- Fatigue
( GH )
- Reduced Quality of Life
( PRL )
- Inability to breastfeed
What is Sheehan’s syndrome?
Post partum hypopituitarism secondary to hypotension ( post partum haemorrhage = PPH )
More common in developing because of haemorrhage control
Anterior Pit enlarges in pregnancy - lactotroph hyperplasia
PPH leads to pituitary infarction
What are the consequences of Sheehan’s syndrome?
- Lethargy, anorexia, weight loss ( ACTH )
- failure of lactation
- Failure to resume periods
- Posterior pit not affected
What is the best radiological way to visualise the pituitary gland?
MRI ( check slide 20, the slighter darker C shape circle is the adenoma + slide 23)
What is Pituitary apoplexy?
Intra-gland haemorrhage
Dramatic presentations with already adenomas
Can be precipitated by anti-coagulants
What are the symptoms of Pituitary Apoplexy?
Severe sudden onset headache
Visual field defect = bitemporal hemianopia
Cavernous sinus involvement may lead to diplopia (IV, V) or ptosis (III)
How do we diagnose hypopituitarism?
Dynamic Pituitary function:
To test ACTH + GH cause hypoglycaemia (<2.2mM) to cause stress and release both hormones and test cortisol
If there is an issue px will remain hypoglycaemic
Can we treat prolactin deficiency?
No
Treatment of GH deficiency?
Daily injection - can give right dosage for children
Measure response by:
- improvement in Quality of life
- Plasma IGF-1
Treatment of TSH deficiency?
Daily levothyroxine
remember, TSH will be low so you cannot use this to adjust dose as you would in primary hypothyroidism
Aim for fT4 above the middle of the reference range
Treatment of ACTH …
Replace cortisol rather than ACTH
Difficult to mimic dirunal variation of cortisol
Option 1: Prednisolone once daily AM ( 3mg )
Option 2: Hydrocortisone x3 daily ( 10/5/10mg)
Sick day rules for patients with ACTH deficiency?
At risk of adrenal crisis (dizziness, hypotension, vomiting, weakness, can result in collapse and death)
Px who take Prednisolone or Hydrocortisone (replacement steriods) must be told sick day rules:
- Steroid alert pendant/bracelet
- Double steroid dose (glucocorticoid not mineralocorticoid) if fever/intercurrent illness
- Unable to take tablets (eg vomiting), inject IM or come straight to A & E
treatment of FSH/LH deficiency in men
For no fertility required : replace tostesterone topically or intramuscular
Measure plasma levels
However this does not restore sperm
For fertility: Induce spermatogenesis by gonadotrophin injections
Works best if hypogonadism occurred after puberty
Measure testosterone and semen analysis ( sperm production may take 6-12 months )
Treatment of FSH/LH deficiency in women?
No fertility required approach:
- Replace oestrogen
- Oral or tropical
- Will need ++ progesterone if intact uterus to prevent endometrial hyperplasia
Fertility required:
- Can induce ovulation by timed gonadotrophin injections (IVF) - LH+FSH
Women presents with altered vision
Optician diagnoses bitemporal hemianopia
MRI shows pituitary macroadenoma
Blood tests show:
9AM cortisol High
fT4 levels low
TSH low
What is diagnosis?
Secondary hypothyroidism
Because TSH is low AND ft4 low.
Because TSH is low cause anterior pituitary
How to asses is levothyroxine dose is correct
Aim to increase fT4 into reference range
