Hypopituitarism & Panhypopituitarism Flashcards
Describe the surrounding anatomy of the pituitary gland
Optic chiasm,
III, IV, VI, Va, Vb cranial nerves
Internal carotid artery
Cavernous sinus
Sphenoid sinus
State the 5 hormones released from the anterior pituitary gland and their associated hypothalamus and peripheral hormones
(CRH ->) ACTH (-> Cortisol, adrenal glands)
(TRH ->) TSH (-> T3/4, thyroid gland)
(GnRH ->) LH/FSH (-> E2/TEST, gonads)
(GHRH ->) GH
(Absence of Dopamine ->) Prolactin
Pituitary tumours can compress surrounding structures. What are the effects of this
- Optic chiasm -> bitemporal hemianopia
- CN III -> Unopposed lateral Rectus & superior oblique muscles (inferolateral pull), ptosis, miosis
- CN IV ->
- CN VI ->
If there is too much hormone what test would you do? If there is too little hormone what test would you do?
Too much -> suppression test
Too little -> stimulating test
State the base line tests for pituitary function
9am ACTH & 9am Cortisol
TSH & Free T3/T4
FSH/LH & E2 or 9am Testosterone
GH & IGF-1
Prolactin
Plasma/Urine osmolality
NOTE - Cortisol & GH usually requires a dynamic test
Describe the 3 dynamic pituitary tests for the HP axis, for ACTH, GH & for ADH
Synacthen Test - ACTH
- Cortisol response to 250mcg synacthen
- Normal response = increase in cortisol by ~150nmol/l
Insulin Stress Test/ Prolonged Glucagon Test - ACTH & GH
- Cortisol & GH response to glucagon
- Normal response = increase in cortisol & GH
Water Deprivation Test - ADH
Hypopituitarism Aetiology
- Vascular
- Inflammatory e.g. TB, sarcoidosis
- Infection e.g. Meningitis/ encephalitis/ abscess
- Neoplasm e.g. pituitary adenoma
- Idiopathic
- Traumatic e.g. subarachnoid haemorrhage
Hypopituitarism Pathophysiology
Anterior pituitary
- ↓ GH → growth failure
- ↓ TSH → secondary hypothyroidism
- ↓ LH/FSH → hypogonadism
- ↓ ACTH → hypoadrenal
- ↓ prolactin → unknown
Posterior pituitary
- ↓ ADH → diabetes insipidus
Define Hypopituitarism & Panhypopituitarism
Hypopituitarism
- Inadequate production of one or more pituitary hormone as a result of damage to the pituitary gland and/or hypothalamus
Panhypopituitarism
- Refers to deficiency of all anterior pituitary hormones
- It is most commonly caused by pituitary tumours, surgery or radiotherapy
Summary of hormones
https://docs.google.com/document/d/1-JwSmWXjmKVn1d9todNNktTFyUDUki59KaTbdEptCTo/edit
Hypopituitarism clinical presentation
- Anatomical effects - headaches & bitemporal hemianopia
- Hypothyroidism - weight gain, cold intolerance, tiredness, constipation, hair loss, dry skin, bradycardia
- Hypoadrenalism - postural hypotension, low Na, hypoglycaemia, fatigue, pallor, weakness
- Hypoprolactinaemia - galactorrhoea, hypogonadism
- LH/FSH deficiency (female) - oligomenorrhea, loss of libido, dyspareunia, infertility, osteoporosis
- LH/FSH deficiency (male) - loss of libido, erectile dysfunction, reduced sexual hair growth, osteoporosis, anaemia, decreased muscle mass
- Growth hormone deficiency - decreased muscle mass, visceral obesity, fatigue, impaired attention/memory
- ADH deficiency - polyuria/polydipsia, low urine osmolality, increased urine osmolality
Hypopituitarism management
** Hormone Replacement **
- Hydrocorisone (cortisol)
- Thyroxine (T4)
- Sex steroids (E2/TEST)
- Desmospray or desmopressin tablet (ADH)
- GH replacement only given to all children or to adults with reduced QOL (to improve cardiac, bone, fat & fitness)
** Definitive Treatment **
Based on underlying cause
If pituitary adenomas -> transphenoidal resection
Hypopituitarism Investigations summary
** Baseline Tests **
9am ACTH & Cortisol
TSH & Free T3/4
FSH/LH & E2/ 9am Testosterone
IGF1
Plasma/Urine osmolality test
** Dynamic Tests **
Synacthen test
Insulin Stress Test or Prolonged Glucagon test
Water deprivation test
** Aetiology Tests **
MRI for tumours
State the effects of Hypopituitarism in child development
Delayed puberty & impaired growth/development
What are the two hormones released from the posterior pituitary gland?
Oxytocin & ADH
What is hypophysitis and what causes it
Inflammation of the pituitary gland (which can lead to hypopituitarism)
- Autoimmune (lymphocytic hypophysitis)
- Infections & granulomatous disease e.g. TB, sarcoidosis
- Medications e.g. immunotherapy induced/ cancer drugs
