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
Hypophysitis clinical presentation & MRI findings
- Headache
- Symptoms of hypopituitarism
- Pituitary stalk thickening
- Homogenous pituitary enlargement
Hypophysitis management
Treat cause e.g. high dose steroids- lymphocytic hypophysitis
Treat associated hypopituitarism (hormone replacement)
What is pituitary apoplexy
Severe bleeding or loss of blood flow to pituitary gland causing rapid expansion of the gland.
Usually occurs in patients with a pre-existing pituitary adenoma.
Pituitary apoplexy clinical presentation
- Severe headache, nausea, vomiting
- Visual defects & ocular palsy (nerve compression)
- Hypopituitarism
- Reduced GCS
Pituitary apoplexy investigations
- MRI
- Pituitary function tests
- Visual field assessment
Pituitary apoplexy management
Acute hormone deficit replacement
Possible surgery depending on clinical features
