hypopituitarism Flashcards
list the causes of hypopituitarism
- craniopharyngioma
- rathkes cyst
- meningioma
- lymphocytic hypophysitis
- non-functioning pituitary adenoma
contrast MRI with CT
MRI
- preferred for viewing pituitary
- better visualisation for soft tissues and vascular
CT
- better at visualising bones and calcifications
- better at viewing pituitary adenomas with calcifications
CT disadvantages
- less optimal soft tissue imaging compared to MRI
- use of intravenous contrast media
- exposure to radiation
craniopharyngioma
- benign tumour
- Arise from squamous epithelial remnants of Rathke’s pouch
- solid or cysts
- Adamantinous: cyst formation and calcification - rare
- Squamous papillary: well circumscribed
Peak ages: 5 to 14 years; 50 to 74 years
Solid, cystic, mixed, extends into suprasellar region
Raised ICP, visual disturbances, growth failure, pituitary hormone deficiency, weight increase
Adamantinous vs squamous papillary craniopharyngioma
Adamantinous: Cyst formation and calcification
Squamous papillary: Well circumscribed
Diagnosis of Craniopharyngioma (4)
- CT
- MRI
- Visual Examination
- Endocrine examination
Pathophysiology of craniopharyngioma (4)
- Squamous epithelial remnants of Rathke’s pouch
- Benign, slow growing tumour infiltrates to surrounding structures
- Mixed solid and cystic parts
- Doesn’t spread to other parts of the body but puts pressure on suprasellar region of skull
Peak ages craniopharyngiomas occur (2)
- 5 to 14 years
- 50 to 74 years
Presentation of craniopharyngioma (5)
- Raised ICP - intercranial pressure
- Visual disturbances (bitemporal hemianopia)
- Growth failure
- Pit. hormone deficiency
- Weight increase
Treatment of craniopharyngioma (3)
- Hormone replacement
- Transsphenoidal surgical removal
- Radiotherapy
Cause of meningiomas
Complication of radiotherapy
Complications of meningioma (3)
- Loss of visual acuity
- Visual field defects
- Endocrine dysfunction
How common are meningiomas?
2nd most common (first is pituitary adenoma)
Types of primary brain tumour (4)
- Glioma, mc type: astrocytoma (90%) (2nd mc paediatric cancer after ALL)
- Oligodendroglioma
- Meningioma
- Schwannoma
what is Rathke’s Cyst
Derived from remnants of Rathke’s pouch
Single layer of epithelial cells with mucoid, cellular, or serous components in cyst fluid
Mostly intrasellar component, may extend into parasellar area
Mostly asymptomatic and small
symptoms of Rathke’s Cyst
Mostly asymptomatic and small
Present with headache and amenorrhoea, hypopituitarism and hydrocephalus
what is Lymphocytic Hypophysitis and what causes it
Inflammation of the pituitary gland due to an autoimmune reaction
- Lymphocytic adenohypophysitis
- Lymphocytic infindibuloneurohypophysitis
- Lymphocytic panhypophysitis
Non-Functioning Pituitary Adenoma
- 20-60yr olds
- 50% of NFPA are incidentalomas
- 50% of macroadenomas have visual disturbances and 50% have headaches
Signs of aggressiveness
in Non-Functioning Pituitary Adenoma
Large size
Cavernous sinus invasion
Lobulated suprasellar margins
Non-Functioning Pituitary Adenoma tests and surgery
No specific test but absence of hormone secretion
* Could have normal pituitary function
* Trans-sphenoidal surgery if threatening eyesight or progressively increasing in size
Clinical Manifestations of hypopituitarism
Depends on which pituitary hormone is deficient
Fatigue
Weight changes
Impaired sleep, pallor, dry skin
Blood pressure changes
Metabolic changes –hyperlipiaemia, insulin resistance, hypoglycaemia
Bowel changes
Sexual dysfunction, amenorrhoea
Polyuria
Testing Pituitary Function
Complex because:
Many hormones: GH, LH/FSH, ACTH, TSH and ADH
May have deficiency of one or all and may be borderline
Circadian rhythms and pulsatile
- Guiding principle:
If the peripheral target organ is working normally the pituitary is working
Testing Gonadal Axis: Men
Primary Hypogonadism - Low T raised LH/FSH
Hypopituitary - Low T normal or low LH/FSH
Anabolic use - Low T and suppressed LH
Measure 0900h fasted T and LH/FSH in pituitary disease
TFT primary hypothyroid
Hypopituitary
graves disease
TSHoma
hormone resistance
Primary Hypothyroid - Raised TSH low Ft4
Hypopituitary - Low Ft4 with normal or low TSH
Graves disease (toxic) - Suppressed TSH high Ft4
TSHoma (very rare) - High Ft4 with normal or high TSH
Hormone resistance - High Ft4 with normal or high TSH
Testing Gonadal Women: Female
- Low oestradiol, high LH and FSH (FSH greater) = Pimary ovarian failure
- Low oestradiol, normal/low LH and FSH, oligo/amenorrhoea = Hypopituitarism
Testing the HPA axis
Circadian Rhythm
Measure 0900h cortisol and synacthen
Primary AI: Low cortisol, high ACTH, poor response to Synacthen
Hypopituitarism: Low cortisol, low or normal ACTH, poor response to synacthen
Testing GH/IGF1 axis
GH is secreted in pulses with greatest pulse at night and low or undetectable levels between pulses
GH levels fall with age and are low in obesity
Measure: IGF-I and GH stimulation test
- Insulin stress test
- Glucagon test
- Other
Prolactin levels
Prolactin under negative control of dopamine
Prolactin is a stress hormone
Measure prolactin or cannulated prolactin (3 samples over an hour to exclude stress of venepuncture
Prolactin may be raised because of:
Stress
Drugs: antipsychotics
Stalk pressure
Prolactinoma
Dynamic Testing
Dynamic stimulation/suppression testing may be useful in select cases to further evaluate pituitary reserve and/or for pituitary hyperfunction
Pituitary Hormone Replacement
Adrenal Insufficiency
Hypothyroidism
Growth Hormone deficiency
Hypogonadism
Vasopressin deficiency
epidemiology hypopituitarism
Prevalence 45 cases per 100, 000
Incidence 4 cases per 100, 000
Mortality is high for untreated hypopituitarism
Lower health status, increased incapacitation and sick days
Pituitary tumours/lesions, radiotherapy, head injury, glucocorticoids/opioids, apoplexy
name the hormone replacement therapies that can be used in hypopituitarism
desmopressin - vasopressin
oestrogen replacement
testosterone placement
growth hormone replacement
thyroxine replacement
trans-sphenoidal surgery
radiotherapy
