Pituitary Disease Flashcards
What are pituitary adenomas?
Benign tumours of the glandular tissue
Can be life threatening - mass effects/secretory actions
How are pituitary adenomas classified according to size?
Microadenoma <1cm
Macroadenoma >1cm
How are pituitary adenomas classified according to function?
Functioning
Non-functioning
How do non-functioning adenomas present?
Mass Effects -bitemoporal heminaopia -ocular palsies -signs of raised ICP -hypothalamic compression sx Hypopituitarism
How do functioning adenomas present?
Acromegaly
Hyperprolactinemia
Cushing’s syndrome
Mass effects as in non-functioning adenomas
What causes bitemoporal heminaopia?
Compression of optic chiasm
What causes ocular palsies?
Compression of CN III, IV & VI
What causes hypopituitarism?
Destruction of normal functioning tissue
What are the symptoms of hypothalamic compression?
Altered appetite
Thirst
Abnormal sleep/wake cycle
What are the signs of raised ICP?
Headache Nausea/Vomiting Confusion (time - location+place) Double vision Pupils w/o light response
What is hyperprolactinaemia?
Excessive prolactin production,stimulating milk production and inhibiting GnRH + gonadotropin production
What are the symptoms of hyperprolactinaemia?
Galactorrhoea (f) Subfertility (m) Oligo/Amenorrhoea Decreased libido Arrested puberty Osteoporosis (long term)
What is acromegaly?
Syndrome characterised by excessive GH production with effects on skeletal/soft-tissue growth
What are the symptoms of acromegaly?
Change in appearance Increased hand/foot size Tiredness Excessive sweating Poor libido Headaches Visual deterioration Sx of DM Sx of hypopituitarism
What are the signs of acromegaly?
Protruding mandible Prominent supraorbital ridge Interdental separation Large tongues Spade-like hands/feet Tight rings Visual field defects Hypertension
What effect does excess GH have in children?
Gigantism (if prior to epiphyseal plate closure)
What is Cushing’s syndrome?
Syndrome characterised by Sx of increased circulating glucocorticoid
What are the symptoms of Cushing’s?
Central weight gain Change of appearance Depression Insomnia Poor libido Thin skin/easy bruising Excess hair growth/acne Sx of DM
What are the signs of Cushing’s?
Moon face Frontal balding Striae Hypertension Pathological fractures Dorsal fat pad (buffalo hump) Proximal myopathy
What is the management for a prolactinoma?
Dopamine agonists (Ropinarole/Bromocriptine) lifelong Reduce tumours but sx arise again if medications stopped
What are the side effects of Ropinarole/Bromocriptine?
Nausea/Vomiting
Dizziness
Syncope
Pulmonary/cardiac/retroperitoneal fibrosis
What is the most common cause of acromegaly?
Almost exclusively a pituitary tumour
Paraneoplastic release of GH from non-pituitary tumours
What investigations are appropriate in suspected acromegaly/gigantism?
IGF-1 (raised, correlated w/ GH)
OGTT (failure to suppress GH secretion, >2mcg/ml at 2hrs)
What is the management for acromegaly?
Somatastatin analogues shrink tumour
Surgery via transphenoidal approach
What is the most common cause of Cushing’s Syndrome?
Exogenous administration of steroids
What are the spontaneous causes of Cushing’s syndrome?
Cushing’s disease - increased ACTH from pituitary (65%)
Ectopic ACTH - non pituitary tumour, SCLC (10%)
Excess adrenal cortisol - adrenal tumour/nodular hyperplasia (25%)
What investigations are appropriate in suspected Cushing’s syndrome?
Cortisol (raised) Dexamethasone suppression (failure to suppress cortisol) 24hr urinary free cortisol
What investigations can be used to localize the cause of Cushing’s syndrome?
Plasma ACTH - adrenal likely, CT
ACTH detectable –> 48hr, high dose dexamethasone suppression test:
-complete/partial suppression = pituitary (MRI sella)
-no suppression = ectopic (CXR)
CRH –> cortisol raised w/ pituitary sources of ACTH
What is the management for a pituitary adenoma?
Transphenoidal surgery
What is the main complication of delaying surgery?
Permanent loss of vision due to prolonged chiasm compression
What is Panhypopituitism?
Defective production of all pituitary hormones
How does Panhypopituitism present?
Fatigue, myalgia, hypotension (GH)
Diabetes insipidus (ADH)
Hypothyroidism (TSH)
What are the pituitary causes of Panhypopituitism?
1o/metastatic tumour Surgical removal/irradiation of pituitary Ischaemic necrosis (hypotensive shock)
What are the hypothalamic causes of Panhypopituitism?
1o brain tumour (craniopharyngoma)
Infarction
Sarcoid
Infection
How is Panhypopituitism diagnosed?
Pituitary hormones (low)
Effector gland hormones (low)
Low response to stimulation tests
Imaging
What is the main cause of diseases of the neurohypothesis?
Damage to hypothalamus
- tumour invasion - infarction
How do diseases of the neurohypothesis present?
Diabetes insipidus (polyuria & polydipsia) if low ADH SIADH if high ADH
