Pathology of Pituitary and Adrenal Glands Flashcards
what is the anterior pituitary derived from
Rathkes pouch
what trophic hormones does the anterior pituitary produce
TSH, ACTH, FSH, LH
what non trophic hormones are produced by the anterior pituitary
GH and prolactin
what is a trophic hormone
one that has a growth affect on endocrine glands and stimulates them to produce their hormones
what is the andenohypophysis
anterior pituitary gland
what is the neurohypophysis
posterior pituitary gland
what does posterior pituitary tissue consist of
is an extension of neural- consists of modified glial cells and axonal processes
what does the posterior pituitary secrete
vasopressin and oxytocin
describe the histology of the posterior pituitary gland
non- myelinated axons of neurosecretory neurones
describe the histology of the anterior pituitary gland
islands, cords of cells,
acidophils,
basophils,
chromophobes
what cells produce GH
type of acidophil called somatotrophs
what type of cell produces PRL
type of acidophil called mammotrophs
what type of cell produces ACTH
type of basophil called corticotrophs
what type of cell produces TSH
type of basophil called thyrotrophs
what type of cell produces FSH, LH
type of basophil called gonadotrophs
what can cause hyperfunction of the anterior pituitary
adenoma, carcinoma
what can cause hypofunction of the anterior pituitary
surgery/ radiation, sudden haemorrhage into gland, ischaemic necrosis (sheehan syndrome in pregnancy), tumours extending into sella, inflammatory conditions (sarcoidosis)
what causes SIADH
ectopic secretion of ADH by tumours
primary disorder int the pituitary
what condition can
pituitary adenomas be associated with
MEN1- werner syndrome
what are pituitary adenomas classified by
cell type/ hormone produced
can be hypo/non functional (mass lesion which compresses surrounding normal pituitary tissues which will atrophy)
can produce more than 1 hormone
what are features of large pituitary adenomas
visual field defects,
can cause pressure atrophy of surrounding normal tissue,
infarction can lead to panhypopituitarism
what are the functional pituitary adenomas
prolactinoma (most common), GH secreting, ACTH secreting
what are the symptoms of a prolactinoma
infertility, lack of libido, amenorrhea
what are the features of a growth secreting hormone
GH causes increase in insulin like growth factors (IGF)
stimulates growth of bone, cartilage and connective tissue
gigantism or acromegaly
what are the symptoms of an ACTH tumour
cushings disease
bilateral adrenocortical hyperplasia
what do functional pituitary carcinomas usually secrete
prolactin or ACTH
what can cause panhypopituitarism
granulomatous inflammation- sarcoidosis
infarction- sheehans syndrome
primary or metastatic tumours
what is a craniopharyngioma
intracranial tumour derived from remnants of rathke’s pouch, often suprasellar
who gets craniopharynogioma
5-15 years
eldery- 6th to 7th decades
what are the symptoms of craniopharyngioma
visual disturbances, children may have growth retardation
what is the prognosis like for craniopharyngioma
very good (especially if under 5cm)
what are the central causes of diabetes insipidus
ADH deficiency
trauma (including surgery), tumours, inflammatory disorders of the hypothalamus an pituitary
what are the nephrogenic causes of diabetes insipidus
renal resistance to ADH effects
what causes SIADH
ectopic production of ADH- paraneoplastic syndrome
how much does an adrenal gland weigh
4-5 grams each
where are the adrenal glands
sit superior and medial to the upper pole of the kidneys
what are the components of the adrenal glands
outer cortex enclosing a central medulla
what diseases can manifest as adrenal pathologies
pituitary disease (ACTH secretion from function adenoma)
Shock, DIC
conditions that damage/ destroy adrenal tissue
is it the cortex or medulla of the adrenal glands that can be affected by hypo/hyper function
both
what can cause hyperfunction of the adrenal cortex
hyperplasia, adenoma, carcinoma
what can cause hypofunction of the adrenal cortex
acute: waterhouse-friderichsen
chronic: addisons disease
what are the congenital causes of adrenocortical hyperplasia - how does it cause it
group of autosomal recessive disorders
where there is a deficiency or lack of enzyme required for steroid biosynthesis which leads to increased androgen production (masculinisation and precocious puberty)
stimulates ACTH release and cortisol hyperplasia
what are the causes of acquired adrenocortical hyperplasia
endogenous ACTH production: cushings disease (pituitary adenoma), ectopic ACTH (paraneoplastic syndrome)
what happens to the adrenal gland in acquired adrenocortical hyperplasia
bilateral adrenal enlargement
diffuse (ACTH driven) or nodular (ACTH independent)
what is produced by the adrenal cortex
aldosterone, cortisol and testosterone
who gets adrenocortical tumours
usually adults, males more than females
what is the usual presentation of an adrenocortical tumour
incidental finding
hormonal effects
mass lesion (almost always carcinomas)
carcinomas with necrosis can cause fever
describe what adenocortical adenomas are like
well circumscribed, encapsulated lesions
usually small
yellow/ brownish surface (lipids)
cells resemble adrenocortical cells
are well differentiates, small nuclei, rare mitoses
can be function, usually not
what are virulising adrenocortical carcinomas usually
malignant
describe the spread of an adrenocortical carcinoma
local invasion (retroperitoneum, kidney)
metastasis (vascular- to liver, lung and bone)
peritoneum and pleura
regional lymph nodes
what is the survival for adrenocortical carcinomas
5 year 20-35%
what is the only definite discriminating factor between adrenocortical tumours
whether or not they metastasis
what features suggest a adrenocortical tumour
large haemorrhage and necrosis frequent mitosis atypical mitosis lack of clear cells capsular or vascular invasion
what is primary hyperaldosteronism
conns- hypersecretion of aldosterone
is conns under the influence of ACTH
yes
what changes to the adrenal gland is conns associated with
diffuse or nodular hyperplasia of both adrenal glands
what can cause hypercortisolism
cushings syndrome
exogenous (iatrogenic) or endogenous (ACTH dependent and independent)
what are the ACTH dependent causes of hypercortisolism
ACTH secreting pituitary adenoma (cushings) ectopic ACTH (small cell lung cancer)
what are the ACTH independent cause of hypercortisolism
adrenal adenoma or carcinoma
non lesional adrenal gland atrophies
what can cause secondary adrenocortical hypofunction
failure to stimulate adrenal cortex (hypothalamic-pituitary disorder)
suppression of adrenal cortex (treatment with steroids)
what can cause acute primary adrenocortical insufficiency
rapid withdrawal of steroid treatment
addisons crisis
adrenal haemorrhage (newborn, antocoagulatant treatment, DIC, septicaemic infection, waterhouse friderichsen)
what can cause chronic primary adrenocortical insifficiency
addisons disease: autoimmune adrenalitis, infections (TB, fungal, HIV), metastases
rare: amyloid, sarcoidosis, haemochromatosis
describe the onset of addisons disease
insidious - manifests once there is a significant decrease in glucocorticoid and mineralocorticoid levels
what are the symptoms of addisons disease
weakness, fatigue, anorexia, nausea, vomiting, weight loss, diarrhoea
pigmentation
what is decreased in addisons
mineralocorticoids (K+ retention, Na+ loss, hyperkalaemia, hyponatraemia, volume depletion and hypotension)
decreased glucocorticoids (hypoglycaemia)
what are the symptoms of addisons crisis
vomiting, abdo pain, hypotension, shock and death
what is the precipitating factor in addisons crisis
stress- infection, trauma, surgery
what is the adrenal medulla innervated by
pre-synaptic fibres from sympathetic nervous system
what cells in the adrenal medulla secrete catecholamines
neuroendocrine (chromaffin) cells
what are the two tumours seen in the adrenal medulla
phaochromocytoma and neuroblastoma
where can neuroblastomas arise
40% in adrenal medulla
remainder along sympathetic chain
what cells make up neuroblastomas
primitive appearing cells, can show maturation and differentiation towards ganglion cells
what cells are pheochromocytomas derived from
chromaffin cells of the adrenal medulla
explain the triad of symptoms of a phaeochromocytoma
headache, hypertension (paroxysmal episodes) and sweating
as secretes catcholamines
what are the complications of phaeochromocytomas
cardiac failure, infarction, arrhythmias, cerebrovascular accident
how do you lab diagnose a phaeochromocytoma
urinary excretion of catecholamines and metabolites
what are the 10%s in phaeochromocytoma
10% are extra-adrenal 10% are bilateral 10% are biologically malignant 10% are NOT associated with hypertension 25% are familial
where do phaeochromocytoma spread to
skeletal metastasis, regional lymph nodes, liver and lung
what genetic condition is phaeochromoytoma a feature of
MEN2