Pituitary gland Flashcards
what is a pituitary microadenoma
<1cm
what is a pituitary macroadenoma
> 1cm
what are some of the complications of a non functional adenoma
compression on optic chiasma to cause bilateral hemianopia
compression on CN3,4,V1,V2,6
pushes out other pituitary cells to cause hypoadrenalism, hypogonadism, hypothyroidism, diabetes insipidus, GH deficiency
physiological causes raised prolactin
breast feeding
stress
lack sleep
pregnancy
pathological causes rasied prolactin
stalk lesions
hypothyroidism
prolactinoma
pharmacological causes raised prolactin
dopamine antagonists
antipsychotics
antidepressants
oral contraceptives, oestrogens, cocaine
prolactinoma presentation in men
impotence
visual field defect
anterior pituitary malfunction
prolactinoma presentation in women
galactorrohea menstrual irregularity infertility amenorrhoea visual field abnormality
investigation of prolactinoma?
serum prolacitn
MRI pituitary
visual fields for bilateral hemianopia
pituitary function testing
management of prolactinoma
cabergoline
dopamine agonist drugs
surgery rarely required as cabergoline can control symptoms and can cause tumour shrinkage
side effects cabergoline
low mood
nausea/vomiting
heart valve/retropritoneal fibrosis
clinical features acromegaly
giant before episeal fusion thickened skin, jaw sweaty, large hands sleep apnoea HTN and HF headaches diabetes visual field defects colonic polyps
what causes headaches in acromegaly
vascular growth
diagnosis of acromegaly?
IGF1 OGTT - expect glucose to suppress GH to <0.4ug/L after glucose dose but in acromegaly there is uncontrolled rise or unchanged visual field check CT/MRI serum pituitary check
first line treatment of acromegaly
surgery, radiotherapy can be considered
2nd line treatment of acromegaly
octreotide to reduce GH and tumour
side effects of octreotide
stinging locally flatulence diarrhoea abdo pain gallstones
what can be used if a growth hormone tumour is co secreting prolactin
cabergoline for some
what can be used last line for acromegaly
pegvisomant
binds to GH receptor to block GH
causes of panhypopituitism
tumours local brain tumours iatrogenic/surgery sarcoid/tb polyarteritis trauma secondary mets hypothalamic disease sheenan syndrome infection/meningitis
what are the possible causes sheenan syndrome
blood loss in pregnancy causes hypotension and pituitary infarct
autoimmune
signs/symptoms of panhypopituitism
menstrual irregularities infertility/impotence gynaecomastia obesity loss facial hair loss axillary/pubic hair dry skin/hair hypothyroid faces growth retardation
diagnosis panhypopituitism
check pituitary function tests
sex hormones, TFT, growth hormones and prolactin
cortisol/ACTH - do cortisol 8/9am or a synacthen
in post menopause LH/FSH should be high
testosterone at 9am
features of familial diabetes insipidus
DIDMOAD diabetes insipidus diabetes mellitus optic atrophy deafness
causes of acquired diabetes insipidus
idiopathic
trauma, surgery, fracture, RTA
tumour, sarcoid, meningitis, external radiation
describe the water deprivation test
NBM for 8-12 hours
check serum and urine osmolalities for 8 hr then give DDAVP and if urine/serum osmol ratio>2 the not DI
management of DI
desmospray
desmopressin oral or injection
injection is more emergency or post surgery
where are somatotrophs found and what do they secrete
ant pituitary
GH
where are mammotrophs found and what do they secrete
ant pituitary
Prolactin
where are corticotrophs found and what do they secrete
ant pituitary
ACTH
where are thyrotrophs found and what do they secrete
ant pituitary
TSH
where are gonadotrophs found and what do they secrete
ant pituitary
FSH/LH
what is a pituitary adenoma and wehat may it secrete
benign pituitary tumour
can secrete any anterior pituitary homes or can be hypo/non functional
what pituitary adenoma is most common
prolactinoma
how common are poituitary carcinomas
very rare
cause of panhypopituitarism
primary/metastatic tumour apoplexy sheehans syndrome DI hypothalamic lesions sarcoid, TB, meningitis subarachnoid haemorrhage surgery/radiation traumatic injury
what is a craniopharyngioma
very rare tumour derived from remnant of rathke’s pouch
slow growing, cystic and may calcify
cause of central DI
ADH deficiency
trauma, tumours and inflammatory disease of the pituitary glands
cause of nephrogenic DI
peripheral renal resistance to ADH
cause of congenital adrenocortical hyperplasia
autosomal recessive disorder with lack of enzyme required for biosynthesis
reduced cortisol continues to stimulate ACTH release and causes hyperplasia
cause of acquired adrenocortical hyperplasia
endogenous ACTH
nodular hyperplasia is independent of ACTH but diffuse isnt
true/false - adrenocortical adenomas are usually functional
false
true/false - adrenocortical carcinomas are usually functional
true
describe the pathological features of an adrenocortical adenoma
well circumscribed and encapsulated
small and 2/3cm
yellow/yellow brown
well differentiated with pale cytoplasm and small nuclei
describe the features of adrenocortical carcinomas
closely resemble adenoma metastasis is definite large size haemorrhage/necrosis lack clear cells capsular/vascular invasion
where do adrenocortical tumours spread
retroperitoneum/kidney
peritoneum/pleura
vascular, bone, liver, lung
regional lymph nodes
exogenous causes of cushings
exogenous steroid use
endogenous causes cushings
ACTH producing adenoma
ectopic ACTH
cause of acute adrenal crisis
rapid withdrawal of steroid therapy
crisis in patient with chronic adrenocortical insufficiency like stress, infection or not physiologically raising steroid dose
massive adrenal haemorrhage
risk factors for massive adrenal haemorrhagwe
newborn infants
anticoagulants
DIC
septicaemic infection
causes of chronic adrenocortical insufficiency
AA adrenalitis
TB, histoplasma, HIV, kaposi’s sarcoma
metastatic breast/lung cancer
sarcoid, haemachromatosis, amyloid
symptoms of addisons disease
weakness fatigue pigmentation anorexia nausea/vomiting diarrhoea
presentation of adrenal crisis?
vomiting abdominal pain hypotension shock death
complications of phaeochromocytoma
heart failure, infarction, arrhythmia, CVA
10% rules to phaeochromocytoma
10% in children 10% bilateral 10% extra adrenal 10% FHx - more 25% 10% not HTN associated 10% malignant
features of MEN2A
phaeo, MTC, parathyroid hyperplasia
features of MEN2B
phaeo, MTC, neuromas, ganglioneuromas, marfanoid habitus
