Endocrine surgery- pituitary, adrenal and MEN Flashcards
Hormones secreted by the anterior pituitary and their “controlling” hypothalamic hormones? (6)
Growth hormone (growth hormone-releasing hormone)
Prolactin (prolactin-inhibiting factor, i.e. dopamine)
Adrenocorticotropic hormone (corticotrophin-releasing ormone)
Lutenizing hormone (GnRH)
Follicle stimulating hormone (GnRH)
Thyroid stimulating hormone (Thyroid releasing hormone)
How does the hypothalamus communicate with the anterior pituitary?
Portal venous system which runs down the hypothalamic stalk
How would the secretion of anterior pituitary hormones be affected by the complete division of the hypothalamic stalk?
Secretion of all hormones would be suppressed, except prolactin which would increase
Imaging modalities for suspected pituitary adenomas?
Contrast-enhanced CT or MRI
Features of acromegaly? (6)
Large extremities Coarsened facial expression Increased sweating and acne Headache Visual field defects (usually bitemporal hemianopia) Carpal tunnel syndrome
Diagnostic test for acromegaly?
IGF-1 levels
Glucose tolerance test (glucose should suppress IGF-1)
Why is IGF-1 used as test for acromegaly rather than GH?
IGF-1 is more stable with a longer half-life; GH secretion is episodic
Treatment of acromegaly? (4)
Trans-sphenoidal removal of adenoma
Drug treatment:
somatostatin analogues (e.g. octreotide)
bromocriptine (dopamine agonist)
pegmivosant ( modified GH analogue- acts as an antagonist at GH receptors)
Features of hyperprolactinaemia in a) males b) females
a) impotence and gynaecomastia
b) galactorrhoea and amenorrhoea
Three main clinical syndromes that result from an anterior pituitary adenoma?
Acromegaly
Hyperprolactinaemia
Cushing’s disease (excess ACTH secretion)
Structure of the adrenal gland and its secretions?
Outer cortex:
zona glomerulosa- aldosterone
zona fasciculata and zona reticularis- cortisol, androgens, oestrogens
Inner medulla-adrenaline, noradrenaline and dopamine
Control of
a) cortisol
b) aldosterone secretion?
a) pituitary ACTH
b) mainly by angiotensin II (as a result of renin release from the renal JGA)
Causes of Cushing syndrome? (4)
Adrenal cortex tumours (usually an adenoma)
Pituitary tumours
Ectopic ACTH secretion
Iatrogenic due to administration of exogenous steroids
Clinical features of Cushing syndrome? (7)
Truncal obesity Buffalo hump Livid striae Proximal muscle weakness Osteoporosis Diabetes Hypertension
Diagnostic tests for Cushing’s syndrome?
24-hour urinary free cortisol
Dexamethasone suppression test
What investigation helps distinguish between adrenal and pituitary causes of Cushing’s?
ACTH
also imaging- MRI pituitary, CT chest and abdomen
Treatment of an adrenal cortex tumour?
Unilateral adrenalectomy, with steroid replacement until the suppressed contralateral adrenal tumour recovers function
How is pituitary Cushing’s managed?
Removal of the adenoma
What is Conn’s syndrome? What are the causes?
Primary hyperaldosteronism due to an adrenal adenoma
Clinical features of hyperaldosteronism?
Hypertension, headache, visual disturbance, hypokalaemia
Primary and secondary causes of hyperaldosteronism?
Primary- Conn’s syndrome (adenoma) and bilateral adrenal hyperplasia
Secondary- due to excess renin secretion
Investigations used in hyperaldosteronism?
Renin and aldosterone levels (renin undetectable in primary)
Plasma/urine aldosterone
Selective adrenal vein sampling/imaging to confirm adenoma
U&Es
What accounts for 80% of phaeochromocytoma? What accounts for the rest?
Tumours of the adrenal medulla
Extra-adrenal tumours
Clinical features of phaeochromocytoma?
Paroxysmal hypertension Tachycardia, palpitations Hypertension Thyrotoxicosis Diabetes mellitus
What proportion of phaeochromocytoma are a) malignant and b) multiple?
a) 10%
b) 10%
Investigation of suspected phaeochromocytoma?
24-hour urinary catecholamines
CT/MRI of the abdomen, MIBG scintigraphy
Pre-surgical management of phaeochromocytoma?
Alpha blockade and beta blockade
Variably penetrant autosomal dominant trait associated with hyperplasia/adenoma of the parathyroid, pancreatic islets and anterior pituitary?
MEN type I
Variably penetrant autosomal dominant trait associated with medullary thyroid cancer, phaeochromocytoma and parathyroid hyperplasia?
MEN type II
Proto-oncogene implicated in MEN Type II?
Ret
Diffuse haemorrhage of the adrenal glands?
Waterhouse-Friderichsen syndrome
Well-circumscribed adrenal nodule with lipid-rich core?
Benign incidental adenoma
