Adrenal Disease Flashcards
What are the two main adrenal medullary tumours?
Neuroblastoma
Phaeochromocytoma
From which cells is Phaeochromocytoma derived?
Chromaffin cells of adrenal medulla
What do Phaeochromocytoma secrete?
Catecholamines
Why is Phaeochromocytoma called the 10% tumour?
10% are extra-adrenal
10% are bilateral
10% are malignant
10% are not assoc. with hypertension
Which adrenal disorder is associated with dark/pigmented skin?
Addison’s disease
high ACTH
What are the main primary adrenal insufficiencies?
Addison’s disease
Congenital adrenal hyperplasia
Malignancy
Adrenal TB
What is the commonest cause of primary adrenal insufficiency?
Addison’s disease
Is Addison’s disease an autoimmune condition?
Yes
Assoc. with autoantibodies in 70%
List clinical features of Addison’s disease
Dizziness Low BP Fatigue, lethargy Anorexia, weight loss Skin pigmentation
What would sodium and potassium levels be like in Addison’s disease?
Low sodium
High potassium
Which diagnostic test is used for Addison’s disease?
Short synACTHen test
give synthetic ACTH and measure cortisol levels
Outline management of adrenal insufficiency
Hydrocortisone 30mg
Fludrocortisone (replace aldosterone)
Patients on hydrocortisone for adrenal insufficiency can stop whenever they want. True/False?
False
Never stop suddenly but can reduce dose
List causes of secondary adrenal insufficiency
Pituitary/hypothalamic tumours
Exogenous steroid use (prednisolone)
What is the effect of exogenous steroid on the H-P-adrenal cortex axis?
Suppress CRH and ACTH
What hormone is in excess in Cushing’s syndrome?
Cortisol
Cushing’s syndrome is commoner in men. True/False?
False
Females
List clinical features of Cushing’s syndrome
Moon-face Abdominal striae Thin skin, easy bruising Proximal myopathy Osteoporosis
What are the ACTH-dependent causes of Cushing’s syndrome?
Pituitary disease/adenoma
Ectopic tumours
What are the ACTH-independent causes of Cushing’s syndrome?
Adrenal disease/adenoma
Nodular hyperplasia
What is the gold-standard test for diagnosing Cushing’s syndrome?
Low-dose dexamethasone suppression test
0.5mg every 6hrs for 2 days; cortisol should be less than 50 in normal circumstances
What is the commonest cause of cortisol excess?
High-dose steroid therapy (e.g. asthma, IBD)
What is primary aldosteronism?
Autonomous production of aldosterone, independent of its regulators
Which syndrome occurs due to aldosteronism?
Conn’s syndrome
What is the commonest cause of secondary hypertension?
Primary aldosteronism
Outline how an aldosterone excess is diagnosed
Measure aldosterone : renin ratio
If raised, do saline suppression test
Failure of aldosterone to suppress by 50% with 2L saline confirms aldosteronism
What are the main causes of aldosteronism?
Adrenal hyperplasiaa
Adrenal adenoma
Genetic mutations
Outline management of primary aldosteronism
Adrenalectomy if unilateral adenoma
Drug (spironolactone) if bilateral hyperplasia
What is the commonest cause of congenital adrenal hyperplasia?
21-alpha-hydroxylase deficiency
What 3 main effects does 21-alpha-hydroxylase deficiency cause?
Low cortisol
Low aldosterone
Excess androgens
What is the classical triad of symptoms in Phaeochromocytoma?
Hypertension or postural hypotension
Headache
Sweating
How is Phaeochromocytoma diagnosed?
MRI scan
MIBG
PET scan
Outline therapy for phaeochromocytoma
Alpha blocker (phenoxybenzamine)
Beta blocker (propranolol/atenolol)
Fluid replacement
Surgical excision
Phaeochromocytoma is assoc. with which clinical syndromes?
MEN 2 (multiple endocrine neoplasia type 2) Von-Hippel-Lindau syndrome Succinate dehydrogenase mutations Neurofibromatosis Tuberose sclerosis
Which gene is affected in MEN 1?
MEN1 gene (11q)
Which gene is affected in MEN 2?
RET gene (10q)
The MEN1 gene is a tumour suppressor. True/False?
True
Is the RET gene a tumour suppressor or proto-oncogene?
Proto-oncogene
Von-Hippel-Lindau syndrome is caused by mutation in which gene?
VHL gene
