12 Adrenal Disorders Flashcards
What is primary adrenal insufficiency (Addison’s disease) due to?
Arises due to destruction of adrenal gland or genetic defect in steroid synthesis
Clinical features of Addison’s disease/primary adrenal insufficiency
- fatigue
- weakness
- anorexia + weight loss
- nausea
- abdominal pain
- hyperpigmentation
How does Addison’s disease cause hyperpigmentation?
- Insufficient adrenal function
- Decreased cortisol
- Negative feedback on ant. Pit reduced
- More POMC needed to synthesis ACTH
- More MSH produced»_space; hyperpigmentation
- ACTH at high level can stimulate receptors of MSH receptors
Clinical features of mineralocorticoid deficiency
- dizziness
- postural hypotension
Clinical features of glucocorticoid deficiency
Hypoglycaemia
hyperpigmentation due to ACTH excess due to reduced cortisol negative feedback
Causes of primary adrenal insufficiency/Addison’s diseas
Autoimmunity
infection
infiltrative processes
Investigations + results of primary adrenal insufficiency
- U&Es
- glucose levels
- FBC
- autoantibodies - (adrenal cortex ab/21-hydroxylase ab)
. - hyponatraemia
- hyperkalaemia
- raised urea
- hypoglycaemia
- anaemia
Diagnosis of Addison’s disease
low 9am cortisol + simultaneously raised ACTH
ATCH/synacthen test for confirmation
Outline the short Synacthen test
What is it used to diagnose?
- ACTH stimulation test
- dose of synacthen given
- blood cortisol checked before, 30 mins + 60 mins after
- cortisol levels should at least double
- failure to indicates adrenal insufficiency
What is long synacthen test used for?
to distinguish between primary adrenal insufficiency (high ACTH) + adrenal atrophy due to secondary adrenal insufficiency (low ACTH)
Management of Addison’s disease/primary adrenal insufficiency
- Lifelong replacement of glucocorticoids (hydrocortisone) + mineralocorticoids (fludrocortisone)
- Education to prevent crises - steroid card and bracelet, emergency HC injection if vomiting, emergency contract details for their endocrinology team
What is needed if a patient with Addison’s disease becomes ill?
double hydrocortisone dose until illness has resolved
What is secondary adrenal insufficiency?
ACTH deficiency due to hypopituitarism
Management of secondary adrenal insufficiency
hydrocortisone replacement
Difference in drug treatment of primary and secondary adrenal insufficiency
Both require hydrocortisone
fludrocortisone only in primary
what is Addisonian crisis?
Life threatening emergency due to adrenal insufficiency
What is Addisonian crisis caused by?
Severe stress
Salt deprivation
Infection
Cold exposure
Trauma
Over exertion
Abrupt steroid drug withdrawal
Clinical features of adrenal crisis
Collapse
Hypotension
Dehydration
Pigmentation
Coma
Vomiting
Pyrexia
What will blood tests show in renal crisis?
Low cortisol level
Low Na
High K
Treatment of Addisonian crisis
IV fluids
IV hydrocortisone 100mg
correct hypoglycaemia
Why should long term steroids not be stopped abruptly?
long term steroids cause ACTH suppression so abrupt stoppage can cause adrenal crisis
What is hyperaldosterionism?
Excessive aldosterone production
What is Conn’s syndrome?
Adrenal adenoma that produces excessive aldosterone
What is primary hyperaldosteronism due to?
- defect in adrenal cortex
- bilateral idiopathic adrenal hyperplasia - most common
- aldosterone secreting adrenal adenoma (Conn’s syndrome)
- low renin levels
What is secondary hyperaldosteronism due to?
- due to over activity of RAAS (excessive renin) > excessive aldosteron release
- renal artery stenosis
- heart failure
- liver cirrhosis + ascites
- high renin levels
Signs/symptoms of hyperaldosteronism
High BP
Stroke
Left ventricular hypertrophy
Hypernatraemia
Hypokalaemia
Headaches
Fatigue
Muscle wekaness
Treatment of hyperaldosteronism
- Primary - aldosterone producing adenomas removed by surgery
- Spironoalactone/eplerenone
- treating the underlying cause
What is the best way to distinguish between primary and secondary hyperaldosteronism?
primary - low renin levels
secondary - high renin levels
What is Cushing’s syndrome?
Features of prolonged high levels of glucocorticoids in the body (cortisol)
Causes of Cushing’s syndrome
- prolonged steroid use
- benign pituitary adenoma secreting ACTH (Cushing’s disease)
- excess cortisol produced by adrenal tumour (adrenal Cushing’s)
- non pituitary-adrenal tumours producing ACTH (paraneoplastic syndromes) e.g. SCLC
What is Cushing’s disease?
Pituitary adenoma secreting excessive ACTH > cortisol release
Clinical features of Cushing’s syndrome
- moon face
- central obesity
- purple abdominal striae
- enlarged fat pad on upper back
- hirsutism
- easy bruising + poor skin healing
- hyperpigmentation
- proximal limb muscle wasting
Why do patients with Cushing’s syndrome have purple striae?
Central obesity from fat redistribution due to cortisol stress the the skin
Weak + thin skin increases proteolysis > purple striae
Investigations of Cushing’s syndrome + what for
- dexamethasone suppression test
- MRI - pituitary adenoma
- CT chest - SCLC
- CT abdomen - adrenal tumours
- FBC - high WBC
- U&E - low K if adrenal adenoma is secretomg aldosterone
What do we do to diagnose Cushing’s?
Dexamethasone suppression test
lack of cortisol suppression indicates Cushing’s syndrome
What are the three types of dexamethasone suppression test?
low dose overnight
low dose 48 hour
high dose 48 hour
what is the action of dexamethasone?
suppresses secretion of ATCH > lowers cortisol
Treatment of Cushing’s syndrome
Removal of underlying cause:
- trans-sphenoidal removal of pituitary adenoma
- surgical removal of adrenal tumour/tumour producing ectopic ACTH
.
- adrenalectomy with life long steroid replacement therapy
- metyrapone: reduces production of cortisol
What is done when surgical removal of the causative tumour of Cushing’s syndrome isn’t possible?
adrenalectomy with life long steroid replacement therapy
More on dexamethasone suppression test
What is phaeochromocytoma?
Chromaffin cell tumour > secrete adrenaline + noradrenaline
What is a paraganglioma?
extra-adrenal pheochromocytoma
Characteristics of phaeochromocytoma
- severe hypertension
- headaches
- palpitations
- excessive sweating
- weight loss
- anxiety + panic attacks
What can untreated phaeochromocytomas cause?
- hypertensive crisis
- encephalopathy
- hyperglycaemia
- pulmonary oedema
- cardiac arrhythmias
Investigations of phaeochromocytoma
- plasma free metanephrines
- 24-hour urine catecholamines
- CT or MRI to look tumour
- genetic testing incl. 1st degree relatives
What are metanephrines?
Breakdown product of adrenaline
Management of phaeochromocytoma
- surgical excision
- alpha blockers e.g. phenoxybenzamine or doxazosin
- B blockers when established on a blockers to reduce risk of hypertensive crisis
A patient presents with hypertension and hypokalaemia, what could the diagnosis be?
Hyperaldosteronism
Cushing’s syndrome ?
What time of day would be best to take a blood sample to measure cortisol levels and why?
Midnight
Blood cortisol levels are normally at their lowest around midnight
