Addison's disease Flashcards
Features
Lethargy, weakness, anorexia, N+V, weight loss, ‘salt-craving’
Hyperpigmentation (especially palmar creases), vitiligo, loss of pubic hair in women, hypotension
Crisis: collapse, shock, pyrexia
Causes
Autoimmune destruction of the adrenal glands is the commonest cause of primary hypoadrenalism in the UK
Other causes:
Primary - TB, metastases, meningococcal septicaemia (Waterhouse-Friderichsen syndrome), HIV, antiphospholipid syndrome
Secondary - pituitary disorders (e.g. tumours, irradiation, infiltration)
Exogenous glucocorticoid therapy
Investigations
ACTH stimulation test (short synacthen) - plasma cortisol is measures 30 minutes after giving Synacthen 250 micrograms IM
Adrenal autoantibodies such as anti-21-hydroxylase may also be demonstrated
If ACTH stimulation test is not readily available then a serum 9am cortisol can be useful: > 500 makes Addison’s v unlikely, < 100 is definitely abnormal, 100-500 should prompt ACTH stimulation test to be performed
Associated electrolyte abnormalities
Hyperkalaemia
Hyponatraemia
Hypoglycaemia
Metabolic acidosis
Management
Hydrocortisone: usually given in 2-3 divided doses. Pts typically require 20-30mg per day with the majority given in the morning dose
Fludrocortisone
Patient education: importance of not missing glucocorticoids, consider MedicAlert bracelet and steroid cards, double glucocorticoid dose during illness
Addisonian crisis: causes
Sepsis or surgery causing an acute exacerbation of chronic insufficiency
Adrenal haemorrhage e.g. Waterhouse-Friderichsen syndrome
Steroid withdrawal
Addisonian crisis management
Hydrocortisone 100 mg IM or IV
1L normal saline infused over 30-60 mins or with dextrose if hypoglycaemic
Continue hydrocortisone 6 hourly until the patient is stable. No fludrocortisone is necessary because high cortisol exerts weak mineralocorticoid activity
Oral replacement may be began after 24 hours and reduced to maintenance dose after 3-4 days
