Adrenal insufficiency
OVERVIEW
Types:
- primary, secondary and tertiary + acute/chronic
Primary = Addison’s
- destruction of > 90% of adrenal glands
- rare
- causes: autoimmune destruction, haemorrhage, tumour (breast and melanoma), infection (Tb, HIV, meningococcemia, purpura fulminans) or inflammatory process
- loss of mineralocorticoid and glucocorticoid activity
Secondary
- insufficient production of ACTH
- rare
- mineralocorticoid function intact
- causes: destruction or dysfunction of the pituitary
Tertiary/Iatrogenic/Relative
- suppression of HPA axis over time
- most common
- cause: administration of exogenous glucocorticoids
- mechanism: chronic ACTH suppression -> adrenal atrophy
ADRENAL CRISIS
- concurrent illness, surgery, failure to take medications
- GI: abdominal pain, vomiting and diarrhoea
- CVS: dehydration, hypotension, refractory shock, poor response to inotropes/pressors
- fever
- confusion
CHRONIC ADRENAL INSUFFICIENCY
- GENERAL: weight loss, arthralgia, myalgia
- CNS: fatigue, anorexia, mood change
- CVS: postural hypotension, syncope, salt craving
- SKIN: pigmentation, vitiligo
- ELECTROLYTES: hypoglycaemia, hyponatraemia, hyperkalaemia, increased urea
INVESTIGATIONS
Diagnosis:
- plasma cortisol level < 80mmol/L
- short synacthen test: 250mcg (normal response = cortisol > 525mmol/L)
Other
- low glucose
- low Na+
- hypo-osmolar
- raised K+
- raised U and Cr
- raised Ca2+ (primary only)
- eosinophilia
MANAGEMENT
- fluid resuscitation
- reversal of electrolyte abnormalities
- high dose hydrocortisone (100mg IV Q6 hrly)
- mineralocorticoid replacement (fludrocortisone PO 0.1mg Q6 hrly) – don’t often use this acutely as with > 50mg of hydrocortisone you get a mineralocorticoid effect
References and links
LITFL
- CCC – Steroid conversion
- CCC – Corticosteroids Overview
- CCC – Steroids and Septic Shock Literature Summaries
- CCC – Corticosteroid therapy for shock
- Basic Science – Pharm 101: Corticosteroids
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Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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