Welcome back to our case of the week. If you remember, this is a 55 year old woman notices that her skin is darker than her twin sister (see picture). She has also been feeling very “run down” lately.
What condition does she have and what testing should you order?
She likely has Addison’s Disease or primary adrenal insufficiency.
Addison’s generally has an insidious onset, and is often initially misdiagnosed. Common symptoms include abdominal pain, poor appetite, weight loss and fatigue. There can be associated hyperpigmentation of the skin, due to high circulating ACTH levels that can activate melanocytes. This may be an early symptom of the disease and is more prominent in sun-exposed areas.
People with Addison’s Disease can also present in Adrenal Crisis. This can present with nausea, vomiting, and severe abdominal pain. The pain can be so severe that it can be hard to rule out an acute abdomen. There can be associated high grade fevers. Electrolyte abnormalities are common, patients may develop hyperkalemia and hyponatremia, along with a mild, non-anion gap metabolic acidosis.
Electrolyte abnormalities seen in Adrenal insufficiency: hyperkalemia hyponatremia, and a mild, non-anion gap metabolic acidosis.
If you suspect a patient has adrenal insufficiency you should order electrolytes (including urine electrolytes and a calcium panel), serum anion gap, kidney function and a blood glucose. There may be associated liver dysfunction/transaminitis and hypothyroidism (polyglandular autoimmune syndrome). A CBC may demonstrate
The treatment of adrenal crisis includes “stress dose steroids” – Usually 100 mg IV hydrocortisone and then 50 mg IV Q8 hours, along with fluid replacement, and treatment of any underlying triggers (like infections).
To diagnose primary adrenal insufficiency, there are multiple steps.
- Confirm inappropriately low circulating serum cortisol level.
- Determine whether low cortisol is ACTH dependent (Secondary adrenal insufficiency) or independent by measuring ACTH levels and performing an ACTH stimulation test (250 mcg of ACTH given and then check serum cortisol levels 30 minutes later).
- Identify the etiology of the adrenal insufficiency (can involve imaging of adrenals or pituitary gland, or CRH stimulation testing).
Don’t forget that patients on steroids at physiologic replacement doses or higher (i.e. > 10 mg) for longer than a month can develop iatrogenic adrenal insufficiency that can last up to a year after they have come off of steroids.