Primary Adrenal Insufficiency

Causes

low cortisol, high ACTH, can use Cosyntropin stimulation test
most common cause: autoimmune adrenalitis
- destruction of all layers of adrenal cortex
- positive 21-hydroxylase antibodies in 90% of cases
- associated with other autoimmune endocrine disorders: celiac, hypothyroidism, hypoparathyroidism, DM, ovarian insufficiency, autoimmune gastritis
If 21-hydroxylase antibody measurement is negative, abdominal CT imaging should be performed.
- Autoimmune disease: atrophic adrenal glands, although normal-sized adrenal glands do not rule out this diagnosis.
- Other causes of cause enlargement of the adrenal glands. These include infiltrative disorders such as lymphoma, sarcoidosis, histoplasmosis, or tuberculosis (the latter can be associated with normal-sized adrenal glands).
- Bilateral adrenal hemorrhage can present as acute adrenal insufficiency and should be considered if unexpected hypotension develops. Risk factors for bilateral adrenal hemorrhage include protein C deficiency, anticoagulation, disseminated intravascular coagulopathy, and sepsis.
- Metastatic disease to the adrenal glands rarely causes adrenal insufficiency if both glands involved.

Preferred treatment for glucocorticoid:

hydrocortisone 2/2 shorter duration of action
total daily dose: 15 to 25 mg divided into bid/tid
15mg in am and 5 mg in afternoon or three times daily
prednisone once daily in am can be used as substitute
dexamethasone: long duration of action can cause more side effects, not used Preferred mineralcorticoid treatment:
fludrocortisone once a day