Autoimmune Adrenalitis (Primary Adrenal Failure)

Autoimmune Adrenalitis: (most common cause of primary adrenal failure)

  • 2/3 of patients have at least one other autoimmune endocrine disorder
    • Most patients have adrenal autoantibodies: 21-hydroxylase antibodies
    • 1st: The zona glomerulosa is affect first: increase in the plasma renin activity
    • 2nd: Zona fasciculate affected next:
      • Diminished cortisol response to response to ACTH
      • Increase in basal plasma ACTH
        • Hyperpigmentation occurs exclusively in primary adrenal insufficiency!
      • Decrease in serum cortisol – symptoms initially noticed by patient!
        • Diagnosis is based on inappropriately low serum cortisol level:
          • Early morning (8am) serum Cortisol level < 3 microgram/dL is consistent with cortisol deficiency.
          • Cortisol level > 15-18 microgram/dL EXCLUDE the diagnosis (when binding protein abnormalities and synthetic glucocorticoid exposure are excluded.
          • Cortisol level 5-12 microgram/dL (NONdiagnostic cortisol level)
            • Perform stimulation testing with synthetic ACTH (Cosyntropin)
              • Normal response: peak serum cortisol level > 20
              • ACTH stimulation testing should NOT be used in the critical care setting
            • Differentiate primary from secondary cortisol deficiency:
              • Look at the 8am plasma ACTH:
                • Primary adrenal failure: ACTH >200 pg/ml
                • Secondary cortisol deficiency: low or inappropriately normal ACTH
              • Primary adrenal failure à Aldosterone deficiency: Hyperkalemia, Hyponatremi

Leave a Reply

Your email address will not be published.