Approach to the Patient: Diagnosis of Primary Adrenal Insufficiency in Adults

Primary adrenal insufficiency (PAI) is easy to diagnose. The challenge is to consider it as a differential diagnosis since it is rare, symptoms develop gradually and are unspecific and common. In Western countries autoimmune aetiology is easy to confirm by measuring autoantibodies against 21-hydroxylase, but it can be more challenging to determine the aetiology in patients without such autoantibodies. Finding the underlying cause is important since this may have prognostic and therapeutic consequences. The cases presented here illustrate the diversity of causes and suggests a practical approach to diagnosis.