27th May 2025

Diagnosis

Symptoms of PAI include:

• Fatigue
• Weakness
• Myalgia and arthralgia
• Weight loss
• Nausea, vomiting, abdominal pain

Signs of PAI include:

• Mucocutaneous hyperpigmentation – commonly on areas of friction e.g. palms, knuckles. 
• Hypotension and postural hypotension.
• Less commonly vitiligo, premature greying, goitre (with Hashimoto’s thyroiditis).

Image Source: Wikimedia Commons (2018) Addison’s Leg’s, Licensed under a creative commons licence. Available for free at: https://upload.wikimedia.org.wikipedia/commons/6/69/Addison%Legs.jpg (Accessed 13 May 2025).

The following laboratory findings are typical in PAI:

Table 1: laboratory findings in primary adrenal insufficiency.

should result in a rise in cortisol for a physiologic response. However, in primary adrenal insufficiency this does not occur i.e. the cortisol will remain low when re-checked following administration of synacthen, as the adrenal glands do not respond to stimulation. 

To investigate the underlying aetiology, the following investigations should be considered:

• Adrenal autoantibody testing.
• Chest x-ray to investigate lung neoplasm or tuberculosis.
• Tuberculosis skin prick or ELISA testing.
• Abdominal x-ray which may show adrenal calcification.
• CT or MRI of adrenal glands.
• MRI of hypothalamus and pituitary if suspicion of a central cause.