Adrenal insufficiency in giant cell arteritis.

Area of Science:

• Endocrinology
• Rheumatology
• Internal Medicine

Background:

• Giant cell arteritis (GCA) is a systemic vasculitis primarily affecting large arteries.
• Long-term glucocorticoid therapy, including prednisolone, is the mainstay treatment for GCA.
• Glucocorticoid use can lead to adrenal insufficiency, necessitating careful monitoring.

Purpose of the Study:

• To determine the frequency of adrenal insufficiency in GCA patients treated with the Norwich prednisolone regimen.
• To evaluate the effectiveness of a sequential testing strategy for adrenal function.

Main Methods:

• A cohort of 353 GCA patients treated with the Norwich prednisolone regimen was analyzed.
• Adrenal function was assessed using 9 a.m. serum cortisol levels as a preliminary test.
• Patients with low cortisol levels underwent dynamic testing with adrenocorticotrophic hormone (ACTH) stimulation.

Main Results:

• Out of 76 patients tested, 8/35 (22.8%) showed insufficient adrenal function based on initial cortisol levels.
• Further ACTH stimulation revealed 8/35 patients (22.8%) had inadequate adrenal reserve.
• A total of 15/353 patients (4.2%) required long-term steroid replacement for adrenal insufficiency.

Conclusions:

• Adrenal insufficiency requiring long-term steroid replacement is uncommon in GCA patients on the Norwich prednisolone regimen.
• Sequential testing with 9 a.m. serum cortisol followed by ACTH stimulation is an efficient strategy for assessing adrenal function in this population.