Endocrine Abstracts

Background: Both cortisol and other adrenal hormones are well known to affect brain structure and function throughout development. Due to destruction of the adrenal cortex, patients with Autoimmune Addison’s disease (AAD) lack production of adrenal hormones and therefore receive lifelong replacement of cortisol and aldosterone, and, for some female patients dehydroepiandrosterone (DHEA). However, replicating the natural rhythm of secretion is difficult, and patients are often exposed to either supra- or infra- physiological adrenal hormone levels. Such long-term hormonal disturbances might be expected to affect the brain on both a structural and functional level. Assessing brain structure in patients with AAD is relevant, as varying treatment-regimes may have detrimental effects on the brain and could lead to problems with cognitive function and mood. The present study therefore investigated grey and white matter structure of the brain in a cohort of young adult patients with AAD.

Methods: T1 and DWI Magnetic Resonance Imaging (MRI) of the brain was done on fifty-two patients with AAD and seventy healthy control participants (aged 19-43). A whole-brain exploratory approach was used to compare patients to controls on estimates of global and regional cortical thickness, surface area, cortical grey matter volume, subcortical volumes, hippocampal and amygdalae subfields (FreeSurfer), and white matter microstructure (FSL TBSS).

Results: Apart from reduced volume of the right superior parietal cortex in male patients, there were no differences in any of the estimates between patients with AAD and healthy controls, when correcting for total intracranial volume and multiple comparisons.

Conclusion: Brain structure of patients with AAD seems to be relatively unaffected at this young adult age. This finding is reassuring and suggests the brain is able to cope with disturbances in adrenal hormone levels. Follow-up studies are needed to determine if the brain of patients with AAD may be affected later in life, or by varying treatment regimes, such as immediate or slow-release hydrocortisone medication.