Endocrine Abstracts

Background: Autoimmune destruction is the most common aetiology of primary adrenal insufficiency (PAI) in Europe and north America. In contrast, tuberculosis is a common cause of PAI in developing countries. More recently, adrenal histoplasmosis (AH) is being increasingly reported from India

Aims: To study the aetiology, clinical presentation and mortality in adults with PAI who were diagnosed between 2006-2019 and to determine the changes in aetiology since an earlier study conducted between 1991–1999.

Materials and methods: We conducted a retrospective study of 89 patients (age 15–83 years), diagnosed with PAI between 2006– 2019. An infective pathology was suspected if adrenals were enlarged (n = 65). Adrenal biopsy was performed in 60 patients. AH was diagnosed by demonstrating Histoplasma on staining/culture; adrenal tuberculosis (AT) by granulomas, culture/GeneXpert positive for M. tuberculosis, or clinical response to anti-tuberculous therapy (ATT); autoimmune aetiology by normal adrenal size, 21-hydroxylase (21-OH) antibody positivity and/or presence of other autoimmune disorders. Patients received anti-fungal/ATT as per guidelines.

Results: Median duration of symptoms prior to presentation was 6 months. Common presentations were anorexia (97%), weight loss (97%), hyperpigmentation (89%), abdominal pain (36%), and fever (48%). Forty-two (47%) patients presented with acute adrenal crisis. The most frequent aetiologies were AH (45%), tuberculosis (19%) and autoimmunity (25%). Forty-five percent of patients with AH were initially misdiagnosed as AT. Patients with AH were similar to those with AT in their clinical presentation, except for shorter duration of symptoms before follow-up. 21-OH antibody was noted almost exclusively in patients with autoimmune aetiology (41%) and only 1/41 (2%) with infective aetiology. Overall mortality was 18%, over follow-up of 38 (range 1–158) months. Mortality was significantly greater among AH (30%), compared with AT (6%) and autoimmune PAI (5%) (P < 0.001 between 3 groups) patients. As compared with our earlier report of patients seen in 1991-99¹, where AH was not diagnosed in any patient, AH was now the most common aetiology of PAI.

Conclusions: A recent appearance of AH was noted over the last 15 years. AH was difficult to differentiate from AT on clinical features alone. Despite appropriate therapy, patients with AH had a worse prognosis compared to other aetiologies of PAI.

Reference

1. Agarwal et al. Natl Med J India 2001 14 23–5.