Evaluation of the hypothalamic-pituitary-adrenal axis in patients with antiphospholipid syndrome

Hypothalamic-pituitary-adrenal (HPA) axis insufficiency is the most common endocrine disorder in patients with antiphospholipid syndrome (APS). Primary adrenal failure because of venous thrombosis and/or adrenal haemorrhage is the leading diagnosis, while another possible mechanism is autoimmune adrenal failure. Prospective evaluation of the HPA axis in patients with APS has not been previously performed.

To evaluate the HPA axis in patients with APS.

Ambulatory patients (age 18 years and older) with APS were given a symptom questionnaire. Baseline aldosterone, corticotropin (ACTH) and adrenal cortex autoantibodies (ACA) were measured. Cortisol was measured at baseline and after 1-mcg ACTH stimulation.

In all, 24 patients (18 women/6 men; mean age 44.6 +/- 16.1 years) participated in the study. Of these, 21 had primary APS with disease duration of 5.8 +/- 6.2 years. Baseline cortisol level was 12.6 +/- 4.2 mg/dl (normal 7-25). After ACTH stimulation, it was 24.7 +/- 4.1 mg/dl and 22.8 +/- 7.4 mg/dl at 30 and 60 min respectively. All patients had a stimulated cortisol level of at least 18 mg/dl, although three patients had stimulated cortisol between 18 and 20 mg/dl, one of which reported previous inhaled steroid treatment. Weakness, dizziness and nausea were reported at baseline by 50%, 38% and 25% of the patients respectively. ACA were negative in all patients examined.

In our cohort, patients with APS did not have HPA axis insufficiency. Partial adrenal insufficiency could not be excluded in two patients. Further longitudinal studies are needed to determine the significance of periodic evaluation of the HPA axis in patients with APS.