Prevalence of Adrenal Insufficiency and Thyroid Dysfunction in Patients with Euvolemic Hyponatremia

Abstract

Hyponatremia is one of the most common electrolyte disturbances encountered in clinical practice, and it can be classified into three categories based on volume status: hypovolemic, euvolemic, and hypervolemic. Euvolemic hyponatremia is frequently associated with conditions like the syndrome of inappropriate antidiuretic hormone secretion (SIADH), hypothyroidism, and adrenal insufficiency. Both adrenal insufficiency and thyroid dysfunction are known to affect sodium regulation, potentially contributing to the development of hyponatremia. This study aims to assess the prevalence of adrenal insufficiency and thyroid dysfunction in patients diagnosed with euvolemic hyponatremia. The study was conducted on 100 patients presenting with euvolemic hyponatremia, defined by low sodium levels (serum Na < 135 mmol/L) in the absence of signs of fluid overload or depletion. Adrenal function was assessed using the 250 µg ACTH stimulation test, and thyroid function was evaluated through serum levels of TSH, free T3, and free T4. The results showed that 15% of patients had adrenal insufficiency, and 20% had thyroid dysfunction, suggesting a significant association between these endocrinopathies and euvolemic hyponatremia. These findings highlight the importance of evaluating adrenal and thyroid function in patients with euvolemic hyponatremia, as early diagnosis and management of these endocrine disorders may improve patient outcomes.

Keywords: Euvolemic hyponatremia, adrenal insufficiency, thyroid dysfunction, ACTH stimulation test, sodium, syndrome of inappropriate antidiuretic hormone secretion (SIADH).