# Recurrent Hyponatremia Mimicking Syndrome of Inappropriate Antidiuretic Hormone Secretion: A Case of Partial Empty Sella Syndrome With Isolated Adrenocorticotropic Hormone Deficiency

## TL;DR

A 45-year-old man with recurring low sodium levels was found to have adrenal insufficiency linked to partial empty sella syndrome, highlighting the importance of proper diagnosis to avoid mismanagement.

## Contribution

This case highlights adrenal insufficiency as a cause of recurrent hyponatremia mimicking SIADH in the context of partial empty sella syndrome.

## Key findings

- The patient's hyponatremia resolved with corticosteroid treatment, indicating adrenal insufficiency.
- Low cortisol and ACTH levels confirmed isolated ACTH deficiency as the primary cause.
- Partial empty sella syndrome was diagnosed as an underlying anatomical condition.

## Abstract

Hyponatremia is one of the most frequently encountered electrolyte disturbances in clinical practice and can serve as the initial manifestation of various underlying conditions. Severe cases are often associated with neurological dysfunction and an increased risk of mortality. While syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH) remains the most common cause, a thorough diagnostic evaluation is essential, as simple sodium supplementation may lead to recurrent hyponatremia and serious complications. Notably, adrenal insufficiency can closely mimic SIADH, and mismanagement in this context may exacerbate the condition. Hereby, we present the case of a 45-year-old male who experienced recurrent episodes of hyponatremia and was ultimately diagnosed with partial empty sella syndrome. The strong temporal association between corticosteroid administration and symptom resolution, along with low cortisol and adrenocorticotropic hormone (ACTH) levels, suggests that adrenal insufficiency was the primary underlying cause of hyponatremia in this patient.