Severe Hyponatremia Uncovering Secondary Adrenal Insufficiency: A Case Report

Introduction. Sodium is a crucial extracellular electrolyte for neuromuscular function, acid-base balance, cellular processes, and osmolarity regulation via transmembrane transport. Sodium deficiency, or hyponatremia, causes plasma hypoosmolarity, leading to water movement into tissues, cellular overhydration, and edema, especially within the brain. This study aimed to determine the cause of severe hyponatremia in a 65-year-old patient. Case Report. A 65-year-old patient was admitted to the emergency department of “Pius Brînzeu” County Emergency Clinical Hospital, Timișoara, Romania, presenting with severe general deterioration, asthenia, headache, vertigo, nausea, vomiting, and epigastric pain. Laboratory tests conducted at the emergency department confirmed the presence of severe hyponatremia. The patient was transferred to the Internal Medicine Clinic, where immediate treatment for hyponatremia was initiated. Subsequent biological and imaging investigations revealed adrenal insufficiency as the underlying cause of severe hyponatremia. Conclusions. Severe hyponatremia is a potentially life-threatening condition, with adrenal insufficiency as a significant underlying cause. Often overlooked due to subtle electrolyte disturbances, accurate diagnosis of secondary adrenal insufficiency is essential, as it requires lifelong hormonal replacement therapy. In such cases, targeted hydrocortisone therapy is vital for restoring hormonal balance, thus ensuring therapeutic efficacy and improving long-term patient outcomes.