Too Dry for Primary Adrenal Insufficiency (PAI): PAI Masked by Volume Depletion

Adrenal insufficiency (AI) is a rare but potentially life-threatening endocrine disorder characterized by inadequate production or impaired response to adrenal hormones. Symptoms may range from acute emergent crisis presenting as hemodynamic shock or may be more chronic in presentation with a gradual onset of nonspecific symptoms. These vague symptoms are often accompanied by typical laboratory findings, such as hyponatremia, hypotension, and hyperkalemia, and point toward a diagnosis of chronic AI. In this case presentation, we demonstrate chronic AI presenting with severe hyponatremia, which was revealed after return to an euvolemic baseline. Because of an insidious presentation, AI can be both an incidental finding and easily missed. This case highlights the importance of evaluating suspected cases of AI at a baseline metabolic and hemodynamic state, including volume status. High clinical suspicion is warranted in these patients to avoid potential emergent adrenal crisis and to provide appropriate replacement therapy once etiology is established.