A Rare Mechanism of Hyponatremia in HIV Disease

Hyponatremia is the most common disorder of body fluid and electrolyte balance in clinical practice. It is associated with increased morbidity, mortality, and length of hospital stay. Little is known about the relationship between hyponatremia and HIV disease. It is thought that hyponatremia in HIV is associated with a syndrome of inappropriate ADH secretion (SIADH), volume depletion, and adrenal insufficiency. Another common association is with Pneumocystis jirovecii (PCP). In early 1990s, there were several reports linking hyponatremia and HIV disease. It was found that these patients with acquired immune deficiency syndrome (AIDS) had abnormal adrenal cortical function. Additionally, these patients showed an abnormally elevated baseline cortisol level and a blunted response to cosyntropin.

Here, we present the case of an HIV patient presenting with hyponatremia and a physical examination suggestive of hypovolemia. Laboratory tests revealed urinary loss of sodium in the setting of normal serum cortisol level. The patient responded well to the administration of a mineralocorticoid hormone.

Glucocorticoid resistance is an unusual cause of hyponatremia, and needs to be identified and treated accordingly.