SUN-203 Hyponatremia and Hyperkalemia in a Child with Chylothorax: Is This Adrenal Insufficiency?

Hyponatremia and Hyperkalemia in a child with chylothorax: Is this adrenal insufficiency? Context: Chylothoraces are relatively rare within the pediatric population. Drainage of a chylothorax can lead to potentially serious complications including electrolyte imbalances and protein loss. The literature on hyponatremia and hyperkalemia developing after a chylothorax drainage is sparse. We report a case of electrolyte derangements after a chylothorax drainage in a pediatric patient. Repeated drainage of a large-volume chylothorax without adequate fluid replacement may lead to electrolyte imbalances that in our case mimicked adrenal insufficiency. Early identification and correct fluid replacement can avoid unnecessary complications of a chylothorax. Case Description: A 2-year-old female with history of congenital left pulmonary lymphangectasia and subsequent pleural effusion was admitted to a pediatric hospital for persistent tachycardia after an outpatient elective chest MRI. A chest tube was placed to drain the effusion with large volume output was noted over the first day (1200 cc/24 hours). Further chemical analysis determined the effusion to be consistent with a chylothorax. Blood work done after chest tube placement demonstrated severe hyponatremia and hyperkalemia. Additionally, the patient was noted to be irritable. Both lab and clinical findings raised concern for possible underlying adrenal insufficiency, and further work-up (i.e. cortisol level, ACTH level) was sent. The patient was started on stress-dose steroids. ACTH and cortisol levels resulted normal. Steroids were subsequently discontinued. The patient’s chest tube output was slowly replaced with normal saline with noted improvement in both lab and clinical findings. Conclusion: Although not well documented in pediatric literature, hyponatremia and hyperkalemia are complications of large-volume drainage of chylothoraces without proper fluid replacement. The subsequent lab findings could be consistent with adrenal insufficiency, however a full clinical picture along with a cortisol and an ACTH level can help differentiate etiologies.