(285) Ring the Alarm! A Case of Salt Wasting in LVAD Patient

Introduction: Hyponatremia is the most common electrolyte derangement encountered in the Intensive care unit (ICU). Most cases can be attributed to the syndrome of inappropriate antidiuretic hormone secretion (SIADH,) but another rare cause of cerebral salt-wasting syndrome (CWHS.) CSWS presents with hypotension and hyponatremia due to excessive sodium excretion in the setting of subarachnoid hemorrhage. SIADH necessitates strict fluid restriction, whereas CSWS requires aggressive fluid supplementation. Sherlock 2006 described a study of 316 patients presenting with subarachnoid hemorrhage and hyponatremia and found that SIADH was diagnosed in 69% of cases and CSWS in 6.5%. We describe a case of a 43-year-old male with end-stage heart failure and a left ventricular assist device (LVAD) who presented with a subdural hematoma complicated by cerebral salt wasting syndrome.

Description: A CT brain revealed a subdural hematoma measuring 1.4 cm with a 1.0 cm midline shift. The patient underwent an emergent craniotomy with evacuation with no complications. He was discharged from the ICU but later returned due to multiple low-flow alarms on the LVAD (flow state of less than 1.5L/hr) despite high mean arterial pressures and perfusion indexes. BNP was persistently elevated above 450. A right heart catheterization demonstrated CVP 8, PAP 36/4 (15), PCWP 7, and fick CO/CI 6.30/3.24. Labs showed a serum uric of 1.6, urine osmolality of 522, serum osmolality of 282, and urine sodium of 147. Serum sodium was as low as 120. The patient was polyuric with four liters of urine a day. Given the clinical presentation and urine analysis, we diagnosed CSWS. He was treated initially with normal saline drip with fludrocortisone daily for 1:1 volume supplementation but required escalation with low-dose desmopressin and intermittent 3% hypertonic saline. Salt tablets were scheduled for serum Na from 135 to 140 and urine output of 2.5 to 3.5 liters daily. The patient's condition finally resolved and he was discharged.

Discussion: CSWS is rare but aggressive fluid hydration and sodium supplementation are necessary for positive clinical outcomes. This remains true even in patients with LVAD. Failure to rapidly treat cerebral salt wasting syndrome can lead to respiratory arrest, brain-stem herniation, and even death.