Tolvaptan use during hyperhydration in paediatric intracranial lymphoma with SIADH

Abstract

SummaryAn 11-year-old boy developed severe syndrome of inappropriate antidiuretic hormone secretion (SIADH) after diagnosis of an intracranial B-cell lymphoma. His sodium levels dropped to 118–120 mmol/L despite 70% fluid restriction. For chemotherapy, he required hyperhydration, which posed a challenge because of severe hyponatraemia. Tolvaptan is an oral, highly selective arginine vasopressin V2-receptor antagonist, which has been licensed in adults for the management of SIADH and has been used in treating paediatric heart failure. Tolvaptan gradually increased sodium levels and allowed liberalisation of fluid intake and hyperhydration. Tolvaptan had profound effects on urinary output in our patient with increases up to 8 mL/kg/h and required close monitoring of fluid balance, frequent sodium measurements and adjustments to intake. After hyperhydration, tolvaptan was stopped, and the lymphoma went into remission with reversal of SIADH. We report one of the first uses of tolvaptan in a child with SIADH, and it was an effective and safe treatment to manage severe SIADH when fluid restriction was not possible or effective. However, meticulous monitoring of fluid balance and sodium levels and adjustments of fluid intake are required to prevent rapid sodium changes.Learning points:Tolvaptan can be used in paediatric patients with SIADH to allow hyperhydration during chemotherapy.Tolvaptan has profound effects on urinary output and meticulous monitoring of fluid balance and sodium levels is therefore warranted.Tolvaptan was well tolerated without significant side effects.

Efficiency of Single Dose of Tolvaptan Treatment During the Triphasic Episode After Surgery for Craniopharyngioma

“…SIADH is a major situation and one of the causes of hyponatremia in hospitalized cases (2). The etiology of SIADH involves excess ADH production due to cranial surgery, malignancies, meningitis-encephalitis, hemorrhage, other cerebral pathologies, pulmonary malignancies and drugs (2,3). In clinical practice, common and gold standard approach to SIADH is fluid restriction (4)(5)(6).…”

“…In more severe forms that also show neurological symptoms, administration of hyperosmolar saline combined with furosemide may be required. Additionally, underlying etiology should be treated if possible (3,5,(6)(7)(8)(9)(10). However, these treatments may be inadequate for some patients with SIADH.…”

“…In the last decade, a new alternative treatment option for SIADH named vaptans has become available (8). Vaptans are arginine-vasopressin receptor antagonists, thus prevent insertion of aquaporin 2 water channels in the apical membrane promoting reabsorption of water and results in excretion of diluted urine (3,5,11). Tolvaptan is a kind of vaptan and is a selective V2 receptor antagonist, whereas conivaptan is a non-selective V1/V2 receptor antagonist (3,5,6,10).…”

“…Vaptans are arginine-vasopressin receptor antagonists, thus prevent insertion of aquaporin 2 water channels in the apical membrane promoting reabsorption of water and results in excretion of diluted urine (3,5,11). Tolvaptan is a kind of vaptan and is a selective V2 receptor antagonist, whereas conivaptan is a non-selective V1/V2 receptor antagonist (3,5,6,10). Conivaptan is the US Food and Drug Administration (FDA) approved U n c o r r e c t e d P r o o f for hypervolemic (nephrotic syndrome, cardiac failure and cirrhosis) or euvolemic hyponatremia (SIADH) treatment in adults but not in children (10).…”

“…Data on the safety, efficacy and optimal dose of tolvaptan in pediatric patients are limited. There are rare case reports about tolvaptan therapy for SIADH in childhood (3,5,6,13). Likewise, there is scarce data with tolvaptan therapy used to treat hypervolemic hyponatremia such as in cardiac failure and nephrotic syndrome in children (14)(15)(16)(17).…”