Bortezomib-induced hyponatremia: tolvaptan therapy permits continuation of lenalidomide, bortezomib and dexamethasone therapy in relapsed myeloma

Epidemiology and predictors of hyponatremia in a contemporary cohort of patients with malignancy: a retrospective cohort study

Background

Hyponatremia is associated with worse outcomes among patients with malignancy. However, contemporary cohort data on epidemiology and risk factors are lacking.

Methods

In this single-centre, retrospective cohort study, patients who received intravenous antineoplastic agents from 2018 to 2020 at Nagoya City University Hospital were enrolled. Associations of demographics, antineoplastic agents, types of malignancy and concomitant medications with hyponatremia, defined as serum sodium concentration ≤130 mmol/l, were analysed by mixed-effects logistic regression and the machine learning-based LightGBM model artificial intelligence technology.

Results

Among 2644 patients, 657 (24.8%) developed at least one episode of hyponatremia. Approximately 80% of hyponatremia was due to sodium wasting from the kidneys. Variables associated with hyponatremia both by mixed-effects logistic regression and the LightGBM model were older age, hypoalbuminemia and higher estimated glomerular filtration rate. Among antineoplastic agents, cisplatin {odds ratio [OR] 1.52 [95% confidence interval (CI) 1.18-1.96]}, pembrolizumab [OR 1.42 (95% CI 1.02-1.97)] and bortezomib [OR 3.04 (95% CI 1.96-4.71)] were associated with hyponatremia and these variables also had a positive impact on predicted hyponatremia in the LightGBM model.

Conclusions

Hyponatremia was common among patients with malignancy. In addition to older age and poor nutritional status, novel antineoplastic agents, including immune checkpoint inhibitors and bortezomib, should be recognized as risk factors for hyponatremia.

Hyponatraemia and the syndrome of inappropriate antidiuresis (SIAD) in cancer

Hyponatraemia is a common electrolyte abnormality seen in a wide range of oncological and haematological malignancies and confers poor performance status, prolonged hospital admission and reduced overall survival, in patients with cancer. Syndrome of inappropriate antidiuresis (SIAD) is the commonest cause of hyponatraemia in malignancy and is characterised by clinical euvolaemia, low plasma osmolality and concentrated urine, with normal renal, adrenal and thyroid function. Causes of SIAD include ectopic production of vasopressin (AVP) from an underlying tumour, cancer treatments, nausea and pain. Cortisol deficiency is an important differential in the assessment of hyponatraemia, as it has an identical biochemical pattern to SIAD and is easily treatable. This is particularly relevant with the increasing use of immune checkpoint inhibitors, which can cause hypophysitis and adrenalitis, leading to cortisol deficiency. Guidelines on the management of acute, symptomatic hyponatraemia recommend 100 mL bolus of 3% saline with careful monitoring of the serum sodium to prevent overcorrection. In cases of chronic hyponatraemia, fluid restriction is recommended as first-line treatment; however, this is frequently not feasible in patients with cancer and has been shown to have limited efficacy. Vasopressin-2 receptor antagonists (vaptans) may be preferable, as they effectively increase sodium levels in SIAD and do not require fluid restriction. Active management of hyponatraemia is increasingly recognised as an important component of oncological management; correction of hyponatraemia is associated with shorter hospital stay and prolonged survival. The awareness of the impact of hyponatraemia and the positive benefits of active restoration of normonatraemia remain challenging in oncology.

[Central nervous system toxicity caused by bortezomib: five case reports and a review of literature]

目的

探讨硼替佐米中枢神经系统（CNS）毒性的临床特点、诊断和治疗。

方法

报道5例由硼替佐米引起的CNS毒性患者并结合现有文献探讨其临床特点。

结果

5例患者中有4例在应用硼替佐米后出现了中枢性发热，主要表现为持续性高热、周身无汗、未能找到感染病灶、对退热药不敏感，停用硼替佐米后症状好转。4例患者中有3例伴随顽固性低钠血症，1例明确诊断为抗利尿不当综合征（SIAD），可能是硼替佐米同时影响了下丘脑体温调节中枢和抗利尿激素神经分泌细胞所致。1例患者诊断为可逆性后部脑病综合征（PRES），表现为应用硼替佐米后出现意识障碍，头CT示双侧半卵圆中心白质密度减低，停用硼替佐米后患者症状消失且未再复发。此外，我们还发现血小板计数可能与硼替佐米CNS毒性的严重程度相关。

结论

硼替佐米的CNS毒性非常罕见，表现为3种形式：SIAD、PRES和中枢性发热，及时识别和治疗对于预防不可逆的神经并发症非常重要。

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.