Cerebral salt wasting syndrome in post-operative pediatric brain tumor patients

Hyponatremia after craniotomy in children: a single-institution review

PURPOSE

Hyponatremia after craniotomy can be associated with increased morbidity. However, the incidence of and factors associated with post-craniotomy hyponatremia in children are not known.

METHODS

We performed a retrospective cohort study of patients aged 0-21 years who underwent craniotomy in 2017-2019 at a single center to determine the incidence of and to identify risk factors for hyponatremia after craniotomy. Indications for craniotomy included tumors (excluding craniopharyngioma), epilepsy, intracranial infection, trauma, craniofacial, suboccipital decompression for the treatment of Chiari malformation, and cerebrovascular disease. Hyponatremia was defined as a serum sodium level ≤ 135 mEq/L any time during the postoperative hospital stay. Statistical significance was defined a priori at p < 0.05.

RESULTS

Postoperative hyponatremia occurred in 61 (25%) of 240 children. On univariate analysis, hyponatremia was associated with younger age (8.5 vs 6.3 years, p = 0.01), use of preoperative anti-epileptic drugs (p = 0.02), need for blood transfusion (p = 0.02), government/private insurance (p = 0.04), and pre-existing hydrocephalus, defined as the requirement for permanent cerebrospinal fluid (CSF) diversion (p = 0.04). On multivariate analysis, only hydrocephalus (OR 2.95, 95% CI 1.03-8.40) remained statistically significant. Hyponatremia most occurred on the first postoperative day, with normonatremia achieved in a median of 14 (IQR 9.8-24.3) h. Hyponatremia was significantly associated with longer length of stay (median 8 vs 3 days, p < 0.01).

CONCLUSION

Hyponatremia was present in 25% of children after craniotomy. Preoperative hydrocephalus as an independent risk factor for hyponatremia after craniotomy.

Concurrent central diabetes insipidus and cerebral salt wasting disease in a post-operative case of craniopharyngioma: a case report

BACKGROUND

Water and electrolyte disorders commonly encountered in children post-surgery involving hypothalamus and posterior pituitary, are central diabetes insipidus, syndrome of inappropriate secretion of anti-diuretic hormone and cerebral salt wasting disease. Delayed diagnosis and inadequate management of such cases may lead to worsened neurological outcomes with a high mortality rate.

CASE PRESENTATION

Here we report the case of a 7-year-old girl who underwent surgical resection of a craniopharyngioma, following which she initially developed central diabetes insipidus. However, later on in the course of her illness she developed symptomatic hyponatremia with natriuresis which was diagnosed to be due to cerebral salt wasting disease. This combination of central diabetes insipidus and cerebral salt wasting syndrome is a rare occurrence and poses a diagnostic challenge. Diagnosis and management can be even more difficult when these conditions precede or coexist with each other.

CONCLUSION

In such cases development of hyponatremia should always prompt consideration of unusual causes like cerebral salt wasting disease in addition to the classically described syndrome of inappropriate secretion of anti-diuretic hormone. Hence, a thorough knowledge of these disorders along with intensive monitoring of fluid and sodium status is critical for timely diagnosis and management of these patients.

Incidence and Possible Predictors of Sodium Disturbance After Craniopharyngioma Resection Based on QST Classification

OBJECTIVE

Serum sodium abnormalities are one of the most common manifestations after radical craniopharyngioma (CP) excision. The aim of this study was to report the incidence and possible predictors of serum sodium disturbance and explore features of sodium destabilization manifestation among QST classification results after CP resection.

METHODS

A retrospective analysis was performed of clinical, biochemical, radiologic, and operative data for 134 successive patients who underwent primary CP removal between September 2016 and March 2018. Univariate and multivariate analyses were conducted to determine predictors.

RESULTS

Sixty patients (44.8%) experienced hyponatremia and 67 patients (50%) hypernatremia; the median time of onset was 6 days and the first day after surgery, respectively. The incidence, onset, severity, and type of sodium disturbance among different types of CP differed significantly based on statistical tests (P < 0.05). Sodium disturbance was more common and severe in patients with type T tumors (P < 0.05). Age, tumor type, and preoperative diabetes insipidus were independent prognostic factors for obvious disorders of serum sodium.

CONCLUSIONS

Hyponatremia/hypernatremia is common after primary CP resection. The site of tumor origin has a direct effect on the growth pattern of CP, which may serve as a useful index for anticipating sodium perturbation after surgery. The level of sodium in children and patients with type T tumors, preoperative diabetes insipidus should be monitored closely throughout hospitalization.

Distribution of plasma copeptin levels and influence of obesity in children and adolescents

In recent years, a more stable AVP surrogate, called copeptin, has been used as an adjuvant diagnostic tool for dysnatremia in adults and appears to be promising even in the pediatric age. The aim of this study is to present the distribution of plasma copeptin in a large pediatric cohort and to observe the influence of fluid consumption and obesity on its values. A cohort of 128 children and adolescents was divided into two groups on the basis of nocturnal deprivation (group A) or free access to oral fluids in the 6-8 h before blood collection (group B). At all distribution percentiles, copeptin levels were higher (p < 0.0001) in group A, as were plasma sodium levels and osmolality (p = 0.02 and p = 0.008, respectively). The influence of BMI on copeptin levels was investigated by dividing the cohort into nonobese (group C) and obese children and adolescents (group D). Copeptin levels were higher in group D (p = 0.04).Conclusion: The measurement of copeptin could represent a useful tool for the diagnostic pathway of dysnatremic conditions, but its interpretation should take into consideration the state of hydration. Furthermore, it could also be a promising marker for obesity and metabolic syndrome, although this hypothesis needs further studies to be confirmed. What is Known: • Copeptin use as a diagnostic tool in AVP-related disorders, such as diabetes insipidus or syndrome of inappropriate secretion of antidiuretic hormone, is well established in adults • In pediatric age, few studies are available, but the preliminary data, including our previous study, seems to be promising. What is New: • In this study, we represent the distribution of copeptin levels in a pediatric cohort and show the significant influence of fluid ingestion on its plasma levels. • Also BMI seems to be a significant variable on copeptin levels and may be used as an obesity marker in pediatric age.

Clinical Approach to Sodium Homeostasis Disorders in Children with Pituitary-Suprasellar Tumors

Children with pituitary-suprasellar tumors are at high risk of developing sodium metabolism disorders since the tumoral mass itself or surgical and medical treatment can damage AVP release circuits. Additional risk factors are represented by the use of hypotonic fluids, the young age, total parenteral nutrition, and obstructive hydrocephalus secondary to tumor pathology. The most frequent hyponatremic disorders related to AVP in these patients are the syndrome of inappropriate ADH secretion and the cerebral/renal salt wasting syndrome, while hypernatremic conditions include central diabetes insipidus (CDI) and adipsic CDI. The main challenge in the management of these patients is to promptly distinguish the AVP release disorder at the base of the sodium imbalance and treat it correctly by avoiding rapid sodium fluctuations. These disorders can coexist or follow each other in a few hours or days; therefore, careful clinical and biochemical monitoring is necessary, especially during surgery, the use of chemotherapeutic agents, or radiotherapy. This monitoring should be performed by experienced healthcare professionals and should be multidisciplinary, including pediatric endocrinologists, neurosurgeons, and oncologists since maintaining sodium homeostasis also plays a prognostic role in terms of disease survival, therapeutic response, hospitalization rate, and mortality. In this review, we analyze the management of sodium homeostasis disorders in children with pituitary-suprasellar tumors and discuss the main challenges in the diagnosis and treatment of these conditions based on literature data and over 30 years of clinical experience at our Department of Pediatric Endocrinology.

Syndrome of Inappropriate Antidiuresis

The syndrome of inappropriate antidiuresis (SIAD) is a common cause of hyponatremia in hospitalized children. SIAD refers to euvolemic hyponatremia due to nonphysiologic stimuli for arginine vasopressin production in the absence of renal or endocrine dysfunction. SIAD can be broadly classified as a result of tumors, pulmonary or central nervous system disorders, medications, or other causes such as infection, inflammation, and the postoperative state. The presence of hypouricemia with an elevated fractional excretion of urate can aid in the diagnosis. Treatment options include fluid restriction, intravenous saline solutions, oral sodium supplements, loop diuretics, oral urea, and vasopressin receptor antagonists (vaptans).

Etiology of postoperative hyponatremia following pediatric intracranial tumor surgery

OBJECT Cerebral salt wasting (CSW) and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) cause postoperative hyponatremia in neurosurgery patients, can be difficult to distinguish clinically, and are associated with increased morbidity. The authors aimed to determine risk factors associated with CSW and SIADH among children undergoing surgery for intracranial tumors. METHODS This retrospective cohort study included children 0-19 years of age who underwent a first intracranial tumor surgery with postoperative hyponatremia (sodium ≤ 130 mEq/L). CSW was differentiated from SIADH by urine output and fluid balance, exclusive of other causes of hyponatremia. The CSW and SIADH groups were compared with basic bivariate analysis and recursive partitioning. RESULTS Of 39 hyponatremic patients, 17 (44%) had CSW and 10 (26%) had SIADH. Patients with CSW had significantly greater natriuresis compared with those with SIADH (median urine sodium 211 vs 28 mEq/L, p = 0.01). Age ≤ 7 years and female sex were significant risk factors for CSW (p = 0.03 and 0.04, respectively). Both patient groups had hyponatremia onset within the first postoperative week. Children with CSW had trends toward increased sodium variability and symptomatic hyponatremia compared with those with SIADH. Most received treatment, but inappropriate treatment was noted to worsen hyponatremia. CONCLUSIONS The authors found that CSW was more common following intracranial tumor surgery and was associated with younger age and female sex. Careful assessment of fluid balance and urine output can separate patients with CSW from those who have SIADH, and high urine sodium concentrations (> 100 mEq/L) support a CSW diagnosis. Patients with CSW and SIADH had similar clinical courses, but responded to different interventions, making appropriate diagnosis and treatment imperative to prevent morbidity.

Water and electrolyte disorders at long-term post-treatment follow-up in paediatric patients with suprasellar tumours include unexpected persistent cerebral salt-wasting syndrome

BACKGROUND

Patients with brain tumours have a high risk of water and electrolyte disorders (WED). Postsurgery diabetes insipidus (DI) may be transient or permanent, the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt-wasting syndrome (CSWS) are usually transient.

METHODS

Retrospective study, including patients with suprasellar tumours, treated at Hôpital Necker, Institut Gustave-Roussy or Institut Curie, in Île-de-France, between 2007 and 2011. WED were noted if they persisted >1 month after surgery.

RESULTS

159 patients were included, 54.1% girls, 43.9% boys. Tumour types were: glioma (43.4%), craniopharyngioma (43.4%), germinoma (11.3%), others (1.9%). Age at diagnosis was 7.1 ± 4.6 years. The median time from end of treatment was 1.9 (0-7.8) years. DI was the most frequent disorder after tumour treatment (50.3%) and was significantly associated with surgery (p < 0.001). Persistent CSWS was present in 3.6%, persistent SIADH in 1.3%. Two cases of hypernatraemia were due to adipsia. Thyrotropin deficiency after treatment was noted in 68.9% of patients tested, adrenocorticotropin deficiency in 66.2%.

CONCLUSIONS

Patients with suprasellar tumours have a high incidence of long-term WED, mainly DI. Assessment of thyrotroph and corticotroph function, and thirst sensation, is necessary to diagnose and manage these disorders correctly. CSWS may be persistent in few patients and requires special attention to prescribe the appropriate care.

Syndrome of inappropriate antidiuretic hormone secretion and cerebral/renal salt wasting syndrome: similarities and differences

Hyponatremia (sodium levels of <135 mEq/L) is one of the most common electrolyte imbalances in clinical practice, especially in patients with neurologic diseases. Hyponatremia can cause cerebral edema and brain herniation; therefore, prompt diagnosis and proper treatment is important in preventing morbidity and mortality. Among various causes of hyponatremia, diagnosing syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral/renal salt wasting syndrome (C/RSW) is difficult due to many similarities. SIADH is caused by excess of renal water reabsorption through inappropriate antidiuretic hormone secretion, and fluid restriction is the treatment of choice. On the other hand, C/RSW is caused by natriuresis, which is followed by volume depletion and negative sodium balance and replacement of water and sodium is the mainstay of treatment. Determinating volume status in hyponatremic patients is the key point in differential between SIADH and C/RSW. However, in most situations, differential diagnosis of these two diseases is difficult because they overlap in many clinical and laboratory aspects, especially to assess differences in volume status of these patients. Although distinction between the SIADH and C/RSW is difficult, improvement of hypouricemia and an increased fractional excretion of uric acid after the correction of hyponatremia in SIADH, not in C/RSW, may be one of the helpful points in discriminating the two diseases. In this review, we compare these two diseases regarding the pathophysiologic mechanisms, diagnosis, and therapeutic point of view.

Hyponatremia in the neurocritical care patient: An approach based on current evidence

In the neurocritical care setting, hyponatremia is the commonest electrolyte disorder, which is associated with significant morbimortality. Cerebral salt wasting and syndrome of inappropriate antidiuretic hormone have been classically described as the 2 most frequent entities responsible of hyponatremia in neurocritical care patients. Nevertheless, to distinguish between both syndromes is usually difficult and useless as volume status is difficult to be determined, underlying pathophysiological mechanisms are still not fully understood, fluid restriction is usually contraindicated in these patients, and the first option in the therapeutic strategy is always the same: 3% hypertonic saline solution. Therefore, we definitively agree with the current concept of "cerebral salt wasting", which means that whatever is the etiology of hyponatremia, initially in neurocritical care patients the treatment will be the same: hypertonic saline solution.

Impact of perioperative hyponatremia in children: A narrative review

For more than 50 years, hypotonic fluids (crystalloids) have been the standard for maintenance fluid used in children. In the last decade, several studies have evaluated the risk of hyponatremia associated with the use of hypotonic vs isotonic fluids, which has lead to an intense debate. Children undergoing surgery have several stimuli for release of antidiuretic hormone, which controls renal water handling, including pain, nausea, vomiting, narcotic use and blood loss. The body’s primary defense against the development of hyponatremia is the ability of the kidneys to excrete free water and dilute urine. Increased levels of antidiuretic hormone can result in hyponatremia, defined as a plasma sodium level < 136 mmol/L, which causes cells to draw in excess water and swell. This manifests as central nervous system symptoms such as lethargy, irritability and seizures. The risk for symptomatic hyponatremia is higher in children than in adults. It represents an emergency condition, and early diagnosis, prompt treatment and close monitoring are essential to reduce morbidity and mortality. The widespread use of hypotonic fluids in children undergoing surgery is a matter of concern and more focus on this topic is urgently needed. In this paper, we review the literature and describe the impact of perioperative hyponatremia in children.

Greater fluctuations in serum sodium levels are associated with increased mortality in children with externalized ventriculostomy drains in a PICU

OBJECTIVES

Dysnatremia is common in critically ill children due to disruption of hormonal homeostasis. Children with brain injury are at risk for syndrome of inappropriate antidiuretic hormone, cerebral salt wasting, and sodium losses due to externalized ventricular drain placement. We hypothesized that among PICU patients managed with an externalized ventricular drain, hyponatremia is common, hyponatremia is associated with seizures and in-hospital mortality, and greater sodium fluctuations are associated with in-hospital mortality.

DESIGN

Retrospective observational study.

SETTING

Tertiary care PICU.

PATIENTS

All pediatric patients treated in the PICU with an externalized ventricular drain from January 2005 to December 2009. Patients were identified by searching the physician order entry database for externalized ventricular drain orders. Hyponatremia was defined as the minimum sodium during patients' externalized ventricular drain time and was categorized as mild (131-134 mEq/L) or moderate to severe (≤ 130 mEq/L). Magnitude of sodium fluctuation was defined as the difference between a patient's highest and lowest sodium during the time in which an externalized ventricular drain was in use (up to 14 d). Seizure was defined as a clinically evident convulsion during externalized ventricular drain presence. A priori confounders were age, history of epilepsy, and externalized ventricular drain indication. Multivariable regression was performed to test the association between sodium derangements and outcomes.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Three hundred eighty patients were eligible. One hundred nine (29%) had mild hyponatremia, and 30 (8%) had moderate to severe hyponatremia. Twenty-eight patients (7%) had a seizure while hospitalized. Eighteen patients died (5%) prior to discharge. Survivors had a median daily sodium fluctuation of 1 mEq/L [0-5] vs non-survivors 9 mEq/L [6-11] (p < 0.001) and a median sodium fluctuation of 5 mEq/L [2-8] vs non-survivors 15 mEq/L [9-24] (p < 0.001) during externalized ventricular drain management. After controlling for a priori covariates and potential confounders, hyponatremia was not associated with an increased odds of seizures or in-hospital mortality. However, greater fluctuations in daily sodium (odds ratio, 1.38; 95% CI, 1.06-1.8) and greater fluctuations in sodium during externalized ventricular drain management were associated with increased odds of in-hospital mortality (odds ratio, 1.59; 95% CI, 1.2-2.11).

CONCLUSIONS

Hyponatremia was common in PICU patients treated with externalized ventricular drains but not associated with seizures or in-hospital mortality. Greater sodium fluctuations during externalized ventricular drain management were independently associated with increased odds of in-hospital mortality.

Timing, duration, and severity of hyponatremia following pediatric brain tumor surgery*

OBJECTIVE

To describe the time course, variability, and magnitude of serum sodium changes among children undergoing intracranial tumor surgery.

DESIGN

Retrospective cohort study.

SETTING

Tertiary children's hospital in Salt Lake City, UT.

PATIENTS

Children 0-19 years undergoing first neurosurgical procedure for an intracranial tumor, treated during January 2001 and February 2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Three hundred nineteen patients were placed in three exclusive groups based on the lowest serum sodium measurement during admission: 1) severe hyponatremia: serum sodium less than or equal to 130 mEq/L; 2) mild hyponatremia: 131-135 mEq/L; and 3) normal sodium: more than 135 mEq/L. Timing and severity of sodium perturbations were assessed within each group. Hundred thirty-seven patients (43%) had mild hyponatremia, 39 (12%) had severe hyponatremia, and 143 (45%) had normal sodium. After surgery, sodium decreased in all groups with lower averaged concentrations during postoperative days 0-1 and 5-6, although patients with severe hyponatremia had the greatest decline. Nearly 80% of hyponatremic patients had mild hyponatremia prior to development of severe hyponatremia; median time between mild hyponatremia and severe hyponatremia was 1.6 days (interquartile range, 0.4-5.6). Seventy-five percent of patients manifest mild hyponatremia within two postoperative days; however, severe hyponatremia developed later with 75% of patients manifesting severe hyponatremia within six postoperative days. Nine patients had initial severe hyponatremia between days 6 and 20 after surgery. Patients with severe hyponatremia had greater sodium variability with significantly lower nadirs, greater maximum values, and larger decreases within 24-hour periods compared with other sodium groups. Seventy-five percent of children with severe hyponatremia spent more than 4 days with abnormally low sodium values. Among hyponatremic patients, obstructive hydrocephalus and age less than 3.5 years were significant independent risk factors for severe hyponatremia.

CONCLUSION

Hyponatremia developed in just over half of children. Young children with hydrocephalus have increased risk of severe hyponatremia. Those with severe hyponatremia need frequent and prolonged monitoring because of risk for repeat sodium changes. Further study is needed to evaluate ideal monitoring and treatment of severe hyponatremia after intracranial tumor surgery.

The incidence of postoperative hyponatremia and associated neurological sequelae in children with intracranial neoplasms

OBJECT

Intracranial tumors are common pediatric neoplasms and account for substantial morbidity among children with cancer. Hyponatremia is a known complication of neurosurgical procedures and is associated with higher morbidity among neurosurgical patients. The authors aimed to estimate the incidence of hyponatremia, identify clinical characteristics associated with hyponatremia, and assess the association between hyponatremia and patient outcome among children undergoing surgery for intracranial tumors.

METHODS

This is a retrospective cohort study of children ranging in age from 0 to 19 years who underwent an initial neurosurgical procedure for an intracranial tumor between January 2001 and February 2012. Hyponatremia was defined as serum sodium ≤ 130 mEq/L during admission.

RESULTS

Hyponatremia during admission occurred in 39 (12%) of 319 patients and was associated with young age and obstructive hydrocephalus (relative risk [RR] 2.9 [95% CI 1.3-6.3]). Hyponatremic patients were frequently symptomatic; 21% had seizures and 41% had altered mental status. Hyponatremia was associated with complicated care including mechanical ventilation (RR 4.4 [95% CI 2.5-7.9]), physical therapy (RR 4 [95% CI 1.8-8.8]), supplemental nutrition (RR 5.7 [95% CI 3.3-9.8]), and infection (RR 5.7 [95% CI 3.3-9.5]). Hyponatremic patients had a 5-fold increased risk of moderate or severe disability on the basis of their Pediatric Cerebral Performance Category score at discharge (RR 5.3 [95% CI 2.9-9.8]). Obstructive hydrocephalus (adjusted odds ratio [aOR] 3.24 [95% CI 1.38-8.94]) and young age (aOR 0.92 [95% CI 0.85-0.99]) were independently associated with hyponatremia during admission. Hyponatremia was independently associated with moderate or worse disability by Pediatric Cerebral Performance Category score at discharge (aOR 6.2 [95% CI 3.0-13.03]).

CONCLUSIONS

Hyponatremia was common, particularly among younger children and those with hydrocephalus. Hyponatremia was frequently symptomatic and was associated with more complicated hospital courses. Hyponatremia was independently associated with worse neurological outcome when adjusted for age and tumor factors. This study serves as an exploratory analysis identifying important risk factors for hyponatremia and associated sequelae. Further research into the causes of hyponatremia and the association with poor outcome is needed to determine if prevention and treatment of hyponatremia can improve outcomes in these children.