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

Low Prevalence of Clinically Significant Hyponatremia following Cranial Vault Reconstruction for Single-Suture Craniosynostosis

BACKGROUND

Patients are commonly monitored for hyponatremia after intracranial procedures, yet the prevalence of hyponatremia after cranial vault reconstruction (CVR) remains unclear. The purpose of this study is to define the prevalence, risk factors, and complications of hyponatremia after CVR to optimize postoperative sodium surveillance protocols.

METHODS

Patients with nonsyndromic, single-suture craniosynostosis who underwent primary CVR between 2009 and 2020 at Michigan Medicine were included (n = 231). Demographic, intraoperative, and postoperative characteristics were compared by postoperative hyponatremia status at P < 0.05 significance. Hyponatremia was defined as mild (<135 mEq/L), moderate (<130 mEq/L), or severe (<125 mEq/L) based on the lowest postoperative laboratory draw.

RESULTS

Twenty-three patients (10.0%) developed mild postoperative hyponatremia. No patient developed moderate or severe postoperative hyponatremia. On multivariable regression, decreased preoperative sodium level (P = 0.03) and decreased preoperative weight (P = 0.02) were significantly associated with mild postoperative hyponatremia. No patient developed complications or required hospital readmission because of hyponatremia.

CONCLUSIONS

This large retrospective cohort study of patients with nonsyndromic single-suture craniosynostosis demonstrated a 10% prevalence of mild, clinically inconsequential hyponatremia and 0% prevalence of moderate or severe, clinically significant hyponatremia after primary CVR. Patients with low preoperative sodium level or weight were at increased risk for developing mild postoperative hyponatremia. The results suggest that patients with preoperative sodium greater than 140 mEq/L or preoperative weight greater than 10 kg may be candidates for limited postoperative sodium surveillance; however, future prospective studies are warranted before implementation.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

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.

Hyponatremia in tuberculous meningitis: A systematic review and meta-analysis

BACKGROUND

Tuberculous meningitis (TBM), manifests as the most severe involvement of the nervous system by Mycobacterium tuberculosis, it has a high mortality rate and a spectrum of systemic and neurological complications that can lead to debilitating or fatal sequelae, whereas hyponatremia is the commonly encountered life-threatening electrolyte disturbance. Thus, our study aimed to determine the prevalence, risk factors and differences in outcomes of hyponatremia in TBM.

METHODS

This systematic review was registered in PROSPERO (CRD42018088089). A comprehensive electronic search was conducted through ten databases to find relevant articles.

RESULTS

A total of 42 studies were included, 24 case reports and 18 retrospective studies. The prevalence rate of hyponatremia among TBM patients was 52% and the rate of death among those patients was 29%. The meta-regression analysis revealed that there was no significant effect of sodium level on the death rate in TBM patients (P-value = 0.9). Additionally, there was no significant difference in sodium level based on sex, and etiologies of hyponatremia.

CONCLUSIONS

Hyponatremia is commonly present in patient with TBM, but it is not significantly correlated to the rate of death. However, it is necessary to treat this potentially life-threatening condition appropriately according to its etiology, further research is needed on its pathophysiology in TBM, its risk factors, and the most appropriate treatment.

High Incidence of Hyponatremia in Patients Operated for Nonsellar/Suprasellar Supratentorial Tumors—A Prospective Observational Study

Background The incidence of hyponatremia is high in supratentorial tumors. However, most studies of supratentorial tumors have included patients with sellar/suprasellar tumors. It is common knowledge that sellar tumors have higher incidence and severity of hyponatremia. Incidence of hyponatremia is not known if we exclude sellar/suprasellar tumors. Therefore, this study was designed to evaluate the incidence of hyponatremia in supratentorial tumors after excluding sellar/suprasellar tumors.

Methods After institutional ethics committee approval and written informed consent, adult patients with supratentorial tumors (nonsellar/suprasellar) were recruited, and data were collected prospectively. In all patients, serum electrolytes were measured every 2 to 3 days. Hyponatremia was defined as serum sodium of <135 mEq/L. All the patients were followed up till death or discharge from the hospital.

Results A total of 61 patients’ data were analyzed. There were 31 male and 30 female patients with an average age of 44 years. There were 23 meningiomas, 36 gliomas, and 2 other tumors. Forty patients (66%) developed hyponatremia during hospital stay. There were 29 mild cases (serum sodium 131–134 mEq/L), 7 were moderate (serum sodium 126–130 mEq/L), and 4 were severe (serum sodium <126 mEq/L). Three hyponatremic meningioma patients died, of which two had mild hyponatremia and one had severe hyponatremia. Duration of hospital stay was longer in hyponatremic patients.

Conclusion The incidence of hyponatremia is high in supratentorial tumor patients after excluding sellar/suprasellar lesions. In the majority of patients, the disturbance is mild. Hyponatremic patients has a longer hospital stay and higher mortality.

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.

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.

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.

Hyponatremia and poor cognitive outcome following pediatric brain tumor surgery

OBJECT

Pediatric intracranial neoplasms are common and cause substantial neurological morbidity. Postoperative hyponatremia is also common and may exacerbate neurological injury. The authors performed an exploratory analysis to evaluate an exposure-response relationship between hyponatremia severity and cognitive function at discharge.

METHODS

A retrospective cohort of patients 0-19 years old who underwent a first intracranial neoplasm surgery at a pediatric tertiary care hospital was reviewed. Outcome was assessed by Pediatric Cerebral Performance Category (PCPC) score of 1-6 at hospital discharge. Poor outcome was defined as PCPC score 3-6, corresponding to moderate or worse disability.

RESULTS

Of 319 total children, 80 (25%) had poor outcomes. One hundred thirty-seven children (43%) had serum sodium concentrations ≤ 131-135 mEq/L and 39 (12%) had serum sodium concentrations ≤ 130 mEq/L. Lower nadir sodium concentration and longer duration of hyponatremia were significantly associated with worsening PCPC score (p < 0.001). Rapid sodium decreases and more hyponatremic episodes were also significantly associated with worsening PCPC score (p < 0.001). After adjustment for patient factors, tumor characteristics, and measures of sodium disruption, multivariable analysis revealed noncortical tumor locations and lower nadir sodium concentration (adjusted odds ratio 0.86, 95% confidence interval 0.78-0.95) were important independent risk factors for poor cognitive outcome.

CONCLUSIONS

Neurocognitive disability and hyponatremia are common in children undergoing surgery for intracranial neoplasms. This study found a significant association between severity of hyponatremia and worsened cognitive outcome, with an apparent exposure-response relationship. These data support the need for careful postoperative monitoring of serum sodium. Further research is needed to determine if prevention and treatment of hyponatremia can improve outcomes in these children.

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.