Hyponatremia in patients with traumatic brain injury: incidence, mechanism, and response to sodium supplementation or retention therapy with hydrocortisone

Initial dysnatremia and clinical outcomes in pediatric traumatic brain injury: a multicenter observational study

PURPOSE

We aimed to investigate the association between initial dysnatremia (hyponatremia and hypernatremia) and in-hospital mortality, as well as between initial dysnatremia and functional outcomes, among children with traumatic brain injury (TBI).

METHOD

We performed a multicenter observational study among 26 pediatric intensive care units from January 2014 to August 2022. We recruited children with TBI under 18 years of age who presented to participating sites within 24 h of injury. We compared demographics and clinical characteristics between children with initial hyponatremia and eu-natremia and between those with initial hypernatremia and eu-natremia. We defined poor functional outcome as a discharge Pediatric Cerebral Performance Category (PCPC) score of moderate, severe disability, coma, and death, or an increase of at least 2 categories from baseline. We performed multivariable logistic regression for mortality and poor PCPC outcome.

RESULTS

Among 648 children, 84 (13.0%) and 42 (6.5%) presented with hyponatremia and hypernatremia, respectively. We observed fewer 14-day ventilation-free days between those with initial hyponatremia [7.0 (interquartile range (IQR) = 0.0-11.0)] and initial hypernatremia [0.0 (IQR = 0.0-10.0)], compared to eu-natremia [9.0 (IQR = 4.0-12.0); p = 0.006 and p < 0.001]. We observed fewer 14-day ICU-free days between those with initial hyponatremia [3.0 (IQR = 0.0-9.0)] and initial hypernatremia [0.0 (IQR = 0.0-3.0)], compared to eu-natremia [7.0 (IQR = 0.0-11.0); p = 0.006 and p < 0.001]. After adjusting for age, severity, and sex, presenting hyponatremia was associated with in-hospital mortality [adjusted odds ratio (aOR) = 2.47, 95% confidence interval (CI) = 1.31-4.66, p = 0.005] and poor outcome (aOR = 1.67, 95% CI = 1.01-2.76, p = 0.045). After adjustment, initial hypernatremia was associated with mortality (aOR = 5.91, 95% CI = 2.85-12.25, p < 0.001) and poor outcome (aOR = 3.00, 95% CI = 1.50-5.98, p = 0.002).

CONCLUSION

Among children with TBI, presenting dysnatremia was associated with in-hospital mortality and poor functional outcome, particularly hypernatremia. Future research should investigate longitudinal sodium measurements in pediatric TBI and their association with clinical outcomes.

Predictive value of hyponatremia for short-term mortality in supratentorial spontaneous intracerebral hemorrhage: a single center study

Background

Hyponatremia is a common electrolyte disturbance in patients with neurological disease; however, its predictive role for outcome in patients with supratentorial spontaneous intracerebral hemorrhage (sICH) is controversial. This study aims to explore the association between hyponatremia within 7 days after bleeding and 90-day mortality in patients with supratentorial sICH.

Methods

A retrospective analysis was conducted at our institution. Patients with sICH meeting the inclusion criteria were enrolled in this study. Multivariate regression analyses were performed to determine the predictive value of hyponatremia (serum sodium <135 mmol/L) for 90-day mortality and functional outcome. Subgroup analysis was performed based on the degree and duration of hyponatremia and therapeutic strategies. The Spearman correlation test was performed to explore the relationship between hyponatremia severity and duration with variables in a multivariate regression model. Kaplan-Meier curve was depicted to reveal the relationship between hyponatremia and mortality. The receiver operating characteristic (ROC) curve was plotted to show the diagnostic effect of the minimum concentration of serum sodium (sodiummin) on 90-day mortality.

Results

A total of 960 patients were enrolled, 19.6% (188) of whom were patients with hyponatremia and 26.0% (250) had 90-day mortality. The incidence of hyponatremia was roughly 2.5 times in non-survivors compared with survivors (34.8% vs. 14.2%). Multivariate regression analysis revealed that hyponatremia was the independent predictor of 90-day mortality (OR 2.763, 95%CI 1.836-4.157) and adverse outcome (OR 3.579, 95%CI 2.332-6.780). Subgroup analysis indicated an increased trend in mortality risk with both duration (more or less than 48 h) and severity of hyponatremia (mild, moderate, and severe) and confirmed the predictive value of hyponatremia for mortality in patients undergoing surgical intervention (external ventricular drainage, craniotomy, and decompressive craniectomy; all p < 0.05). The Spearman correlation test indicated no moderate or strong relationship between hyponatremia severity and duration with other variables in the multivariate model (all |rs| < 0.4). The ROC curve suggested the moderate diagnostic performance of sodiummin for mortality in both general patients and subgroups of therapeutic method patients (AUC from 0.6475 to 0.7384).

Conclusion

Hyponatremia occurring in the first 7 days after bleeding is an independent predictor of 90-day morality and adverse outcome. Rigorous electrolyte scrutiny in patients treated surgically is required.

High Urinary Sodium Concentrations in Severe SIADH: Case Reports of 2 Patients and Literature Review

We present two cases of severe hyponatremia secondary to syndrome of inappropriate secretion of antidiuretic hormone (SIADH) with very high urine sodium concentrations (>130 mmol/L). The first patient had hyponatremia from traumatic brain injury (TBI) while the second case had a history of recurrent SIADH triggered by various causes including gastritis. In both cases, fluid administration and/or consumption worsened the hyponatremia. Although a low urine sodium of <30 mmol/L is highly suggestive of hypovolemic hyponatremia and good response to saline infusion, there is lack of clarity of the threshold of which high urine sodium concentration can differentiate various causes of natriuresis such as SIADH, renal or cerebral salt wasting. Apart from high urine osmolality (>500 mOsm/kg), persistence of high urine sodium concentrations may be useful to predict poor response to fluid restriction in SIADH. More studies are needed to delineate treatment pathways of patients with very high urine osmolality and urine sodium concentrations in SIADH.

BNP and NT-proBNP Concentrations in Paired cerebrospinal Fluid and Plasma Samples of Patients with Traumatic Brain Injury

BACKGROUND

The aim of this study was to investigate the secretion patterns of brain natriuretic peptide (BNP) and N-terminal-proBNP (NT-proBNP) after traumatic brain injury (TBI) and to analyze the source of them in cerebrospinal fluid (CSF).

MATERIALS AND METHODS

We synchronously measured BNP and NT-proBNP concentrations in paired CSF and plasma samples from 22 moderate to severe TBI patients and 40 healthy control patients. The CSF and/or plasma ratio of albumin (Q_Albumin) was calculated daily. The BNP and NT-proBNP levels of CSF and plasma were compared between TBI patients and control patients.

RESULTS

CSF BNP and NT-proBNP levels peaked on day 3 after injury, as did the plasma BNP and NT-proBNP levels. The CSF BNP and NT-proBNP levels in TBI patients were elevated from day 1, which was significantly higher than control group (P < 0.05 and P < 0.01, respectively). However, in plasma, only NT-proBNP levels were significantly higher than in the control group from day 2 (P < 0.05). In addition, Q_BNP, defined as CSF BNP concentration and/or plasma BNP concentration, was significantly higher in TBI patients than in the control group (P < 0.01). However, Q_Albumin remained within ranges of a mild to moderate dysfunction of blood-brain-barrier in TBI patients.

CONCLUSIONS

CSF BNP concentrations are elevated and peak on day 3 after moderate to severe TBI. CSF BNP may originate from the brain and may be a potential biomarker of TBI.

Hyponatraemia and hypernatraemia: Disorders of Water Balance in Neurosurgery

Disorders of tonicity, hyponatraemia and hypernatraemia, are common in neurosurgical patients. Tonicity is sensed by the circumventricular organs while the volume state is sensed by the kidney and peripheral baroreceptors; these two signals are integrated in the hypothalamus. Volume is maintained through the renin-angiotensin-aldosterone axis, while tonicity is defended by arginine vasopressin (antidiuretic hormone) and the thirst response. Edelman found that plasma sodium is dependent on the exchangeable sodium, potassium and free-water in the body. Thus, changes in tonicity must be due to disproportionate flux of these species in and out of the body. Sodium concentration may be measured by flame photometry and indirect, or direct, ion-sensitive electrodes. Only the latter method is not affected by changes in plasma composition. Classification of hyponatraemia by the volume state is imprecise. We compare the tonicity of the urine, given by the sodium potassium sum, to that of the plasma to determine the renal response to the dysnatraemia. We may then assess the activity of the renin-angiotensin-aldosterone axis using urinary sodium and fractional excretion of sodium, urate or urea. Together, with clinical context, these help us determine the aetiology of the dysnatraemia. Symptomatic individuals and those with intracranial catastrophes require prompt treatment and vigilant monitoring. Otherwise, in the absence of hypovolaemia, free-water restriction and correction of any reversible causes should be the mainstay of treatment for hyponatraemia. Hypernatraemia should be corrected with free-water, and concurrent disorders of volume should be addressed. Monitoring for overcorrection of hyponatraemia is necessary to avoid osmotic demyelination.

Acute kidney injury after brain injury: does it exist?

Acute kidney injury (AKI) is frequent after cerebral insults, with an incidence close to 10% in both traumatic brain injury (TBI) and cerebrovascular disease. AKI in this context has substantial impact on mortality and neurological outcome. Numerous factors may play a role in the development of AKI after brain injury: intravascular volume depletion, raised-intra-abdominal pressure, rhabdomyolysis or sepsis in TBI; age, ischemic heart disease or arteriosclerotic disease in stroke. However, brain-kidney crosstalk mechanisms are complex and there remains a strong rationale for a causal relationship between brain and kidney injury. Cerebral lesions might alter renal function through a neuro-endocrine pathway combining sympathetic system, renin-angiotensin-aldosterone and glucocorticoid activation. Altogether these systems impair renal autoregulation ultimately leading to AKI. In addition, cerebral lesions might lead to a systemic inflammatory response making the kidney vulnerable for dysfunction. Indeed, inflammation and immune system activation are core mechanisms for the development of AKI. Last, direct lesions of specific area of the brain might lead to vasomotor changes and AKI. In this work, we reviewed the epidemiology of AKI after brain injury and examine potential mechanisms suggesting a causal relationship between these two entities.

Variability in Serum Sodium Concentration and Prognostic Significance in Severe Traumatic Brain Injury: A Multicenter Observational Study

BACKGROUND/OBJECTIVE

Dysnatremia is common in severe traumatic brain injury (TBI) patients and may contribute to mortality. However, serum sodium variability has not been studied in TBI patients. We hypothesized that such variability would be independently associated with mortality.

METHODS

We collected 6-hourly serum sodium levels for the first 7 days of ICU admission from 240 severe TBI patients in 14 neurotrauma ICUs in Europe and Australia. We evaluated the association between daily serum sodium standard deviation (dNa_SD), an index of variability, and 28-day mortality.

RESULTS

Patients were 46 ± 19 years of age with a median initial GCS of 6 [4-8]. Overall hospital mortality was 28%. Hypernatremia and hyponatremia occurred in 64% and 24% of patients, respectively. Over the first 7 days in ICU, serum sodium standard deviation was 2.8 [2.0-3.9] mmol/L. Maximum daily serum sodium standard deviation (dNa_SD) occurred at a median of 2 [1-4] days after admission. There was a significant progressive decrease in dNa_SD over the first 7 days (coefficient - 0.15 95% CI [- 0.18 to - 0.12], p < 0.001). After adjusting for baseline TBI severity, diabetes insipidus, the use of osmotherapy, the occurrence of hypernatremia, and hyponatremia and center, dNa_SD was significantly independently associated with 28-day mortality (HR 1.27 95% CI (1.01-1.61), p = 0.048).

CONCLUSIONS

Our study demonstrates that daily serum sodium variability is an independent predictor of 28-day mortality in severe TBI patients. Further prospective investigations are necessary to confirm the significance of sodium variability in larger cohorts of TBI patients and test whether attenuating such variability confers outcome benefits to such patients.

Incidence of hyponatremia in patients given levetiracetam vs. phenytoin for early posttraumatic seizure prophylaxis

BACKGROUND

Levetiracetam and phenytoin are comparable for acute posttraumatic seizure(PTS) prophylaxis. Levetiracetam-induced hyponatremia has been reported in non-trauma patients. We studied hyponatremia in posttraumatic intracranial hemorrhage(ICH) patients receiving either drug.

METHODS

Retrospective review of patients with ICH receiving PTS prophylaxis was performed. Patients were categorized by degree of sodium nadir: normal, mild, moderate, or severe, and analyzed by levetiracetam versus phenytoin. Patients were matched 2:1 regarding age and injury severity score(ISS). Incidence and treatment for hyponatremia was examined.

RESULTS

1735 ICH patients received PTS prophylaxis over an 8-year period. After exclusions and matching, there were 282 phenytoin and 564 levetiracetam patients. Age, ISS and initial sodium were comparable between the matched cohorts. There was no clinically significant difference in the rate or degree of hyponatremia. Treatment was more common in levetiracetam patients.

DISCUSSION

There was a small but clinically insignificant difference in the incidence of hyponatremia in traumatic ICH patients receiving levetiracetam vs. phenytoin for PTS prophylaxis. There was an increased rate of intervention for hyponatremia in the levetiracetam group, possibly due to a coincidental preventive paradigm shift.

Pharmacotherapy of sodium disorders in neurocritical care

PURPOSE OF REVIEW

To describe the pathophysiology and pharmacotherapy of dysnatremia in neurocritical care patients.

RECENT FINDINGS

Sodium disorders may affect approximately half of the neurocritical care patients and are associated with worse neurological outcome and increased risk of death. Pharmacotherapy of sodium disorders in neurocritical care patients may be challenging and is guided by a careful investigation of water and sodium balance.

SUMMARY

In case of hyponatremia, because of excessive loss of sodium, fluid challenge with isotonic solution, associated with salt intake is the first-line therapy, completed with mineralocorticoids if needed. In case of hyponatremia because of SIADH, fluid restriction is the first-line therapy followed by urea if necessary. Hypernatremia should always be treated with hypotonic solutions according to the free water deficit, associated in case of DI with desmopressin. The correction speed should take into consideration the symptoms associated with dysnatremia and the rapidity of the onset.

Inappropriate Antidiuretic Hormone Secretion and Cerebral Salt-Wasting Syndromes in Neurological Patients

The differential diagnosis of syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt-wasting syndrome (CSWS) in patients with neurological disorders has been a perplexing clinical controversy. The purpose of this review is to summarize the characteristics and risk factors of patients with different types of neurological disorders complicated by hyponatremia (HN) and review various methods to distinguish SIADH from CSWS. Common neurological disorders with high rates of HN include subarachnoid hemorrhage (SAH), traumatic brain injuries, stroke, cerebral tumors, central nervous system (CNS) infections, and Guillain-Barré syndrome (GBS), which have their own characteristics. Extracellular volume (ECV) status of patients is a key point to differentiate SIADH and CSWS, and a comprehensive assessment of relevant ECV indicators may be useful in differentiating these two syndromes. Besides, instead of monitoring the urinary sodium excretion, more attention should be paid to the total mass balance, including Na⁺, K⁺, Cl^-, and extracellular fluid. Furthermore, the dynamic detection of fractional excretions (FE) of urate before and after correction of HN and a short-term infusion of isotonic saline solution may be useful in identifying the etiology of HN. As for brain natriuretic peptide (BNP) or N-terminal prohormone of BNP (NT-proBNP), more prospective studies and strong evidence are needed to determine whether there is a pertinent and clear difference between SIADH and CSWS.

Autonomic dysfunction following traumatic brain injury: translational insights

Although there is a substantial amount of research on the neurological consequences of traumatic brain injury (TBI), there is a knowledge gap regarding the relationship between TBI and the pathophysiology of organ system dysfunction and autonomic dysregulation. In particular, the mechanisms or incidences of renal or cardiac complications after TBI are mostly unknown. Autonomic dysfunction following TBI exacerbates secondary injury and may contribute to nonneurologial complications that prolong hospital length of stay. Gaining insights into the mechanisms of autonomic dysfunction can guide advancements in monitoring and treatment paradigms to improve acute survival and long-term prognosis of TBI patients. In this paper, the authors will review the literature on autonomic dysfunction after TBI and possible mechanisms of paroxysmal sympathetic hyperactivity. Specifically, they will discuss the link among the brain, heart, and kidneys and review data to direct future research on and interventions for TBI-induced autonomic dysfunction.

Risk Factors for Recurrent Hematoma After Surgery for Acute Traumatic Subdural Hematoma

OBJECTIVE

The development of postcraniotomy hematoma (PCH) after surgery for acute traumatic subdural hematoma (aSDH) has been associated with an increased risk of a poor outcome. The risk factors contributing to PCH remain poorly understood. Our aim was to study the potential risk factors for PCH in a consecutive series of surgically evacuated patients with aSDH.

METHODS

A total of 132 patients with aSDH treated at Turku University Hospital (Turku, Finland) from 2008 to 2012 were enrolled in the present retrospective cohort study. The demographic, clinical, laboratory, and imaging data were collected from the medical records. A comprehensive analysis of the data using 6 different univariate methods, including machine learning and multivariate analyses, was conducted to identify the factors related to PCH.

RESULTS

The incidence of PCH after primary surgery for traumatic aSDH was 10.6%. The patients experiencing PCH were younger (P = 0.04). No difference was found in the use of anticoagulant or antiplatelet medication for the patients with and without PCH. Multivariate analyses identified alcohol inebriation at the time of injury (odds ratio [OR], 12.67; P = 0.041) and hypocapnia (OR, 26.09; P = 0.003) as independent risk factors for PCH. The patients with PCH had had hyponatremia (OR, 0.08; P = 0.018) less often, and their maximal systolic blood pressure was lower (OR, 0.94; P = 0.009). The area under the curve for the multivariate model was 0.96 (P = 0.049), with a Youden index of 0.88.

CONCLUSIONS

The results suggest that alcohol inebriation at the time of injury and hypocapnia during hospitalization are risk factors for the development of PCH.

[A case of cerebral salt wasting syndrome caused by minor head injury]

An 80-year-old woman who was hospitalized due to small subarachnoid hemorrhaging caused by a bruise in the left temporal region of the brain. Nausea/vomiting and malaise appeared after dinner on the fourth day of the illness. Head computed tomography showed that the post-traumatic status was almost normal; however, the sodium ion (Na⁺) level was 114 mEq/L, indicating severe hyponatremia. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) following a head injury was initially suspected, and water restriction and saline fluid replacement were initiated. However, the Na⁺ level did not improve, and signs of dehydration emerged. On the seventh day of the illness, drinking water restriction was discontinued, and 3% sodium chloride fluid replacement was initiated. The patient subsequently followed a favorable course, and the Na⁺ level remained normal even after fluid replacement was discontinued. It is important to differentiate between SIADH and cerebral salt wasting syndrome (CSWS), as the treatment of the two are diametrically opposite. However, distinguishing between these two diseases at an early onset can be difficult, as they have very similar laboratory findings. CSWS can occur in patients with minor head injury, as in the present case, so we should bear this disease in mind as a differential diagnosis, even when imperceptible graduations are recognized in patients.

A swine model of intracellular cerebral edema - Cerebral physiology and intracranial compliance

Cerebral edema leading to elevated intracranial pressure (ICP) is a fundamental concern after severe traumatic brain injury (TBI), stroke, and severe acute hyponatremia. We describe a swine model of water intoxication and its cerebral histological and physiological sequela. We studied female swine weighing 35-45 kg. Four serum sodium intervals were designated: baseline, mild, moderate, and severe hyponatremia attained by infusing hypotonic saline. Intracranial fluid injections were performed to assess intracranial compliance. At baseline and following water intoxication wedge biopsy was obtained for pathological examination and electron microscopy. We studied 8 swine and found an increase in ICP that was strongly related to the decrease in serum sodium level. Mean ICP rose from a baseline of 6 ± 2 to 28 ± 6 mm Hg during severe hyponatremia, while cerebral perfusion pressure (CPP) decreased from 72 ± 10 to 46 ± 11 mm Hg. Brain tissue oxygen tension (PbtO₂) decreased from 18.4 ± 8.9 to 5.3 ± 3.0 mm Hg. Electron microscopy demonstrated intracellular edema and astrocytic foot process swelling following water intoxication. With severe hyponatremia, 2 cc intracranial fluid injection resulted in progressively greater ICP dose, indicating a worsening intracranial compliance. Our model leads to graded and sustained elevation of ICP, lower CPP, and decreased PbtO₂, all of which cross clinically relevant thresholds. Intracranial compliance worsens with increased cerebral swelling. This model may serve as a platform to study which therapeutic interventions best improve the cerebral physiological profile in the face of severe brain edema.

Hyponatremia is a potential predictor of progression in radiation-induced brain necrosis: a retrospective study

Background

To investigate the prognostic value of hyponatremia, defined as serum sodium level < 135 mEq/L, in radiation-induced brain necrosis (RN) patients.

Methods

We performed a retrospective analysis of the RN patients (The patients included in our study had a history of primary cancers including nasopharyngeal carcinoma/glioma/oral cancer and received radiotherapy previously and then were diagnosed with RN) treated in Sun yat-sen Memorial Hospital from January 2013 to August 2015. Patients without cranial magnetic resonance imaging (MRI) scan and serum sodium data were excluded. Progression was identified when the increase of edema area ≥ 25% on the MRI taken in six months comparing with those taken at the baseline. Factors that might associate with prognosis of RN were collected. Multivariable logistic regression analyses were used to identify potential predictors.

Results

We total included 135 patients, 32 (23.7%) of them with hyponatremia and 36 (26.7%) with RN progression. Percentage of progression was roughly three fold in hyponatremia patients compared with nonhyponatremia patients (53.1% versus 18.4%), translating into a 5-fold increased odds ratio (P <  0.001). Multivariable analyses identified hyponatremia as a potential predictor of progression (OR, 4.82; 95% CI [1.94–11.94]; P = 0.001).

Conclusions

Hyponatremia was identified as a potential predictor for the progression of patients with RN. Hyponatremia management in patients with RN should be paid much more concern in clinical practice.

Impact of etiology, age and gender on onset and severity of hyponatremia in patients with hypopituitarism: retrospective analysis in a specialised endocrine unit

BACKGROUND

Hyponatremia can unmask hypopituitarism and secondary adrenal insufficiency. This is important, since the need to screen for steroid deficiency, in patients with hyponatremia is often neglected.

PATIENTS AND METHODS

In a retrospective study, twenty-five patients (13f/12m, age 58.9 ± 18.6 years) with hyponatremia (119.7 ± 10.5 mmol/L) were identified among 260 in-patients treated for hypopituitarism in our specialized endocrine unit, over the last decade. We analyzed clinical characteristics, etiology, and severity of hypopituitarism in patients who presented with hyponatremia.

RESULTS

Hyponatremia was recorded in 9.6% of our patients with hypopituitarism. In 80.7% it was the key to diagnosis of hypopituitarism. All patients with hyponatremia were steroid deficient with complete hypopituitarism compared to 75% (steroid deficient) and 60% (complete hypopituitarism) of the patients in the cohort. The most common etiology of hypopituitarism was non-functioning pituitary macro adenoma (NFPA) (n = 128, 49.2%). Patients with hyponatremia were divided into two groups, based on the etiology of hypopituitarism: Group 1. with NFPA n = 15 (5F/10M), mean age 71.47 ± 4.8 years, who were significantly older compared to patients with hyponatremia from other rare causes of hypopituitarism in Group 2. n = 10 (8F/2M), mean age 40.2 ± 15.3 years (p < 0.01), such as: congenital hypopituitarism(n = 2), Sheehan's syndrome (n = 2), intracranial aneurysm (n = 2), lymphocytic hypophysitis (n = 1), traumatic brain injury (n = 1), surgery and radiotherapy for astrocytoma (n = 1), pituitary metastasis from bronchial carcinoma (n = 1). Hyponatremia was more severe in Group 2. compared to Group 1. (113.5 ± 10.9 mmol/L vs. 124.3 ± 8.1 mmol/L, p < 0.01). Older age (p = 0.0001) and number of endocrine deficiencies (p < 0.05) were identified as predictive factors for hyponatremia by multivariate analysis in patients with hypopituitarism.

CONCLUSION

Hyponatremia is an important presenting feature of pituitary disease and a strong indicator of life-threatening steroid deficiency. Old age and severity of hypopituitarism are major risk factors for hyponatremia. In older patients NFPA is the most common etiology, while other rare causes of hypopituitarism are more prevalent in younger patients with hyponatremia.

Prevention and Treatment of Hyponatremia in Patients with Subarachnoid Hemorrhage: A Systematic Review

BACKGROUND

Current guidelines for the management of hyponatremia in patients with subarachnoid hemorrhage (SAH) are not based on a systematic assessment of the literature. We evaluated published studies on the efficacy and safety of current preventative and treatment strategies for hyponatremia in patients with SAH.

METHODS

We searched the Cochrane Central Register of Controlled Trials, Embase, MEDLINE, and PubMed for relevant studies. Primary outcomes of interest included neurologic functional outcomes, symptomatic vasospasm, and others. Secondary outcomes included measures of sodium and volume status.

RESULTS

We included 5 out of 117 identified studies: 1 before-and-after observational trial (using fludrocortisone) and 4 randomized controlled trials (2 using fludrocortisone; 2 using hydrocortisone). All 5 trials had a high risk of bias in at least 1 domain. We could not perform a meta-analysis of functional outcomes; however, individual studies did not demonstrate statistically significant differences. Mineralocorticoid use did not statistically significantly reduce the incidence of symptomatic vasospasm (relative risk, 0.60; 95% confidence interval, 0.35-1.03; I² = 0%). The studies did not report other primary outcomes. In the 4 RCTs, mineralocorticoid use reduced natriuresis and volume contraction.

CONCLUSIONS

Current evidence does not demonstrate a benefit of preventative treatment with mineralocorticoids in clinically important outcomes, although a difference cannot be ruled out due to imprecision. Larger well-designed trials are needed to establish the impact of mineralocorticoids and fluid and sodium supplementation strategies on clinically relevant outcomes in the prevention and treatment of hyponatremia in patients with SAH.

Hyponatremia in Traumatic Brain Injury: A Practical Management Protocol

BACKGROUND

Hyponatremia (defined as serum sodium <135 mEq/L) is the most common electrolyte abnormality in traumatic brain injury (TBI) and is also an independent predictor of poor neurologic outcome. The reported incidence of hyponatremia varies widely in literature reports, and there is continuing difficulty in clearly differentiating between the 2 common causes of hyponatremia with natriuresis: the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt wasting (CSW). We encounter hyponatremia frequently in our practice, and we therefore decided to review data from our center to estimate the incidence of hyponatremia and the results of our management strategies, and attempt to formulate simple guidelines for the correction of hyponatremia in TBI.

METHODS

A retrospective analysis of 1500 consecutively admitted patients with TBI was performed by the use of electronic records and radiographic review. Hyponatremia was defined as serum sodium <135 mEq/L, and natriuresis as a urine spot sodium of more than >40 mEq/L. The incidence of TBI, its management, and the effect of fludrocortisone were evaluated.

RESULTS

The incidence of hyponatremia was 13.2%. Early therapy with fludrocortisone significantly reduced the duration of hospital stay (P < 0.05). Traumatic subarachnoid hemorrhage was the most common abnormality on the admission computed tomographic scan in patients who experienced hyponatremia.

CONCLUSION

Early initiation of fludrocortisone in the setting of hyponatremia with natriuresis decreases the hospital stay. This protocol is probably safer in a tropical country where fluid restriction might be harmful. It also eliminates the need to differentiate between SIADH and CSW.

Concurrence of Inappropriate Antidiuretic Hormone Secretion and Cerebral Salt Wasting Syndromes after Traumatic Brain Injury

Syndrome of inappropriate antidiuretic hormone (SIADH) and cerebral salt wasting syndrome (CSWS) as the two most common neuroendocrine diseases, have been recognized and understood by many neurologists. Although SIADH and CSWS are the common causes of central hyponatremia after traumatic brain injury (TBI), a few cases are mixed, with the coexistence of the two pathological pathomechanism. However, the mixed type of both SIADH and CSWS has not been clearly reported in any literature. Here, we present the first description of the concurrent syndrome of SIADH and CSWS after TBI in four patients who underwent standard diagnostic procedures, treatment and follow up. Our findings further support that this rare neuroendocrine disease may exist in clinical practice, in which the traditional-conventional treatment shows poor efficacy.

Scientific Basis of Hyponatremia and Its Clinical Presentations

Purpose

To describe causes, pathophysiologic mechanisms, and classifications of hyponatremia, and to describe clinical symptoms and underlying disease states associated with different levels of hyponatremia.

Summary

The key to comprehending hyponatremia is to understand body water content and plasma osmolality and accurately assess arterial volume. Hyponatremia results from sodium dilution because of retained water or sodium depletion because of electrolyte loss in excess of water loss. Body sodium, water, and extracellular fluid (ECF) volume are tightly regulated by mechanisms that act to maintain a closely controlled concentration of solutes in the ECF. These forces act to regulate water content and sodium excretion to maintain normal intravascular volume. The body closely defends normal plasma osmolality within a narrow range primarily by controlling the release of arginine vasopressin (AVP) and via the thirst mechanism. A number of factors can stimulate inappropriate AVP release and cause or worsen hyponatremia. Dysregulation of AVP plays an important role in heart failure and cirrhosis, common causes of hypervolemic hyponatremia.

Conclusion

Body water content and plasma osmolality are tightly regulated by the action of AVP. A variety of disease states are associated with hyponatremia related to inappropriate AVP release. The cause of the electrolyte disturbance must be determined, because it can have profound implications for treatment. Differential diagnosis can be guided by observation of the rapidity of onset as well as volume status changes. If untreated or treated inappropriately, hyponatremia can impact morbidity and mortality.

Hyponatremia upon presentation to the emergency department - the need for urgent neuroimaging studies

This study aims to evaluate the necessity of urgent neuroimaging for emergency admissions exhibiting symptomatology of profound hyponatremia. We retrospectively analyzed the medical records of all patients admitted to the emergency room of the University Hospital Münster from 2010 to 2014 with a serum sodium value < 125 mmol/L. From 52918 emergency admissions, 261 patients with profound hyponatremia were identified, of whom 140 (54%) had neurological symptoms. Unspecific weakness and confusion were the most prevalent of these symptoms (59%). Focal neurological signs [FNS] were present in 31% of cases and neuroimaging was performed in 68% (95/140) of symptomatic patients. Multiple logistic regression analysis identified FNS, seizures, altered consciousness and age as independent predictors for conducting neuroimaging (all p < 0.05). Significant pathological findings consistent with acute symptomatology were evident in 17 cases, all of whom had FNS. Recursive partitioning analyses confirmed FNS as the best predictor of neuroimaging pathology (p < 0.001). Absence of FNS had a negative predictive value of 100% [95% confidence interval: 93-100%] for excluding neuroimaging pathology. In conclusion, emergency patients with profound hyponatremia frequently show nonspecific-neurological symptoms and may undergo neuroimaging unnecessarily. The lack of FNS may serve as a valuable criterion for withholding neuroimaging until hyponatremia has been corrected.

MANAGEMENT OF ENDOCRINE DISEASE: Neuroendocrine surveillance and management of neurosurgical patients

Advances in the management of traumatic brain injury, subarachnoid haemorrhage and intracranial tumours have led to improved survival rates and an increased focus on quality of life of survivors. Endocrine sequelae of the acute brain insult and subsequent neurosurgery, peri-operative fluid administration and/or cranial irradiation are now well described. Unrecognised acute hypopituitarism, particularly ACTH/cortisol deficiency and diabetes insipidus, can be life threatening. Although hypopituitarism may be transient, up to 30% of survivors of TBI have chronic hypopituitarism, which can diminish quality of life and hamper rehabilitation. Patients who survive SAH may also develop hypopituitarism, though it is less common than after TBI. The growth hormone axis is most frequently affected. There is also accumulating evidence that survivors of intracranial malignancy, who have required cranial irradiation, may develop hypopituitarism. The time course of the development of hormone deficits is varied, and predictors of pituitary dysfunction are unreliable. Furthermore, diagnosis of GH and ACTH deficiency require dynamic testing that can be resource intensive. Thus the surveillance and management of neuroendocrine dysfunction in neurosurgical patients poses significant logistic challenges to endocrine services. However, diagnosis and management of pituitary dysfunction can be rewarding. Appropriate hormone replacement can improve quality of life, prevent complications such as muscle atrophy, infection and osteoporosis and improve engagement with physiotherapy and rehabilitation.

Cerebral Salt-Wasting Syndrome Caused by Minor Head Injury

A 34-year-old woman was admitted to hospital after sustaining a head injury in a motor vehicle accident (day 1). No signs of neurological deficit, skull fracture, brain contusion, or intracranial bleeding were evident. She was discharged without symptoms on day 4. However, headache and nausea worsened on day 8, at which time serum sodium level was noted to be 121 mEq/L. Treatment with sodium chloride was initiated, but serum sodium decreased to 116 mEq/L on day 9. Body weight decreased in proportion to the decrease in serum sodium. Cerebral salt-wasting syndrome was diagnosed. This case represents the first illustration of severe hyponatremia related to cerebral salt-wasting syndrome caused by a minor head injury.

Improving on Laboratory Traumatic Brain Injury Models to Achieve Better Results

Experimental modeling of traumatic brain injury (TBI) in animals has identified several potential means and interventions that might have beneficial applications for treating traumatic brain injury clinically. Several of these interventions have been applied and tried with humans that are at different phases of testing (completed, prematurely terminated and others in progress). The promising results achieved in the laboratory with animal models have not been replicated with human trails as expected. This review will highlight some insights and significance attained via laboratory animal modeling of TBI as well as factors that require incorporation into the experimental studies that could help in translating results from laboratory to the bedside. Major progress has been made due to laboratory studies; in explaining the mechanisms as well as pathophysiological features of brain damage after TBI. Attempts to intervene in the cascade of events occurring after TBI all rely heavily on the knowledge from basic laboratory investigations. In looking to discover treatment, this review will endeavor to sight and state some central discrepancies between laboratory models and clinical scenarios.

[The rate of hyponatremia in neurosurgical patients (comparison between the data from the Burdenko Neurosurgical Instutite and the literature) and recommendations for the diagnosis and treatment]

Hyponatremia is a relatively frequent and serious complication in patients with various neurosurgical pathologies.

OBJECTIVE

This study is aimed at assessing the incidence of hyponatremia in neurosurgical patients depending on the pathology.

MATERIAL AND METHODS

This paper presents a retrospective analysis 39 479 cases of patients operated on at the Burdenko Neurosurgical Institute from 2008 to 2014.

RESULTS

A total of 785 hyponatremic patients with Na level lower than 130 mmol/l (2% of all operated patients) were identified. Mortality in patients with hyponatremia was 14.3%, which is tenfold higher compared to the rest of population of patients without hyponatremia who were operated on during the same period. In adults, hyponatremia most frequently occurred after resection of craniopharyngiomas (11%) and as a result of acute cerebrovascular accident (22%). In children, it occurred after resection of craniopharyngiomas (10%), astrocytomas (7%), ependymomas (24%), and germ cell tumors (10.5%).

CONCLUSION

This study, which was mainly statistical one, was not aimed at detailed investigation of hyponatremia in different groups of neurosurgical patients. We only tried to draw the attention of various experts to those categories of patients, where focused and in-depth developments are more than important. Obviously, already gained international experience should be taken into account for this

PURPOSE

Therefore, this article presents the literature data on the etiology and pathogenesis of hyponatremia. We describe the details of the various classifications of hyponatremia, its clinical symptoms, diagnosis, and treatments, primarily based on the recommendations of the last European consensus of various specialists (2014).

Sodium and Potassium Relating to Parkinson's Disease and Traumatic Brain Injury

Alkali metals, especially sodium and potassium, are plentiful and vital in biological systems. They take on important roles in health and disease. Such roles include the regulation of homeostasis, osmosis, blood pressure, electrolytic equilibria, and electric current. However, there is a limit to our present understanding; the ions have a great ability and capacity for action in health and disease, much greater than our current understanding. For the regulation of physiological homeostasis, there is a crucial regulator (renin-angiotensin system, RAS), found at both peripheral and central levels. Misregulation of the Na(+)-K(+) pump, and sodium channels in RAS are important for the understanding of disease progression, hypertension, diabetes, and neurodegenerative diseases, etc. In particular, RAS displays direct or indirect interaction important to Parkinson's disease (PD). In this chapter, the relationship between the regulation of sodium/potassium concentration and PD was sought. In addition, some recent biochemical and clinical findings are also discussed that help describe sodium and potassium in the context of traumatic brain injury (TBI). TBI is caused from the heavy striking of the head; this strongly affects ion flux in the affected tissue (brain) and damages cellular regulation systems. Thus, inappropriate concentrations of ions (hyper- and hyponatremia, and hyper- and hypokalemia) will perturb homeostasis giving rise to important and far reaching effects. These changes also impact osmotic pressure and the concentration of other metal ions, such as the calcium(II) ion.

Hyponatremia in Neurotrauma: The Role of Vasopressin

Hyponatremia is frequent in patients suffering from traumatic brain injury, subarachnoid hemorrhage, or following intracranial procedures, with approximately 20% having a decreased serum sodium concentration to <125 mmol/L. The pathophysiology of hyponatremia in neurotrauma is not completely understood, but in large part is explained by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). The abnormal water and/or sodium handling creates an osmotic gradient promoting the shift of water into brain cells, thereby worsening cerebral edema and precipitating neurological deterioration. Unless hyponatremia is corrected promptly and effectively, morbidity and mortality increases through seizures, elevations in intracranial pressure, and/or herniation. The excess mortality in patients with severe hyponatremia (<125 mmol/L) extends beyond the time frame of hospital admission, with a reported mortality of 20% in hospital and 45% within 6 months of follow-up. Current options for the management of hyponatremia include fluid restriction, hypertonic saline, mineralocorticoids, and osmotic diuretics. However, the recent development of vasopressin receptor antagonists provides a more physiological tool for the management of excess water retention and consequent hyponatremia, such as occurs in SIADH. This review summarizes the existing literature on the pathophysiology, clinical features, and management of hyponatremia in the setting of neurotrauma.

Cerebral salt wasting after traumatic brain injury: a review of the literature

Electrolyte imbalances are common among patients with traumatic brain injury (TBI). Cerebral salt wasting (CSW) is an electrolyte imbalance characterized by hyponatremia and hypovolemia. Differentiating the syndrome of inappropriate antidiuretic hormone and CSW remains difficult and the pathophysiological mechanisms underlying CSW are unclear. Our intent was to review the literature on CSW within the TBI population, in order to report the incidence and timing of CSW after TBI, examine outcomes, and summarize the biochemical changes in patients who developed CSW. We searched MEDLINE through 2014, hand-reviewed citations, and searched abstracts from the American Association for the Surgery of Trauma (2003-2014). Publications were included if they were conducted within a TBI population, presented original data, and diagnosed CSW. Publications were excluded if they were review articles, discussed hyponatremia but did not differentiate the etiology causing hyponatremia, or presented cases with chronic disease. Fifteen of the 47 publications reviewed met the selection criteria; nine (60%) were case reports, five (33%) were prospective and 1 (7%) was a retrospective study. Incidence of CSW varied between 0.8 - 34.6%. The populations studied were heterogeneous and the criteria used to define hyponatremia and CSW varied. Though believed to play a role in the development of CSW, increased levels of natriuretic peptides in patients diagnosed with CSW were not consistently reported. These findings reinforce the elusiveness of the CSW diagnosis and the need for strict and consistent diagnostic criteria.

Neuropsychology of Neuroendocrine Dysregulation after Traumatic Brain Injury

Endocrine dysfunction is a common effect of traumatic brain injury (TBI). In addition to affecting the regulation of important body functions, the disruption of endocrine physiology can significantly impair mental functions, such as attention, memory, executive function, and mood. This mini-review focuses on alterations in mental functioning that are associated with neuroendocrine disturbances in adults who suffered TBI. It summarizes the contribution of hormones to the regulation of mental functions, the consequences of TBI on mental health and neuroendocrine homeostasis, and the effects of hormone substitution on mental dysfunction caused by TBI. The available empirical evidence suggests that comprehensive assessment of mental functions should be standard in TBI subjects presenting with hormone deficiency and that hormone replacement therapy should be accompanied by pre- and post-assessments.

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.

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.

Hyponatremia in Patients with Spontaneous Intracerebral Hemorrhage

Hyponatremia is the most frequently encountered electrolyte abnormality in critically ill patients. Hyponatremia on admission has been identified as an independent predictor of in-hospital mortality in patients with spontaneous intracerebral hemorrhage (sICH). However, the incidence and etiology of hyponatremia (HN) during hospitalization in a neurointensive care unit following spontaneous intracerebral hemorrhage (sICH) remains unknown. This was a retrospective analysis of consecutive patients admitted to Detroit Receiving Hospital for sICH between January 2006 and July 2009. All serum Na levels were recorded for patients during the ICU stay. HN was defined as Na <135 mmol/L. A total of 99 patients were analyzed with HN developing in 24% of sICH patients. Patients with HN had an average sodium nadir of 130 ± 3 mmol/L and an average time from admission to sodium <135 mmol/L of 3.9 ± 5.7 days. The most common cause of hyponatremia was syndrome of inappropriate antidiuretic hormone (90% of HN patients). Patients with HN were more likely to have fever (50% vs. 23%; p = 0.01), infection (58% vs. 28%; p = 0.007) as well as a longer hospital length of stay (14 (8–25) vs. 6 (3–9) days; p < 0.001). Of the patients who developed HN, fifteen (62.5%) patients developed HN in the first week following sICH. This shows HN has a fairly high incidence following sICH. The presence of HN is associated with longer hospital length of stays and higher rates of patient complications, which may result in worse patient outcomes. Further study is necessary to characterize the clinical relevance and treatment of HN in this population.

Endocrinological disorders affecting neurosurgical patients: An intensivists perspective

Management of critically ill neurosurgical patients is often complicated by the presence or development of endocrinological ailments which complicate the clinical scenario and adversely affect the prognosis of these patients. The anatomical proximity to the vital centers regulating the endocrinological physiology and alteration in the neurotransmitter release causes disturbances in the hormonal homeostasis. This paves the way for development of diverse disorders where single or multiple hormones may be involved which can have deleterious effect on the different organ system. Understanding and awareness of these disorders is important for the treating intensivist to recognize these changes early in their course, so that appropriate and timely therapeutic measures can be initiated along with the treatment of the primary malady.

Incidence, Etiology and Outcomes of Hyponatremia after Transsphenoidal Surgery: Experience with 344 Consecutive Patients at a Single Tertiary Center

Hyponatremia is often seen after transsphenoidal surgery and is a source of considerable economic burden and patient-related morbidity and mortality. We performed a retrospective review of 344 patients who underwent transsphenoidal surgery at our institution between 2006 and 2012. Postoperative hyponatremia was seen in 18.0% of patients at a mean of 3.9 days postoperatively. Hyponatremia was most commonly mild (51.6%) and clinically asymptomatic (93.8%). SIADH was the primary cause of hyponatremia in the majority of cases (n = 44, 71.0%), followed by cerebral salt wasting (n = 15, 24.2%) and desmopressin over-administration (n = 3, 4.8%). The incidence of postoperative hyponatremia was significantly higher in patients with cardiac, renal and/or thyroid disease (p = 0.0034, Objective Risk (OR) = 2.60) and in female patients (p = 0.011, OR = 2.18) or patients undergoing post-operative cerebrospinal fluid drainage (p = 0.0006). Treatment with hypertonic saline (OR = −2.4, p = 0.10) and sodium chloride tablets (OR = −1.57, p = 0.45) was associated with a non-significant trend toward faster resolution of hyponatremia. The use of fluid restriction and diuretics should be de-emphasized in the treatment of post-transsphenoidal hyponatremia, as they have not been shown to significantly alter the time-course to the restoration of sodium balance.

Neurosurgical Hyponatremia

Hyponatremia is a frequent electrolyte imbalance in hospital inpatients. Acute onset hyponatremia is particularly common in patients who have undergone any type of brain insult, including traumatic brain injury, subarachnoid hemorrhage and brain tumors, and is a frequent complication of intracranial procedures. Acute hyponatremia is more clinically dangerous than chronic hyponatremia, as it creates an osmotic gradient between the brain and the plasma, which promotes the movement of water from the plasma into brain cells, causing cerebral edema and neurological compromise. Unless acute hyponatremia is corrected promptly and effectively, cerebral edema may manifest through impaired consciousness level, seizures, elevated intracranial pressure, and, potentially, death due to cerebral herniation. The pathophysiology of hyponatremia in neurotrauma is multifactorial, but most cases appear to be due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Classical treatment of SIADH with fluid restriction is frequently ineffective, and in some circumstances, such as following subarachnoid hemorrhage, contraindicated. However, the recently developed vasopressin receptor antagonist class of drugs provides a very useful tool in the management of neurosurgical SIADH. In this review, we summarize the existing literature on the clinical features, causes, and management of hyponatremia in the neurosurgical patient.

Cerebral salt-wasting syndrome due to hemorrhagic brain infarction: a case report

INTRODUCTION

Cerebral salt-wasting syndrome is a condition featuring hyponatremia and dehydration caused by head injury, operation on the brain, subarachnoid hemorrhage, brain tumor and so on. However, there are a few reports of cerebral salt-wasting syndrome caused by cerebral infarction. We describe a patient with cerebral infarction who developed cerebral salt-wasting syndrome in the course of hemorrhagic transformation.

CASE PRESENTATION

A 79-year-old Japanese woman with hypertension and arrhythmia was admitted to our hospital for mild consciousness disturbance, conjugate deviation to right, left unilateral spatial neglect and left hemiparesis. Magnetic resonance imaging revealed a broad ischemic change in right middle cerebral arterial territory. She was diagnosed as cardiogenic cerebral embolism because atrial fibrillation was detected on electrocardiogram on admission. She showed hyponatremia accompanied by polyuria complicated at the same time with the development of hemorrhagic transformation on day 14 after admission. Based on her hypovolemic hyponatremia, she was evaluated as not having syndrome of inappropriate secretion of antidiuretic hormone but cerebral salt-wasting syndrome. She fortunately recovered with proper fluid replacement and electrolyte management.

CONCLUSIONS

This is a rare case of cerebral infarction and cerebral salt-wasting syndrome in the course of hemorrhagic transformation. It may be difficult to distinguish cerebral salt-wasting syndrome from syndrome of inappropriate antidiuretic hormone, however, an accurate assessment is needed to reveal the diagnosis of cerebral salt-wasting syndrome because the recommended fluid management is opposite in the two conditions.

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.

Hyponatremia is an independent predictor of in-hospital mortality in spontaneous intracerebral hemorrhage

BACKGROUND AND PURPOSE

Hyponatremia is the most frequent electrolyte disturbance in critical care. Across various disciplines, hyponatremia is associated with increased mortality and longer hospital stay, yet in intracerebral hemorrhage (ICH) no data are available. This the first study that investigated the prevalence and clinical associations of hyponatremia in patients with ICH.

METHODS

This observational study included all consecutive spontaneous ICH patients (n=464) admitted during a 5-year period to the Department of Neurology. Patient characteristics, in-hospital measures, mortality, and functional outcome (90 days and 1 year) were analyzed to determine the effects of hyponatremia (Na<135 mEq/L). Multivariable regression analyses were calculated for factors associated with hyponatremia and predictors of in-hospital mortality.

RESULTS

The prevalence of hyponatremia on hospital admission was 15.6% (n=66). Normonatremia was achieved and maintained in almost all hyponatremia patients<48 hours. In-hospital mortality was roughly doubled in hyponatremia compared with nonhyponatremia patients (40.9%; n=27 versus 21.1%; n=75), translating into a 2.5-fold increased odds ratio (P<0.001). Multivariable analyses identified hyponatremia as an independent predictor of in-hospital mortality (odds ratio, 2.2; 95% confidence interval, 1.05-4.62; P=0.037). Within 90 days after ICH, hyponatremia patients surviving hospital stay were also at greater risk of death (odds ratio, 4.8; 95% confidence interval, 2.1-10.6; P<0.001); thereafter, mortality rates were similar.

CONCLUSIONS

Hyponatremia was identified as an independent predictor of in-hospital mortality with a fairly high prevalence in spontaneous ICH patients. The presence of hyponatremia at hospital admission is related to an increased short-term mortality in patients surviving acute care, possibly reflecting a preexisting condition that is linked to worse outcome due to greater comorbidity. Correction of hyponatremia does not seem to compensate its influence on mortality, which strongly warrants future research.