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

[Current Aspects of Intensive Medical Care for Traumatic Brain Injury - Part 2 - Secondary Treatment Strategies, Long-term Outcome, Neuroprognostics and Chronification]

This two-part article deals with the intensive medical care of traumatic brain injury. Part 1 addresses the primary treatment strategy, haemodynamic management and multimodal monitoring, Part 2 secondary treatment strategies, long-term outcome, neuroprognostics and chronification. Traumatic brain injury is a complex clinical entity with a high mortality rate. The primary aim is to maintain homeostasis based on physiological targeted values. In addition, further therapy must be geared towards intracranial pressure. In addition to this, there are other monitoring options that appear sensible from a pathophysiological point of view with appropriate therapy adjustment. However, there is still a lack of data on their effectiveness. A further aspect is the inflammation of the cerebrum with the "cross-talk" of the organs, which has a significant influence on further intensive medical care.

Suspected cerebral salt wasting syndrome secondary to traumatic brain injury in a dog

OBJECTIVE

To describe a dog with suspected cerebral salt wasting syndrome (CSWS) secondary to traumatic brain injury (TBI).

CASE SUMMARY

A 2-month-old intact male Chihuahua-American Pitbull Terrier mix weighing 1.94 kg presented to a veterinary teaching emergency room after suffering bite wound-penetrating trauma to the head. Treatment was initiated with hyperosmotic agents, fluid resuscitation, and analgesia. The dog's neurologic dysfunction warranted hospitalization and continuous monitoring. Within 24 hours, the dog developed hyponatremia (133 mmol/L compared to 143 mmol/L on presentation [reference interval 142-149 mmol/L]). As the dog had concurrent tachycardia, increase in urine sodium concentration, polyuria, and weight loss, a diagnosis of cerebral salt wasting was suspected. A 2% hypertonic saline constant rate infusion was administered for volume replacement, and the patient showed improvement in clinical signs and blood sodium concentration. The dog was discharged on Day 5. Recheck examination showed significant neurologic improvement with sodium just below the low end of the reference range (141 mmol/L [reference interval 142-149 mmol/L]).

NEW OR UNIQUE INFORMATION PROVIDED

This is the first description of suspected CSWS in veterinary medicine. Hyponatremia is a common finding in critically ill neurologic people, including those with TBI, and is typically associated with either syndrome of inappropriate antidiuretic hormone or CSWS. As treatment recommendations for syndrome of inappropriate antidiuretic hormone and CSWS are diametrically opposed, identifying the presence of hyponatremia and distinguishing between these 2 clinical entities is critical for improving patient care for those with TBI. This case highlights the characteristics and clinical progression regarding the diagnosis and management of suspected CSWS.

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.

A Review of Electrolyte, Mineral, and Vitamin Changes After Traumatic Brain Injury

INTRODUCTION

Despite the prevalence of traumatic brain injury (TBI) in both civilian and military populations, the management guidelines developed by the Joint Trauma System involve minimal recommendations for electrolyte physiology optimization during the acute phase of TBI recovery. This narrative review aims to assess the current state of the science for electrolyte and mineral derangements found after TBI.

MATERIALS AND METHODS

We used Google Scholar and PubMed to identify literature on electrolyte derangements caused by TBI and supplements that may mitigate secondary injuries after TBI between 1991 and 2022.

RESULTS

We screened 94 sources, of which 26 met all inclusion criteria. Most were retrospective studies (n = 9), followed by clinical trials (n = 7), observational studies (n = 7), and case reports (n = 2). Of those, 29% covered the use of some type of supplement to support recovery after TBI, 28% covered electrolyte or mineral derangements after TBI, 16% covered the mechanisms of secondary injury after TBI and how they are related to mineral and electrolyte derangements, 14% covered current management of TBI, and 13% covered the potential toxic effects of the supplements during TBI recovery.

CONCLUSIONS

Knowledge of mechanisms and subsequent derangements of electrolyte, mineral, and vitamin physiology after TBI remains incomplete. Sodium and potassium tended to be the most well-studied derangements after TBI. Overall, data involving human subjects were limited and mostly involved observational studies. The data on vitamin and mineral effects were limited, and targeted research is needed before further recommendations can be made. Data on electrolyte derangements were stronger, but interventional studies are needed to assess causation.

Syndrome of Inappropriate Antidiuresis: From Pathophysiology to Management

Hyponatremia is the most common electrolyte disorder, affecting more than 15% of patients in the hospital. Syndrome of inappropriate antidiuresis (SIAD) is the most frequent cause of hypotonic hyponatremia, mediated by nonosmotic release of arginine vasopressin (AVP, previously known as antidiuretic hormone), which acts on the renal V2 receptors to promote water retention. There are a variety of underlying causes of SIAD, including malignancy, pulmonary pathology, and central nervous system pathology. In clinical practice, the etiology of hyponatremia is frequently multifactorial and the management approach may need to evolve during treatment of a single episode. It is therefore important to regularly reassess clinical status and biochemistry, while remaining alert to potential underlying etiological factors that may become more apparent during the course of treatment. In the absence of severe symptoms requiring urgent intervention, fluid restriction (FR) is widely endorsed as the first-line treatment for SIAD in current guidelines, but there is considerable controversy regarding second-line therapy in instances where FR is unsuccessful, which occurs in around half of cases. We review the epidemiology, pathophysiology, and differential diagnosis of SIAD, and summarize recent evidence for therapeutic options beyond FR, with a focus on tolvaptan, urea, and sodium-glucose cotransporter 2 inhibitors.

[Hyponatremia : Etiology, diagnosis and acute therapy]

Hyponatremia is one of the most common electrolyte disorders in emergency departments and hospitalized patients. Serum sodium concentration is controlled by osmoregulation and volume regulation. Both pathways are regulated via the release of antidiuretic hormone (ADH). Syndrome of inappropriate release of ADH (SIADH) may be caused by neoplasms or pneumonia but may also be triggered by drug use or drug abuse. Excessive fluid intake may also result in a decrease in serum sodium concentration. Rapid alteration in serum sodium concentration leads to cell swelling or cell shrinkage, which primarily causes neurological symptoms. The dynamics of development of hyponatremia and its duration are crucial. In addition to blood testing, a clinical examination and urine analysis are essential in the differential diagnosis of hyponatremia.

Biophysiologic Monitoring for the Neurosurgical Patient

Biophysiologic monitoring exists as a method of collecting objective information about the neurosurgical patient throughout their treatment and recovery process. Such data is crucial for an improved understanding of the disease processes while providing the surgeon additional clarity as they decipher the next best steps in decision-making and medical recommendations. In the current review article, the authors discuss the commonly used wearable and placeable monitoring devices and the biophysiological data that can be collected to monitor, as well as, assess the neurosurgical patient. Special focus is placed on invasive and non-invasive neurologic monitoring devices, but important and commonly used monitors for the rest of the body are also discussed as they relate to the neurosurgical patient. Last, the authors review new, as well as, upcoming devices and measurements to better analyze the neurosurgical patient's bodily function and physiologic status as needed. The synthesis of methods contained herein may provide meaningful guidance for neurosurgeons in effectively monitoring and treating their patients while also helping to guide their future efforts in patient biophysiologic monitoring developments within neurosurgery.

Traumatic retroclival hematoma complicated with hyponatremia and delayed traumatic intracranial hematoma in an adult: A case report

Intracranial hematoma is a common variety of brain insults in trauma. However, posterior fossa hematoma in the retroclival location is quite unusual. There are limited numbers of case reports regarding traumatic retroclival hematoma. Some are managed with surgery in this condition. We present a traumatic retroclival hematoma in a 34-year-old gentleman who sustained brain trauma in a motor vehicle accident. His condition was further complicated by hyponatremia and delayed traumatic intracerebral hematoma in a distant location. The only symptom he had later was severe headache which could be attributed to delayed traumatic intracerebral hematoma and hyponatremia. He was managed conservatively and discharged on the 12th day from the hospital.

Suspected Cerebral Salt Wasting Syndrome with Cervical Spinal Lesion in a Domestic Shorthair Cat

A 12-year-old spayed female domestic short cat was presented with tetraplegia. The cat also showed signs of hyponatremia and dehydration, which were rapidly corrected by intravenous fluid infusion. Based on thorough physical and neurological examinations, the patient was suspected of having an intracranial disease. MRI revealed a high-signal T2 image of the bilateral parietal cerebral cortical gray matter junction, which is associated with fast electrolyte calibration, and a high-signal T2 image of the C2 spinal cord ventral area, which is associated with ischemic myelopathy. The cat reappeared three days later due to anorexia. Laboratory examinations revealed that the cat was clinically dehydrated and exhibited hyponatremia. Other causes of hyponatremia were excluded through history-taking, laboratory examination, imaging, and therapeutic response to fluid therapy, except for cerebral salt-wasting syndrome (CSWS). The cat was discharged 3 days after the start of fludrocortisone therapy with electrolytes within the normal range. Magnetic resonance imaging (MRI) was performed again 1 month after hospitalization, and the cerebral lesion disappeared, but the spinal cord lesion worsened compared to the previous image. The patient was euthanized due to the progression of the spinal lesion, with a poor prognosis and poor quality of life. This is the first case of suspected CSWS with a cervical spinal lesion in a cat.

A Probable Association of Aseptic Meningoencephalitis, Complicated With Cerebral Salt Wasting Syndrome Following COVID-19 Vaccination: A Case Report

Coronavirus disease-19 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred worldwide, and it affected millions of people around the world and killed millions of lives without a definitive treatment. During this challenging time, vaccine production has been hugely carried out leading to the invention of many vaccines against COVID-19. As any vaccine can have some side effects, COVID-19 vaccines also need surveillance and reporting side effects worldwide. Currently, more than 10 vaccines are available against SARS-CoV-2 infection globally. There are many neurological complications reported by SARS-CoV-2 vaccines. There are some reported neurological complications, such as ischemic stroke, Guillain-Barré syndrome, transverse myelitis, Bell's palsy, cerebral venous sinus thrombosis, optic neuritis, meningoencephalitis, small fiber neuropathy, and Tolosa-Hunt syndrome. We present a case of an elderly man who presented with fever, fits, hyponatremia, and polyuria following COVID-19 vaccination and was found to have cerebral salt wasting (CSW) with the exclusion of other causes.

Late-Onset Intracranial Hemorrhage Presenting as Refractory Hyponatremia: A Case Report

Here, we report a case of refractory hyponatremia and delayed intracranial hemorrhage following a head injury. A 70-year-old male patient was admitted with complaints of left chest pain and light-headedness after a fall. Hyponatremia recurred despite the correction with intravenous saline. Head computed tomography revealed a chronic subdural hematoma. The subsequent introduction of tolvaptan improved hyponatremia and disorientation. Delayed intracranial hemorrhage is a differential cause of refractory hyponatremia after head contusion. This case is clinically relevant because (i) the diagnostic delay of late-onset intracranial hemorrhage is common but fatal, and (ii) refractory hyponatremia can be a hint of late-onset intracranial hemorrhage.

Trifluoperazine reduces apoptosis and inflammatory responses in traumatic brain injury by preventing the accumulation of Aquaporin4 on the surface of brain cells

Currently, no specific and standard treatment for traumatic brain injury (TBI) has been developed. Therefore, studies on new therapeutic drugs for TBI treatment are urgently needed. Trifluoperazine (TFP) is a therapeutic agent for the treatment of psychiatric disorders that reduces edema of the central nervous system. However, the specific working mechanism of TFP is not fully understood in TBI. In this study, the immunofluorescence co-localization analysis revealed that the area and intensity covered by Aquaporin4 (AQP4) on the surface of brain cells (astrocyte endfeet) increased significantly after TBI. In contrast, TFP treatment reversed these phenomena. This finding showed that TFP inhibited AQP4 accumulation on the surface of brain cells (astrocyte endfeet). The tunel fluorescence intensity and fluorescence area were lower in the TBI+TFP group compared to the TBI group. Additionally, the brain edema, brain defect area, and modified neurological severity score (mNSS) were lower in the TBI+TFP. The RNA-seq was performed on the cortical tissues of rats in the Sham, TBI, and TBI+TFP groups. A total of 3774 genes differently expressed between the TBI and the Sham group were identified. Of these, 2940 genes were up-regulated and 834 genes were down-regulated. A total of 1845 differently expressed genes between the TBI+TFP and TBI group were also identified, in which 621 genes were up-regulated and 1224 genes were down-regulated. Analysis of the common differential genes in the three groups showed that TFP could reverse the expression of apoptosis and inflammation genes. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the differentially expressed genes (DEGs) were highly enriched in the signaling pathways regulating inflammation. In conclusion, TFP alleviates brain edema after TBI by preventing the accumulation of AQP4 on the surface of brain cells. Generally, TFP alleviates apoptosis and inflammatory response induced by TBI, and promotes the recovery of nerve function in rats after TBI. Thus, TFP is a potential therapeutic agent for TBI treatment.

Disorders of Salt and Water Balance After Pituitary Surgery

Transsphenoidal surgery is the first-line treatment for many clinically significant pituitary tumors and sellar lesions. Although complication rates are low when performed at high-volume centers, disorders of salt and water balance are relatively common postoperatively. Both, or either, central diabetes insipidus (recently renamed arginine vasopressin deficiency - AVP-D), caused by a deficiency in production and/or secretion of arginine vasopressin, and hyponatremia, most commonly secondary to the syndrome of inappropriate antidiuresis, may occur. These conditions can extend hospital stay and increase the risk of readmission. This article discusses common presentations of salt and water balance disorders following pituitary surgery, the pathophysiology of these conditions, and their diagnosis and management.

Hyponatremia in the emergency department

Hyponatremia, defined as a serum sodium <135 mmol/L, is frequently encountered in patients presenting to the emergency department. Symptoms are often unspecific and include a recent history of falls, weakness and vertigo. Common causes of hyponatremia include diuretics, heart failure as well as Syndrome of Inappropriate Antidiuresis (SIAD) and correct diagnosis can be challenging. Emergency treatment of hyponatremia should be guided by presence of symptoms and focus on distinguishing between acute and chronic hyponatremia.

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.

Differential diagnosis between syndrome of inappropriate antidiuretic hormone secretion and cerebral/renal salt wasting syndrome in children over 1 year: proposal for a simple algorithm

Hyponatremia, especially if acute and severe, can be a life-threatening condition. Several conditions can trigger hyponatremia. In this review, we will discuss two conditions that can determine euvolemic hyponatremia: the cerebral/renal salt wasting (CRSW) syndrome and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), including the two subtypes: reset osmostat (RO) and nephrogenic syndrome of inappropriate antidiuresis (NSIAD) and their differential diagnoses. Despite the passage of over 70 years since its first description, to date, the true etiopathogenesis of CRSW syndrome, a rare cause of hypovolemic/euvolemic hyponatremia, is almost unknown. SIADH, including RO and NSIAD, is sometimes difficult to differentiate from CRSW syndrome; in its differential diagnosis, the clinical approach based on the evaluation of the extracellular volume (ECV) was proven insufficient. We therefore suggest a simple diagnostic algorithm based on the assessment of the degree of hyponatremia, urinary osmolality, and the assessment of the fraction of urate excretion (FEUa) in conditions of hyponatremia and after serum sodium correction, to be applied in children over 1 year of life.

Cerebral Salt Wasting Syndrome Caused by Severe Traumatic Brain Injury in a Pediatric Patient and Review of the Literature

Background

Following acute traumatic brain injury, cerebral salt wasting (CSW) syndrome is considered as an important cause of hyponatremia apart from syndrome of inappropriate antidiuretic hormone. Differentiation between the two syndromes is crucial for the initiation of an adequate treatment. Case Presentation. We report a 15-year-old female adolescent, admitted to intensive care for acute severe traumatic brain injury. During his hospitalization, she developed a hyponatremia with an increase of urine output and hypovolemia. So, the most probable diagnosis was CSW. Initially, she was treated by hypertonic saline and volume expansion. However, his sodium level continued to fall despite infusion of hypertonic saline. That is why fludrocortisone was introduced initially at 50 μg/day then increased to 150 μg/day. Fludrocortisone was continued for the next months. Serum sodium level was 138 mmol/L after one month of treatment.

Conclusion

Hyponatremia may occur after severe traumatic brain injury that is why an adequate treatment initiated on time is necessary in order to reduce morbidity and mortality.

Clinical case of combined diabetes insipidus and cerebral salt-wasting syndrome in a patient with craniocerebral and spinal injury

Introduction. Cerebral salt-wasting syndrome and diabetes insipidus are serious complications of craniocerebral injury and spinal cord injuries. Each of the syndromes in some cases causes a life-threatening condition. This determines the importance of timely diagnosis and emergency intensive care measures. In the literature, there are only single descriptions of combinations of these symptoms in one patient.Clinical case report. A victim with craniocerebral injury and cervical spinal cord injury underwent, according to emergency indications, emptying and drainage of a tense subgaleal hematoma of the fronto-parieto-occipital region, spinal cord decompression, and stabilization of the spine. Postoperative follow-up and intensive care: on the 1st day the rate of diuresis was 2.5 mL/kg/h, blood glucose level – 14.18 mmol/L, and sodium level – 148–158 mmol/L. The patient was diagnosed with diabetes insipidus, and a therapy with desmopressin at a dose of 0.6 mg/day, restoration of fluid volume with hypotonic solutions, and correction of hyperglycemia was started. On the 4th day blood sodium level was 133 mmol/L, and blood glucose level – 8.67 mmol/L. On the 5th day, hyponatremia of 126–115 mmol/L was noted with a diuresis rate of 4 mL/kg/h and glicemya level of 7.86 mmol/L. The development of cerebral salt-wasting syndrome was diagnosed, and the infusion of hydrocortisone 400 mg/day and of 10% NaCl solution was started. On the 6th day glucose level returned to normal. On the 9th day of follow-up, an increase in the volume of diuresis was again observed, and desmopressin therapy was continued. Stable normalization of water-electrolyte balance, urine output, and glucose levels were observed on the 16th day of follow-up.Conclusion. Monitoring of fluid balance and electrolyte composition of blood serum, and adequate replacement therapy were the conditions for successful treatment of a rare combination of diabetes insipidus and cerebral salt-wasting syndrome in patients with concomitant craniocerebral and spinal cord injuries.

iTRAQ-based proteomic profiling reveals protein alterations after traumatic brain injury and supports thyroxine as a potential treatment

Traumatic brain injury (TBI) is a primary cause of disability and death across the world. Previously, RNA analysis was widely used to study the pathophysiological mechanisms underlying TBI; however, the relatively low correlation between the transcriptome and proteome revealed that RNA transcription abundance does not reliably predict protein abundance, which led to the emergence of proteomic research. In this study, an iTRAQ proteomics approach was applied to detect protein alterations after TBI on a large scale. A total of 3937 proteins were identified, and 146 proteins were significantly changed after TBI. Moreover, 23 upregulated proteins were verified by parallel reaction monitoring (PRM), and fold changes in 16 proteins were consistent with iTRAQ outcomes. Transthyretin (Ttr) upregulation has been demonstrated at the transcriptional level, and this study further confirmed this at the protein level. After treatment with thyroxine (T4), which is transported by Ttr, the effects of T4 on neuronal histopathology and behavioral performance were determined in vivo (TBI + T4 group). Brain edema was alleviated, and the integrity of the blood brain barrier (BBB) improved. Escape latency in the Morris water maze (MWM) declined significantly compared with the group without T4 treatment. Modified neurological severity scores (mNSS) of the TBI + T4 group decreased from day 1 to day 7 post-TBI compared with the TBI + saline group. These results indicate that T4 treatment has potential to alleviate pathologic and behavioral abnormalities post-TBI. Protein alterations after T4 treatment were also detected by iTRAQ proteomics. Upregulation of proteins like Lgals3, Gfap and Apoe after TBI were reversed by T4 treatment. GO enrichment showed T4 mainly affected intermediate filament organization, cholesterol transportation and axonal regeneration. In summary, iTRAQ proteomics provides information about the impact of TBI on protein alterations and yields insight into underlying mechanisms and pathways involved in TBI and T4 treatment. Finally, Ttr and other proteins identified by iTRAQ may become potential novel treatment targets post-TBI.

Cerebral salt-wasting syndrome in a patient with status epilepticus: a rare association

Hyponatraemia is one of the most common and serious electrolyte abnormalities in patients with neurological diseases. Assessing the intravascular fluid status, urine sodium, urine and serum osmolality helps to narrow down the differential diagnosis. Differentiation between cerebral salt-wasting syndrome (CSWS), diabetes insipidus and syndrome of inappropriate antidiuretic hormone (SIADH) secretion is absolutely necessary for correct management of hyponatraemia in this group of patients. In this case report, we have presented a 46-year-old gentleman who was admitted to intensive care unit (ICU) with status epilepticus and developed hyponatraemia during course of his ICU stay, diagnosed as CSWS and managed with normal saline and fludrocortisone. His serum sodium gradually improved, consciousness was regained and later shifted to general ward on antiepileptic treatment.

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.

Hyponatremia in Patients with Hematologic Diseases

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

An Integrative Review of Cerebral Salt Wasting Syndrome

BACKGROUND

Although cerebral salt wasting syndrome (CSWS) is widely recognized, its clinical characteristics, diagnostic criteria, and management have not been clearly defined. This study was undertaken to comprehensively review current literature and provide a more complete picture of CSWS. This review also aimed to provide information for nurses on how to differentiate cerebral salt wasting syndrome from syndrome of inappropriate antidiuretic hormone secretion.

METHODS

An integrative review was performed. Searches were conducted between May and July 2018. The primary information sources were CINAHL, Google Scholar, MEDLINE, PubMed, Scopus, and Web of Science. Included articles were published from 1954 to July 2018.

RESULTS

The essential features of CSWS are hyponatremia, hypovolemia, and increased urine output. Treatment regimens may be determined based on the acuity and severity of hyponatremia and hypovolemia as well as evident symptoms and signs.

CONCLUSION

This review may help neuroscience nurses become knowledgeable about CSWS for the drafting of appropriate nursing care plans and also be able to differentiate CSWS from syndrome of inappropriate antidiuretic hormone secretion as early as possible for timely and proper management.

Gradient washout and secondary nephrogenic diabetes insipidus after brain injury in an infant: a case report

Background

Disorders of water and sodium balance can occur after brain injury. Prolonged polyuria resulting from central diabetes insipidus and cerebral salt wasting complicated by gradient washout and a type of secondary nephrogenic diabetes insipidus, however, has not been described previously, to the best of our knowledge. We report an unusual case of an infant with glioblastoma who, after tumor resection, was treated for concurrent central diabetes insipidus and cerebral salt wasting complicated by secondary nephrogenic diabetes insipidus.

Case presentation

A 5-month-old Hispanic girl was found to have a large, hemorrhagic, suprasellar glioblastoma causing obstructive hydrocephalus. Prior to mass resection, she developed central diabetes insipidus. Postoperatively, she continued to have central diabetes insipidus and concurrent cerebral salt wasting soon after. She was managed with a vasopressin infusion, sodium supplementation, fludrocortisone, and urine output replacements. Despite resolution of her other major medical issues, she remained in the pediatric intensive care unit for continual and aggressive management of water and sodium derangements. Starting on postoperative day 18, her polyuria began increasing dramatically and did not abate with increasing vasopressin. Nephrology was consulted. Her blood urea nitrogen was undetectable during this time, and it was thought that she may have developed a depletion of inner medullary urea and osmotic gradient: a “gradient washout.” Supplemental dietary protein was added to her enteral nutrition, and her fluid intake was decreased. Within 4 days, her blood urea nitrogen increased, and her vasopressin and fluid replacement requirements significantly decreased. She was transitioned soon thereafter to subcutaneous desmopressin and transferred out of the pediatric intensive care unit.

Conclusions

Gradient washout has not been widely reported in humans, although it has been observed in the mammalian kidneys after prolonged polyuria. Although not a problem with aquaporin protein expression or production, gradient washout causes a different type of secondary nephrogenic diabetes insipidus because the absence of a medullary gradient impairs water reabsorption. We report a case of an infant who developed complex water and sodium imbalances after brain injury. Prolonged polyuria resulting from both water and solute diuresis with low enteral protein intake was thought to cause a urea gradient washout and secondary nephrogenic diabetes insipidus. The restriction of fluid replacements and supplementation of enteral protein appeared adequate to restore the renal osmotic gradient and efficacy of vasopressin.

Mineralocorticoid Dysfunction during Critical Illness: A Review of the Evidence

The recent demonstration of the significant reduction in mortality in patients with septic shock treated with adjunctive glucocorticoids combined with fludrocortisone and the effectiveness of angiotensin II in treating vasodilatory shock have renewed interest in the role of the mineralocorticoid axis in critical illness. Glucocorticoids have variable interactions at the mineralocorticoid receptor. Similarly, mineralocorticoid receptor-aldosterone interactions differ from mineralocorticoid receptor-glucocorticoid interactions and predicate receptor-ligand interactions that differ with respect to cellular effects. Hyperreninemic hypoaldosteronism or selective hypoaldosteronism, an impaired adrenal response to increasing renin levels, occurs in a subgroup of hemodynamically unstable critically ill patients. The suggestion is that there is a defect at the level of the adrenal zona glomerulosa associated with a high mortality rate that may represent an adaptive response aimed at increasing cortisol levels. Furthermore, cross-talk exists between angiotensin II and aldosterone, which needs to be considered when employing therapeutic strategies.

Low brain endocannabinoids associated with persistent non-goal directed nighttime hyperactivity after traumatic brain injury in mice

Traumatic brain injury (TBI) is a frequent cause of chronic headache, fatigue, insomnia, hyperactivity, memory deficits, irritability and posttraumatic stress disorder. Recent evidence suggests beneficial effects of pro-cannabinoid treatments. We assessed in mice levels of endocannabinoids in association with the occurrence and persistence of comparable sequelae after controlled cortical impact in mice using a set of long-term behavioral observations in IntelliCages, motor and nociception tests in two sequential cohorts of TBI/sham mice. TBI mice maintained lower body weights, and they had persistent low levels of brain ethanolamide endocannabinoids (eCBs: AEA, OEA, PEA) in perilesional and subcortical ipsilateral brain tissue (6 months), but rapidly recovered motor functions (within days), and average nociceptive responses were within normal limits, albeit with high variability, ranging from loss of thermal sensation to hypersensitivity. TBI mice showed persistent non-goal directed nighttime hyperactivity, i.e. they visited rewarding and non-rewarding operant corners with high frequency and random success. On successful visits, they made more licks than sham mice resulting in net over-licking. The lower the eCBs the stronger was the hyperactivity. In reward-based learning and reversal learning tasks, TBI mice were not inferior to sham mice, but avoidance memory was less stable. Hence, the major late behavioral TBI phenotype was non-goal directed nighttime hyperactivity and "over-licking" in association with low ipsilateral brain eCBs. The behavioral phenotype would agree with a "post-TBI hyperactivity disorder". The association with persistently low eCBs in perilesional and subcortical regions suggests that eCB deficiency contribute to the post-TBI psychopathology.

Salt wasting syndrome in brain trauma patients: a pathophysiologic approach using sodium balance and urinary biochemical analysis

BACKGROUND

To explore the underlying mechanisms leading to the occurrence of hyponatremia and enhanced urinary sodium excretion in brain trauma patients using sodium balance and urinary biochemical analysis.

METHODS

We conducted a retrospective analysis of a local database prospectively collected in 60 brain trauma patients without chronic renal dysfunction. Metabolic and hemodynamic parameters were averaged over three consecutive periods over the first seven days after admission. The main outcome investigated in this study was the occurrence of at least one episode of hyponatremia.

RESULTS

Over the study period, there was a prompt decrease in sodium balance (163 ± 193 vs. -12 ± 154 mmol/day, p < 0.0001) and free water clearance (- 0.7 ± 0.7 vs. -1.8 ± 2.3 ml/min, p < 0.0001). The area under the ROC curves for sodium balance in predicting the occurrence of hyponatremia during the next period was 0.81 [95% CI: 0.64-0.97]. Variables associated with averaged urinary sodium excretion were sodium intake (R² = 0.26, p < 0.0001) and fractional excretion of urate (R² = 0.15, p = 0.009). Urinary sodium excretion was also higher in patients with sustained augmented renal clearance over the study period (318 ± 106 vs. 255 ± 135 mmol/day, p = 0.034).

CONCLUSION

The decreased vascular volume resulting from a negative sodium balance is a major precipitating factor of hyponatremia in brain trauma patients. Predisposing factors for enhanced urinary sodium excretion were high sodium intake, high fractional excretion of urate and augmented renal clearance over the first seven days after ICU admission.

Cerebral Salt-wasting Syndrome in a Critically Ill Patient: An Easily Neglected Syndrome in Intensive Care Unit (ICU)

BACKGROUND

Cerebral salt-wasting syndrome (CSWS), which usually secondary to cerebral diseases, is characterized by hyponatremia and hypovolemia. In clinical practice, it is quite difficult to distinguish CSWS from other hyponatremia syndrome, especially in Intensive Care Unit (ICU) where the conditions of patients are more complicated. Nonetheless, it is crucial because treatments might be fundamentally different.

CASE PRESENTATION

We discuss a case of patient who presented with refractory hyponatremia and hypovolemia after traumatic brain injury, finally was diagnosed with CSWS, and successfully treated with corticotropin.

CONCLUSIONS

This case report provides a unique opportunity to observe the trigger of subdural effusion-induced CSWS, and also it provides the classical therapy for CSWS in a critically ill patient. In view of the difficulty to tell CSWS from other similar diseases in ICU, ICU doctors should be aware of such condition.

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.

[Symptomatic hyponatremia in a 43-year-old woman after a skiing accident with head injuries]

This article reports the case of a 43-year-old woman who presented to the emergency room with headache and paresthesia after a fall on the head while skiing. She had clinical signs of volume depletion and blood test showed severe hyponatremia. Cerebral imaging was unremarkable. The diagnosis of cerebral salt-wasting syndrome (CSWS) was made, which is defined by the presence of extracellular volume depletion due to a tubular defect in renal sodium transport in patients with normal adrenal and thyroid function. The disease is mostly secondary to a neurological disease or head trauma. The patient rapidly improved after volume therapy and treatment with mineralocorticoids. The differentiation of CSWS from the syndrome of inappropriate antidiuretic hormone (SIADH) secretion can be challenging but the distinction is important because treatment options are very different.

Posterior pituitary dysfunction following traumatic brain injury: review

Neurohypophysial dysfunction is common in the first days following traumatic brain injury (TBI), manifesting as dysnatremia in approximately 1 in 4 patients. Both hyponatremia and hypernatremia can impair recovery from TBI and in the case of hypernatremia, there is a significant association with excess mortality. Hyponatremia secondary to syndrome of inappropriate antidiuretic hormone secretion (SIAD) is the commonest electrolyte disturbance following TBI. Acute adrenocorticotropic hormone (ACTH)/cortisol deficiency occurs in 10-15% of TBI patients and can present with a biochemical picture identical to SIAD. For this reason, exclusion of glucocorticoid deficiency is of particular importance in post-TBI SIAD. Cerebral salt wasting is a rare cause of hyponatremia following TBI. Hyponatremia predisposes to seizures, reduced consciousness, and prolonged hospital stay. Diabetes insipidus (DI) occurs in 20% of cases following TBI; where diminished consciousness is present, appropriate fluid replacement of renal water losses is occasionally inadequate, leading to hypernatremia. Hypernatremia is strongly predictive of mortality following TBI. Most cases of DI are transient, but persistent DI is also predictive of mortality, irrespective of plasma sodium concentration. Persistent DI may herald rising intracranial pressure due to coning. True adipsic DI is rare following TBI, but patients are vulnerable to severe hypernatremic dehydration, exacerbation of neurologic deficits and hypothalamic complications, therefore clinicians should be aware of this possible variant of DI.

Diabetes Insipidus and Syndrome of Inappropriate Antidiuretic Hormone in Critically Ill Patients

Diabetes insipidus and the syndrome of inappropriate antidiuretic hormone secretion lie at opposite ends of the spectrum of disordered renal handling of water. Whereas renal retention of water insidiously causes hypotonic hyponatremia in syndrome of inappropriate antidiuretic hormone secretion, diabetes insipidus may lead to free water loss, hypernatremia, and volume depletion. Hypernatremia and hyponatremia are associated with worse outcomes and longer intensive care stays. Moreover, pathologies causing polyuria and hyponatremia in patients in intensive care may be multiple, making diagnosis challenging. We provide an approach to the diagnosis and management of these conditions in intensive care patients.

[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.

Hyponatraemia and seizures in Merrem's hump-nosed pit viper (Hypnale hypnale) envenoming: a case report

Background

Hump-nosed pit vipers (Genus: Hypnale) are medically important snakes in Sri Lanka and South India. Merrem’s Hump-nosed pit viper (Hypnale hypnale) frequently leads to potentially fatal envenomings in Sri Lanka and India. Venom-induced consumption coagulopathay (VICC), local envenoming and acute kidney injury (AKI) are the commonest effects of the envenoming by this snake.

Case presentation

We report a previously unreported presentation of H. hypnale envenoming, with an isolated urinary salt loss leading to moderate hyponatraemia resulting seizures. The patient was treated with careful fluid and electrolyte management. No antivenom is currently available for H. hypnale envenoming.

Conclusion

In the absence of any evidence of venom induced consumptive coagulopathy, acute kidney injury and cerebral haemorrhage, we hypothesize that this effect is likely due to the presence of a natriuretic peptide in H. hypnale venom, similar to the natriuretic peptides identified in few other snake venoms.

Cerebral salt wasting syndrome in patients with minor head trauma - two case reports

We describe two polytrauma patients without severe head trauma who developed Cerebral Salt Wasting Syndrome (CSWS) during their stay in our ICU with natriuresis, hyponatremia and hypovolemia. Hyponatremia encountered in CSWS and the syndrome of inadequate antidiuretic hormone secretion (SIADH) is a common electrolyte finding in patients with severe head trauma, subarachnoid hemorrhage, malignancy and infections of the central nervous system. CSWS was an unexpected electrolyte finding in our patients with minor head trauma without neurological or neurosurgical problems. To rule out other causes of hyponatremia (SIADH, secondary adrenal dysfunction and thyroid dysfunction) a correct diagnosis is very important, as proper treatment of CSWS with fluid and salt replacement will decrease mortality and morbidity. In conclusion, CSWS should be suspected in any polytrauma patient with minor head trauma and hyponatremia.

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.

Cerebral Salt Wasting Syndrome following Head Injury in a Child Managed Successfully with Fludrocortisone

Cerebral salt wasting (CSW) syndrome is an important cause of hyponatremia in head injuries apart from syndrome of inappropriate antidiuretic hormone (SIADH). Proper diagnosis and differentiation between these two entities are necessary for management as the treatment is quite opposite in both conditions. Fludrocortisone can help in managing CSW where alone saline infusion does not work. We report a 17-month-old female child with head injury managed successfully with saline infusion and fludrocortisone.