Is cerebral salt wasting always present in patients with traumatic brain injury?

Abstract

Background:

Traumatic brain injury (TBI) is a leading cause of global mortality and disability. Cerebral salt wasting (CSW), a TBI complication, causes sodium loss and hypovolemia, worsening outcomes. This study examines CSW’s association with bleeding volume, ventricular enlargement, and subarachnoid hemorrhage (SAH). The study aimed to analyze the correlation between CSW in TBI.

Methods:

A total of 55 patients were recruited at Hasan Sadikin Bandung General Hospital from January to May 2024. These patients were profiled for demographics, and imaging findings such as ventriculomegaly, subarachnoid hemorrhage, and volume bleeding will be assessed for correlation between CSW and other parametric. Data were analyzed using the Statistical Package for the Social Sciences v25.

Results:

A total of 55 consecutive patients with TBI were evaluated. The average age was 45-year-old males, and females were not significantly different. The study found that the volume of bleeding <10cc was present in 58.2% of cases, accompanied by SAH in 40% and CSW in 29.1%. The results indicated a significant relationship between TBI and CSW, with a P < 0.05, and 13 patients with severe TBI. In addition, the study showed a significant association between variations in bleeding volume, ventriculomegaly, and SAH with TBI, also with a P < 0.05.

Discussion:

Patients with TBI are prone to developing CSW, which in turn results in worse outcomes, including higher morbidity and mortality rates.

INTRODUCTION

Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Among the various complications that can arise after TBI, cerebral salt wasting (CSW) is a condition that has a significant impact on patients. CSW is characterized by excessive sodium loss through urine, leading to hyponatremia which can cause neurological disorders.[3]

Hyponatremia is commonly found in TBI patients because the central nervous system plays an important role in water and sodium homeostasis. The presence of hyponatremia can worsen the patient’s prognosis. A previous study by Sherlock et al., reported that hyponatremia was experienced by 46.8% of TBI patients, 50.7% in subdural hematoma, 25% in epidural hematoma, 47.9% in cerebral contusion, and 50% in diffuse axonal injury patients.[11] A study conducted by Albanese et al., also reported that hyponatremia in TBI patients increased mortality by 14.3%.[1]

An epidemiological study revealed that the prevalence of CSW in TBI patients is higher than expected. Understanding the mechanism of CSW development is still controversial, and the diagnosis of CSW is often challenging for medical practitioners. The symptoms and early signs of CSW may be similar to those of the syndrome of inappropriate antidiuretic hormone secretion (SIADH), another complication of TBI.[6] Therefore, this study will examine the factors associated with the development of CSW in TBI patients and will assess early prediction of the occurrence of this condition.[2]

Several studies have attempted to identify risk factors associated with CSW in TBI patients. As such, a study conducted by Shen et al., identified several risk factors, including TBI severity, changes in cerebral ventricular volume, and the presence of cerebral edema.[4,10] The study also showed that further understanding of these factors could help in early diagnosis and appropriate treatment for TBI patients.

In addition, the use of head computed tomography (CT) scans in the initial assessment has become important in establishing the diagnosis. Head CT scans can provide an accurate visual image of the patient’s brain condition and radiological signs that have a correlation with the development of CSW.[5] Therefore, the use of data from head CT scans as a diagnostic tool has the potential to predict CSW which will be explained in this study.

MATERIALS AND METHODS

This study was carried out retrospectively with a cross-sectional design where the independent and dependent variables were assessed at the same time. Data collected from the medical record and assessed the incidence of hyponatremia (sodium serum <135 mEq/L) after 1 month of trauma incidence. This study was conducted for 3 months from March to May 2024. The sampling was conducted in accordance with the inclusion and exclusion criteria. The sampling techniques are calculated based on the minimum sample formula using the consecutive sampling method.

Inclusion and exclusion criteria

The inclusion criteria are TBI patients performed by the CT scan of the head, the regulation of medical records, patients with chronic hyponatremia (history of congestive heart failure, liver cirrhosis, and chronic kidney failure), and TBI patients who died within 48 h after arriving at the emergency room. The exclusion criteria are incomplete medical records, no electrolyte serum data, patients with comorbidities including renal, thyroid, or adrenal diseases before the TBI, and patients with spinal cord injuries.

Statistical analysis

The characteristic of participants was carried out by descriptive statistics, such as frequencies and percentages. Bivariate analysis using Chi-square test was used to analyze the association between independent variables and TBI. All statistical analyses were performed by the Statistical Package for the Social Sciences (SPSS) version 25.0 (IBM Corp., Armonk, NY, USA).

RESULTS

In this study, a total of 55 participants were recruited according to the standard sampling method. Based on the age group, the age group >50 years is the largest with 27 patients (49.1%), followed by the age group 35–49 years, 15–24 years, and 25–34 years with 13 (23.6%), 11 (20%), and 4 (7.3%), respectively. There was no significant difference in gender where the male group was 28 (50.9%) and the female group was 27 (49.1%). Most patients were included in the mild GCS group (45.5%), followed by the severe (29.0%) and moderate group (25.5%).

The CT-scan outcomes included in the characteristics are bleeding volume and ventricular enlargement. Bleeding volume <10 cc was mostly found, namely 32 patients (58.2%). Meanwhile, ventricular enlargement was found in 21 patients (38.2%) less than patients who did not find ventricular enlargement, namely 34 patients (61.8%). Patients who experienced subarachnoid hemorrhage (SAH) were 22 (40%). Meanwhile, CSW syndrome was found in 16 patients (29.1%). The distribution of characteristics in patients can be seen in Table 1.

Table 1:

Characteristic of participants

In this study, the difference in TBI severity was significantly related to the incidence of CSW syndrome with a P < 0.05. The incidence of CSW was mostly found in the severe TBI group, which was 13 patients. The results can be seen in Table 2.

Table 2:

The association between TBI severity and CSW

The differences in bleeding volume were significantly related to the incidence of CSW syndrome with a P < 0.05. The incidence of CSW was mostly found in the group with bleeding volume >30 cc, which was 11 patients. The results can be seen in Table 3.

Table 3:

The association between blood volume and CSW

The ventricular enlargement was significantly associated with the occurrence of CSW syndrome with a P < 0.05. The occurrence of CSW was mostly found in the group with ventricular enlargement, which was 12 patients. The results can be seen in Table 4.

Table 4:

The association between ventricle and CSW

SAH was significantly associated with CSW syndrome with a P < 0.05. The incidence of CSW was mostly found in the group with SAH, which was 14 patients. The results can be seen in Table 5.

Table 5:

The association between SAH and CSW

DISCUSSION

CSW syndrome is a condition of loss of sodium from the kidneys during a head injury, resulting in hyponatremia and reduced volume of extracellular fluid. This syndrome began to be first introduced by Peter et al., in 1950.[8] At present, it is still unknown about the cause of the mechanism of CSW. In general, the mechanism occurs due to primary natriuresis which causes hypovolemia and sodium depletion in large quantities.[5]

Previous studies reported that CSW often occurs in SAH patients with high hyponatremia incidence to 57%.[5] Leonard et al.,[7] revealed that CSW was found in TBI patients as much as 0.8–34% and appeared within a few days to 2-day posthead injury. A study by Rajagopal et al.,[9] also reported that the incidence of hyponatremia was 13.2% in head injury patients with half experiencing moderate hyponatremia (49.49%) and 21.71% experiencing severe hyponatremia. SAH is the most common abnormality at 59.5%. The study also found that differences in the degree of TBI have a significant relationship with the incidence of CSW with the value of P < 0.001.[9]

CSW is associated with bleeding in the head; only a few CSW cases reported the presence of an infarction stroke.[7,12] A case report reveals that the manifestation of CSW syndrome appears not in the initial stage but at an advanced stage with excessive hemorrhagic and edema transformation in cardiogenic infarction strokes. A significant relationship was found between the volume of bleeding and CSW.[12]

Studies discussing the relation between ventricular enlargement with CSW are still limited. However, it is suspected that there is a relationship between ventricular enlargement the severe TBI. In this study, ventricular enlargement was found to have a significant relationship with CSW. Thus, the presence of ventricular bleeding can increase the risk of CSW syndrome.

Patients with TBI are very important to distinguish between CSW and SIADH because both have different diagnostic criteria. In addition, assessment and monitoring of Na, water loss, and extracellular volume are needed to assess the two diagnoses. The difference that stands out in these disorders is the volume of plasma and excretion of Na and CL from urine.[13] CSW syndrome is usually characterized by low plasma volume with symptoms of dehydration, low serum osmolality, and the amount of excretion of Na and CL through urine, while SIADH shows the volume of high plasma with low osmolality. Low central venous pressure confirms volume depletion so that it leads to a diagnosis of CSW syndrome.[2] In addition, hemoconcentration is another laboratory result that is useful in the CSW diagnosis.

Volume estimation is important for diagnosis, because patients with SIADH show euvolemic or hypervolemic conditions, while CSW syndrome shows hypovolemic conditions.[13] It is very difficult for doctors to confirm whether a patient has low extracellular volume through observation. Electrolyte balance must be monitored daily to avoid diagnostic errors. Hence, the treatment can be more optimal.

This study has several limitations. This study was an observational design and had a small sample size. Potential bias can arise from both participant selection and data analysis processes. The small sample size also provides inadequate results so that the results cannot be fully relied on. In addition, this study was also conducted in only one hospital.

CONCLUSION

Patients with TBI have a tendency to develop CSW. The occurrence of CSW is often associated with bleeding in the brain. In addition, there is a significant relationship between CSW and bleeding volume. Ventricular enlargement is also associated with CSW, as it reflects the severity of traumatic brain injury. Clinical symptoms of CSW syndrome usually appear in the advanced stage which can be characterized by excessive edema and hemorrhagic transformation. Further research with a larger number of samples and obtained from several places (multi-center) is needed to provide meaningful research results.

Ethical approval:

Ethical approval was not required for this study because it was conducted using retrospective, secondary data obtained from anonymized patient medical records. No direct patient involvement, intervention, or access to identifiable personal information occurred during the study. Therefore, according to institutional and ethical guidelines, this type of research is exempt from formal ethical approval (ethical waiver).

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

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