Syndrome Of Inappropriate Antidiuretic Hormone Research Articles

The Syndrome of Inappropriate Antidiuresis

Abstract The syndrome of inappropriate antidiuresis (SIAD)–the most frequent cause of hypotonic hyponatremia–is mediated by nonosmotic release of arginine vasopressin (AVP), which promotes water retention by activating renal vasopressin type 2 (V2) receptors. There are numerous causes of SIAD, including malignancy, pulmonary and central nervous system diseases and medications. Rare activating mutations of the V2 receptor can also cause SIAD Determination of the etiology of SIAD is important because removal of the stimulus for inappropriate AVP secretion offers the most effective therapy. Treatment of SIAD is guided by symptoms and their severity as well as the level of plasma sodium. In the absence of severe symptoms which require urgent intervention, many clinicians focus on fluid restriction as a first-line treatment. Second-line therapeutic options include loop diuretics and salt tablets, urea, and V2 receptor antagonists.

Comparative study of the effectiveness of tolvaptan versus urea in patients with hyponatremia caused by SIADH

Background and objectivesHyponatraemia is common in elderly and hospitalised patients, often caused by the syndrome of inappropriate antidiuretic hormone secretion (SIADH). This study evaluates the efficacy and safety of tolvaptan and urea in patients with hyponatraemia and SIADH. Materials and methodsAn observational cohort study was conducted on 198 patients with SIADH and hyponatraemia (Na+ <135 mmol/L) at the Complejo Hospitalario Universitario de Pontevedra from January 2015 to May 2022. Of these, 86 were treated with tolvaptan (average dose of 7.5 mg) and 112 with urea (average dose of 15 g). The primary outcome was the normalisation of sodium levels (Na ≥ 135 mmol/L). ResultsThe tolvaptan group showed higher sodium concentrations at the end of therapy compared to the urea group (ME = 136, IQR = 135-137 vs. ME = 134, IQR = 132-137; p < 0.001). The time to normalise sodium was shorter with tolvaptan (4 ± 3.4 days) compared to urea (6 ± 3.6 days; p = 0.03). A higher percentage of patients achieved sodium normalisation with tolvaptan (83.72% vs. 59.82%; p = 0.005). Tolvaptan had more adverse effects, such as dry mouth, thirst, and sodium overcorrection, while urea caused dysgeusia, abdominal pain, and diarrhea. There were no significant differences in mortality between the groups. ConclusionsTolvaptan was more effective and quicker than urea in normalising sodium levels, though it showed a higher percentage of adverse effects, which did not require discontinuation of the drug.

THE ETIOLOGICAL PROFILE AND ALTERATIONS IN CEREBROSPINAL FLUID CHARACTERISTICS IN PATIENTS WITH BACTERIAL MENINGITIS

Currently, bacterial meningitis (BM) remains a form of life-threatening infectious pathology, with a mortality rate ranging from 4% to 35% and poor prognosis often accompanied by diverse specific and non-specific complications, including infectious toxic shock, cerebral edema, ventricular inflammation, hydrocephalus, acute cerebrovascular accidents, venous sinus thrombosis, disseminated intravascular coagulation (DIC) syndrome, respiratory distress syndrome (RDS) syndrome, inappropriate secretion of antidiuretic hormone, and systemic inflammatory response syndrome. In clinical practice, the early identification of the causative microorganism and the implementation of proper antibiotic treatment, as well as a comprehensive assessment of the patient's status and management, are crucial for minimizing a risk of related severe complications and mortality. The BM etiology is characterized by a highly variable nature, contingent upon a multitude of factors such as geographic location, temporal context, patient age, immunological status, and other variables. Over the past two to three decades, advancements in conjugate vaccines and the use implementation of antibiotic treatment have brought about alterations in the spectrum of pathogens responsible for meningitis. The objective of this study was to delve into the etiological profile and prognostic implications of cerebrospinal fluid (CSF) parameters among patients with diagnosed meningitis admitted to the Neuroinfectious Diseases Division of the Infectious Clinical Hospital №2 (Moscow) between 2022 and 2023. A retrospective analysis of medical records of meningitis patients admitted to the Infectious Clinical Hospital №2 during 2022–2023 was conducted. The data were analyzed using the k-means clustering algorithm implemented in the Loginom analytics software to create a scenario, as well as OLAP cubes. The study involved the analysis of medical records for 110 patients aged 18-89 years old. Among the BM pathogens identified, Neisseria meningitidis emerged as the most prevalent in this patient cohort, accounting for 68.2% of cases. Within the group of meningococcal meningitis cases, serovariants A and W135 were the most frequently detected, accounting for 49.3% and 33.3%, respectively. Significant alterations in cerebrospinal fluid parameters, characterized by elevated cell counts and lowered glucose levels, were observed among patients with purulent meningitis resulting from serogroup A Neisseria meningitidis infections. A combination of elevated baseline cell level along with high concentrations of proteins, and lactate, coupled with the presence of D-dimer in cerebrospinal fluid, has been associated with a severe disease progression and the emergence of critical and life-threatening sequelae.

Long-Term Persistence of Inappropriate Antidiuretic Hormone Secretion Following Minor Head Injury.

While the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is typically transient, it can persist after even minor head trauma, highlighting the importance of long-term follow-up in cases of post-traumatic hyponatremia.Urea therapy is effective and well-tolerated for managing chronic hyponatremia in SIADH, offering a sustainable long-term treatment option.Even mild hyponatremia can lead to subtle but impactful cognitive and motor symptoms.

Real-time intraoperative ultrasound imaging of the posterior pituitary gland during endoscopic endonasal approach.

Pituitary adenomas are amongst the most common benign central nervous system tumors, and often require resection via an endoscopic endonasal approach (EEA). Two of the most common associated complications are central diabetes insipidus (DI) and syndrome of inappropriate antidiuretic hormone secretion (SIADH). Both are thought to be caused by manipulation of the posterior pituitary gland (PPG), making intraoperative visualization and preservation of this structure critical. Intraoperative endoscopic endonasal ultrasound (IEUS) may present an optimal tool for this purpose. This study aims to describe the appearance and morphology of the PPG on IEUS. This study included all pituitary adenoma surgeries during which IEUS was utilized and the PPG was visualized between 1/1/2022, and 12/31/2023. Demographic, clinical, pathological, and radiological data were retrospectively collected. The PPG was described as either hypoechoic, isoechoic, or hyperechoic as compared to the anterior pituitary gland and adenoma, and the morphology of the PPG was further classified as ellipse or crescent shaped. The PPG was hypoechoic in all 43 cases included in our final cohort (100.0%). Morphologically, the PPG appeared elliptical in 27 cases (62.8%), and crescent shaped in 16 cases (37.2%). The PPG can typically be visualized by IEUS as a hypoechoic structure immediately anterior to the posterior wall of the sella turcica, with elliptical morphology being the most common appearance. These characteristics can be used by the skull base surgeon to more confidently identify the position and morphology of the PPG intraoperatively for its' preservation.

Hyponatremia Associated with the Use of Common Antidepressants in the All of Us Research Program.

Selective serotonin reuptake inhibitor (SSRI), serotonin-norepinephrine reuptake inhibitor (SNRI), and norepinephrine-dopamine reuptake inhibitor (NRI) antidepressants can cause hyponatremia through syndrome of inappropriate antidiuretic hormone secretion (SIADH). This study assesses the differential risks of hyponatremia associated with commonly prescribed SSRIs (fluoxetine, paroxetine, sertraline, citalopram, escitalopram), SNRIs (duloxetine, venlafaxine) and NRI (bupropion), as well as omeprazole as a reference, with a retrospective observational cohort study in the All of Us Research Program, a national multicenter research cohort containing de-identified electronic health records (EHR). Participants who had been prescribed monotherapy with any of eight common antidepressants were included, with each drug considered as a separate arm indexed with a start date. Events were defined as the first occurrence of a low plasma sodium measurement or a clinical diagnosis recorded for either hyponatremia or SIADH. Those who did not have events were censored at their last plasma sodium measurement. A total of 17,439 individuals were exposed to one of the eight antidepressants as monotherapy. The overall incidences for hyponatremia were 0.87% in the first 30 days and 10.5% in the first 3 years in the antidepressant arms. Compared to sertraline, duloxetine (hazard ratio [HR] = 1.37 [1.19-1.58]) and escitalopram (HR = 1.16 [1.01-1.33]) were associated with the highest overall risk of hyponatremia, and bupropion (HR = 0.83 [0.73-0.94]) and paroxetine (HR = 0.78 [0.65-0.93]) were associated with the lowest risk. The risks were unchanged after adjusting for comorbidity and polypharmacy. Such information could help guide providers in managing patients and their risks of hyponatremia when on common antidepressants.

Empagliflozin Raises Sodium in SIADH Patient, Enabling Timely Surgery

AbstractEmpagliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, induces osmotic diuresis via glucosuria and may represent a novel therapeutic approach for managing syndrome of inappropriate antidiuretic hormone secretion (SIADH). This case report details the successful use of empagliflozin to correct persistent hyponatremia in a 78-year-old man with SIADH, awaiting elective abdominal surgery for hernia repair over several months. The patient, who had a history of hypertension and multinodular thyroid goiter with normal thyroid function tests, continued to experience low serum sodium levels despite discontinuing enalapril, previously used for hypertension management. An extensive evaluation confirmed a diagnosis of SIADH, with sodium levels initially ranging between 124 and 128 mmol/L. Traditional management, including fluid restriction, failed to normalize his sodium levels, leading to repeated cancellations of his scheduled surgery due to persistent hyponatremia. In October 2023, treatment with empagliflozin was initiated, leading to a gradual increase in sodium levels. Within 3 weeks, his serum sodium had normalized to 134 mmol/L, accompanied by a rise in serum osmolality. As a result, the elective surgery was successfully performed without complications. These findings suggest that empagliflozin, in combination with fluid restriction, offers a promising treatment option for improving sodium levels in patients with SIADH, helping avoid unnecessary delays in elective surgical interventions.

Duloxetine-induced syndrome of inappropriate antidiuretic hormone secretion in a patient with neuropathic pain.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) induces hyponatremia accompanied by uric acid reduction. We report a case of a patient with small-cell lung cancer who developed SIADH with hypouricemia after duloxetine treatment and discuss the potential underlying mechanisms. SIADH and hypouricemia improved after duloxetine was switched to mirogabalin.

Long-term Outcome of a Chihuahua With Idiopathic Syndrome of Inappropriate Antidiuretic Hormone Secretion.

An approximately 3 yr old female Chihuahua was presented for evaluation of polyuria and polydipsia noted by the owner after adoption. Serum biochemistry and urinalysis revealed hyponatremia, hypochloremia, hypo-osmolality, and normal fractional excretion of sodium. Serum antidiuretic hormone concentration was 5.54 pg/mL and serum copeptin concentration was 135.40 pg/mL. The antidiuretic hormone value was above the reported range for healthy dogs and was considered inappropriate in light of serum osmolality. Idiopathic syndrome of inappropriate antidiuretic hormone secretion was considered the most likely diagnosis after excluding other potential causes, such as diuretic use, renal disease, adrenal disease, and thyroid dysfunction. The dog remains clinically well 2 yr after diagnosis without specific treatment other than minimal dietary salt supplementation. This case is unique because of the absence of systemic or neurologic signs, good long-term outcome without treatment, and use of novel diagnostic testing.

A smart lab on a wearable microneedle patch with convolutional neural network‐enhanced colorimetry for early warning of syndrome of inappropriate antidiuretic hormone secretion

AbstractFrequent nocturia‐induced nighttime visits aggravate falls in seniors, requiring synthetic antidiuretic drugs that risk the dangerous syndrome of inappropriate antidiuretic hormone secretion (SIADH), thus the detection of sodium ion and uric acid alterations during treatment is obligatory for drug‐safe management. Herein, we design a convolutional neural network (CNN)‐enhanced smart wearable microneedle array‐based colorimetric (WMNC) sensor to independently detect in vivo interstitial fluid (ISF) sodium ions and uric acid alterations. The WMNC sensor is composed of a vacuum tube‐driven microneedle array patch and a built‐in colorimetric sensing paper, enabling an efficient ISF extraction and rapid colorimetric assay. Furthermore, leveraging self‐designed CNNs, the WMNC sensor efficiently eliminates the influence of ambient light on colorimetric outcomes, facilitating a rapid and accurate colorimetric result classification. This study provides an ISF‐based rapid, intuitionistic, user‐friendly, wearable point‐of‐care technique for the elderly suffering from nocturia in monitoring their health status for early warnings of SIADH.

8252 Central Adrenal Insufficiency Masquerading as Syndrome of Inappropriate Antidiuretic Hormone (SIADH): A Case Report

Abstract Disclosure: J.G. Sazon: None. J.L. Reyes: None. J.V. Chua: None. S.A. Kho: None. Hyponatremia, the most common electrolyte imbalance encountered in clinical practice, has various causes and presentation. Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) is a frequent hospital-related cause, potentially leading to misdiagnosis with adrenal insufficiency due to shared clinical features which may cause potential deleterious effect. We present a case of a 41-year-old male hyponatremic patient with a two-month history of progressive generalized body weakness and lightheadedness, initially managed as SIADH. Upon admission, the patient persistently showed low serum sodium level (122mmol/L) (NV: 135-145mmol/L), exhibited signs of euvolemic hyponatremia despite fluid restriction, intravenous furosemide, and sodium chloride tablets. Further work-up revealed normocytic normochromic anemia (Hgb 107 g/L) (NV: 120-160g/L), elevated ESR of (31mm/hr) (NV: 0-15mm/hr), low Ft4 (2.97 pmol/L) (NV: 12-22 pmol/L) and normal TSH (2.2 uIU/mL) (NV: 0.27-4.20 uIU/mL). During hospital stay, he experienced an episode of hypotension at 80/50mmHg and hypoglycemia at 65 mg/dL. Investigation revealed adrenal insufficiency secondary to pituitary macroadenoma with apoplexy as showed in magnetic resonance imaging. Patient was started on Prednisone. Pre-operatively, hydrocortisone 100mg IV every 8 hours preoperatively. He underwent transsphenoidal surgery; excising a 2.5cm soft and grayish suprasellar mass. Post-operatively, he was given Prednisone and Levothyroxine resulting in symptom improvement and normal sodium levels.The occurrence of hyponatremia due to adrenal insufficiency is relatively uncommon, emphasizing the need for heightened suspicion when assessing patients with prolonged or recurring hyponatremia. This paper highlight the need to replace glucocorticoid prior supplementation of thyroid hormone in such cases, averting the occurrence of adrenal crisis. This case indicated a mechanism of persistent hyponatremia attributed to secondary adrenal insufficiency, with added therapeutic benefits observed through the use of glucocorticoids and transsphenoidal surgery. Presentation: 6/1/2024

8431 Triphasic response of pituitary stalk post anoxic injury in a mechanically ventilated patient

Abstract Disclosure: P. Henriquez Feliz: None. H. Neizer: None. E. Alshdifat: None. F. Abdulkarim: None. T. Mazhude: None. T. Zahra: None. Introduction: A phenomenon may manifest wherein the pituitary undergoes a triphasic response following an inciting event. Phases include diabetes insipidus (DI) followed by Syndrome of inappropriate Antidiuretic Hormone (ADH), and finally a recurrence of DI. Research has established that this is a common complication to neurosurgical interventions but there are limited reports following anoxic brain injury. This case demonstrates a potential pituitary stalk injury after an anoxic brain injury. Case: Unknown 30 year old male found by EMS with pulseless electrical activity cardiac arrest likely from polysubstance use. Returned of spontaneous circulation after 30 minutes in the emergency department. Total downtime unknown. Managed by Intensive Care Unit. Scans were negative. Initial blood work showed eunatremia with a specific gravity (sg) 1.068 and serum osmolarity (Sosm) 311. Eventually, developed hypernatremia, 163 mmol/L, and a urine osmolarity (Uosm) of 428 mosm, raising concern for central DI (CDI). Responded to hypotonic fluids not requiring desmopressin at that time. On day 10, developed severe hyponatremia 113 mmol/L with a Uosm of 774, suggesting ADH mediated response or excessive free water intake. Sodium normalized after managed with fluid restriction. On day 16, patient developed hypernatremia, 178 mmol/L, and Uosm of 869 mosm. Suggestive of CDI recurrence. Treated with desmopressin and hydrocortisone. Discussion: Changes in water-electrolyte balances may occur after anoxic brain injury. The mechanism is believed to arise from axonal shock due to disruptions in vascular supply leading to unregulated release of ADH from degenerating posterior pituitary, causing oliguria and hyponatremia, and subsequent permanent DI from loss of neurons. These stages may last 5-7 days on initial phase, and the second phase can extend anywhere from 2-14 days. In this case, phases one and two lasted four and three days, respectively. It is important to acknowledge that timelines may vary based on management initiation and recognition of transition between stages. CDI treatment involves hypotonic fluids with desmopressin. Our patient was initially managed with free water due to low suspicion for CDI. During shift towards suspected second phase, Uosm increased, urine output and sodium dropped significantly. However, it is uncertain whether this was due to axonal injury causing SIADH or a consequence of hypotonic fluids causing increased response of ADH. As predicted during triphasic response, patient became oliguric with a net negative fluid balance of &amp;gt;10L and Uosm of 869. Therefore, desmopressin was started with good response. Further follow up was unattainable as neurological status deteriorated preceding to brain death. Most cases reported showed hypoattenuation lesion of posterior pituitary on MRI; MRI would have been required to determine if there was injury to the pituitary in this case. Presentation: 6/2/2024

A real-world pharmacovigilance study using disproportionality analysis of United States Food and Drug Administration Adverse Event Reporting System events for vinca alkaloids: comparing vinorelbine and Vincristine

ABSTRACT Background Vinca alkaloids are widely used in cancer treatment for their ability to target microtubule dynamics. While their efficacy in treating certain cancers is well-established, the full spectrum of their adverse event profiles remains an area of ongoing research. Methods We analyzed AEs related to vinorelbine and vincristine using a retrospective case/non-case approach with data from the FDA Adverse Event Reporting System (FAERS). We applied various algorithms to detect AE signals: the reporting odds ratio (ROR) and proportional reporting ratio (PRR) measured disproportionality and association strength; the Bayesian confidence propagation neural network (BCPNN) calculated the Information Component (IC) for associations against background rates; and the multi-item gamma Poisson shrinker (MGPS) yielded empirical Bayes geometric mean (EBGM) values, accounting for reporting variability. Results Both medications significantly involve the blood and lymphatic systems, with vinorelbine reporting 401 cases in this System Organ Class (SOC), exhibiting a ROR of 17.4, PRR of 12.4, IC of 3.63, and EBGM of 12.38. An intersection analysis of Preferred Terms (PTs) has uncovered previously unreported AEs shared by both drugs, including posterior reversible encephalopathy syndrome and inappropriate antidiuretic hormone secretion. Conclusions This analysis highlights the need for ongoing research of the risks associated with vinorelbine and vincristine.

Primary Hyperaldosteronism with Syndrome of Inappropriate Antidiuretic Hormone (SIADH) and Nephrocalcinosis

Primary Hyperaldosteronism with Syndrome of Inappropriate Antidiuretic Hormone (SIADH) and Nephrocalcinosis

Efficacy of Low-Dosage Tolvaptan for Treatment of Profound Hyponatremia in Syndrome of Inappropriate Antidiuresis: An Open-Label Randomized Controlled Trial

Efficacy of Low-Dosage Tolvaptan for Treatment of Profound Hyponatremia in Syndrome of Inappropriate Antidiuresis: An Open-Label Randomized Controlled Trial

Síndrome de secreción inadecuada de hormona antidiurética

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is defined as a disorder in renal free water excretion control due to the inability to suppress the secretion of antidiuretic hormone (ADH) or vasopressin. The most frequent causes are usually acquired, notable among which are central nervous system involvement, malignancy, pulmonary diseases, or drugs. Up to 35% of admitted patients have hyponatremia, of which up to 40% can be attributed to SIADH. It is considered acute when it occurs in less than 48hours. It can trigger vomiting, convulsions, coma, and death due to cerebral herniation resulting from increased intracranial pressure. Chronic forms are more common and entail symptoms such as nausea, confusion, weakness, or agitation. In order to diagnose it, it is necessary to identify the presence of a true hypoosmolar euvolemic hyponatremia, ruling out other hormonal abnormalities or drug use. Treatment of the acute form is based on the emergency use of hypertonic saline solution, avoiding excessively rapid sodium correction that would trigger an osmotic demyelination syndrome. In the case of chronic hyponatremia, water restriction, increased osmole intake, and tolvaptan can be used in addition to acting on the triggering causes.

Exploring the Effectiveness of Urea in Hyponatremia Due to Syndrome of Inappropriate Antidiuretic Hormone Secretion: A Comprehensive Systematic Review and Meta-Analysis

Exploring the Effectiveness of Urea in Hyponatremia Due to Syndrome of Inappropriate Antidiuretic Hormone Secretion: A Comprehensive Systematic Review and Meta-Analysis

Urea to Treat Hyponatremia Due to Syndrome of Inappropriate Antidiuretic Hormone Secretion: A Systematic Review and Meta-Analysis

Rationale & ObjectiveThe use of urea to treat hyponatremia related to the Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) has not been universally adopted due to questions about effectiveness, safety, and tolerability. This systematic review and meta-analysis of observational studies aimed to address these questions. Study DesignThis PRISMA-guided study examined published research across four electronic databases. Study PopulationsPatients with SIADH-related hyponatremia. Selection CriteriaClinical trials and observational studies reporting at least one outcome related to serum sodium concentration, symptom resolution, or adverse effects after oral or nasogastric urea administration. Data ExtractionData extraction was performed independently by two reviewers using a standardized form recording study characteristics, participant demographics, intervention details, and treatment outcomes. Analytical ApproachA meta-analysis was conducted using the restricted maximum likelihood method for the random-effects model to assess the effect of urea treatment on serum sodium and serum urea compared to other treatment modalities. Subgroup analyses were conducted based on treatment duration and SIADH severity. ResultsUrea treatment significantly increased serum sodium [mean difference (MD) = 9.08 (95%CI 7.64-10.52), p < 0.01] and urea [MD = 31.66 (95%CI 16.05-47.26), p < 0.01] in patients with SIADH albeit with significantly high heterogeneity. Subgroup analysis based on the treatment duration showed a significant rise in the serum sodium level after 24 hours, two, five, seven, and fourteen days, as well as after one year of treatment. Greater increases in serum sodium levels after treatment with urea occurred in patients with severe (<120 mEq/L) [MD = 18.04 (95%CI 13.68-22.39)] than with moderate (120-129 mEq/L [MD = 7.86 (95%CI 6.78-8.94)] or mild (130-135 mEq/L) [MD = 8.00 (95%CI 7.31-8.69)] SIADH induced hyponatremia. Urea treatment was comparable to fluid restriction [MD = 0.81 (95%CI: -0.93-2.55), p = 0.36) and vaptans [MD = -1.96 (95%CI: -4.59-0.66, p = 0.14) but superior to no treatment [MD = 7.99 (95%CI 6.25-9.72), p < 0.01]. Urea was associated with minor adverse events, with poor palatability being most common. LimitationsAs no RCTs investigating urea as a treatment for hyponatremia were identified for inclusion, these analyses were based on observational studies. ConclusionsUrea is safe and effective for managing SIADH-induced hyponatremia. These finding suggest that urea may be a useful treatment modality in resource-limited settings or when other treatments are contraindicated or poorly tolerated.

Cerebral salt wasting syndrome in an elderly patient with cerebral small vessel disease.

Hyponatremia is a common electrolyte disturbance seen among the acute geriatric admissions with two common diagnostic entities; the syndrome of inappropriate antidiuretic hormone (SIADH) and cerebral salt wasting syndrome (CSWS) that have different clinical and biochemical presentations, different pathogenesis and therapeutic approaches. Hyponatremia caused by CSWS in patients with cerebral small vessel disease (cSVD) a prevalent condition among the elderly, can be masked in geriatric patients with concomitant fluctuating neurological deficits. Correct diagnosis is crucial to appropriate management. In this case report we describe an association between hyponatremia caused by CSWS in a patient with cSVD.

Deciphering Familiar Conundrum of Cerebral Salt Wasting Syndrome vs Syndrome of Inappropriate Secretion of Antidiuretic Hormone and Establishing Role of Hyponatremia in Patients of Tuberculous Meningitis as a Predictor of Outcome.

Introduction: Hyponatremia is one of the most common electrolyte abnormalities [35-71%] associated with tuberculous meningitis [TBM]. It is an independent predictor of patient outcome. Cerebral salt wasting syndrome [CSWS] and syndrome of inappropriate secretion of antidiuretic hormones [SIADH] are two common causes of hyponatremia in patients with TBM. This study targets patients with tuberculous meningitis to provide a detailed analysis of hyponatremia in TBM patients and it’s predictive value in terms of outcome and also describes the distinguishing features of CSWS and SIADH. Materials and methods: This was a clinical, prospective study of 31 patients with TBM in which various parameters were analysed . Serial sodium levels were recorded on the day of admission, day 2, 7 and 28. Patients with hyponatremia were divided into CSWS and SIADH. Results: In this study, 24[77.42%] patients had hyponatremia. In 14 [58%], hyponatremia was due to CSWS and in 10[42%] of the patients with hyponatremia it was SIADH. Hyponatremia was related to disease severity, GCS score, hospital stay, ventilator stay and patient outcome. CSWS was more strongly associated with disease severity than SIADH. Conclusion: Hyponatremia is a common electrolyte imbalance in patients with TBM and a direct and valid predictor of disease outcome. CSWS should be differentiated from SIADH due to the different treatment strategies.