European Journal of Cardiovascular Medicine

emergencies worldwide and represents a major cause of acute abdominal pain requiring immediate intervention. Despite significant advances in diagnostic imaging, laboratory markers, and clinical scoring systems, accurately distinguishing uncomplicated appendicitis from its complicated forms—such as gangrenous or perforated appendicitis—remains a persistent challenge [1,2]. Delay in diagnosis or misclassification may lead to serious consequences including peritonitis, abscess formation, sepsis, prolonged hospital stay, and increased morbidity. Therefore, early identification of patients at risk for complicated appendicitis is crucial for optimizing surgical decision-making and improving patient outcomes.

Traditional markers such as leukocytosis, neutrophilia, and C-reactive protein (CRP) are routinely employed but often lack the specificity or predictive reliability required to guide urgent management, particularly in patients with equivocal clinical features [3]. This limitation has prompted the search for alternative, inexpensive, and widely available laboratory parameters that may serve as early indicators of disease severity.

Recent evidence has highlighted the potential role of serum sodium as a prognostic marker in patients with acute inflammatory conditions. Hyponatremia, commonly defined as serum sodium <135 mEq/L, is frequently encountered in hospitalized patients and is increasingly recognized as a marker of severe systemic inflammation [4,5]. The mechanism is thought to be mediated by inflammatory cytokines—particularly IL-6—which induce non-osmotic release of antidiuretic hormone (ADH), leading to water retention and dilutional hyponatremia [6,7]. This cytokine-driven mechanism has been demonstrated in several inflammatory and infectious diseases and is now being studied in acute abdominal conditions, including appendicitis.

Several studies have suggested that patients with complicated appendicitis are more likely to present with lower serum sodium levels, and hyponatremia may correlate with the severity of underlying inflammation [8–10]. Kim et al. reported a strong association between hyponatremia and appendiceal perforation, while Kaser et al. found serum sodium to be a specific marker of complicated disease in older adults. More recent systematic reviews have supported these findings, emphasizing the potential diagnostic value of serum sodium as a readily available biochemical tool [9,10]. However, despite emerging evidence, its incorporation into routine diagnostic pathways has not yet been standardized, and additional studies from diverse clinical settings are required to strengthen the evidence base.

Given this context, the present study aims to evaluate the diagnostic utility of serum sodium in differentiating uncomplicated from complicated acute appendicitis. By assessing sodium levels at presentation and correlating them with operative and histopathological findings, our study seeks to determine whether hyponatremia can serve as an inexpensive, rapid, and reliable marker to predict disease severity and guide early clinical decision-making.

This comparative observational study was conducted in the Department of General Surgery at Bhagat Phool Singh Government Medical College for Women. All patients aged 15–65 years presenting with clinical features of acute appendicitis to the emergency or outpatient department were evaluated through detailed history, physical examination, laboratory investigations, and ultrasonography.

Blood samples were obtained at admission to measure serum sodium, platelet count, and platelet indices. Routine preoperative blood investigations were also performed. Based on operative findings and histopathological examination, patients were categorized into uncomplicated appendicitis and complicated appendicitis (gangrenous or perforated).

Patients with hematological malignancies, essential thrombocytosis, SIADH, diabetes, hypertension, immunocompromised status, pregnancy, radiologically proven alternate diagnoses, liver or renal disease, hyperaldosteronism, alcoholism, fever, or drug intake affecting liver parameters were excluded.

A total sample size of 80 patients (40 in each group) was calculated using mean serum sodium values from previous studies at 95% confidence. Data were entered in Microsoft Excel and analyzed using SPSS software. Continuous variables were expressed as mean ± SD and compared using the Student’s t-test. Categorical variables were compared using the chi-square test. Diagnostic accuracy was assessed using ROC curve analysis. A p-value <0.05 was considered statistically significant.

This comparative observational study was conducted in the Department of General Surgery at Bhagat Phool Singh Government Medical College for Women. All patients aged 15–65 years presenting with clinical features of acute appendicitis to the emergency or outpatient department were evaluated through detailed history, physical examination, laboratory investigations, and ultrasonography.

Blood samples were obtained at admission to measure serum sodium, platelet count, and platelet indices. Routine preoperative blood investigations were also performed. Based on operative findings and histopathological examination, patients were categorized into uncomplicated appendicitis and complicated appendicitis (gangrenous or perforated).

Patients with hematological malignancies, essential thrombocytosis, SIADH, diabetes, hypertension, immunocompromised status, pregnancy, radiologically proven alternate diagnoses, liver or renal disease, hyperaldosteronism, alcoholism, fever, or drug intake affecting liver parameters were excluded.

A total sample size of 80 patients (40 in each group) was calculated using mean serum sodium values from previous studies at 95% confidence. Data were entered in Microsoft Excel and analyzed using SPSS software. Continuous variables were expressed as mean ± SD and compared using the Student’s t-test. Categorical variables were compared using the chi-square test. Diagnostic accuracy was assessed using ROC curve analysis. A p-value <0.05 was considered statistically significant.

Acute appendicitis remains one of the most common surgical emergencies worldwide, yet timely differentiation between uncomplicated and complicated forms continues to challenge clinicians despite advances in imaging and laboratory diagnostics. Early identification of complicated appendicitis is crucial because delayed intervention is associated with a substantially higher rate of perforation, morbidity, and mortality [1,2]. Traditional biomarkers such as leukocytosis and neutrophilia lack sufficient specificity, especially in borderline or atypical presentations [3]. Recently, attention has shifted toward inexpensive biochemical indicators, particularly serum sodium, which has emerged as a potential surrogate marker of inflammatory severity due to its relationship with cytokine-mediated antidiuretic hormone secretion [5–8]. In this context, the present study aimed to evaluate the diagnostic utility of serum sodium in predicting complicated appendicitis.

In this study, we evaluated the role of serum sodium as a predictive marker for complicated acute appendicitis and found a strong and statistically significant association between hyponatremia and disease severity. Patients with complicated appendicitis demonstrated markedly lower serum sodium levels compared to those with uncomplicated disease, and hyponatremia was present in 70% of complicated cases versus only 15% of uncomplicated cases. This observation reinforces the growing evidence that serum sodium may serve as a reliable biochemical indicator of underlying inflammatory severity in appendicitis.

The pathophysiological basis for hyponatremia in complicated appendicitis is well established. Severe intra-abdominal inflammation leads to elevated levels of pro-inflammatory cytokines such as IL-1β and IL-6, which stimulate non-osmotic release of antidiuretic hormone (ADH). This results in water retention and dilutional hyponatremia. Our findings are consistent with earlier studies by Kim et al. [9], Kaser et al. [10], and Giannis et al. [11], all of whom reported significantly lower sodium levels in patients with perforated or gangrenous appendicitis. The high odds ratio (OR 5.32) observed in our study further confirms that hyponatremia substantially increases the likelihood of complicated disease.

The diagnostic performance of serum sodium demonstrated by the ROC analysis in our study (AUC 0.84) indicates good discriminatory ability. A cut-off value of 134 mEq/L provided optimal sensitivity and specificity, comparable to previous investigations that have recommended thresholds between 133–135 mEq/L [9–11]. Importantly, serum sodium outperformed conventional markers such as total leukocyte count and neutrophil percentage, which although elevated in complicated cases, showed weaker predictive ability. This positions serum sodium as a valuable adjunct to standard diagnostic tools, particularly in settings where advanced imaging modalities may not be readily available.

The strength of our study lies in its comparative design and use of histopathology and operative findings to classify disease severity. However, certain limitations must be acknowledged. This was a single-center analysis with a modest sample size, which may limit the generalizability of the results. Serum sodium levels can be influenced by factors such as hydration status, medications, and comorbidities, although we minimized these confounders through strict exclusion criteria. Future multicentric prospective studies with larger cohorts would help validate the cut-off values and further refine the clinical utility of hyponatremia as a prognostic marker.

Despite these limitations, our study highlights that serum sodium is an inexpensive, widely available, and clinically useful biomarker that can aid in early identification of complicated appendicitis. Incorporating serum sodium into initial assessment protocols may facilitate faster triage, prompt surgical decision-making, and improved patient outcomes.

The present study demonstrates that serum sodium is a valuable and reliable biochemical marker for predicting complicated acute appendicitis. Patients with complicated disease showed significantly lower sodium levels, and hyponatremia was strongly associated with higher odds of perforation or gangrenous changes. Serum sodium also exhibited superior diagnostic accuracy compared to conventional inflammatory markers, highlighting its usefulness as an inexpensive, rapidly available, and widely accessible tool for early risk stratification. Incorporating serum sodium into initial clinical evaluation may assist clinicians in timely decision-making, prioritizing surgical intervention, and ultimately improving patient outcomes. Further multicentric prospective studies with larger sample sizes are recommended to validate these findings and establish standardized sodium cut-off values for clinical practice

1. O'Connell PR. The Vermiform Appendix. In: Williams NS, Bulstrode CJK, O’Connell PR, editors. Bailey & Love’s Short Practice of Surgery. 25th ed. London: Arnold; 2008. p.1204–8.
2. Von Titte SN, McCabe CJ, Ottinger LW. Delayed appendicectomy for appendicitis: causes and consequences. Am J Emerg Med. 1996;14:620.
3. Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med. 1986;15:557–64.
4. Drake FT, Flum DR. Improvement in the diagnosis of appendicitis. Adv Surg. 2013;47:299–328.
5. Swart RM, Hoorn EJ, Betjes MG, Zietse R. Hyponatremia and inflammation. Nephron Physiol. 2011;118:45–51.
6. Park SJ, Shin JI. Inflammation and hyponatremia. Korean J Pediatr. 2013;56:519–22.
7. Leung AA, McAlister FA, Rogers SO, et al. Preoperative hyponatremia and complications. Arch Intern Med. 2012;172:1474–81.
8. Takeyama H, Mizushima T, Iijima H, et al. Platelet activation and inflammatory markers. Dig Dis Sci. 2015;60:3418–22.
9. Kim DY, Nassiri N, de Virgilio C, et al. Hyponatremia and complicated appendicitis. JAMA Surg. 2015;150:911–2.
10. Kaser SA, Furler R, Evequoz DC, Maurer CA. Hyponatremia as a marker in diverticulitis and appendicitis. Gastroenterol Res Pract. 2013;2013:462891.
11. Giannis D, Matenoglou E, Moris D. Hyponatremia as a marker of complicated appendicitis. Surgeon. 2020;18:295–304.