Snakebite envenomation is a significant but neglected tropical disease. The World Health Organization estimates nearly 5.4 million global snakebites annually, resulting in 2.7 million envenomations and more than 100,000 deaths with India being disproportionately affected [1] [2]. Snakebite morbidity and mortality not only arise from systemic envenomation but also from complications such as acute kidney injury (AKI). AKI is a leading complication, especially following viper evenomation, with multifactorial pathophysiology including direct nephrotoxicity, hemolysis, rhabdomyolysis, disseminated intravascular coagulation (DIC), and hypovolemic shock [3,4]. In resource-limited settings, the availability of renal replacement therapy remains the most important determinant of survival. Prior studies estimates an AKI incidence of 14% to 45% among snakebite victims in India [5–9] with mortality data declining due to improved health care access but continuous to high in delayed presenters [10]. Yet regional data from northern india is scarce, prompting this prospective study to classify, incidence, predictors and outcomes of AKI in patients presenting to a tertiary care hospital in northern India. Furthermore, dialysis dependence following envenomation remains underexplored in Indian cohorts. The study sought to contribute to evidence for early recognition, targeted management, and prevention of renal complications in envenomed patients.

Study Design and Setting This study was conducted prospectively at the Department of Medicine, Sardar Patel Medical College, Bikaner, Rajasthan, India, across 18 months, with institutional ethical clearance. Written informed consent was taken from all participants or their guardians. Inclusion and Exclusion Criteria Adults ≥18 years presenting with confirmed snakebite and clinical evidence of envenomation were included. Exclusions were: pre-existing CKD, diabetic nephropathy, obstructive uropathy, or prior renal replacement therapy. Data Collection Demographic details and medical details were recorded including bite-to-hospital time, site of bite, local symptoms (pain, swelling, necrosis), and systemic manifestations (vomiting, bleeding, hematuria, oliguria, neurological deficits). Laboratory investigations included complete blood count, renal function tests, coagulation profile, liver function tests, and urine microscopy. All patients were treated with polyvalent anti-snake venom (ASV) as per national guidelines. Dialysis was initiated when indicated. Definition of AKI AKI was defined according to KDIGO guidelines: rise in serum creatinine ≥0.3 mg/dL within 48 hours, or ≥1.5 times baseline within 7 days, or urine output <0.5 mL/kg/h for 6 hours. Outcomes Primary outcomes were incidence of AKI, dialysis requirement, and in-hospital mortality. Secondary outcomes included dialysis dependence at discharge and correlations between clinical/laboratory variables and AKI development. Statistical Analysis Data were analyzed using SPSS v25. Continuous variables were expressed as mean ± SD, categorical variables as percentages. Associations between variables and AKI were analyzed using chi-square test or Fisher’s exact test. A p-value <0.05 was considered significant.

Baseline Characteristics A total of 117 patients with snakebite envenomation were studied. Males constituted 56.4% (n=66) and females 43.6% (n=51) with mean age of 36.4 ± 12.9 years. Most were rural residents (83.8%), and farmers (44.4%) (Table 1). Table 1 – Baseline characteristics of study participants (n=117) Variable Value Mean age (years) 36.4 ± 12.9 Male: Female ratio 1.29:1 Rural residence 83.8% Occupation – Farmer 44.4% Bite Characteristics Lower limb bites were predominant (76%), with right-sided bites significantly associated with higher risk of AKI (p=0.0001). Upper limb bites accounted for 24%. Most patients presented within 2–4 hours of bite, though 25% presented after >6 hours. Clinical Features Swelling (64.1%) and cellulitis (44.4%) were the common local manifestations. Systemic features included vomiting (38%), bleeding (21%), and neurological symptoms (6%). Incidence and predictors of AKI AKI was observed in 17.1% (n=20) significantly associated with delayed hospital presentation (75%) i.e. after more than two hours of bite with p=0.001. AKI was also significantly associated with hematuria, oliguria and thrombocytopenia. Cellulitis, though common, did not show any significant correlation with AKI. Table 2 – Clinical and laboratory predictors of AKI Predictor AKI (%) Non-AKI (%) p-value Hematuria 50 2 0.04 Oliguria 60 12 0.003 Thrombocytopenia 55 22 <0.0001 Cellulitis 38 46 NS Of the 20 AKI patients, 75% (15) of AKI patient required dialysis. 50% remained dialysis dependent at discharge. In-hospital mortality occurred in 10% of AKI cases (n= 2) both females and no deaths were observed in non-AKI patients. The mean duration of hospitalization was 8.6 ± 4.2 days; longer for AKI patients (11.2 days vs. 7.1 days, p=0.002).

AKI incidence in snakebite cases in this study (17.09%) was lower as compared to previous Indian studies (20-45%) albeit with higher rates of dialysis requirements and dependence, possibly due to late hospital refferal and severe renal involvement [5–9]. The adult male victims predominated, reflecting occupational risks, consistent with Patil et al. [5] and Mukhopadhyay et al. [8]. The rural predominance also matched reports by Singh et al. [7] and Dharod et al. [6]. Hematuria, oliguria, and thrombocytopenia emerged as significant predictors of AKI in this study, corroborating findings of Vikrant et al. [9] and Priyamavada et al. [11]. Bite-to-needle time was strongly correlated with AKI, echoing the observations of Dharod et al. [6] and Venkatappa et al. [12]. Mortality was lower as compared to priors reports by Priyamavada et al. (21.5%) [11] and Venkatappa et al. (38%) [12], likely due to timely dialysis initiation. Long-term sequelae were concerning, with 50% dialysis dependence, in agreement with Waikhom et al. [13] and Ariga et al. [14], who documented CKD progression after snakebite AKI. Strengths of this study included prospective design and comprehensive evaluation of clinical and laboratory predictors. Limitations included a relatively small AKI subgroup and lack of long-term follow-up.

Acute kidney injury remains a critical complication of snakebite envenomation in rural India. Prompt hospital transfer and timely administration of anti-snake venom are essential to minimize morbidity. Regional differences in AKI highlight the importance of local protocols and the need for further multicenter research.

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