Epidemiology, Clinical Profile and Severity of Snakebite Cases in a Tertiary Care Centre in Kochi.

Envenomation due to snakebite is a major global health problem, particularly in tropical and subtropical regions. Snakebite-related mortality and morbidity constitute an important public health concern in rural areas of Africa, Asia, Latin America, and New Guinea, where exposure to snakes is common and access to timely medical care may be limited.[1,2]

Snake envenomation predominantly affects rural agrarian populations in developing tropical and subtropical countries. Males are more frequently affected, accounting for approximately 59% of victims, with economically productive individuals between 15 and 50 years of age being particularly vulnerable.[2] The World Health Organization (WHO) recognizes snakebite as an occupational hazard, especially in South-East Asian countries. Individuals engaged in occupations such as rice farming, plantation work involving rubber and coffee, herding, hunting, fishing and fish farming are at increased risk. Other high-risk activities include catching and handling snakes for food, snake charming and display, leather manufacturing, particularly from sea snakes, and the preparation of traditional medicines.[3-6]

The burden of snakebite is further aggravated by delays in receiving appropriate medical treatment. In many developing countries, nearly 80% of snakebite victims initially seek treatment from traditional practitioners before approaching modern healthcare facilities, resulting in significant delays in the administration of appropriate therapy.[7] Recognizing its substantial impact on vulnerable populations, snakebite was included in the WHO list of neglected tropical diseases in 2009.[8,9]

In Kerala, farmers engaged in rubber, paddy, and coffee cultivation, particularly those working in hilly terrains, constitute a vulnerable group. The prevailing agrarian crisis further increases their socioeconomic vulnerability.[9] Consequently, morbidity and mortality resulting from snakebite can have serious economic and social consequences, affecting not only the individual but also the livelihood and well-being of their families. Therefore, understanding the epidemiological and clinical profile of snakebite envenomation is essential for developing effective preventive strategies and improving timely medical management.

AIMS AND OBJECTIVES

The present study aims to study the epidemiology and clinical profile of snakebite cases presenting to a tertiary care centre, Medical Trust Hospital, Kochi, during the period from September 2017 to September 2018. The study also aims to assess the outcome and severity of snakebite envenomation by evaluating the coagulation profile, clinical and laboratory features of renal failure, and mortality among affected individuals.

Study Design

The present study was designed as an observational study conducted at Medical Trust Hospital, Kochi. The study was carried out over a period of one year, from September 2017 to September 2018. The study population comprised all patients admitted to the hospital with a history of snakebite during the study period, irrespective of age or sex. The epidemiological and clinical characteristics of the patients were assessed, along with relevant clinical and laboratory parameters, to evaluate the severity and outcome of snakebite envenomation.

Inclusion and Exclusion Criteria

Patients of any age or sex who were admitted to Medical Trust Hospital, Kochi, during the study period with a proven history of snakebite were included in the study. A proven history of snakebite was defined as cases in which the snake was seen and identified by the patient or accompanying persons, or the snake was brought to the hospital for identification. Cases with an unknown bite, suspected or suspicious bites, insect bites, or those with a previous history of renal failure or coagulopathy were excluded from the study.

Sample Size Calculation

Based on the previous study (A study of clinical profile of snake bite at a tertiary care center by Gaurav Bhalla) it is observed that the mortality rate due to snake bite is 5.79, precision is 5% and with 95% Confidence Interval the minimum required sample size is 84.

We used here the software n master 2.0 the following formula has been used for sample size calculation.

Formula:

N=z_ ((1-∝/2)) ^2 p (1-p)/d^2

Where,

P: Expected proportion=0.579

D: Absolute precision =5

A/2: Desired Confidence level=95%

N=84

Calculation

Sample size n= [1.962 *0.0579(1-0.0579)]/ {.5}2=84

Data Collection Procedure

Data collection was carried out using a structured data collection proforma for all eligible patients admitted with snakebite. Relevant clinical details were recorded, including age, sex, time elapsed since envenomation, site of bite, history of first aid received, local manifestations such as swelling, cellulitis, haemorrhagic bullae and gangrene, lymphadenopathy, and systemic bleeding manifestations including petechiae, ecchymosis, epistaxis, haemoptysis, melena and evidence of intracranial haemorrhage. Urine output and the presence of haematuria were also documented. Laboratory investigations included complete blood count haemoglobin, RBC count, packed cell volume, MCV, MCH, MCHC, total leukocyte count, three-part differential count, platelet count and mean platelet volume. Urine examination was performed for albumin and microscopic abnormalities, along with measurement of blood urea and serum creatinine. Bleeding time and clotting time were assessed, with the 20-minute whole blood clotting test performed according to WHO guidelines. For this test, 2 mL of freshly collected venous blood was placed in a clean, dry glass vessel and left undisturbed at ambient temperature for 20 minutes, after which the vessel was gently tilted once; failure of the blood to clot and its flowing out of the vessel was considered indicative of prolonged coagulation time. Prothrombin time and activated partial thromboplastin time were also recorded.

Statistical Analysis

The collected data were entered into a Microsoft Excel datasheet and analyzed using IBM SPSS Statistics version 22 (IBM SPSS Statistics, Somers, NY, USA). Categorical variables were expressed as frequencies and proportions, while continuous variables were summarized as mean and standard deviation. The Chi-square test was used to assess the association between categorical variables, and the paired t-test was used to compare quantitative variables measured before and after treatment. Data were graphically represented using Microsoft Excel and Microsoft Word in the form of bar diagrams, pie charts and scatter plots, as appropriate. A p-value of <0.05 was considered statistically significant.

Table 1. Demographic characteristics of the study population

Table 1 illustrates the demographic profile of the 90 study participants. The mean age of the study population was 40.51 ± 14.264 years, with the largest proportions belonging to the 26–35 years and 46–55 years age groups (25.6% each). Males constituted 67.8% of the study population, while females constituted 32.2%. There was no statistically significant association between age and sex.

Table 2. Clinical characteristics of snakebite cases

Table 2 summarizes the major clinical characteristics of the snakebite cases. Viper bites were predominant (76.7%), followed by cobra (21.1%) and krait (2.2%). Lower-limb bites accounted for 86.7% of cases. First aid was received by 70.0% of patients. Local reactions were observed in 96.7%, with edema and tenderness being the predominant manifestation (94.4%). Bite marks were present in 97.8% and lymphadenopathy in 66.7%. The median time since envenomation was 180 minutes, with 41.1% presenting within 100 minutes. No significant association was observed between sex and site of bite or between time since envenomation and receipt of first aid.

Table 3: Bleeding manifestations, anti-snake venom response, renal failure and outcome

Table 3 observes the distribution of important systemic manifestations and outcomes. Most patients had no bleeding manifestations (74.4%), while bleeding from the bite site was seen in 21.1%. Anti-snake venom was not given to 63.3% of patients, while 24.4% received and responded to it. Renal failure was present in 35.6% of cases. Overall, 96.7% survived and mortality was 3.3%.

Table 4: Association of clinical factors with outcome

Table 4 illustrates the association of major clinical variables with patient outcome. There was no statistically significant association between outcome and snake identification, time since envenomation, anti-snake venom response, first aid or urine routine examination. However, bleeding manifestations showed a statistically significant association with outcome (χ² = 9.094, p = 0.028), with multiple-site bleeding being observed in 33.3% of patients who died.

Table 5: Association of bleeding manifestations and urine findings with snake type and envenomation time

Table 5 summarizes the relationships between bleeding manifestations, urine abnormalities, snake type and time since envenomation. Abnormal urine findings were more frequent among patients with bleeding from the bite site (63.2%) and among those with intracranial haemorrhage or multiple-site bleeding (100% each), although the association was not statistically significant. There was also no significant association between bleeding manifestations and snake type or between bleeding manifestations and time since envenomation.

Table 6: Association of renal failure with clinical and laboratory parameters

Table 6 demonstrates the association between renal failure and selected clinical parameters. Among patients with renal failure, 65.6% had viper bites and 34.4% had bleeding from the bite site. No statistically significant association was found between renal failure and snake type, urine routine examination, outcome, time since envenomation or bleeding manifestations. However, response to anti-snake venom showed a statistically significant association with renal failure (p = 0.024).

Table 7: Comparison of blood urea and serum creatinine between day 1 and day 3

Table 7 compares renal biochemical parameters between day 1 and day 3. The mean blood urea increased from 29.79 ± 16.90 mg/dL on day 1 to 61.81 ± 45.68 mg/dL on day 3, with a statistically significant difference (p = 0.006). Similarly, mean serum creatinine increased from 1.17 ± 0.62 mg/dL to 2.42 ± 1.73 mg/dL, which was also statistically significant (p = 0.001).

Snakebite is a common and potentially life-threatening emergency in the study area, with Russell’s viper being the predominant vasculotoxic snake and cobra the common neuroparalytic snake. Delayed hospitalization was associated with increased morbidity and mortality. Early administration of ASV was associated with better outcomes, while the 20-minute whole blood clotting test served as a simple and reliable tool for detecting coagulopathy. Early recognition of respiratory insufficiency, renal dysfunction and timely interventions such as ventilatory support and haemodialysis are essential to reduce complications and mortality. Adequate availability of ASV, close monitoring and prompt management of complications, along with public education regarding prevention, first aid and early hospital referral, are crucial for improving outcomes in snakebite envenomation.

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