Severity Grading, Management, Outcome and Epidemiological Profiling of Snakebite Victims in Tertiary Care Hospital in South India: 5 Years Retrospective Study Clinical profile and

Objective: We conducted this study to do epidemiological and clinical profiling of the patients with snake bite in a tertiary care referral centre, situated in suburban area of Dakshin Kannada district, Karnataka, south India. Materials and Method: This retrospective, record based study was done by analysing medical records of all the patients of snake bite admitted over 5years from June 2015 to July 2019. It included demographic details and clinical profiling. Based on presenting complaint, clinical sign/symptoms and laboratory reports snake envenomation patients were divided into neurotoxic and hemotoxic group. The severity grading, amount of ASV used and outcome assessed in both the groups. Results: Total 108 patient records were analysed, maximum of which were males (64.8%) in age group of 15-30 years (46.2%). In majority of the cases the species of snake was not identified (67.5%). Dry bites were reported in 40.7% cases, among envenomated cases, 68.7% presented with hemotoxic syndrome, 29.7% with neurotoxic syndrome and 0.9% had both the features. In all envenomated patients with increasing bite to needle time, the grade of severity, amount of used ASV, duration of hospital stay and complications were found to increase. Conclusion: Snake bite is a neglected life threatening condition, which is a preventable disease. Tourniquet is still very commonly used first aid technique, which can be deleterious. The lack of education and awareness about snake bite management was evident and active mass education is clearly needed.


Introduction
There are almost 216 species of snakes in India and out of these only 60 are considered as poisonous 1 . In India, there are mainly four species of snake majorly poisonous; cobras or Naja naja, krait or Bungarus caeruleus, Russell's viper or Daboia russelli, and saw-scaled viper or Echis carinatus 2 . All snake bite does not lead to envenomation, 70% of all snakes are non poisonous and poisonous snakes envenomate only in 50% 3 of cases. Snake envenomation is a medical emergency. In 2009 WHO enlisted snake bite as neglected tropical condition 4 . According to WHO report, maximum number of snake bite has been reported from South Asia, Southeast Asia, and sub-Saharan Africa 5, 6 . Every year highest number of mortality due to snake envenomation occurs in India, which ranges from 5,000 to 13,000 cases annually 5,6 . The exact mortality due to snake bite may be even higher in India as many deaths go unreported in rural areas.
Clinico -toxicologically, nature of snake envenomation is categorized into hemotoxic, neurotoxic, and myotoxic syndromes 7 . We undertook this research for clinico-epidemiological profiling, and to find the risk factors which affects the outcome of different snake envenomation.

Methodology
The present retrospective, record based study was done in Srinivas Institute of Medical Science & Research Centre (SIMS&RC), on all the patients of snake bite admitted over a period of 5 years, from July 2015 to June 2019. It is the only tertiary care health facility in 20 km area, serving population of Mangalore city, suburban outskirts of Mangalore city, rural population of Udupi district, adjoining districts of coastal Karnatka and northern districts of Kerala.
Recorded information was entered in a pre-coded proforma which included demographic and clinical data. The data related to part of the body which was bitten, any first aid/ traditional treatment received, time to reach hospital after snake bite and time in receiving ASV after bite (bite to needle time) were collected for the entire patient. If snake species was identified at time of bite, that was also noted.
It is the hospital policy to admit all snakebite patients to Intensive care unit (ICU) and get done complete blood count, coagulation profile, renal function test, serum electrolytes including sodium, potassium and chloride. Patients were followed for 24 hours for "dry bite" confirmation and discharged after a day. In ICU, the 20 WBCT (whole blood clotting test) was done to assess venom induced defibrinogenation 8 and used as a guide for further dosing of ASV in hemotoxic patients. Patients with signs of envenomation were administered ASV, which is known to cause allergic reaction, shock, anaphylaxis and serum sickness, these were also looked in the records.
Cobras and krait both belongs to elapid family and their envenomation leads to neurotoxic and cardiotoxic features 8 , local effects are supposed to be more common with cobra envenomation but by medical record evaluation it was difficult to differentiate both species. Russell's viper and saw-scaled viper venoms are vasculotoxic 8 and produce severe necrotising local effects. So for evaluation, all the patients of envenomation were majorly divided into two groups, neurotoxic group and hemotoxic group. According to the presenting complaints we tried to grade the severity of snake bite from grade 1 (mild) to grade 4 (very severe) in both hemotoxic and neurotoxic group, based on Kumar et al study 9 . The amount of ASV received according to the grade of severity also noted.

Results
A total of 108 patients of snake bite were admitted to the hospital during the study period. The maximum numbers of snake bite patients were reported in month of July-September and none in the months of January and February. Most of the patients were bitten during 6-11pm (77, 71.29%), at residence and roadside while walking (76, 70.37%) and in lower extremity (67, 62.03%). One patient had reached hospital after 3 days due to cellulitis at the site of bite; she had earlier received ASV in some other centre, as all the information was present in the medical record so she was not excluded from the study. In majority of the cases the cause of delay was because of not considering it dangerous. Maximum patients did not receive any first aid and 2 (1.8%) patients arrived with immobilisation. Dry bite was confirmed in 44 (40.74%) patients. Out of 64 cases of snake envenomation, 44(68.75%) were categorised as hemotoxic and 19(29.7%) were categorised as neurotoxic syndrome. One patient had presented within half an hour of Krait bite in hand which was sustained while cutting tree, two fang marks were present, profusely bleeding from the site of bite, tourniquet was tied, drooping of eyelid, difficulty in speaking, blurred vision and gait abnormality were present. On investigation, coagulopathy was present (INR 7.8). He left against medical advice in view of financial constrains.

Risk factor assessment
Delay in presentation to hospital lead in increase in grade of severity. Application of tourniquet lead to increased requirement of ASV.

Discussion
The study was conducted in SIMS&RC, which is situated in suburban area of Mangalore, Dakshin Kannada district, Karnataka, South India. The Dakshin Kannada district is sheltered by Western Ghats on the east, which is the only remaining rain forest in India and home to several species of reptiles 10 .
We explored medical records of 108 snakebite victims and found that mostly young males in age group of 15-30 years were victims bitten by the snake in the lower limb, which may be because ambulant population are at higher risk of snake bite. The maximum bites reported in months of July -September, which is the monsoon season and activity of snake increases during that season 11 , which was in close agreement to previous studies [11][12][13][14] . Most of the patients were bitten during the time of dusk and night at residence and roadside while walking, which was due to diminished vision and accidentally stepping on the snakes. Occupationally most of the victims were students and house wives, which were unlike other studies where agriculture was most common occupation 14,15 . It may be the result of occupational difference in the population. Agriculture is not a major occupation of people in Dakshin Kannada 16 .
Contrary to the major believe that all snake bite results in envenomation, we found that 40.7% patients were either bitten by non poisonous snakes or there was no envenomation (dry bite) in case of poisonous snake bites. The studies conducted in other states of India, like Kerala found 66% 17 dry bite cases and in Himachal Pradesh it was found to be 43% 12 .
In current study, maximum patients reported to hospital within 6 hours of bite and early arrival lead to lesser degree of severity. The amount of ASV used was found to be higher in severe grades and duration of stay was also longer due to development of complications. The direct correlation of early presentation and better outcome has earlier been demonstrated in other studies 11,18 . There was no mortality reported in our study which could be because of early presentation of the patient to the hospital.
In current study, 29.6% patients came with tourniquet, in other studies conducted in South India almost 30 19 -50 15 % patients came with tourniquet application. The tourniquet is known to be potentially dangerous in snake bite cases as it leads to gangrene, increased fibrinolysis, bleeding in the occluded limb, peripheral nerve palsies and intensification of local envenomation 8 . In current study it was found that the amount of ASV used in same grade of severity was more in the patients with tourniquet application in both hemotoxic and neurotoxic groups.
Maximum patients (73, 67.59%) did not receive any first aid. The knowledge to immobilise the bitten part of the body, as muscle contraction promotes venom absorption 8 , was majorly lacking. Only 2 patients arrived with splint. The need of mass education about first aid of snake bite was obvious.
Hemotoxic syndrome was more common among envenomated patients that neurotoxic syndrome, which could be the result of more prevalence of Viper snakes in the region. This finding was in close accordance to studies conducted in neighbouring regions 11,14,15 . The average ASV used was more in neurotoxic group, which may be because the elapid venom are small molecules, gets rapidly absorbed in the blood stream and needs higher dose of ASV for neutralisation 8,11 .
In hemotoxic group, coagulopathy was most common complication followed by cellulitis, ulceration in the limb, renal failure, sepsis, necrotising fasciitis and compartment syndrome. These results were almost similar to other studies conducted on viper snake bite patients 11,19,20 . In neurotoxic group; ptosis, external ophthalmoplegia, pain, swelling at the site of bite, abdominal pain, vomiting, discolouration, blisters, local rise of temperature, bulbar weakness and gait abnormality were presenting features, which were comparable to other studies done earlier 8,12 .
To summarise, India is capital of snake bites 21 so we need to focus on mass education about first aid and importance of early arrival in management of snake bite.
The amount of venom absorption can be decreased by immobilisation and early administration of ASV can cure the disease. The alternative treatment in any form can be deleterious and can make the prognosis poor.

Limitation:
It was a retrospective study so few data may be missing. Snake species identification was limited to very few cases so species specific severity grading could not be done. As neuroparalytic features were common to both Cobra and Krait, it was difficult to differentiate both the species based on medical record data evaluation, so both analysed together.
Financial support and sponsorship: Nil.

Conflict of Interest:
There are no conflicts of interest.
Ethical Approval: The study was approved by the ethics committee of Srinivas Institute of Medical Sciences & Research Centre, Mangalore.