Snake envenomation in children: Experience from a tertiary care hospital in Northern India

Abstract

Background

Snakebite in children is a medical emergency of significant public health concern. Owing to physiological differences, the potential of snake venom causing tissue damage and long-term sequelae is more pronounced in paediatric age group. We aimed to determine the clinical profile and outcome in children suffering with snake envenomation.

Methods

The retrospective observational study reviewed the clinical case records of children aged 0–18 years, admitted with features of snake envenomation from January 2021 to December 2022 Demographic profile, clinical features, treatment and outcome were analysed using descriptive statistics.

Results

Eleven children with snakebite were admitted during the study period. The mean age of study population was 11.63 (±3.9) years. Nine children (81.8%) were residing in rural area, majority (72.7%) of the children experienced the snakebite between May and August. Extremities were the most commonly affected site as seen in seven (63.6%) children. Pain and swelling at the bite site were the commonest symptoms seen in nine (81.8%) children, neurotoxic features were evident in seven (54.5%) cases, while four (36.3%) cases manifested vasculotoxic features. Invasive ventilatory support was required in four (36.3%) cases and all such children were extubated with successful outcome. Anti-snake venom (ASV) was administered in all 11 children and no adverse reactions were observed. No mortality was reported during the study.

Conclusion

Envenomation toxidrome depends on the prevalent snake species inhabiting the various geographic regions within the same country.

Introduction

The World Health Organization (WHO) estimates that about 5 million snakebites occur each year, resulting in up to 2.7 million envenoming, 400,000 amputations and between 81,000 and 138,000 deaths each year.¹ Realizing the global burden, WHO declared snakebite as a neglected tropical disease in 2017 and called for concerted global action aiming to mitigate the disabilities and deaths by 2030. In India, around 90% of snakebites are caused by the ‘big four’ among the crawlers - common krait, Indian cobra, Russell's viper and saw scaled viper.² A nationally representative mortality study, on trends in snakebite-related mortality, has documented about 1.2 million snakebite deaths from 2000 to 2019.³ Anti-snake venoms (ASV) are effective treatments to prevent or reverse most of the harmful effects of snakebite envenoming and therefore included in the WHO Essential Medicines List. India is a country of rich geographical and cultural diversity, thus explaining variability in types of snake envenomation, i.e. vasculotoxic/myotoxic/neurotoxic in different geographical areas within the same country. There is a dearth of literature on paediatric snake envenomation from northern states of the country, especially where this study was undertaken. It is an industrial hub where regional deforestation and urbanization leading to altered habitats and ecosystem as a whole, has resulted in clustering of snakebite cases.⁴ Some of the common species that are seen include cobra, python, sand boa and red snake.⁵ There is a need to understand the predominant type of paediatric snake envenomation in this affected part of the country, thus guiding effective implementation of specific treatment strategies and improving the overall outcome. Hence the present study was conducted with an objective of assessing the clinico–epidemiological profile and in-hospital outcome of paediatric snakebite victims, admitted to a tertiary care hospital of northern India.

Materials and methods

The present hospital-based, retrospective observational study was conducted at the Department of Paediatrics, of a tertiary care teaching hospital located in western Uttar Pradesh. This study was approved by the Institutional Ethical Committee and informed consent was obtained from parents/guardians of children, who participated in the study. As it was a retrospective study, formal sample size was not calculated. All good clinical practice guidelines as per declaration of Helsinki were followed during the study.

After obtaining written informed consent from the caregivers, the clinical case records of children aged 0–18 years admitted to our hospital with history of snakebite and features of snake envenomation as defined by National guidelines⁶ from January 2021 to December 2022 were included. Patients with incomplete or unavailable data, features of dry bite, i.e. no manifestations of snake envenomation after 24 h of incurring snakebite were excluded. Syndromic approach was used to identify and manage such children, which included following features⁶:

• 1.Progressive painful swelling: local necrosis, blistering, ecchymosis, painful swelling, Compartment syndrome.
• 2.Neuroparalytic: Descending neuromuscular paralysis, bulbar palsy, ptosis, ophthalmoplegia, diplopia, respiratory arrest.
• 3.Vasculotoxic: Bleeding, coagulopathy, capillary leakage leading to hypovolemic shock, acute kidney injury
• 4.Myotoxic: Muscle ache, muscle swelling, involuntary contractions of muscles

The clinical case records of the children finally included in the study, were retrieved from hospital's medical record department. The relevant demographic, details about fang marks, bite site, clinical features, haematological, biochemical, clotting parameters, complications, time to arrive at hospital, therapeutic management, need for ASV including its dosage, adverse effects, need for invasive ventilation, duration of hospital stay and in-hospital outcome were recorded using a predesigned proforma. Data was entered into Microsoft Excel and analysed. Descriptive statistics were used in the study. Frequency distributions of categorical data were reported as proportion and as mean (SD) for continuous variables. Diagnosis and management of paediatric snake envenomation was done in Paediatric Intensive Care Unit (PICU) as per the standard treatment protocol.^6,7 Lyophilized polyvalent ASV (available in freeze dried form) was used on the affected children, its dosage and administration were strictly as per the protocol, for neuroparalytic clinical features – ASV 10 vials stat as intravenous (IV) infusion over 30 min followed by 2nd dose of 10 vials after 1 h if no improvement within 1st hour. In addition to this, inj. atropine 0.05 mg/kg followed by inj. neostigmine 0.04 mg/kg IV was administered in neurotoxic bites to reverse ptosis, neostigmine dose (0.01 mg/kg) with atropine was repeated every 30 min for 5 doses followed by tapering of dose at 1 h, 2 h, 6 h and 12 h. If no response after 3rd dose, atropine was stopped. Progressive neuroparalytic features in older children and adolescents were monitored using arterial blood gas analysis, single breath count defined as number of digits counted in one exhalation, breath holding time, and ability to complete one sentence in one breath, while in younger children, intensity of cry whether loud or husky helped in identifying impending respiratory failure.⁶

Progression for vasculotoxicity were assessed using 20 Minute Whole Blood Clotting Test (20WBCT), bleeding time (BT), clotting time (CT), prothrombin time (PT), activated partial thromboplastin time (APTT), complete blood count (CBC) urine for haemoglobin/myoglobin, kidney function tests, serum electrolytes. For vasculotoxic snakebite- 10 vials of polyvalent ASV stat over 30 min as IV infusion, followed by 6 vials 6 hourly as bolus therapy till clotting time normalized and/or local swelling subsided. Liquid or reconstituted ASV is diluted in 5–10 ml/kg body weight of normal saline. All patients were strictly monitored every 5 min for first 30 min, then at 15 min for 2 h for manifestation of a reaction. An intake-output chart was maintained and colour of urine was observed for early detection of acute kidney injury. All the admitted patients were minutely followed till their discharge/death from the hospital.

Results

During the study period, total 102 cases of snake envenomation were admitted. After excluding 86 adult cases who were aged above 18 years, 16 children of snake envenomation aged 0–18 years were finally enrolled into our study. Two children had features suggestive of dry bite, clinical case records were found incomplete in three cases, thus 11 children were finally included in the analysis. Epidemiological profile and clinical description of these cases are depicted in Table 1 and Table 2 respectively.

Table 1.

Epidemiological and demographic profile of all study cases.

Characteristics	N = no. of patients	Frequency (%)
Age distribution
<10 yrs	04	36.4%
10 yrs & above	07	63.6%
Sex distribution
Male	09	81.8%
Place of residence
Urban/rural	02/09
Season & month
Monsoon (May–August)	08	72.7%
Post monsoon (Sept–Dec)	03	27.3%
Timing of bite
Early morning (3am–6am)	07	63.6%
Daytime (11am to 3pm)	02	18.2%
Night (7pm–10pm)	02	18.2%
Distribution of bite site
Upper limb	05	45.4%
Lower limb	02	18.2%
Presence of Fang marks	07	63.6%
Snake species
Known	01	9.1%
Unknown	10	90.9%
Time taken to arrive at hospital (hrs)
Within 4 h	09	81.8%
5–10	01	9.1%
>10	01	9.1%
Pre-referral treatment
Tourniquet placement	01	9.1%
Immobilisation	02	18.2%
Incision over bite site	02	18.2%

Table 2.

Clinical features, treatment & outcome of children with snake envenomation during the study period.

Case No.	Age/sex	Clinical features	Time to arrive at hospital (in hours)	Treatment and duration of invasive ventilation (wherever applicable)	Outcome	Duration of hospital stay (days)
1	5 yrs/M	Pain and progressive swelling over the bitten limb	2 h	ASV 10 vials and supportive treatment	Discharge	2
2	10 yrs/M	Pain and swelling over the bitten site, ptosis, speech and swallowing difficulties, altered sensorium, respiratory failure, shock	9 h	ASV 30 vials, ventilatory support (5 days), inotropes	Left against medical advice	8
3	9 yrs/M	Local pain and swelling, local bleeding, syncope, ptosis, altered sensorium	2 h	ASV 15 vials and supportive treatment	Discharge	4
4	11 yrs/F	Local pain and swelling, syncope, ptosis, altered sensorium, respiratory failure, shock	3 h	ASV 20 vials, ventilatory support (3 days), inotropes, blood transfusion	Discharge	6
5	17 yrs/M	Local Pain and swelling, ptosis, syncope	0.5 h	ASV 10 vials and supportive treatment	Discharge	2
6	17 yrs/M	Abdominal pain and vomiting	1.5 h	ASV not given, only supportive treatment	Discharge	2
7	9 yrs/M	Local pain and swelling, cellulitis, ptosis, respiratory failure, shock	14 h	ASV 35 vials, ventilatory support (1 day), inotropes, blood transfusion	Discharge	10
8	14 yrs/M	pain and rapidly progressive swelling of bitten limb	1.5 h	ASV 10 vials and supportive treatment	Discharge	3
9	12yrs//M	Pain, swelling, local bleeding, abdominal pain, syncope, ptosis, ophthalmoplegia, speech and swallowing difficulties, altered sensorium, respiratory failure, shock	8 h	ASV 15 vials, ventilatory support (3 days)	Discharge	7
10	16 yrs/M	Ptosis, syncope	2 h	ASV 10 vials and supportive treatment	Discharge	4
11	8 yrs/F	Local pain and swelling	2 h	ASV not given, only supportive treatment	Absconded	1

There were nine male and two female children with a male to female ratio of 4.5:1 and nine (81.8%) children were residents of rural areas. Seven children (63.6%) were aged between 10 and 18 years, and mean age of the study population was 11.63 (±3.9) years.

As shown in Table 1, eight (72.7%) children incurred snakebite during the monsoon season that spans from May to August. Seven (63.6%) children got accidently bitten by snakes in their sleep in the early morning hours, whereas equal number of cases got envenomed both during day and night. Extremities were the commonest site for snakebite, as evident in seven (63.6%) children. Of the total 11 children, in only one case the snake species was identified by the parents as being a cobra.

As illustrated in Table 2, local features of snake envenomation including pain and swelling were observed in nine cases. Seven (63.6%) children progressed to develop neurotoxic features comprising of ptosis, ophthalmoplegia, and bulbar palsy. Of these seven cases, respiratory failure was eminent in four children requiring invasive ventilatory support. Hypovolemia and shock-necessitating ionotropic support were seen in four cases who presented with features of neuroparalytic envenomation.

All admitted patients were managed as per the National Guidelines and were subsequently followed till their discharge from the hospital. Of the eleven patients, nine were discharged to home, one patient after receiving treatment for eight days and clinical stabilization, left against medical advice while the other who suffered from local features of pain and swelling at the bite site, absconded after 24 h of admission. In our study, zero in-hospital mortality was reported amongst all the 11 admitted children.

Discussion

The amount of venom injected is equal in both the adult as well as paediatric population, Weber et al. in their study have suggested that children would sustain more severe toxicity because of an increased venom-body mass ratio. Conversely, the larger adult body mass may provide a diluent for the snake toxin, theoretically causing a less potent envenomation.⁸

In the present study, the mean age of children getting affected by snake envenomation was 11.63 ± 3.9 years with male predominance (81.8%). Similar reports of male preponderance were observed in studies from eastern and southern India.9, 10, 11 Contrary to this, female preponderance was reported from a Nigerian study, but the reason was not well defined.¹²

Adverse living conditions, poor lighting, sleeping on floor, heavy rodent infestation aggravates the situation of snake bites, thus affecting rural India to a greater extent as reflected by high rural to urban ratio (4.9:1) in our study. Seven children were accidentally bitten by snakes during early morning hours while they slept on the floor. This phenomenon was also reported by another Indian study where 51 children developed rapidly progressive neuroparalysis after incurring snakebite during midnight/early morning hours.¹³

In India, the monsoon season is associated with an increase in snake numbers, flooding of their habitats and migration to human dwellings, putting people at higher risk of bites. Thus, more vigilance and preventive measures are advised to be followed particularly during monsoon in our country. Eight cases (72.7%) were reported during May to August in this study, coinciding with rainy season and rigorous farming activity in the country. Similar pattern of seasonal distribution was seen in earlier studies.9, 10, 11^,14

In the present study, eight cases arrived at the hospital within 4 h of getting bitten, while three cases reached late as they followed traditional cultural practices leading to undue complications, increased ASV requirement and prolonged hospital stay. In rural India, traditional healers are looked upon with great faith and hope, leading to false practices like incision at bitten site, use of tourniquet etc. These factors cause delay in seeking specific treatment and ASV administration, thus resulting in unfavourable outcome. Similar observations were reported by another Indian study on 30 children with snakebite, where they compared ASV requirement, complications, duration of hospital stay and outcome between two groups (early vs late arrival).⁹

Usually human beings get accidently bitten while walking barefoot or sleeping on floor as a defensive response by a frightened snake. Most of the bites were incurred during early morning, where the patients were unaware due to being asleep. Extremities are relatively more exposed than the rest of the body, thus explaining the involvement of upper and lower limbs (63.6%) in our study.

In the present study, nine children presented with local features of envenomation (Figure) and none of them required surgical intervention. In contrast to this, the overall rate of limb amputation and fasciotomy without antivenom therapy was 11.4% and 44% respectively as reported by other authors.¹⁵ This difference is attributable to prompt access and timed administration of ASV in our study patients.

Fig 1.

Swelling and blister formation at the snakebite site.

Neurotoxic features were observed in six children (54.5%) which included ptosis, ophthalmoplegia, descending neuromuscular paralysis leading to bulbar paralysis and respiratory arrest, necessitating invasive ventilatory support in four cases with duration ranging from 1 to 5 days. Vasculotoxic features like capillary leakage, hypovolaemia and shock requiring inotropes were seen in four children (36.4%) during the study. The neurotoxicity was more commonly observed during our analysis, contrary to findings reported in Odisha,⁹ Himachal Pradesh,¹⁶ and Puducherry¹⁷ where vasculotoxic bites were more prevalent. It may indicate the prevalence of neurotoxic snakes inhabiting this part of the country. Another comparative study on community-based survey and hospital clinical data on snakebite from northern Bihar confirmed that cobras and kraits continue to be responsible for most venomous bites.¹⁸ Studies have shown a geographical variation in our country with regard to snake envenomation, with neuroparalytic bites predominating in the northern part of the country and vasculotoxic in the Southern part.¹⁹

Antivenom administration was shown to be statistically significant for rapid improvement in haemostatic disorders, reduced blood transfusions and fasciotomy for compartment syndrome as well as a shortened length of stay in PICU by a few authors.¹⁵ The ASV dose used in our study ranged from 10 vials to 35 vials, progressive neuro-paralytic features and ongoing bleeding diathesis required higher ASV dose in few cases. Higher ASV requirements resulting due to delayed referral and more complicated clinical course were also seen in Odisha, where 30 children of snakebite were reviewed.⁹

Evidence to suggest appropriate dose regimen in children is still lacking and may form an essential aspect for future recommendations. No adverse effect was noted after ASV administration in our study contrary to development of serious adverse reactions in 42.6% and 18.5% cases as observed by Hooda et al and Suganthi et al respectively.^17,20 The reasons for such hypersensitivity reactions to ASV were not clearly mentioned in these studies, thus suggesting the need for further research on this aspect.

With well-equipped intensive care, provision and free availability of ASV round the clock, all 11 children received protocolized treatment, were recovered and discharged with few exceptions. One patient after feeling stable and improved health condition left against medical advice (LAMA), while another with mild local symptoms absconded after 24 h of observation. Surgical intervention was not required in our cases as prompt ASV administration facilitated rapid recovery from pain and progressive limb swelling. Duration of hospital stay ranged from 2 to 10 days. No fatality occurred among the enrolled children as also supported by the telephonic follow-up done for the remaining two children (one LAMA and the other absconded case), which ascertained their well-being and favourable outcome. A retrospective analysis of 308 children with snakebite in Puducherry reported 11.7% mortality. Age below 5 years, activity at/after the bite, neurotoxic envenomation and need for additional ASV dose were found to be independent predictors of poor outcome.²¹ A similar correlation was observed by another Indian study analysing 111 children, who presented with Early Morning Neuroparalytic Syndrome after snakebite.¹³ Contrary to this, lower mortality rate was reported by an eastern India study conducted on 30 children with snakebite.⁹ The lesser mortality in this study is explained by smaller sample size and ASV availability in few children prior hospitalization to this centre.

Our study faced several limitations, firstly the retrospective nature of the study. Secondly, owing to a small sample size over a shorter time frame, results could not be generalized for paediatric population as a whole. Follow-up of the affected cases was not performed and thus long-term outcome could not be commented upon. As it was a hospital-based study, asymptomatic children having suffered from snakebite but not requiring hospitalization could not be analysed leading to under-estimation of this menace. Therefore, large-scale, prospective, multi-centric studies involving the long-term outcome in such children, and community-based surveys may provide more information.

Conclusion

On the basis of our study findings, we speculate neurotoxic snakebites to be the predominant type among children residing in this geographical location of the country. Prompt availability of ASV and its timed administration in envenomed children has resulted in favourable in-hospital outcome in our study. Antivenom dosing, novel anti-venom therapies, long-term outcome and impact on neurodevelopment, serve as potential areas for ongoing and future research.

Patients/ Guardians/ Participants consent

Parents/ guardians informed consent was obtained.

Ethical clearance

Institute/hospital ethical clearance certificate was obtained.

Source of support

None.

Disclosure of competing interest

The authors have none to declare