Snake bites with Neuropsychiatric Presentation ─ A Study in Hill Tracts of Bangladesh

Background: Snake bite is a common medical emergency and one of the important causes of mortality and morbidity in hill tracts of Bangladesh. Neurological and psychiatric features predominate as both early and late features of snake bite patients and need to be identified correctly for proper management. Objective: The aim of this study was to find out the pattern of early and late neuropsychiatric manifestations of snake bite in hill tracts with clinical outcomes. Materials and Methods: This descriptive hospital-based study was done on 121 snake bite patients during the period from January 2015 to July 2016 using simple, direct, standardized questionnaire with history, neurological examination and psychiatric evaluation. Results: Majority of cases (71.9%) were admitted into hospital after two hours of snake bite. Lower limb was the commonest site (75.2%) of bite. Generalized weakness (50.4%) and anxiety (52.9%) were the commonest early neurological and psychiatric manifestations. Numbness (57%) and depression (33.9%) were the commonest late neurological and psychiatric manifestations among survivors; 37.2% needed referral to tertiary care hospital and 34.7% received antivenom. Death rate was 17.4% and 73.6% were cured completely without complication. Conclusion: As neurological and psychiatric manifestations are common in both early and late stages in snake bite in hill tracts, these are to be considered in the total management to decrease mortality and morbidity.


Introduction
Snake bite results in a punctured wound inflicted by the animal fangs and sometimes resulting in envenomation.Snake species mostly are not venomous and they typically kill their prey by constriction rather than venom.In every continent except Antarctica, venomous snake can be found.Between 1.2 to 5.5 million snake bite occurs worldwide each year, with 421,000-1,841,000 envenomation and 20,000-94,000 deaths. 1,2Such wide-ranging estimates reflect the challenges of collecting accurate data in the regions most affected by venomous snakes; many victims do not seek hospital treatment, and reporting and record keeping are generally poor.There are more than 3500 species of snakes, but only 250 are venomous. 3,4n South Asia due to low death rate with high nonvenomous snakes, less than 25% cases reported to hospital for management. 5 Bangladesh about 200 species are found of which 52 are poisonous and 1500 to 3000 people die every year out of about 30 thousand snake bite cases. 6Only five snake species of them are dangerously poisonous to humans.These are King Cobra, Common Cobra, Common Krait, Russell's Viper and Saw Scaled Viper.The most common poisonous snake is Common Krait.The King Cobra lives in the dense rain forest of the hills. 7,8s there are no proper guidelines about management of snake bite in hill tracts, haphazard and ineffective treatment is being given to the tribal victims, thus adding to mortality and morbidity among hill tract people.This aspect is important because management of snake bite starts from proper identification of type of snake, effective first aid given at the site of bite, proper reassurance of the victim and speedy transport to the hospital for timely administration of proper dosage of anti-venom serum along with other supportive measures.This can invariably reduce the mortality and morbidity of these cases to a great extent.
Due to lack of transport facility and trained health care workers to identify early and late neurological and psychiatric presentations in hill tracts, it is common to delay for hospital admission.A large number of deaths in hilly areas can be prevented with prompt treatment, timely administration of anti-venom and other supportive measures.
In our country few studies are available regarding snake bites.So the present study was carried out in hill tracts to determine the neurological and psychiatric manifestations with outcome in both poisonous and nonpoisonous snake bites.This will help to manage the snake bite cases as early as possible to decrease the mortality and morbidity.

Materials and Methods
This descriptive observational hospital-based study was done in Rangamati Sadar Hospital, Rangamati, Bangladesh during the period January 2015 to July 2016.The study population included all those tribal patients who were admitted as snake bite cases during this period.Both poisonous and nonpoisonous snake bite cases were included for the study.Patients with history of trauma, insect bite or thorn prick were excluded.The data were also obtained from hospital case records, direct interrogation from relatives, friends and persons accompanying the patients.A full detailed history and proper systemic, neurological and psychiatric evaluation was performed by authors with consultant physicians.Early features were evaluated immediately after hospital admission.Late features were evaluated after four weeks among survivors.Data were collected, tabulated and statistical analysis was performed using software SPSS version 16.0.

Ethical considerations
Informed written consent was obtained from all participants.Those identified to have severe psychological distress were referred to appropriate psychiatric services for further assessment and followup.Ethical clearance was obtained from Chittagong Medical College Hospital Ethical Committee (CMCH: Ref: 123/004/2015).

Results
Total 121 snake bite cases were admitted into hospital during our study period (eighteen months).Among them, 68 (56.2%) cases showed sign symptoms of envenomation due to poisonous snake bite and 53 cases were nonpoisonous snake bites.Timing of hospital admission is very important both for management and prognosis purpose.We studied admission time from snake bite to hospital arrival.Only 28.1% patients (n=34) were admitted within two hours and 71.9% were admitted after two hours of snake bite (Table I).

Table I: Snake bite to hospital admission time
We also assessed body parts involved in snake bite.As spread of venoms depends on body part involved, blood supply and movement of the bite area, it is important to assess the common site involved.Our study found lower limb as the commonest site for snake bite (75.2%, n=91).Lowest incidence occurred in head neck region (2%) (Table II).

Discussion
This study assessed for both neurological and psychiatric features of snake bites in the hill tracts with final outcomes.Both early as well as delayed stage features were assessed by consultant physician.
According to the study findings the highest neurological features observed were generalized weakness (early) and numbness (late).Neurological features were observed both in poisonous and nonpoisonous snake bite cases.In nonpoisonous cases it is probably due to anaphylactic reaction from bite area and psychological stress.The highest psychiatric manifestations found were anxiety (early) and depression (late).Anxiety was reduced in late cases probably due to survival from snake bite.
[8][9][10] A study done in India showed 37% cases as upper limb area involvement which is dissimilar to our study. 4ost of the cases were admitted into hospital after two hours.4][5] In 2014 another research work at Bangladesh found ptosis was the commonest neurotoxic feature which is dissimilar to our study. 6he difference happens due to different snake species in hill tracts and delay in hospital admission. 7][10] About one-third cases received anti-venom which is lower compared to the studies done in India, Sri Lanka and Thailand.for the first time by our study.This study reveals that only one-third patients received anti-venom after snake bite.Death rate was high relative to other studies done in Bangladesh.It may be due to late arrival to hospital or due to failure of early administration of anti-venom.
Early evaluation of neurological and psychiatric manifestations will improve the diagnostic accuracy and treatment outcome in hill tracts.This can ameliorate the prognosis in snake bite patients.Primary care doctors and consultants need to develop systematic strategies to screen for early and late neuro-psychiatric features to decrease the mortality and morbidity of snake bite in hill tracts.

Table II :
Sites of snake bitesThis study revealed immediate and late neurological and psychiatric features of snake bite.Each patient was allowed for multiple answers.Immediate features were assessed after hospital admission.Late features were assessed after one month of snake bite.Both *Each patient was allowed to respond with multiple answers Fig 1. Immediate neurological presentations of snake bites *Each patient was allowed to respond with multiple answers Fig 2. Immediate psychiatric manifestations of snake bites Among 121 snake bite patients 110 (90.9%) survived.

Table III :
Final outcome of snake bite with neuropsychiatric manifestations