Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Evaluating temporal patterns of snakebite in Sri Lanka: The potential for higher snakebite burdens with climate change(Sri Lanka Medical Association, 2018) Ediriweera, D.S.; Diggle, P.J.; Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Jayamanne, S.F.; Isbister, J.K.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: Snakebite is a neglected tropical disease that has been overlooked by healthcare decision makers in many countries. Previous studies have reported seasonal variation in hospital admission rates due to snakebites in endemic countries including Sri Lanka, but seasonal patterns have not been investigated in detail. METHODS: A national community-based survey was conducted during the period of August 2012 to June 2013. The survey used a multistage cluster design, sampled 165,665 individuals living in 44,136 households and recorded all recalled snakebite events that had occurred during the preceding year Log-linear models were fitted to describe the expected number of snakebites occurring in each month taking into account seasonal trends and weather conditions, and addressing the effects of variation in survey effort during the study and due to recall bias amongst survey respondents RESULTS: Snakebite events showed a clear seasonal variation. Typically, snakebite incidence was highest during November to December followed by March to May and August, but this varied between years due to variations in relative humidity, which is also a risk-factor. Low relative humidity levels was associated with high snakebite incidence. If current climate change projections are correct, this could lead to an increase in the annual snakebite of burden of 35,086 (95% CI: 4 202 a€" 69,232) during the next 25 to 50 years. CONCLUSION: Snakebite in Sri Lanka shows seasonal variation Additionally, more snakebites can be expected during periods of lower than expected humidity. Global climate change is likely to increase the incidence of snakebite in Sri Lanka.Item Development of a Snakebite risk map for Sri Lanka(Sri Lanka Medical Association, 2016) Ediriweera, D.S.; Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Wijayawickrama, B.A.; Jayamanne, S.F.; Isbister, G.K.; Dawson, A.; Giorgi, E.; Diggle, P.J.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION: Snakebite is a public health problem in Sri Lanka and about 37,000 patients are treated in government hospitals annually. At present, health care resources which are required to manage snakebite are distributed based on the administrative boundaries, rather than based on scientific risk assessment. OBJECTIVES: The aim of the study is to develop a snakebite risk map for Sri Lanka. METHOD: Epidemiological data was obtained from a community-based island-wide survey. The sample was distributed equally among the nine provinces. 165,665 participants (0.8%of the country’s population) living in 1118 Grama Niladhari divisions were surveyed. Generalized linear and generalized additive models were used for exploratory data analysis. Model-based geostatistics was used to determine the geographical distribution of snakebites. Monte Carlo maximum likelihood method was used to obtain parameter estimates and plug-in spatial predictions were obtained. Probability contour maps (PCM) were developed to demonstrate the spatial variation in the probability that local incidence does or does not exceed national snakebite incidence. RESULTS: Individual point estimate snakebite incidence map and PCM were developed to demonstrate the national incidence of snakebite in Sri Lanka. Snakebite hotspots and cold spots were identified in relation to the national snakebite incidence rate. Risk maps showed a within-country spatial variation in snakebites. CONCLUSIONS: The developed risk maps provide useful information for healthcare decision makers to allocate resources to manage snakebite in Sri Lanka.Item Estimates of disease burden due to snakebite in Sri Lankan hospitals(Sri Lanka Medical Association, 2003) Kasturiratne, A.; Pathmeswaran, A.; Fonseka, M.M.D.; Lalloo, D.G.; Brooker, S.; de Silva, H.J.INTRODUCTION: There have been no country-wide studies or estimates of disease burden due to snakebite in Sri Lankan hospitals. OBJECTIVES: To assess disease burden due to snakebite and estimate relative frequency of the biting species in hospitals situated in different parts of the country. METHODS: Hospital morbidity and mortality data on snakebite was obtained for each administrative district. Sri Lanka was divided into 5 zones based on climate and available data on snake habitat (Zone 1-wet zone altitude <900m; Z2-intermediate zone; Z3-dry zone, Z4-wet zone altitude >900m; Z5-northern and north-western dry zone). Administrative districts were allocated to zones based on their geographical location and population using geographical information systems technology. Hospital morbidity and mortality data were collated for the 5 zones. A survey among physicians (37 physicians in 42 hospitals covering the 5 zones) was used (Delphi technique) to estimate the proportion of snakebites by different species and requirement of hospital resources, in each zone. Results: There was a clear difference in incidence of hospital admissions due to snakebite in the different zones (Z3-3.5 and Z4-0.4 per 1000 population). The distribution of bites by individual species also varied between zones (deadly venomous species Z3-85%, Z2-45%), moderately venomous and mildly-venomous species Z4-100%, Zl-70%). These trends corresponded to estimates of requirements for AVS and other hospital facilities (in 2000, Z3-86100 vials of AVS, 7380 Intensive care unit patient-days; Zl-26400 vials of AVS, 2640ICU patient-days). CONCLUSIONS: Incidence of hospital admissions due to snakebite and estimates of relative medical importance of different snake species show geographic variation within the country. This is reflected in estimates of requirements for facilities. Zoning based on environmental information rather than on political boundaries could lead to better distribution of health care resources for management of snakebite in hospitals situated in different parts of the country.Item Beliefs and knowledge regarding snakebite in rural Sri Lanka: a qualitative survey(Sri Lanka Medical Association, 2003) Makita, L.S.; Nandasena, S.; Costa, M.R.A.; Kasturiratne, A.; Pathmeswaran, A.; Lalloo, D.G.; de Silva, H.J.OBJECTIVES: To identify common beliefs and assess knowledge regarding snakebite in rural Sri Lanka, and their influence on health-seeking behaviour. METHODS: Qualitative methods (focus group discussions and key informant interviews) were used to obtain data in five rural locations in wet, intermediate and dry zones. Data was subjected to "framework analysis" involving familiarisation, identification of thematic frame, indexing and coding, charting, mapping, and interpretation. RESULTS: People are aware of risk-behaviour associated with snakebite, and have reasonable knowledge regarding venomous and non-venomous snakes. However, differences in nomenclature sometimes lead to confusion in identifying species. Beliefs and legends, which are linked to religion, have lead people to respect the cobra. Traditional healers claim they can determine the snake species, clinical manifestations that may occur, and prognosis, based on phenomena, such as, day of the week and phase of the moon when the bite took place. They still employ treatment methods, such as wound incision with broken glass and scalp incision for applying potions. Although there is respect for traditional healing, there is acceptance of the efficacy of western medicine. Beliefs, such as, anti-venom though effective is toxic, long-term effects of snake venom can be completely neutralised only by traditional medicine, and producing the dead snake is essential for treatment in hospitals, lead people to seek treatment by traditional healers rather than in hospitals. CONCLUSIONS: Beliefs and misconceptions influence health-seeking behaviour following snakebite. There seems to be a growing acceptance of western medicine. However, traditional healing methods are still popular, but include harmful^rjractices. This information could form a basis for. educational intervention.Item Underestimation of snakebite mortality by hospital statistics in the Monaragala District(Sri Lanka Medical Association, 2005) Fox, S.; Rathuwithana, A.C.; Kasturiratne, A.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION: Estimates of snakebite mortality rely upon deaths recorded in hospital. This study compared the number of recorded snakebite deaths in hospitals with registered deaths from the same district. METHODS: Snakebite mortality data for the period 1999-2003 were obtained for all hospitals in Monaragala District from the Medical Statistics Unit, Colombo. Data on snakebite as a certified cause of death for the district were obtained from the Registrar General's Department. Hospital mortality data were cross-checked at 7 of the 18 hospitals in the district [Base Hospital Monaragala, District Hospitals Bibile, Kataragama, Siyambalanduwa, Medagama and Wellawaya, and Rural Hospital Ethimale], accounting for 66% of recorded deaths. Registrar General's data were cross-checked at 19 of the 33 Divisional Secretariats in the District. RESULTS: We found that the data recorded centrally corresponded to what was documented in hospitals and Divisional Secretariats that we visited. For the 5-year period, there were 27 snakebite deaths recorded in hospitals in the Monaragala District. However, death registrations for the same district identified 72 deaths due to snakebite. The true number of snakebite deaths in Monaragala District was, therefore, 2.7 (95% confidence interval 2.0 - 3.7) times higher than the number of deaths recorded in hospitals. CONCLUSION: Our study convincingly demonstrates that hospital data underestimate the true burden of snakebite mortality; many victims probably die before reaching hospital. Although our study was limited to the Monaragala district, the findings probably reflect the situation in many areas of Sri Lanka where snakebite is a problem and public amenities are limited. We recommend large scale community surveys to more accurately determine the magnitude of snakebite mortality in this country.Item Delayed psychological morbidity in victims of snakebite envenoming(Sri Lanka Medical Association, 2010) Williams, S.S.; Wijesinghe, C.A.; Jayamanne, S.F.; Buckley, N.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.OBJECTIVES: We assessed delayed somatic symptoms, depressive disorder, post-traumatic stress disorder (PTSD) and impairment in functioning among snakebite victims. The psychological impact of snakebite on its victims has not been systematically studied. METHODS: The study had qualitative and quantitative arms. In the quantitative arm, 88 persons who had systemic envenoming following snakebite from the Polonnaruwa District were randomly identified from an established research database and interviewed 12 to 48 months (mean 30) after the incident. 88 persons with no history of snakebite, matched for age, sex, geograpical location and occupation acted as controls. A modified version of the Beck Depression Inventory, Post-Traumatic Stress Symptom Scale, Hopkins Somatic Symptoms Checklist and Sheehan Disability Inventory, together with a structured questionnaire were administered. In the qualitative arm, focus group discussions among snakebite victims explored common somatic symptoms attributed to envenoming. Results: Snakebite victims had more symptoms as measured by the modified Beck Depression Scale (mean 19.1 vs 14.4) and Hopkins Symptoms Checklist (38.9 vs. 28.2) compared to controls (p<0.001). 48(54%) victims met criteria for depressive disorder compared to 13(15%) controls. 11(12.5%) victims also met criteria for PTSD. 24(27%) claimed that the snakebite caused a negative change in their employment; 9(10.2%) had stopped working. 15(17%) victims claimed residual physical disability, and themes identified in the qualitative arm included blindness, tooth decay, body aches, tiredness and weakness. CONCLUSIONS: Snakebite causes delayed psychological morbidity, a complication not previously documented.Item Low-dose adrenaline, promethazine and hydrocortisone, (alone and in combination) in the prevention of acute adverse reactions to antivenom following snakebite: a randomised, double blind, placebo-controlled trial(Sri Lanka Medical Association, 2011) de Silva, H.A.; Pathmeswaran, A.; Ranasinha, C.D.; Jayamanne, S.; Samarakoon, S.B.; Hittharage, A.; Kalupahana, R.; Ratnatilaka, G.A.; Uluwatthage, W.; Aronson, J.K.; Armitage, J.M.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: Envenoming from snakebites is most effectively treated by antivenom. However, the antivenom available in South Asian countries commonly causes acute allergic reactions, anaphylactic reactions being particularly serious. We have assessed whether adrenaline, promethazine, and hydrocortisone prevent such reactions in secondary referral hospitals in Sri Lanka. METHODS: We randomized 1007 patients, using a 2x2x2 factorial design, in a double-blind, placebo-controlled trial of adrenaline (0.25 mi of a 1:1000 solution subcutaneously), promethazine (25 mg intravenously), and hydrocortisone (200 mg intravenously), a!one and in all possible combinations. The interventions or matching placebo were given immediately before infusion of antivenom. Patients were monitored for mild, moderate, or severe adverse reactions for at least 96 hours. The pre-specified primary endpoints were the effects of the interventions on the incidence of severe reactions over 48 hours. Results: 752 (75%) patients had acute reactions to antivenom; 9% mild, 48% moderate, 43% severe; 89% of the reactions occurred within one hour and 40% of all patients were given rescue medication during the first hour. Compared with placebo, adrenaline significantly reduced severe reactions to antivenom by 43% at one hour (95%CI 25-67) and by 38% (26-49) over 48 hours; hydrocortisone and promethazine did not. Adding hydrocortisone negated the benefit of adrenaline. CONCLUSIONS: Pre-treatment with tow-dose adrenaline was safe and reduced the risk of acute severe reactions to snake antivenom. This may be of particular importance in countries where adverse reactions to antivenom are common, although the need to improve the quality of available antivenom cannot be overemphasized.Item Health seeking behavior of snakebite victims in Sri Lanka: findings from an island-wide community-based study(Sri Lanka Medical Association, 2014) Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Ediriweera, E.P.D.S.; Wijayawickrama, B.A.; Jayamanne, S.F.; Isbister, G.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: Health seeking behaviour of snakebite victims in the community has rarely been described and we investigated this as part of a community-based island-wide study on snakebite in Sri Lanka. METHODS: The national snakebite study was conducted in a!! 25 districts, in SriJ_anka in 2012/2013. 44,136 households were sampled in randomly selected clusters. In these households, any member reported to have experienced a snake bite within the preceding 12 months was considered a case. Data related to the health seeking behavior of snakebite were obtained using an interviewer-administered questionnaire. RESULTS: Among 165,665 individuals surveyed, 695 (60% males; median age 43 years) snakebite victims were identified. 323 (46.5%) had evidence of envenoming. 682 (98.2%) had sought health services after the bite. 381 (54.8%) sought allopathic medicine and 99.7% of them obtained this service from the state health sector, while 43.3% sought alternative medicine. The lowest rates of seeking allopathic medicine were seen in the Kalutara (8.7%) and Kegalie (10.7%) districts while highest rates were seen in the districts Mannar, Mullativu and Kilinochchi (100%). Puttalam (92.9%), Vavuniya (92.3%},) Ampara (89.5%), Jaffna (88.9%) and Anuradhapura (86.0%) also had high rates. 70.1% of the victims with envenoming sought allopathic medicine. Victims who had envenoming were significantly more likely to seek allopathic medicine (OR=3.35; 95% confidence interval 2.44-4.59) than those without envenoming. CONCLUSIONS: A considerable proportion of snake bite victims still seek alternative medicines in Sri Lanka.'A wide variation of practices exists across the country. Victims with envenoming are more likely to seek allopathic medicine.Item Community incidence of snakebite and envenoming in Sri Lanka; results of a national survey(Sri Lanka Medical Association, 2014) Pathmeswaran, A.; Kasturiratne, A.; Gunawardena, N.K.; Wijayawickrama, B.A.; Jayamanne, S.F.; Ediriweera, D.S.; Isbister, G.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: We undertook the first ever country-wide community-based survey to determine the incidence of snakebite in Sri Lanka. METHODS: Data were collected through household interviews by trained data collectors.125 clusters were allocated to each of the 9 provinces of the country. Within each province the clusters were divided among the districts in proportion to their population. A Grama Niladhari (GN) division was defined as a cluster for data collection. The clusters were selected using simple random sampling, and in each cluster 40 households were sampled consecutively from a random starting point. RESULTS: Data relating to 165,665 individuals (0.8% of the population of Sri Lanka) living in 44,136 households in 1,118 clusters was collected from June 2012 to May 2013. 695 (males 418) snakebites and 323 (males!93) significant envenomings (local tissue necrosis or systemic envenoming) were reported during the 12 months preceding the interview. The overall community incidence of snakebites and significant envenoming were 398 and 151 per 100,000 population, respectively. 446 (64.2%) bites and 208 (64.4%) envenomings were in people aged 30 to 59 years. There was wide variation between districts, the worst affected being Mullaitivu, Anuradhapura, Batticaloa, and Poionnaruwa, ali in the dry zone, mainly agricultural areas of the country. CONCLUSIONS: Sri Lanka has a high community incidence of snakebite and envenoming with a marked geographical variation.This variation underlines both the inaccuracy of extrapolating data of localised surveys to national or regional levels and the need to prioritise distribution of resources for treatment of snakebite even in small countries.Item Development and assessment of a psychological intervention for snakebite victims(Sri Lanka Medical Association, 2014) Wiiesinahe, C.A.; Williams, S.S.; Dolawatta, N.; Wimalaratne, A.K.G.P.; Kasturiratne, A.; Wijewickrema, B.; Jayamanne, S.F.; Lalloo, D.G.; Isbister, G.K.; Dawson, A.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: There is significant delayed psychological morbidity and negative psycho-social impact following snakebite. However, no psychological support is provided to victims. We aimed to develop and assess the effectiveness of a brief intervention which can be provided by non-specialist medical officers aimed at reducing psychological morbidity. METHODS: In a single blind clinical trial at Polonnaruwa Hospital, 187 snakebite victims were randomised into three arms. One arm received no psychological intervention (Group A; n=59; control). Group B (n=60) received psychoeducation at discharge from hospital. Group C (n=68) received psychoeducation and a.second intervention one month later based on cognitive behavioural principles. All patients were assessed six months after discharge from hospital using standardised tools for presence of psychological symptoms and level of functioning. RESULTS: Compared with Group A, there was a significant reduction in anxiety symptoms measured by the Hopkins Psychiatric Symptom check list (16.9% vs. 5.9%, p=0.047, Chi-Squared test) and a non-significant trend towards improvement in the level of functioning measured by the Sheehan Disability inventory (6.47 vs. 4.69) in Group C, but not in Group B. There was no difference in rates of depression and post-traumatic stress disorder (PTSD) between the three groups. CONCLUSIONS: Our preliminary findings suggest that brief psychological interventions which include psychoeducation plus cognitive behavioural therapy given by non-specialist doctors, but not psychoeducation alone seem to reduce anxiety and facilitate a trend towards improved function in snakebite victims. However, these interventions had no effect on depression or PTSD.
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