jiafm, 2010-32(2) april-june. - forensic medicine

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ISSN 0971-0973 J Indian Acad Forensic Med, 32(2)Original research paperPattern of Renal Pathology in Fatal Envenomation by Indian Cobra(Naja naja)*Dr. Partha Pratim Mukhopadhyay M.D., Ph.D., **Dr.Sulekha Ghosh D.C.P, M.D., ***Dr.T. K.Ghosh, D.C.P.AbstractDeaths due to poisonous snakebite are a significant health related problem especially the rural heartland ofin tropical countries. Renal involvement in snakebite is well documented especially so in bites by the Viperidaegroup. The Elapidae family consisting of cobra and kraits among other varieties are mainly considered neurotoxic.The venom of neurotoxic variety predominantly has direct depressing action on the respiratory center andneuromuscular junction. We investigated the renal changes at autopsy and histology of fatal cobra bites.This series included autopsy examination of 14 cases of fatal cobra bite in our hospital-based study.Dissected kidneys were sectioned, stained with hematoxylin & eosin stain and histological examination was doneunder light microscope. Five cases from head injury subject were used as control. The study reveals renalinvolvement in 64.28 %of fatal bites by Indian cobra (Naja naja) primarily considered neurotoxic. The major renalchanges were tubular necrosis 1(7.14%), cortical necrosis 3 (21.42%) and interstitial nephritis 3(21.42%). This factis worth giving due consideration during management and monitoring of cases of envenomation by cobra.Key Words: Snake Bite, Renal Pathology, Indian Cobra, Cortical Necrosis, Glomerulopathy, AutopsyIntroduction:Death due to poisonous snakebite is asignificant health related problem especially in therural heartland of South Asian countries. [1, 2] Theincidence of renal failure in poisonous snakebitevaries from 13% to 22%. [3, 4] Renal involvement insnakebite is well documented. [5, 6, 7] Bites by theViperidae group are the main cause of renal failure.[8, 9] The Elapidae family consisting of cobra andkraits among other varieties are mainly consideredneurotoxic.For clinical convenience poisonous snakesare broadly grouped into haemotoxic (Vipers) andneurotoxic (Cobra and Kraits). [10] The venom ofneurotoxic variety predominantly has directdepressing action on the respiratory center andneuromuscular junction. Snake venom contains theenzymes and non –enzyme proteins that mediate thetissue reactions. The treatment however involvescommonly polyvalent anti-serum. The present workwas designed to examine the incidence, pattern andspectrum of renal lesion in snakebite by Indian cobra(Naja naja) from the autopsy sample.Corresponding Author:Dr. Partha Pratim Mukhopadhyay*Associate ProfessorDepartment of Forensic and State MedicineBurdwan Medical College, Burdwan, West Bengal,India, PIN -713104Email: drpartha99md@gmail.com**Associate Professor, Department Of Pathology***Demonstrator, Department of PathologyMaterials and Methods:In India snakebites are unnatural deaths thatneed to be examined at autopsy (medico-legal)according to statutory rules. The series includedautopsy examination of 14 cases of fatal cobra bite inour hospital-based study. All the cases were from thesurrounding area under the jurisdiction of the localpolice administration. The sample consisted of allfatal cobra bite cases examined at complete forensicautopsy by the first author in 2009 during his routinemedico legal postmortem work The cases included allknown deaths due to cobra bite. The subjects werefrom those admitted to the hospital and receivedtreatment at Emergency ward.The snake type was retrieved from records, policeinquest, history or the offending snake captured/killed and examined. Unknown bites were excluded.Brought dead subjects with history of snakebite werealso excluded from the study. Autopsy wasconcluded within six hours of death. Any case withovert local necrotic changes and evidence ofcouagulopathy were summarily excluded.At complete autopsy all findings wererecorded in a standard protocol.Only themorphological changes in the kidneys wereconsidered for the present study. Dimensions andweight of the kidneys were recorded. Macroscopicand microscopic studies were done.Dissected kidneyswere sectioned, stained with hematoxylin & eosinstain and histological examination was done underlight microscope. Five cases from head injury subjectwere used as control.132
J Indian Acad Forensic Med, 32(2) ISSN 0971-0973The pathologists noted histopathologicalfindings. The slides were coded and blinding wasdone to keep the type of snake unknown to theobservers (other authors). The results were pooledand analyzed.Observation / Results:In the present series of 14 cases of fatal bitesby Naja naja the mean and standard deviation of ageat death was 26.5 and 8.92 respectively. Themacroscopic examination of the kidneys showedbilateral congestion in all the 14 cases. Bilateral subcapsular pinpoint hemorrhages were noted in onefemale subject. On section (longitudinal) all thekidneys showed congestion of cortex and medulla.Intense medullary congestion was seen in five cases.Cortical hemorrhage (pin point) was found in onecase (7.14%).The pattern of renal changes(histopathological findings) is seen from Table 1.64.28% of cobra bites had some renal lesion apartfrom congestion. The major renal changes athistology found in the neurotoxic group were tubularnecrosis 1(7.14%), cortical necrosis 3 (21.42%) andinterstitial nephritis 3(21.42%). Focal corticalnecrosis was seen in 2(14.28%) cases. Glomerularchanges (glomerular collapse and fibrin deposition)were seen in 2(14.28%) cases of fatal cobra bite.Discussion:In the present study 9 (64.28%) of the cobrabites showed distinct renal lesions at autopsy(confirmed and classified by histopathology). Itclearly indicates acute renal failure as the leadingmechanism of death in snakebite. Our findings arenot in consonance with earlier documented studies.[3, 4, 5] The spectrums of renal lesions were also notconsistent with previous published works. [6, 7, 8]This finding of the present work is distinct from earlyworks [8, 9] where haemotoxic bites were onlyreported to cause nephropathy.The study highlights the renal involvementin cobra bite cases contrary to the known fact thatthose are mainly neurotoxic. This observation can beexplained by two possible mechanisms. Firstly allsnake venoms are mixed toxins that have intrinsicactivity on the kidneys. Secondly there is a highpossibility of immunologically mediated nephropathyin snakebite. The interstitial nephritis (21.42%)observed in this series supports our contention (Fig1). Some earlier workers [7] however have refutedthis. Another mechanism of renal involvement incommon neurutoxic bites is ischaemia inducednephropathy especially cortical and tubular lesions.This work is our preliminary observation based onour experience of the prominent renal morphologicalchange at autopsy in fatal cases of cobra bite.This fact is worth giving due considerationduring management and monitoring of cases ofenvenomation by cobra. Also there is ample scope ofspecial investigation on the biochemical andimmunological components of the venom of this.This prompts further large-scale investigations withmore detailed pathology of cobra bite withultrstructural and molecular studies. The predominantmechanisms mediating the changes in kidney may bedifferent but the organ damage found at autopsy issignificant for planning management. Polyvalentantivenom is still the mainstay of therapy in mostcountries. The major organ failure needs closemonitoring and support. Renal involvement that hasbeen less frequently reported in known neurotoxicbites is indeed a problem to reckon with inemergency care. This is particularly important inrural areas of South Asian countries whereprevalence of snakebite is alarmingly high.Table 1:Major histo-pathological changes found in thefatal cases of snakebite (Naja naja naja) (n=14)Sr. No. Lesions No. of cases (%)1. No Renal change 5(35.7%)2. Glomerular change 2(14.28)3. Tubular necrosis 1(7.14)4. Cortical necrosis 3(21.42)5. Interstitial nephritis 3(21.42)References:1. Warrel DA. Snake bite. The Lancet 2010; 375(9708): 77-88.2. Hati A K, Mondal M, De M K, Mukherjee M, Hati R N.Epidemiology of snakebite in the district of Burdwan, WestBengal. Journal of Indian Medical Association.1992; 90:145-47.3. Chugh K S, Pal Y, Chakravarty R N, Dutta B N, MehtaR, Sabhiya R, Mondal A K, Sommers S C et al. Acuterenal failure following poisonous snake bite. Am J KidneyDisease. 1984; 4: 30-38.4. Mittal B V. Acute renal failure following poisonoussnakebite. Journal of Postgraduate Medicine.1994; 40(3):123-26.5. Ali G, Kak M, Kumar M, Bali S K, Tak S I, Hassan G,Wadhwa M B. Acute renal failure following Echis carinata(saw scaled viper) envenomation. Indian Journal ofNephrology. 2004; 14: 177-181.6. Sakhuja V, Kohli H S. Snake bite and acute renal failure.Saudi Journal of Kidney Diseases and Transplantation. 2003;14(2): 165-176.7. Sitprija V. Snake bite nephropathy. Nephrology. 2006;11(5): 442-448.8. Dutta T K, V Mukta. Snake Bite. Journal of Indian MedicalAssociation.2006; 104(5): 250-52.9. Bandyapadhyay S K, Ghosh S, Bandyapadhyay R, DuttaA. Prognostic factors in haemotoxic viper bite; analysis ofdata from a referral hospital. J Indian Med Assoc. 2009;107(10): 12-13.10. Sant S M, Purandarg N M. Autopsy study of cases ofsnakebite with special reference to renal lesions. J PostgradMed. 1992; 18: 181-183.133
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