CHAPTER Management of Snake Bite - An Update

63 Joseph K Joseph, Manoj P Jose, Jaideep Menon

India is estimated to have the highest snake bite mortality and malena, chemosis, macular bleed, excessive in the world with WHO estimates placing the number menstrual bleed, bleeding from bite site or the between 15,000 to 30,000 per annum. The oftquoted figure canula, bleeding into muscles, bleeding from till recently was around 50,000. Conservative estimates gingival sulci, epistaxis. Bleeding into skin put the deaths related to snakebite in between 35,000- & mucous membrane may show evidence of 50,000 per year in India alone. It is quite unfortunate that petichiae, purpura, epistaxis. most of the deaths in our country are due to fright and • Hypotension resulting from hypovolemia or direct wrong line of treatment. vasodilatation. The first thing to be verified is whether it is a snake bite • Low back pain, loin pain indicative of an early renal at all. And if so whether it was a venomous snake bite. failure or retroperitoneal bleeding. The passing of The victim may be shown a chart with photographs of reddish or dark brown urine or declining or no venomous snakes in the area to help identification. urine output. Symptoms of pain out of proportion to the extent of injury are typical of envenomation. If the pain seems • Lateralising neurological symptoms and proportional to the injury seen, it may not be a snake bite asymmetrical pupils maybe indicative of at all and could be an injury from other causes. intracranial bleeding The species identification does not really change the GENERAL SIGNS AND SYMPTOMS OF ELAPID medically management at present, as the ASV we use is ENVENAMATION polyvalent i.e ASV which neutralizes the venom of all the Swelling and local pain (Cobra). Local necrosis and or “Big Four”. The currently used polyvalent ASV would not blistering (Cobra) cover king cobra bites, sea snake bites and would have nil or very minimal benefit in pit viper bite. Descending paralysis, initially of muscles innervated by the cranial nerves, commencing with ptosis, diplopia or PATIENT ASSESSMENT PHASE ON ARRIVAL ophthalmoplegia. The patient complains of difficulty in Deal with any life threatening symptoms on presentation focusing and the eye lids feel heavy. i.e. Airway, breathing and circulation. If there is evidence of a bite, where the skin has been broken, give Tetanus Dysphagia, dysguesia involvement of sense of smell, toxoid. diaphoresis. Circum oral pallor and paraesthesia, profound thirst, miosis, abdominal pain, vomiting, DIAGNOSIS PHASE – SYMPTOMS painful lymphadenopathy, palpitation, breathlessness, Hemostatic abnormalities are prima facie evidence of chest pain, Paralysis of jaw and tongue may lead to upper a viper bite. Cobras & Krait do not cause haemostatic air way obstruction and aspiration of pooled secretions disturbances. All the vipers can cause renal failure. because of the patients inability to swallow. Russell’s Viper can also manifest neurotoxic symptoms in Bulbar paralysis and respiratory failure. Paradoxical a wide area of India, especially southern India. This can respiration, as a result of the intercostal muscles becoming sometimes cause confusion and further work is necessary paralysed is a frequent sign. to establish how wide this area might be. The neurotoxic symptoms of Russell’s Viper are believed to be pre- Hypoxia due to inadequate ventilation can cause cyanosis, synaptic or krait like in nature. altered sensorium and coma. GENERAL SIGNS & SYMPTOMS OF VIPERIDAE Stomach pain which may suggest submucosal haemorrhage in the stomach (Krait). ENVENOMATION • Local pain & swelling and erythema over bitten Krait bite often present in the early morning with paralysis part., Tender enlargement of local lymph nodes, that can be mistaken for a stroke. Local necrosis and or blistering, Vomiting, abdominal pain LATE ONSET ENVENOMING The patient should be kept under close observation for at • The victim may bleed from any orifice or organ, least 24 hours. Many species, particularly, the Krait and hemoptysis, epistaxis, hematuria, hematemesis the Hump nosed pit viper are known for the length of TOXICOLOGY 348 and dry asthemechanism under review isthecontact for 20minutes. Itisimportantthatthetube isclean,glass and leftatambient temperature clean, dryglass testtube A fewmillilitersoffreshvenous bloodisplacedinanew, method (Figure1). tube capillary the to superior significantly is It training. and canbecarriedoutat thebedsidewithoutspecial the mostreliabletestofcoagulation inhematotoxicbite 20 minute whole blood clotting test (20 WBCT) considered damaged skeletal muscles may causeacutekidneyinjury. after thebite.Myoglobinand potassium released from Myoglobinemia andmyoglobinuriadevelop 3to8hours sufficiently affected tocauserespiratoryfailure. are muscles respiratory the until conscious remains Thepatient occur. ptosis with paralysis flaccid between 30minutesto3½ hours afterthebite. progressive stiffness and tenderness of the muscles become noticeable thirst, sweating andvomiting,generalisedaching,trismus, symptoms includeheadache,athickfeelingofthetongue, the dominant effect of envenoming by these snakes. Early lymph nodeisunusual.Generalisedrhabdomyolysis is minimalornolocalswelling andinvolvement oflocal The biteisusuallypainlessandmaygounnoticed.There minutes. Theremaybevery littleswelling atthebitesite. injected, slightlocalpaindevelops afterabouteightto30 But ifalethaldosehasbeen site immediatelyafterbite. In the case of a cobra bite there is very little pain at the bite appear. any signs of envenomation can take much longer to lower downonthefootinhardtissueareaandthus Juvenile snakes8to10incheslong,tendbitethevictim season whensnakesgenerallygive birthtotheiryoung. This isalsoparticularlypertinentatthestartofrainy well documentedoccurance. take between 6to12hours.Lateonsetenvenoming isa time itcantakeforsymptomstomanifest.Oftenthis INVESTIGATION BITE BY SEA SNAKE Fig. 1:20min Whole bloodclottingtest (20min WBCT) • • in pitviperbites. especially become abnormalonly24hoursafterthebite species. But itoccasionally happens thattheparameters normal 20 WBCT and clot lysis would exclude viperidae reports arenormal, no furthertriagewould be needed. A twice moreat3hourintervals6 hours.Ifall next the repeated atonehourinterval tillsixhoursafterbiteand admission for threehours.Ifeverything isnormal, carried outeveryThe testshouldbe 30minutesfrom will inhibit the contact element of the clotting mechanism. tube mustnothave beenwashed with detergentas this liquid thenthepatienthasincoagulableblood. The test and thengentlytilted,notshaken.Ifthebloodisstill The glassvessel shouldbeleftundisturbedfor20minutes tubesor syringes willgiveused. falsereadingsandshouldnotbe bottles, ofplastic use The mechanism. clotting Renal function: Bloodurea,Serumcreatinine repeated onthe thirdday. DIC Work up:D.Dimer, FDP, Fibrinogenwhich are ULN Coagulation Workup:CT, BT, APTT >1.5 ULN, PT >1.5 repeated 6hourlythefirst 24hoursinviperidaebite. ESR, DLC, TLC, Peripheral smear(Figure2).Platelet count-which is PCV, Hemoglobin, Haematological: OTHERUSEFUL TESTS a cobra. ofa The likelihood “dry bite”fromamongthe“bigfour”is most with hours. 24 first the in mostly Similarly, themortalityduetoelapidaebitesare 6 hours, the shortesttimeframebeingforseasnakes. first the within symptoms show would viperidae. Mostseasnake,kraitandcobrabite than rather bite Elapidae with common more are The onsetofsymptomsandsuddenprogression hours. 2 first the over interval minutes 15 at repeated is done in suspectedelapidaebitesandthesame counting testis Simultaneously, asinglebreath

CHAPTER 63 349 ) in Rajasthan, where the effectiveness Cardiovascular abnormalities, hypotension, shock abnormalities, Cardiovascular cardiac arrythmia, abnormal ECG. vomiting or abdominal pain. and severe Persistent Evidence of Systemic Envenoming Evidence of coagulopathy: Primarily detected by 20 minute WBCT[whole blood bleeding systemic spontaneous or visible &APPT clotting test] PT from gums etc. Evidence of inability ophthalmoplegia, muscle paralysis, to lift Neurotoxicity: head –broken neck sign. Ptosis, external ASV DOSAGE ASV OTHER DETERMINANTS ARE DETERMINANTS OTHER PROPHYLACTIC REGIME - REACTIONS ASV OF PREVENTION ASV OF DOSE TEST ANTI-SNAKE VENOM VENOM (ASV) ANTI-SNAKE CRITERIA ADMINISTRATION ASV Symptoms and signs being not a useful guide for Symptoms and having no deciding the degree of envenomation in of Venom to determine the level diagnostic methods only be could adopted ASV regimen blood or tissue, any an estimate. venom, Viper Russel ASV neutralizes 0.6 mg. of of 1 ml. 0.45 & 0.45 mg. of krait venom, 0.6 mg. of Cobra venom, mg. of saw-scaled viper venom. • • & subcutaneously 0.25 – 0.3 mg adrenaline 1 : 1000 given (deep IM) pre-medication ASV to the victim has a known sensitivity If with adrenaline, hydrocotisone and anti histamine may reactions. severe be advisable, in order to prevent value no predictive been shown to have dose have Test reaction and or late serum in detecting anaphylactoid should not be used. These reactions are not IgE mediated They may also pre-sensitise but activated. complement the patient and thereby create greater risk. Anti Snake Venom (ASV) is the mainstay of treatment. of treatment. mainstay is the (ASV) Snake Venom Anti The ASV available in India is polyvalent i.e it is effective viper species; Russells the four common against all viper. and saw scaled cobra, common krait common the Hump-nosed such as known species There are ASV is where polyvalent (hypnale hypnale) pit viper known to be ineffective. In addition there are regionally (Echis viper scaled saw sachureki’ as such species specific carinatus Sachureki ASV may be questionable. of polyvalent only and should commodity costly ASV is a scarce, be administered when envenomation. Unbound, free flowing venom, there can only are or tissue stream in the blood it is be neutralized when definite signsfluid. In of addition, Anti Snake should not therefore be used reactions and anaphylactic Venom carries risks of unnecessarily. 1. patient with hemotoxic snake bite snake with hemotoxic patient Managing Pain pain at the bite Snake bite can often cause severe as be treated with pain killers such can etc. This paracetamol. Mild opiates like Ketorolol 50 mg. can of pain. In cases severe orally for relief of be used IV. pain, ketorolol can be given severe Handling tourniquets surge to a massive lead can removal Sudden leading to neurological paralysis, of venom etc. hypotension due to vasodilation, The tests repeated on a daily basis are : Hb, PCV, are : Hb, PCV, The tests repeated on a daily basis urine protein. CBC, urea, creatinine, platelets and normalizes The coagulation work up usually within 24 to 48 hours of treatment. Exceptions are where it may in cases of certain pit viper species, to normalize. take up to 2-3 weeks Fig. 2: Peripheral smear showing schistocytes showing smear and burr cells in a 2: Peripheral Fig. SNAKE BITE TREATMENT PROTOCOL – TREATMENT PHASE TREATMENT – PROTOCOL TREATMENT BITE SNAKE 1. 2. of the tourniquet, check for the presence * Before removal of pulse distal to the tourniquet. • which crenated RBC, A peripheral smear is also sent for in “helmet”cell ) or burr schistocytes (fragmented red cells/ envenomation suggest systemic are looked for. These cells and along with thrombocytopenia are markers for MAHA (microangiopathic haemolytic anaemia). Liver function Tests Liver (CPK) Muscle Enzymes: Creatinine phosphokinase Biochemistry: Na, K and Blood Sugar & Protein Urine: Checked for myoglobin, Haemoglobin ABO, Rh (at the earliest as blood doesn’t Blood group : clot later) Pressure/PR/RR Oxygen saturation/BP/Postural Blood Arterial Blood gases. the depending on to be repeated may have same The clinical course of the patient. • TOXICOLOGY 350 measures are usefulobjective methodstoassess this. following The effective. is neostigmine the if determine should beclosely observedThe patient for1hourto kg. IM and thedoseofatropineis0.05mg/ dose is0.04mg/kg IV.with 0.6mg.ofatropine The paediatricneostigmine administration of1.5to2mg. ofneostigmineIMtogether Test” willbeadministered.Thistestinvolves In the case of neurotoxic envenomation the “Neostigmine Russells Viper. However itisworthtryinginthese cases. pre-synaptic neurotoxinsuchasthoseoftheKraitand the overThere issomedoubt Cobra. the thoseof itsusefulnessagainst as such neurotoxins synaptic post for effective failure andneurotoxicsymptoms. It isparticularly life ofacetylcholine andcanthereforereverse respiratory Neostigmine is an anticholinesterase that prolongs the is enough). ASV vial 20 cases of majority in (Usually effective. not is polyvalent which against one as identified is species ASV repeat ASV 6hourlyuntilcoagulationisrestored,unlessa ASV administered in onehourtime.Repeat20WBCT and (continued coagulationdisturbance)another8-10vialsof of 20WBCT is evidenceofabnormality is done.Ifthere in under6hours). After initial6hours,another20WBCT until next 6 hours (Liver unable to replace clotting factors abnormality 10 vials of ASV given. No additional ASV As alreadyexplained,initialbloodtestreveals coagulation • • • • • • NEOSTIGMINE TEST NEUROTOXIC ENVENOMATION REPEAT DOSE IN HAEMATOTOXIC ENVENOMATION RUSSELL VIPER interval for2hours. minutes 15 at then and minutes 30 first intervalfor Continue tomonitorthevitalsignsat5minutes administered over 1 hour period at constant speed. shock continuethe ASV. All ASV aretobe is nothavingsignsandsymptomsofanaphylactic 15 minutesandwatch forreactions.Ifthepatient Saline andtostartwith10-15dropsperminutesfor Begin with10vialsof ASV in100mlofNormal Start IVNormalSalinewithwideboreneedle. any remainingfreeflowing venom. injected andduringthenext12hourstoneutralize neutralizing power toneutralizetheaverage amountofvenom sufficient is there with 10 that ensures vials Starting power., neutralizing sufficient (10 Vial) to250ml.Startingwith10vialensures The totalrequireddose will bebetween 100ml viper venom. 1 viali.e10ml. of ASV neutralises 6 mg.of Russells Venom. 1 ml.of ASV neutralizes0.6mg.ofRussells Viper 147 mg.+7)ofvenom. Russell’s Viper injectsonanaverage 63mg.(5to • • should bere-assessed. administered, after 1-2hours. At thispointthepatient into respiratoryfailure,thena further dose should be the symptoms have worsened or if the patienthas gone has beenunsuccessful in reducing the symptoms, or if has caused considerable confusion.Iftheinitialdose The ASV regimerelatingtoneurotoxicenvenomation hour, Neostigmineshouldbestopped. hours. Ifthereisnoimprovements insymptoms after 1 the samedoseatincreasingintervalsrepeating of2to12 IV athalfhourlyintervals for5injection,followed by positive, 0.5 mgof Neostigmine IM and 0.6 mg. Atropine of hematotoxicenvenomation. IftheNeostigminetestis Treat the patientwith10 vial of ASV initially as in thecase amount ofvenom into adultsandchildren. is targetedatneutrlisingthe venom. Snakeinjectthesame Children receive thesame ASV dosageasadults.The ASV vials toprevent recurrenceisnotnecessary. recurrence of envenomation is established. Additional No furtherdosesof ASV arerequired,unlessaproven no benefitinreversing envenomatio mechanism. Large doses of ASV, over longperiod,have hours. the bodyrecoversAfter that using itsown by few first the in possible only is synaptic envenoming neurotoxic post of “reversibility” that suggests Evidence serves nousefulpurpose. been neutralized by this point. Therefore, further ASV to theassumptionthatallcirculatingvenom wouldhave therapy should be stopped. This recommendation is due 20 vialsof ASV andissupported onaventilator, ASV Once thepatientinrespiratoryfailure,hasreceived given toaneurotoxicallyenvenomed patient. ASV. 20vialsisthemaximumdose of ASV thatshould be ASV after1-2hoursasaseconddoseanddiscontinue worsen or inrespiratoryfailurerepeat10more vials of Initial doseof10vialsgiven andifsymptomspersistor ASV IN NEUROTOXIC ENVENOMATION: ASV IN CHILDREN REPEAT DOSE – NEUROTOXIC ENVENOMATION in themeasure. improvement shouldbevisiblebyanimprovement neostigmine is20minutes,soby30minutesany is repeated.Theaverage bloodplasmatimefor measurement the minutes 10 Every recorded. and between theupperandlower incisorsaremeasured distance isselected,thebreathcountor For example, ifsinglebreathcountor inter incisor FEV1 orFVC maintained. lower incisors), Length of time upward gaze can be distance (measuredbetweenupper & the covered bythedescending eye lid),Interincisor Single breathcount,mmofIrisuncovered (amount CHAPTER 63 351 2005; 18:71-5. , Polymorphonuclear 3 2007; 101:85-90. occurs in Viperidae bites due in Viperidae occurs Soc Trop Med Hyg ASV will be discontinued temporarily. 0.5 mg of 1 ASV will be discontinued in adults. Children IM be given :1000 adrenaline to 0.01 mg/kg adrenalin IM . are given used is adrenaline if outcome patient better is There early < 20,000/mm Low Platelets leucolytosis with presence of band form, crenated leucolytosis with presence of band concentration at presentation – Haemo RBC, Dimer, – D Raised capillary leak, indirectly denotes low fibrinogen, Low serum protein and albumin, swelling haemoglobinuria, bilateral parotid Head” appearance, Giddiness, syncope “Viper bite, immediately following a snake agitated thirst. behaviour – cerebral anoxia, profound Mohapatra B, Warrell DA, SuraweeraW, Bhatia P, Dhingra DA, SuraweeraW, Mohapatra B, Warrell K, Whitaker R, Jha P. Rodriguez PS, Mishra N, Jotkar RM, Million Death Study Collaborators. Snakebite mortality in PLoS mortality survey. India: a nationally representative Negl Trop Dis 2011; 5:e1018. in India- envenomation Joseph K Joseph; Viperidae Handbook of Toxinology, Springer 2014. of cases Authenticated ID et al, First Joseph J K, Simpson by humpnosed pit viper in life threatening envenoming India- Trans R . Punde DP. Management of snakebite in rural Maharashtra experience. Natl Med J India : a 10 year COMPLICATIONS COMPLICATIONS REFERENCES ASV REACTIONS ASV BITE VIPER IN INDICATORS PROGNOSTIC POOR 2. 3. 4. Capillary leak syndrome 1. If anyaphylaxis is evident, then is evident, If anyaphylaxis • • • proteins of compact to heamorrhagins degrading the basement membranes, shifting fluid from intravascular to interstitial space. ARDS, acute kidney injury, pitutary Hypotension and, complications neurological and cardiac insufficiency are are the important locked in syndrome in elapid bites complications. usually with with usually key The failure. acute renal determining of for signs is to look treatment ASV on to decide factor be neutralized can only activity venom venom current if it is unattached.Perform a 20 WBCT and determine if present is present. If coagulopathy is any coagulatopathy If no coagulopathy treat is evident renal ASV. administer failure. is where the victim neurotoxic envenoming In case of failure respiratory ptosis, as such symptoms evidencing etc, it is probably one dose of 8 to 10 wise to administer is present. ASV to ensure that no unbound venom vials of Spontaneous systemic bleeding such as gum as gum such bleeding systemic Spontaneous etc. sites bleeding, venepuncture from bleeding Blood to 30 minutes. stops within 15 usually Post- in 6 hours. is usually restored coagulability Cobra the as such envenoming neurotoxic synaptic as early after as 30 minutes may begin to improve such envenoming Pre-synaptic neurotoxic ASV. takes a considerable time to as the krait usually Rhabdomyolysis and hemolysis Active improve. few hours and urine return to may cease within In patient its normal colour. with shock, blood after 30 minutes. pressure may increase product and has a half life of 90 hours and therefore product and has a 2 VICTIMS WHO ARRIVE LATE ARRIVE VICTIMSWHO SNAKE BITE IN PREGNANCY IN BITE SNAKE ASV IN SPECIAL SITUATION SPECIAL IN ASV ANTI HEAMOSTATIC MAXIMUM ASV DOSAGE GUIDANCE DOSAGE ASV MAXIMUM HEAMOSTATIC ANTI RECURRENT ENVENOMATION RECURRENT RECOVERY SIGNS RECOVERY A frequent problem witnessed in our country is victims in our A frequent problem witnessed days, late after the bite, often after several arrive who There is very little definitive data published on the effects the on published data definitive little very is There are Pregnant women pregnancy. snake bite during of as other victims. treated in exactly the same way Victims Requiring Life SavingVictims Surgery Life Requiring which indicate may develop symptoms rare cases, In very the to save order in required is surgery saving that life An example would be a patient who presents with victim. signs of an intracranial bleed. Before surgery can take in order in the victim place, coagulation must be restored a higher to avoid catastrophic bleeding. In such cases the on solely vials) 25 (upto justified is ASV of dose initial basis on guaranteeing a restoration of coagulation after 6 hours. The normal guidelines are to administer ASV every 6 every ASV The normal guidelines are to administer However, restored. hours until coagulation has been been 30 vials have what should the clinician do after say, persists? administered and the coagulation abnormally be that should questions a number of are There species one for considered. Firstly, is the envenoming which polyvalent ASV is effective? For examplenosed by the Hump been established that envenomation it has to normal not respond (Hypnale Hypnale) does Pit Viper case the in as, cause a be may This 2007]. al et ASV[joseph upto 3 weeks of Hypnale, coagulopathy can continue When coagulation has been restored no further ASV further no been restored has When coagulation of a recurrence should be unless proven administered, a ASV Indian established. is coagulation abnormality F(ab) • is not required in a prophylactic dose to prevent re to prevent dose is not required in a prophylactic envenomation.