SNAKE BITE presentation... Ppt..........

Snake bite

1. SNAKE BITE Dr. Soujanya Assistant Professor

2. EPIDEMIOLOGY Recent estimates - worldwide each year 1.2 million to 5.5 million snakebites occur With 4 lakh to 1crore envenomation And 20,000 to 1lakh deaths

3. VENOMOUS SNAKES FOUND IN INDIA Family Specific name Common name Viperidae Daboia russalie Echis carinatus Russell’s viper Saw scaled viper Hydrophidae Enhydrina schistosa Sea snake Elapidae Bungarus fasciatus Bungarus caeruleus Naja naja Ophiophagus hannah Banded krait Common krait Spectacled cobra King cobra

4. FIELD MANAGEMENT Rapid transport to medical facility to provide supportive care (ABC ) Any jewellery or tight fitting clothing near bite should be removed to avoid constriction from anticipated soft tissue swelling Apply splint to bitten extremity to limit movement and lessen bleeding

5. CLINICAL PRESENTATION

6. CLINICAL PICTURE DEPENDS ON- Species involved Anatomic location of bite Amount of venom injected Season of the bite Whether snake is fed or unfed Area covered or uncovered Dry or incomplete bite Multiple bites Venom injection in the vessel Weight of victim Time elapsed between bite and administration of ASV

7. Non venom related symptoms NON SPECIFIC SYMPTOMS RELATED TO ANXIETY Palpitations, sweating, tremulousness, tachycardia, tachypnoea, elevated BP , cold extremities and paresthesia May have dilated pupils – s/o sympathetic overactivity SIGNS AND SYMPTOMS OF ENVENOMATION Redness, increased temperature, persistant bleeding and tenderness locally

8. DRY BITE Bites by non venomous snakes/ bites by venomous species not accompanied by injection of venom 10-80% range of dry bites for various poisonous snakes Symptoms due to anxiety and sympathetic overactivity may be present Symptoms associated with panic or stress sometimes mimic early envenoming symptoms

9. NEUROPARALYTIC ( Progressive weakness, elapid envenomation) Typical symptoms within 30 min – 6 hrs in cobra bite 6– 24 hrs in krait bite ( can occur upto 36 hrs) 5D’s and 2P’s 5D’s – diplopia, dysarthria, dysphonia, dyspnea , dysphagia 2P’s – ptosis, paralysis Related to 3 rd , 4 th , 6 th and lower cranial nerve paralysis Finally paralysis of intercostal and skeletal muscles occur in descending order Other signs of impending respiratory failure are diminished

10. To identify impending respiratory failure in adults- SINGLE BREATH COUNT – number of digits counted in one exhalation - >30 is normal BREATH HOLDING TIME – Breath held in inspiration - >45 sec is normal Ability to complete one sentence in one breatth Refer to higher centre immediately after giving Atropine Neostigmine ( AN ) injection for intensive monitoring

11. VASCULOTOXIC ( hemotoxic or Bleeding; viperine envenomation) LOCAL MANIFESTATIONS Prominence – Russel’s viper > saw scaled viper > pit viper MANIFESTATIONS Local swelling, bleeding, blistering and necrosis Tender enlargement of local draining lymphnode Pain at bite site and severe swelling leading to compartment syndrome – identified by Pain on passive movement Absence of peripheral pulses Hypoesthesia over fuels of nerve passing through compartment

12. SYSTEMIC MANIFESTATIONS Visible systemic bleeding from the action of hemorrhagins Bleeding/ecchymosis @ injection site Skin and mucous membranes show E/o Petechiae, purpura, ecchymosis, blebs and gangrene Acute abdominal tenderness –s/o GI or retro peritoneal bleeding Lateralising neurological symptoms such as assymetrical pupils – indicative of intracranial bleeding Consumptive coagulopathy detected by 20WBCT develops as early as within 30 min from time of bite (may be delayed)

13. LIFE THREATENING COMPLICATIONS (due to renal involvement) Presents with hematuria,hemoglobinuria, followed by oliguria, anuria with Acute kidney injury (AKI) Bilateral renal angle tenderness Passage of discoloured urine( reddish or dark brown) or declining urine output Deteorating renal signs – rising serum creatinine, urea , or potassium some species e.g. Russell’s viper and saw scaled vipers frequently cause acute kidney ininjury LONG TERM SEQUELAE – E.g. pituatary insufficiency with Russell’s viper, sheehan’s syndrome or amenorrhea in females

14. PAINFUL PROGRESSIVE SWELLING Indicative of local venom toxicity Local necrosis, swollen limb, taut and shiny skin, blistering with reddish black fluid at and around bite site Ecchymosis due to destruction of vessel wall by venom Significant painful swelling potentially involving whole limb and extending onto the trunk Leads to compartment syndrome.

15. MYOTOXIC (sea snake bite) Muscle aches, muscle swelling, involuntary contraction of muscles Passage of brown urine Compartment syndrome, cardiac arrhythmias due to hyperkalemia, acute kidney injury due to myoglobinuria, and subtle neuroparalytic signs

16. OCCULT SNAKE BITE Krait bite victims often present early morning with paralysis with no local signs Typical presenting history – pt was healthy at night, in the morning gets up with severe epigastric/umbilical pain with vomitings persistent for 3-4 hrs and follwed by typical NEUROPARALYTIC symptoms within next 4-6 hrs ( No history of snake bite) Unexplained respiratory distress in children in the presence of ptosis or sudden onset of acute flaccid paralysis in a child ( locked in syndrome) - highly suspicious of krait bite in endemic areas Early morning symptoms with Acute abdomen with or without neuroparalysis can be mistaken for acute appendicitis, Stroke ,GB syndrome Strong clinical suspicion and careful examination can avoid unnecessary investigations and help in avoiding undue delay in initiation ofASV

17. PATIENT ASSESSMENT ON ARRIVAL TO HOSPITAL

18. CRITICAL VASCULOTOXIC patients Present with Bleeding from multiple orifices with hypotension, reduced urine output, obtunded mentation, cold extremities Need urgent attention and ICU care for volume replacement, pressor support, dialysis and infusion of blood and blood products NEUROPARALYTIC Patients Present with respiratory paralysis, tachypnoea or bradypnoea or paradoxical respiration, obtunded mentation and peripheral skeletal muscle paralysis Need urgent ventilator support with endotracheal intubation

19. NON-CRITICAL TAKE HISTORY REGARDING Time elapsed since the snake bite What the victim was doing at the time of bite H/o sleeping on floor previous night If any traditional practices have been used Brief medical history ( date of last tetanus immunization, use of any medication, presence of any systemic disease and history of allergy) If the victim has brought the snake, identification of species should be carried out carefully, since crotalids can envenomate even when dead.

20. PHYSICAL EXAMINATION And 20- min WBCT Careful assessment of bite site and signs of local envenomation and examination of patient Monitor vitals and Do 20 minute whole blood clotting time If clotted, the test should be carried out every 1 hr from admission for three hrs and then 6 hrly for 24hrs In not clotted, repeat 6 hrs after administering loading dose of ASV In case of neurotoxic envenomation repeat clotting test after 6 hrs

21. INVESTIGATIONS 20 minute whole blood clotting time – to diagnose coagulopathy Complete blood picture – to determine degree of hemorrhage or hemolysis and to detect thrombocytopenia RFT and LFT’s Coagulation studies- to diagnose consumptive coagulopathy Measurement of creatine kinase and testing of urine for blood or myoglobin- for suspected rhadomyolysis ABG, ECG, Chest X Ray – in severe envenomations or in pts with significant comorbididties

22. HOSPITAL MANAGEMENT ABC Monitoring of vitals , cardiac rhythm , oxygen saturation and urine output Secure two large bore iv lines in unaffected extremities Fluid resuscitation with isotonic saline 20-40 ml/kg iv ; if hemodynamic instability is present (5% Albumin can be tried if response to saline is inadequate) Vasopressors ( norepinephrine , dopamine) – only if venom induced shock persists after aggressive volume resuscitation and antivenom administration Invasive hemodynamic monitoring ( central venous / continous arterial pressures ) is helpful but risky if coagulopathy has devoloped

23. DO’S 💯 ☑️ Thorough history and complete physical examination Removal of bandages and wraps applied in the field Objective evaluation Leading edge of the swelling Ecchymosis Tenderness Measurement of limb circumference every 15 min until local tissue effects have stabilised Victims of neurotoxic envenomation need close monitoring for evidence of cranial nerve dysfunction (ptosis) – may precede overt signs of impending airway compromise necessitating ET intubation and Mechanical ventilation

24. AVOID❌ Incising and suction to bite site ( exacerbates local tissue damage ; increases risk of infection) Application of poultices,ice and electric shock Venom sequestration devices Eg: lympho occlusive bandages ,torniquets ( intensify local tissue damage by restricting the spread of potentially necrotising venom) Tourniquet use can result in loss of function,ischemia and limb amputation even in the absence of envenomation

25. ANTIVENOM – MAINSTAY OF R X Produced by injecting animals ( horses/sheep) with venoms from medically important snakes GOAL – to allow antibodies to bind and deactivate circulating venom components before they attach to target tissues and cause deleterious effects Limited efficacy in preventing local tissue damage caused by necrotising venoms Should be administered as soon as need for it is identified ( Eg cranial nerve dysfunction as evidence of neurotoxicity) Effective only in reversing active venom toxicity ( no benefit in reversing effects that have been already established Eg : renal failure , paralysis

26. INDICATIONS FOR ANTIVENOM ADMINISTRATION Significant progressive local findings ( Eg : soft tissue swelling that crosses a joint) Involvement of more than half of bitten limb Rapidly spreading Extensive blistering or bruising Severe pain Evidence of systemic envenomation

27. PRECAUTIONS DURING ASV ADMINISTRATION ASV supplied in dry powder form has to be reconstituted by diluting in 10 ml of distilled water or normal saline Should be given only by IV route, slowly, with physician at bed side during initial period Rate of infusion can be increased gradually in the absence of a reaction until full starting dose has been administered ( over ~1hr) Epinephrine should be kept ready Must never be given IM route because of poor bioavailability Do not inject ASV locally at the bite site – not effective, extremely painful and may increase intra compartmental pressure

28. DOSE OF ASV FOR NEUROPARALYTIC SNAKEBITE ASV 10 vials stat as infusion over 30 minutes followed by 2 nd dose of 10 vials after 1 hour if no improvement within 1 st hr

29. FOR VASCULOTOXIC SNAKEBITE Low dose infusion therapy- 10 vials for Russell’s viper or 6 vials for saw scaled viper as stat infusion over 30 minutes followed by 2 vials every 6 hrs as infusion in 100ml of normal saline till clotting time normalizes or for 3 days which ever is earlier OR High dose intermittent bolus therapy- 10 vials of polyvalent ASV stat over 30 min as infusion, followed by 6 vials 6 hourly as bolus therapy till clotting time normalizes and/ or local swelling subsides No ASV for sea snakebite or pit viper bite ,as available ASV does not contain antibodies against them The range of venom injected is 5mg- 147mg; the total required dose range between 10 and 30 vials as each vial neutralizes 6mg of Russell’s viper venom.

30. REPEAT DOSE OF ASV IN VASCULOTOXIC OR HEMOTOXIC ENVENOMATION Administer ASV every 6 h until coagulation is restored If 30 vials of ASV have been administered reconsider whether continued administration ofASV is serving any purpose, particularly in the absence of proven systemic bleeding IN NEUROTOXIC ENVENOMATION Repeat ASV when there is worsening neurotoxic or cardiovascular signs even after 1-2 hr Maximum dose – 20 vials If coagulation abnormality persists, give FFP or cryoprecipitate ( fibrinogen, factor VIII ), fresh whole blood, if FFP not available or platelet concentrate

31. ADVERSE REACTIONS TO ANTIVENOM EARLY ANAPHYLAXIS LATE SERUM SICKNESS Clinical features Tachycardia, rigors, vomiting, urticaria to severe dyspnea, laryngeal edema bronchospasm, hypotension Treatment stop antivenom temporarily Im epinephrine 0.01mg/kg upto 0.5mg Iv antihistaminic diphenhydramine Glucocorticoid Hydrocortisone 2mg/kg upto 100mg Clinical features Devolops 1-2 weeks after ASV administration Myalgias, Arthralgias, fever, chills, utricaria, lymphadenopathy, renal/ neurological dysfunction Treatment Systemic glucocorticoids Oral prednisolone 1-2 mg/kg daily until symptoms resolve Taper over 1-2 weeks Antihistaminics and analgesics for supportive treatment

32. MANAGEMENT OF NEUROTOXIC ENVENOMATION Oxygen support Assisted ventilation- The duration of mechanical ventilation in snakebite victims is short since neuroparalysis reverses quickly with prompt administration of ASV ASV alone cannot be relied uponto save the life of a patient with bulbar and respiratory paralysis Their condition improves after Atropine neostigmine (AN) therapy

33. ATROPINE NEOSTIGME (AN) DOSE- Atropine 0.6 mg followed by neostigmine (1.5mg) to be given IV stat Repeat dose of neostigmine 0.5mg with Atropine every 30 min for 5 doses Thereafter to be given as tapering dose at 1 hr, 2hr, 6 hrs and 12 hrs Majority improve within first 5 doses If neostigmine is effective, ptosis improvement is visible after 30 min of dosage Stop AN dosage if- Complete recovery from neuroparalysis ( cobra bite) Side effects – fasciculations or bradycardia No improvement after 3 doses ( krait bite) Krait affects pre- synaptic fibres where calicium ion acts as NT Give Inj. Calicium gluconate 10ml IV slowly over 5-10 min every 6 th hrly and continue till nueroparalysis recovers ( may last 5-7 days)

34. MANAGEMENT OF VASCULOTOXIC SNAKEBITE Strict bed rest to avoid even minor trauma Screen for hematuria, hemoglobinuria, myoglobinuria by Dipstick method Volume replacement - If patient has signs of intravascular volume depletion, Give fluid challenge with 2 litres isotonic saline over one hr Fluid challenge must be stopped immediately if pulmonary edema devolops Forced alkaline diuresis (FAD) - If the patient has oliguria or dipstick positive for blood give a trial of FAD within first 24 hrs of the bite to avoid pigment nephropathy leading to ACUTE TUBULAR NECROSIS Delayed FAD has no role

35. SEQUENCE OF FAD Inj. Furosemide 40mg IV stat Inj. Normal saline 500 ml + 20 ml of NaHCO 3 over 20 min Inj. Ringer’s lactate 500ml + 20 ml of NaHCO 3 over 20 min Inj. 5% dextrose 500ml + 10 ml of KCL over 90 min Inj. Mannitol 150 ml over 20 min Whole cycle completes in 2h 30 min and urine output of 3 ml/min is expected If patient responds to First cycle continue for 3 cycles If there is no response to furosemide discontinue FAD and refer patient for dialysis Dialysis is indicated if blood urea > 130mg/dl ; sr.creatinine > 4 mg/dl

36. FOR COAGULOPATHY In case of prolonged CT, PT ,APTT patient needs FFP administration FFP should be given after ASV administration for rapid resoration of clotting function Administer 10-15 ml/kg of FFP within over 30-60 min within 4 hrs of ASV administration Aim is to restore coagulation function (i.e, INR < 2, at 6 hr after ASV administration was commenced) Heparin is ineffective against venom induced thrombosis and may cause bleeding- should never be used

37. MANAGEMENT OF SEVERE LOCAL ENVENOMING If ASV is NOT administered - local necrosis,intracompartmental syndrome and even thrombosis of major vessels are more likely Surgical intervention may be needed but risks of surgery must be outweighed against life threatening complications of local envenoming For cellulitis Give prophylactic broad spectrum antibiotics- Inj. Amoxyclav 1.2 g IV TID for first 7 days ; then switch to oral Tab. Amoxyclav 625 mg TID for further 3-7 days Inj. Metronidazole 400mg IV TID for 7 days Reduce dosage in patients with acute kidney injury in viper bites as these drugs are excreted through kidneys

38. RECOVERY PHASE / ADEQUATE RESPONSE TO ASV Response to ASV infusion is marked by normalisation of BP , Within 15-30 min Bleeding stops , though coagulation profile takes upto 6 hrs to normalise Neurotoxic envenoming of cobra bite ( post synaptic) begins to improve within first 30 min , but patients may require 24-48 hrs for full recovery Active hemolysis and rhabdomyolysis may cease within few hrs and the urine returns to its normal colour ( red colour may persist for some days if damage to renal papillae occurred)

39. OTHER MEASURES Clean the bite site with povidine iodine solution For progressive swelling – limb elevation and glycerine + MgSO 4 dressings can help Leave blisters alone; Allow them to heal spontaneously If there is local necrosis, excise and apply saline dressings Administer booster dose of Tetanus toxoid injection, if not vaccinated earlier or vaccination history is unreliable For mild pain – Tab paracetamol and for severe pain- Tramadol oral or iv can be given Morbidity and mortality depends on the age and size of victim, comorbid conditions as well as nature of first aid given

40. DISCHARGE AND FOLLOW UP If no symptoms and signs develop after 24 hrs ,the patient can be discharged Keep the patient under observation for 48 hrs if ASV was infused At the time of discharge patient should be advised to return to emergency if- Worsening of Pain and swelling at the bite site Evidence of Bleeding Difficulty in breathing Altered sensorium Reduced urine output Patients should as be explained about signs and symptoms of serum sickness which may manifest after 5-10 days

41. REFERENCES HARRISONS 21 ST EDITION

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