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SNAKE BITES/scorpion stings Snake bite is common life-threatening in many countries. Farmers, hunters, rice-pickers are ...
Clinical features & assessment Key questions to ask a victim are: The body part bitten? How long ago? What sort of sna...
Clinical features & assessment The venom is detected from a dry swab of the bite site using  monoclonal antibody techniqu...
Clinical features & assessment
Clinical features & assessment
Management: Reassuring the patient Immobilising the bitten area to minimise venom spread Identifying the snake. Applic...
Management: All patients with suspected envenoming should be observed  for 12-24 hours, as the initial manifestations may...
Management: The inj site is observed for at least 10 mins for the redness,  hives, pruritus or other adverse effects. Th...
Management: INDICATIONS FOR ANTIVENIN ADMINISTRATION IN  SNAKE BITES Cardiogenic shock Spontaneous systemic bleeding I...
SNAKE BITES There are three types of antivenin reaction: Early anaphylactoid Pyrogenic Late. If an immediate anaphyla...
SNAKE BITES Additional antivenin (e.g. the contents of 1-5 vials) should be  administered if swelling progresses or if sy...
SNAKE BITES
SNAKE BITES
SCORPION STINGS The most important venomous animals after snakes. Most scorpion species produce a venom which causes onl...
SCORPION STINGS Two types of scorpion venom exist: 1.Venom of genera Hadrurus, Vejovis, Uroctonus only effects,  includi...
SCORPION STINGS The sharp pain after a sting is quickly followed by  paraesthesiae& numbness in the area due to periphera...
SCORPION STINGS: Management Local pain & paraesthesiae are best treated with local  compresses & oral analgesics. Patien...
SCORPION STINGS: Management Tachyarrhythmias can be treated with IV metoprolol or  esmolol. Prazosin, an α-adrenoceptor ...
SCORPION STINGS: Management
SCORPION STINGS: Management
Single-choice Qs:1. The most useful bed-side test to suggest snake bite   envenemoation is:A. Prothrombin time.B.20 minute...
Single-choice Qs:2. Management of snake bite includes all except:A.Immobilize the bittenpart.B. Apply a firm bandage.C. In...
Single-choice Qs:3.The following features occur in scorpion sting rather than snake   bites except:A. Piloerrection.B.hypo...
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Poisoning snake2012+MCQs.

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Poisoning snake2012+MCQs.

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Poisoning snake2012+MCQs.

  1. 1. SNAKE BITES/scorpion stings Snake bite is common life-threatening in many countries. Farmers, hunters, rice-pickers are at particular risk Prompt medical treatment is vital. 3-5 million victims /year, 50 000 deaths , 400 000 amputations. 40% of bites do not produce signs of envenoming. It is difficult to predict which bites will produce symptoms or the clinical outcome, all victims should be brought under medical care as quickly as possible. Poisonous species of snake fall into the families. Snake venoms are complex mixtures of proteins & small polypeptides with enzymatic activity. Snake venoms are neurotoxins, haematotoxins (haemorrhagic or coagulopathic) or cardiotoxins often occur in combination.
  2. 2. Clinical features & assessment Key questions to ask a victim are: The body part bitten? How long ago? What sort of snake? Friends / relatives will frequently bring the snake with the patient; it should be handled as little as possible since it may only be injured rather than dead. The amount of venom injected via a bite is highly variable, depending on the length of time since the snake last ate& its aggression. Snake venom detection kits are available in some countries.
  3. 3. Clinical features & assessment The venom is detected from a dry swab of the bite site using monoclonal antibody techniques. The 20-minute whole blood-clotting test is a useful bedside tool in remote areas; a 2-3 ml sample of venous blood from the victim is left undisturbed at ambient temperature for at least 20 minutes. The vessel containing the blood is then tipped once & may be compared with a normal control. If it has not clotted, there is haemostatic disturbance from systemic envenoming. All patients should have a full blood count, urea/electrolytes, liver function tests, creatine kinase, troponins, ECG.
  4. 4. Clinical features & assessment
  5. 5. Clinical features & assessment
  6. 6. Management: Reassuring the patient Immobilising the bitten area to minimise venom spread Identifying the snake. Application of a firm bandage to occlude lymphatic drainage is appropriate, but tourniquets are unhelpful since they do not prevent the spread of venom & frequently applied incorrectly. Incisions at the bite site &attempts to suck out the venom by mouth should not be made. A large-bore IV cannula inserted on an unaffected limb. BP, coagulation,renal, neurological, cardiorespiratory status must be monitored, as hypotension, anaphylactic shock, renal failure, respiratory distress may develop rapidly.
  7. 7. Management: All patients with suspected envenoming should be observed for 12-24 hours, as the initial manifestations may be delayed, especially with elapid bites. Pain/ vomiting should be managed symptomatically. Aspirin should not be used ,may aggravate bleeding. In severe coagulopathy with thrombocytopenia causing DIC, large quantities of fresh frozen plasma, cryoprecipitate , platelets are required if the response to antivenin is poor. The most appropriate therapy is timely administration of the species-appropriate antivenin when indications. Before starting antivenin, ask about history of allergy & intradermal sensitivity test performed by injecting 0.02 ml of saline-diluted antiserum at a site distant from the bite.
  8. 8. Management: The inj site is observed for at least 10 mins for the redness, hives, pruritus or other adverse effects. The shorter the interval between inj & reaction, the greater the degree of sensitivity. 0.5 ml 1:1000 adrenaline must be available when antiv given A negative skin test does not rule out a reaction following administration of the full antivenin dose. The rate antivenin should be based on the severity of the case& the patients tolerance to the antivenin. The entire initial dose should be given as soon as possible within 4 hours of the bite. In severe envenoming, antivenin given up to 24 hours after the bite has been shown to reverse coagulation deficits.
  9. 9. Management: INDICATIONS FOR ANTIVENIN ADMINISTRATION IN SNAKE BITES Cardiogenic shock Spontaneous systemic bleeding Incoagulable blood Neurotoxicity Haematuria Other evidence of haemolysis/rhabdomyolysis Rapidly progressive extensive local swelling Bites on digits by snakes with known necrotic venoms
  10. 10. SNAKE BITES There are three types of antivenin reaction: Early anaphylactoid Pyrogenic Late. If an immediate anaphylactoid reaction occurs, administration of antivenin should be immediately discontinued &the patient given an oral antihistamine or IM adrenaline ( 0.5 ml of 1:1000) as appropriate. Infusion of the antivenin can be restarted, but at a slower rate. Corticosteroids are commonly given to treat serum sickness, although their value remains to be established. Bites by large snakes may need relatively high antivenin doses, particularly in children or small adults.
  11. 11. SNAKE BITES Additional antivenin (e.g. the contents of 1-5 vials) should be administered if swelling progresses or if systemic features of envenoming increase in severity & new manifestations such as hypotension or reduced haematocrit appear. The use of ancillary drugs, such as anticholinesterases for neurotoxic envenoming, remains contentious. If pulses are lost in a bitten limb, compartment syndrome should be suspected & surgical assessment requested. Wound débridement& later skin grafting are occasionally required, especially in cobra & viper bites, but should never be carried out until the coagulation profile is normal. Awareness &avoidance of the habitat of snakes are the major means of preventing snakebite.
  12. 12. SNAKE BITES
  13. 13. SNAKE BITES
  14. 14. SCORPION STINGS The most important venomous animals after snakes. Most scorpion species produce a venom which causes only minor local reactions in humans, but in Mexico, Tunisia, Algeria, Morocco, Libya scorpion stings are a serious health hazard. Scorpions do not attack humans& escape when disturbed. Stings occur after a person accidentally steps on or involuntarily presses the scorpion (when it is trapped inside shoes or clothes) or when reaching under dead wood or stones. Clothes / shoes need to be inspected closely & shaken& sitting or sleeping places checked when camping in rural districts where scorpions are common
  15. 15. SCORPION STINGS Two types of scorpion venom exist: 1.Venom of genera Hadrurus, Vejovis, Uroctonus only effects, including sharp burning, swelling, discoloration,very rarely, anaphylaxis. In envenoming by more poisonous species, Leiurus, common in the M. East, systematic manifestations develop, transfer to ICU required. 2. Venom, of genera of the poisonous varieties of Centruroides / Mesobuthus, contains neurotoxins block sodium channels& leads to spontaneous depolarisation of parasympathetic &sympathetic nerves results in tachycardia, hypertension, sweating, piloerection, hyperglycaemia & pulm oedema (esp Mesobuthus species)& seizures.
  16. 16. SCORPION STINGS The sharp pain after a sting is quickly followed by paraesthesiae& numbness in the area due to peripheral nerve effects, muscle fasciculation& finally drowsiness. With Centruroides& Mesobuthus there is no swelling at the sting site.
  17. 17. SCORPION STINGS: Management Local pain & paraesthesiae are best treated with local compresses & oral analgesics. Patients with significant envenoming should be hospitalised for at least 12 hours& observed for cardiovascular / neurological sequelae. More severe symptoms may require airway support& 1-2 vials of IV antivenin. The effectiveness of antivenin is controversial, but it is beneficial in the very young, the elderly or those with severe hypertension. True anaphylaxis to antivenin occurs rarely. Serum sickness is common after antivenin but is usually self- limiting & easily controlled with corticosteroids/histamines.
  18. 18. SCORPION STINGS: Management Tachyarrhythmias can be treated with IV metoprolol or esmolol. Prazosin, an α-adrenoceptor antagonist, is indicated if hypertension or pulmonary oedema develops. Prazosin also stimulates the secretion of insulin (which often falls during envenoming) & prevents hyperglycaemia. Other treatments, as calcium or sympathomimetic drugs, are of little value.
  19. 19. SCORPION STINGS: Management
  20. 20. SCORPION STINGS: Management
  21. 21. Single-choice Qs:1. The most useful bed-side test to suggest snake bite envenemoation is:A. Prothrombin time.B.20 minute whole blood clotting test.C. INR.D.Plateletes count.E. PTT.
  22. 22. Single-choice Qs:2. Management of snake bite includes all except:A.Immobilize the bittenpart.B. Apply a firm bandage.C. Incision & sucking of the bittensite.D. IV cannula on unaffected limb.E.Reassure the ptient.
  23. 23. Single-choice Qs:3.The following features occur in scorpion sting rather than snake bites except:A. Piloerrection.B.hypoglycemia.C.Hyperglycemia.D. Hypertension.E.siezures.

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