CME Snake Bite.pptx snake bite snake bite

toxin ed good readup on poison like snake

1. Snake bite & Drug poisoning Presenter : HO DEVEEN Supervisor : DR ROHAYU

2. Classification There are several families of snakes in Malaysia that are venomous. All members of the family of Elapidae, Viperidae and a few in the family Natricidae are potentially dangerous to humans when bitten. Elapidae Natricidae Viperidae True Viper ( V i per i n a e ) P i t V i pe r s (Crotalinae) Red-necked Keelback (Rhabdophis S u b m i n iat u s )

3. Elapidae Cobras, king cobra, kraits, coral snakes, sea snakes and their allies. long, thin , with large smooth symmetrical scales (plates) on the top (dorsum) of the head. Hv relatively short fixed front fangs . No loreal scale between the pre-ocular and nasal scales. Some (cobras) - raise the front part of their body off the ground, spread & flatten the neck to form a hood. Naja sumatrana - spray its venom for 1m/more towards the eyes of perceived enemies. Sea snakes - flattened paddle-like tails and their ventral scales are greatly reduced in size or absent. Viperidae Hv relatively long fangs - normally folded against the upper jaw and are erected during a bite . Special sense organ (the loreal pit organ,situated between the nostril and the eye ) - detect their warm-blooded prey. The toxinology of venoms from crotalinae snakes is significantly different from that of venoms from viperinae snakes. Natricidae Medically important : the red-necked keelback ( Rhabdophis subminiatus ) - potential to cause significant coagulopathy . Several other species of the genus occur in malaysia & their medical significance is so far unknown.

4. Identify snake by it’s exernal appearance/ match with pictures Look for fangs (use forceps) *fang marks- 2 prick marks ~ 1.25- 2.5cm apart Absent: non-venomous Present: Venomous Short anterior fangs Long Anterior Fangs Flat oar-like tail Large shield scales on head Distinct triagular head Hydropiidae (Sea Snakes) Elapidae (cobras, kraits, coral snakes) Viperidae (Vipers)

5. Species Identification The snakes can be recognized by their morphological features such as : Size Shape Colour Markings Behaviour Some patterns (alternating black and yellow circumferential bands of the banded krait) are distinctive for certain species. Proper identification of the snake is possible only by examining the snake if it was killed or restrained and brought to the hospital. Verification of snake identification is best to be performed by experts .

6. Elapidae C o b r a s Kraits Coral snakes

7. Naja kaouthia / Monocled cobra / Ular senduk LOCAL EFFECT SYSTEMIC EFFECT Pain Swelling Tissue damage Paralysis Leucitus monocled Cobra Presence of a white ring when seen from the back

8. Naja sumatrana / Equatorial spitting cobra / Ular senduk sembur LOCAL EFFECT SYSTEMIC EFFECT Pain & swelling Local necrosis with or without paralysis Venom opthalmia Local necrosis with or without paralysis Cardiac dysrythmia

9. Ophiophagus Hannah / King cobra / Ular tedung selar LOCAL EFFECT SYSTEMIC EFFECT Pain Swelling Tissue damage Paralysis

10. Kraits Ular Katang Tebu Ular Katang Kepala Merah LOCAL EFFECT SYSTEMIC EFFECT None or minimal Paralysis

11. Coral snakes (landsnakes) LOCAL EFFECT Mild to moderate SYSTEMIC EFFECT Potential paralysis (limited case reports) Banded pattern on the ventral part

12. Sea snakes / Ular laut LOCAL EFFECT Minimal SYSTEMIC EFFECT Rhabdo m y olysi s causing renal failure & hyperkalaemia Paralysis

13. Viperidae True Viper (Viperinae) Pit Vipers (Crotalinae)

14. Calloselasma rhodostoma Malayan pit viper (Ular kapak bodoh) Ovophis convictus Mountain pit viper (Ular kapak gunung) LOCAL EFFECTS Pain, swelling, bruising, blistering, necrosis, bleeding S Y S T E M I C EFFECTS Consumptive coagulopathy, t h r o m b o c y t o pe n i a LOCAL EFFECTS Pain, swelling, bruising, bleeding

15. LOCAL EFFECTS Pain, swelling, bruising, bleeding SYSTEMIC EFFECTS Consumptive coagulopathy, t h r o m b o c y t o pe n i a Crytelytrops p u r p u r e o m a c u l a t u s Mangrove pit viper (Ular kapak bakau) Trimeresurus (Popeia) fucata Thai peninsula pit viper Trimeresurus (Popeia) buniana Tioman island pit viper (Ular kapak Tioman) Trimeresurus (Popeia) nebularis Cameron pit viper (Ular kapak Cameron)

16. LOCAL EFFECTS Pain, swelling, bruising, bleeding SYSTEMIC EFFECTS Consumptive coagulopathy, t h r o m b o c y t o pe n i a Trimeresurus (Parias) hageni Hagen’s green pit viper Trimeresurus (Parias) sumatranus Sumatran pit viper Trimeresurus wiroti Leaf nose palm pit viper

17. Tropidolaemus wagleri / Wagler’s or temple pit viper / Ular kapak tokong 1 8 M al e F e m al e Size difference between male and female LOCAL EFFECT SYSTEMIC EFFECT Pain S w e lli n g Does not cause coagulopathy

18. Natricidae Rhabdophis s u b m i n i a t u s Red-neck keelback These snakes are commonly found near water, lakes, ponds, and in gardens. Systemic effects: Intracranial bleed. Nausea. Coagulopathy. DIC.

19. Local symptoms and signs fang marks local pain local bleeding bruising lymphangitis (raised red lines tracking up the bitten limb) lymph node enlargement inflammation (swelling, redness, heat) blistering local infection, abscess formation necrosis

20. - Neurotoxins - Myotoxins - Hematotoxins ew ouse an’s life ery appening” “ v e r y Types of Snake Venoms

21. Elapidae N e u r o t o x i c venom Toxin (proteins) bind to acetylcholine receptors at the motor endplate → release acetylcholine at the nerve endings at neuromuscular junctions causing damage, preventing further release of transmitter → paralysis.

22. Viperidae H a e m a t o t o x i c venom serine proteases & procoagulant enzymes (thrombin-like /activate factor X, prothrombin & other clotting factors) These enzymes stimulate blood clotting with formation of fibrin in the blood stream → cause paradoxic incoagulable blood because most of the fibrin clot is broken down immediately by the body’s own plasmin fibrinolytic system. Sometimes within 30 minutes of the bite, the levels of clotting factors are so depleted (“ consumption coagulopathy ”) that the blood will not clot.

23. Spontaneous systemic bleeding Bilateral chemosis (conjunctival oedema) He m o p t y s i s I n t r ac r ania l bleeding Spo nt aneou s Gum bleeding

24. Neurotoxins Drowsiness, paraesthesiae abnormalities of taste and smell “heavy” eyelids - ptosis ,external ophthalmoplegia paralysis of facial muscles and other muscles innervated by the cranial nerves nasal voice, aphonia regurgitation through the nose, difficulty in swallowing secretions respiratory and generalised flaccid paralysis.

25. Myotoxins Generalized pain, stiffness and tenderness of muscles Trismus Skeletal muscle breakdown Myoglobinaemia and myoglobinuria develop 3–8 hours after the bite  Acute renal failure with hyperkalemia within 6-12hours Respiratory & cardiac arrest

26. cobra-spit ophthalmia (eye injuries from spitting cobras) intense burning, stinging pain, followed by profuse watering of the eyes with production of whitish discharge, congested conjunctivae, spasm and swelling of the eyelids, photophobia, clouding of vision and temporary blindness

27. Clinical Assessment WHEN Exact date and time (monitor progression of signs & symptoms) WHERE Possible specied involved. HOW What was the patient doing before the bite? Particular behaviour of snake (hooding/spitting). Number and duration of bites. Fate of the snake – escaped/captured/killed. Description of the snake & pictures if available. WHERE Part of the body bitten by the snake. WHAT Manipulation/primary treatment – tourniquet, cutting the wound, suction, apply traditional medications. Treatment by healthcare facility – medication given, procedures done. Anaphylaxis risk - determine allergies, history of snake bite or antivenom administration, history of anaphylaxis, history of exposure to snakes (e.g., snake handlers, snake catchers) Obtain targeted history

28. General N& V, malaise, abdominal pain, weakness,drowsiness, prostration. Cardiovascular Dizziness, fainting or light-headedness, collapse, shock, hypotension, cardiac arrhythmias and pulmonary oedema. Haematology Prolonged bleeding from the bitten/venepuncture site, conjunctiva, oral cavity, petechial rashes or bleeding from occult sites (GI, urinary, intracranial bleeding, APH). Neurological Descending type of paralysis, ptosis, external opthalmoplegia, paralysis of facial muscles and other muscles innervated by cranial nerves. The patient may have a nasal voice, aphonia or dysphagia, regurgitation through the nose, difficulty in swallowing secretions leading to respiratory and generalised flaccid paralysis. Musculoskeletal Generalised severe myalgia, stiffness, tenderness, dark-coloured & renal urine, and oliguria/anuria. Signs & symptoms

29. Resuscitation Assess for airway and breathing problem due to paralyzing neurotoxic effect. Assess local wound and control bleeding as necessary. General examination Assess vital signs – BP, PR, RR, SpO 2 , pain score, temperature. Bite site examination Look for puncture wound (fang/teeth marks), swelling, inflammation, bruising (early sign of dermonecrosis), blistering. Initiate RPP measurement. DO NOT mark the wound with permanent marker, use removable tape for labelling. Take serial good quality picture to monitor progress. Draining lymph nodes Palpate for tenderness or enlargement (serial assessment). Systemic signs Assess for: General: non-specific features (nausea, vomiting). Neurotoxic effect. Coagulopathy due to haematotoxic effect. Rhabdomyolysis. Examination

30. I n v e s ti g a ti o n s Coagulation profile: Prolong APTT, INR. Repeat 6-hrly. FBC: Low Hb, raised Hct & low platelet in pit vipers bite. Renal profile: Electrolyte imbalance (repeated vomiting), early hyperkalaemia (rhabdomyolysis), rise in creatinine (renal failure) - in sea snake bites Creatine kinase: Early detection of rhabdomyolysis. Urinalysis: Assess myoglobinuria, haematuria, proteinuria. LFT: Rise in liver enzymes due to mild hepatic dysfunction after severe local muscle damage. ECG: To detect arrythmias in Naja species bite. ABG: To monitor and assess respiratory dysfunction, to detect metabolic acidosis in renal failure. D-dimer and fibrinogen level: Raised if coagulopathy present.

31. First aids REFER AHA2010. Part17 – first aid Reassure the victim Immobilize the bitten limb Avoid any interference with the bite wound Apply a constricting band proximal to the wound – loose enough to admit a finger between the band and the area of wound (applied in 30min of bite) should not be released until the patient is under medical care in hospital & resuscitation facilities are available. Try to get the snake identified/bring it along (make sure it is dead!)

32. Transport to Hospital where they can receive medical care (dispensary or hospital) as quickly Any movements reduced to an absolute minimum to avoid increasing the systemic absorption of venom If possible, patients should be placed in the recovery position, in case they vomit

33. Hospital treatment triage A irway B reathing (respiratory movements ) C irculation (BP, PR, arterial pulse) D isability of the nervous system (level of consciousness) E xposure and environmental control

34. Physical examination Examination of the bitten part - extent of swelling, tenderness, local LN enlargement, blistering, necrosis General examination Skin and mucous membrane – petechiae , purpura , ecchymoses Abdominal tenderness- abd /retroperitoneal bleeding Loin pain – acute renal ischemia ( Russel’s viper)

35. Generalised rhabdomyolysis Painful active and passive movements Myoglobinuria Neurotoxic envenoming: Bulbar and respiratory paralysis Ptosis Opthalmoplegia Trismus “Broken neck sign” : muscle flexing the neck maybe paralyzed

36. Initial managements Close VS monitoring Oxygen supply IV cannula Input output charting Blood and urine investigations Circulation chart of bitten limbs – documentation & marking of level and size of swelling

37. FYI

38. • GENERAL MANAGEMENT Immobilize bitten limb & examine the bite site Position = neutral position / same level as the heart . X IM injections = pit-viper snakebite victims (risk of haematoma, potential risk of coagulopathy) → oral/IV preferred. Venom exposure in the eye - eye irrigation with copious amounts of normal saline (5 to 10 litres). 5. In severe pain: analgesic X NSAIDS in pit-viper bite. Administer anti-venom as indicated. If bleeding : DO NOT GIVE BLOOD AS A SUBTITUTE to antivenom Examine the bite site Swelling Bleeding N e u r o v a s c u l a r compromise Clinical finding suggesting neurovascular compromise : Serial monitoring with intracompartment pressure measurement or Bedside doppler

39. • ANTIVENOM THERAPY Definitive tx for snake envenomation. Types: Monovalent antivenom : Ig for venom of a single species. Polyvalent antivenom : Ig to mixture of venoms from different species. Acts as immunotherapy : The choice of antivenom is clear provided the diagnosis of envenoming species is correct, or the syndrome approach is rightly applied. The dosing regimen requires optimal monitoring of syndrome progression and clinical judgment from case to case. ANTIVENOM VENOM TOXINS x toxins inactive + Enhancing toxin elimination from body binding to venom toxins Immunocomplex

40. Indications Systemic manifestations Haemostatic abnormalities. Neurotoxic signs. Cardiovascular abnormalities. Acute renal failure. Haemoglobinuria/myoglobinuria. Local manifestations Local swelling involving more than half of the bitten limb (in the absence of a tourniquet) within 48 hours of the bite. Rapid extension of swelling (for example, beyond the wrist or ankle within a few hours of bite on the hands or feet). Enlarged tender lymph nodes draining the bitten limb. In Malaysia Depend greatly antivenom from Thailand (QSMI) Dosage Low dosage (Elapid venoms) Higher dose ( Vipenid / Crotalid venoms) Administration Choices of antivenom done by trained physician IV Adrenaline should be prepare to treat possible anaphylaxis reaction Even if systemic envenoming has persisted for weeks : CAN BE REVERSED local necrosis of bite can be prevented if antivenom is given few hours after the bite

41. After antivenom infusion. Must monitor at least 1 hour after infusion Response Generally : N&V, generalized aches/ pain may dissapear Spontaneous systemic bleeding : Stops within 15- 30 minutes Blood coagulability : Restored in 3-9 hours In shock pt : BP will raise within first 30-60 minutes / bradycardia may resolve Active haemolysis / Rhabdomyolisis : ceases after few hours

42. Criteria for repeating initial dose 1. Blood incoagulability is persistence / recurrence in 6 hours Pt bleed briskly Deteriorating neurotoxicity / CVS Tx of bitten part DO NOT DO FASCIOTOMY antivenom should be optimized . IX: Tissue pressure measurement Necrotizing Fascitis : Managed with broad spectrum antibiotics + antivenom + debridement REPEAT INITIAL DOSE WITHIN 1-2 HOURS

43. Antivenom reactions Early anaphylactic reactions (10-180min)- IV Adrenaline can be given Pyrogenic / endotoxin reaction (1-2H)- corticosteroids can prevent delayed and recurrent anaphylaxis Late serum sickness reaction (Develop 1-12, mean 7 days after treatment)- treated with prednisolone

44. Mx of Venom Ophthalmia Commonly in Naja Sumatrana (Spitting Cobra) Signs & symptoms severe stinging pain diminution of vision excessive watering in eyes severe blepharospasm corneal erosion After copious irrigation Look for any snake bite (Fluorescein stain : TRO corneal abrasion) Refer to opthal Topical analgesic Atropine Topical antibiotics (When there is corneal abrasion)

45. Supportive management Anti-cholinesterases C o br a s A n t i b i o t i c s Presence of local tissue necrosis / dermonecrosis Extensive tissue damage ( eg : bitten by Phyton)

46. Follow up / Rehabilitation Systemic envenomation Advised to go to hospital if antivenom related illness develop Lab testing 5-7 days post discharge (review the PT ) Local envenomation Patient may need to come for daily dressing Patient with co-morbidity (DM/ immunocompromised) Refer to plastic surgery / ortho surgeon Refer to Physiotherapy / Occupational therapist OTHER THAN TREATING PT PHYSICALY, we also need to address patient psychosocially. Pt may have PTSD.

47. SUMM A R Y References Guideline: Management of Snake Bite, MOH Malaysia (2017). Guidelines for the management of snake-bites, WHO (2010).