Snake of medical Importance P oisonous Non- Poisonous Ptyas mucosa – Rat Snake Checkered keelback- Paani Sarpa Coelognathus helena – Common Trinket Snake( Himalayan sarpa ) Amphiesma stolatum – Buff-striped Keelback Dendrelaphis tristis – Bronzeback Tree Snake Common Name Type of Venom Common Krait Neurotoxic Banded Krait Neurotoxic Russell’s Viper Hematotoxic Green Pit Viper Hematotoxic (mild) Himalayan Pit Viper Hematotoxic (mild)
Non-Poisonous snake
Features
Common non- poisonous snakes
Indian Rat snake( Dhamin ) Seen in village and farmland Eats frogs and small birds Often mistaken for cobra due to its size and holding behavior
Checkered keelback(Paani Sarpa) Common near rivers, ponds and rice field feeds on fish and frogs
Himalayan Trinket( Chameli Sarpa) Slender hunts, rodents and birds found in forests and near human settlements
Green keelback(hariyo dhamin) Found in forests and hilly area feeds on frogs and insects Shy and harmless
Indian python ( अ ि जङगर ) Non-poisonous found in terai region, forests grasslands slow moving ,shy and non-aggressive kills prey by constriction
Poisonous Snake Common venomous snakes include: Common Krait ( Bungarus caeruleus ) Indian Cobra ( Naja naja ) Russell’s Viper ( Daboia russelii ) These snakes cause neurotoxic or hematotoxic effects, which can be fatal if untreated.
Common cobra(Goman, nag) Found in Terai region active during early morning and evening hours, warm and humid months (May to October)
Krait Common Krait(seto kalo chure sarpa) Banded krait(laxmi sanp,pahelo kalo chure sarp) found mainly in the Terai region It is nocturnal and highly active at night.
Viperadae Russel’s viper Pit viper(Haryou sarpa) Found in terai and lower hills They are active during the day and are often found in fields, grasslands.
Sign and symptoms of Non-poisonous snake bite Local pain Swelling Redness Puncture/scratch marks No neurotoxic or hemotoxic symptoms Possible mild infection if untreated
Signs and Symptoms of Poisonous snake
General Manifestations
Local effects Cobra Swelling and local pain with or without erythema or discoloration at the bite site. Blistering, bullae formation and local necrosis are also common. If it is infected, there may be abscess formation. Krait Usually do not cause signs of local envenoming and can be virtually painless. Viper Swelling, blistering, bleeding, and necrosis at the bite site, sometimes extending to the whole limb. Persistent bleeding from fang marks, wounds or any injured parts of the body. Swelling or tenderness of regional lymph node.
Systemic M anifestations Hematotoxic Bleeding may from venipuncture site, gums, Epistaxis Hemoptysis Melena, rectal bleeding Hematuria, bleeding from vagina Subconjunctival hemorrhage Petechiae, purpura, ecchymosis Neurotoxic Ptosis Ophthalmoplegia Pupillary dilatation- often non- responsive to light Inability (or limitation) to open mouth Numbness around lips and mouths Neurotoxic Tongue extrusion- inability to protrude the tongue beyond incisors teeth. Inability to swallow Broken neck sign Skeletal muscle weakness. Loss of gag reflex Paradoxical breathing Respiratory failure
Diagnosis No investigations available that can help diagnose the neurotoxic manifestations Neurotoxic
Diagnosis Hematotoxic 20- minute whole blood clotting test (20WBCT) Bleeding time (BT) and clotting time (CT) Prothrombin time and International normalization ratio (INR) fibrinogen, d- dimer Kidney function test and liver function test Complete blood count, blood group Urine for RBCs or myoglobin Creatine kinase
MANAGEMENT
TREATMENT OF SNAKEBITE ENVENOMING
Recommended F irst aid T reatment REASSURANCE Most are nonvenomous snakes. Many are dry bites. Treatable condition. IMMOBILIZAT ION With a splint or sling. Pressure immobilization in case of purely neurotoxic snake bite Pressure pad immobilization Remove rings, jewelries, tight fittings and clothing RAPID TRANSPORT To decrease the delay in accessing the emergency care and reduce mortility
Rapid clinical assessment and resuscitation A – Airway Check if the airway is clear and look for obstruction (especially in neurotoxic envenoming). Provide oxygen immediately using nasal prongs, catheter, or mask. Prepare for intubation if respiratory failure is present. B – Breathing Assess the patient’s breathing rate and effort. Provide bag-mask ventilation if breathing is inadequate. C – Circulation Monitor blood pressure and pulse . In cases like Russell’s viper bite , treat shock with: IV fluids (normal saline) , Blood transfusion if bleeding.
Cont.. D – Disability (Neurological status) Assess level of consciousness and neurological function. Look for signs of neurotoxicity : ptosis, paralysis, respiratory depression. Reassess regularly using a neurological scoring system if available. E – Exposure & Environment Fully expose patient to examine bite site and swelling. Prevent hypothermia during examination. Observe for signs of systemic envenoming (bleeding, swelling, etc.)
What to do and what not to do in snake bite
ANTIVENOM TREATMENT
Antivenom in Nepal
Indication Of Antivenom Administration Signs/Symptoms Evidence of Neurotoxicity - Ptosis - External ophthalmoplegia - Broken neck sign - Respiratory difficulty Evidence of Coagulopathy Positive 20-minute Whole Blood Clotting Test (20 WBCT) - Visible spontaneous systemic bleeding (e.g., bleeding gums) - Rapid extension of local swelling ( more than half of limb , not due to pit viper bite or tight tourniquet) Evidence of Cardiovascular Collapse - Shock and hypotension (especially in Russell’s viper bite) Evidence of Acute Kidney Injury (AKI) - Low urine output , dearranged RFT
Route of Administration Route Patient Type Dilution Administration Rate Notes IV Infusion Adult 5–10 ml/kg body weight (≈ 250–500 ml) of isotonic saline or glucose Infusion at 2 ml/min Most commonly used route Children 3–5 ml/kg body weight of isotonic saline or dextrose water Infusion at 2 ml/min IV Injection Adult/Child Reconstituted antivenom (no specific dilution mentioned) Slow IV at 2 ml/min Rarely practiced Each vial is diluted with 10 ml. of sterile water as supplied with the antivenom
Antivenom Dose Type of Envenoming Dose Dilution & Administration Repeat Dose Criteria Neurotoxic Envenoming Initial Dose: 10 vials (100 ml) Dilute with 100–400 ml of dextrose water or saline; IV infusion at 2 ml/min (over 40–60 min @ 60–70 drops/min) Only if neurological signs deteriorate (not just persist); administer 5 vials (50 ml) as IV push @ 2 ml/min Hematotoxic Envenoming (e.g., Russell’s viper) Initial Dose: Same as neurotoxic envenoming (10 vials) Same dilution and IV infusion method Repeat every 6 hours if 20WBCT or other coagulation tests remain abnormal; administer 5 vials (50 ml) as IV push @ 2 ml/min Pediatric Dose Same as adult dose Snakes inject equal venom regardless of age Same as adults
Response to treatment General symptoms may disappear vary quickly. Spontaneous systemic bleeding usually stops within 15- 30 min. Blood pressure may increase within 30-60 min. Neurotoxicity may improve as early as 30 min. Blood coagulability is usually restored in 3-9 hrs.
Reasons for failure to respond to antivenom
Supportive care
When antivenom is not available
Treatment of the Bitten Part
Prevention o f Snakebite
Cont ..
Nursing care
References National Guidelines for Snakebite Management in Nepal- 2019