Upload
remedy
View
48
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Snake Bite ,Bee sting and Scorpian Bite. Dr Pavan .M MD(A &EM), VMKVMC. Epidemiology. 3 million bites and 1,50,000 deaths/year from venomous snake worldwide. Bites highest in temperate and tropical regions. 3000 species of snakes, out of them only 10-15% of snakes are venomous - PowerPoint PPT Presentation
Citation preview
Dr Pavan .M MD(A &EM), VMKVMC
Epidemiology3 million bites and 1,50,000 deaths/year
from venomous snake worldwide. Bites highest in temperate and tropical
regions.3000 species of snakes, out of them only
10-15% of snakes are venomous97% of all snake bites are on the
extremities
Common Snakes - INDIA
Cobras(nagraj) –Naja naja,N.oxiana,
N.kabuthia
Neurotoxicity usually
predominates.
Common krait(karayat)-Bungarus caeruleus
Russell’s viper(kander)-Daboia russeliiHeat-sensing facial pits (hence the name "pit vipers").
Echis.carinatus(afai)-Saw scaled viper
Approximately 2500 different species of snakes are known. Approximately
Non Poisonous Snakes Head - Rounded
Fangs - Not presentPupils - RoundedAnal Plate - Double row Bite Mark - Row of small teeth.
Poisonous Snakes Head – Triangle Fangs – Present Pupils - Elliptical pupil Anal Plate - Single row Bite Mark - Fang Mark
Snake Venom
Snake venom is highly modified saliva
Mechanism of toxicityCytotoxic effects on tissuesHemotoxicNeurotoxicSystemic effects.Toxic dose. The potency of the venom
and the amount of venom injected vary considerably.
20% of all strikes are "dry" in which no venom is injected.
Snake Venom, Necrosis Proteolytic enzymes have a trypsin-like activity.
Hyaluronidase splits acidic mucopolysaccharides and promotes the distribution of venom in the extracellular matrix of connective tissue.
Phospholipases A2- break down membrane phospholipids -causes cellular membrane damage
Contd..all these enzymes cause oedema,
blister formation and local tissue necrosis
Snake Venom ,Paralysis
block the stimulus transmission from nerve cell to muscle and cause paralysisdoes not penetrate the blood-brain barrier
Contd..postsynaptic effects are reversible with
antivenom and neostigmine.presynaptic nerve terminal, e.g. beta-
bungarotoxin and here neostigmine will not be effective.
Snake venom, Hemorrhagesactivate prothrombin (e.g. ecarin
from Echis carinatus) Effect on fibrinogen and convert it into
fibrin -thrombin-like activity, such as crotalase (rattlesnake venom)
Activate factor 5, factor 10 , Protein CActivate or inhibit platelet aggregationHaemmorhagins- cause endothelial
damage
Clinical syndromic approachSyndrome 1Local envenoming (swelling etc) with bleeding/clotting disturbances VIPERIDAE
Syndrome 2
Ptosis, external opthalmoplegia, facial paralysis etc and dark brown urine=Russell's viper, Sri Lanka and South India
Syndrome 3 Local envenoming (swelling etc) with
paralysis=Cobra or king cobra
Syndrome 4
Paralysis with minimal or no local envenoming
Krait, Sea snake
Syndrome 5
Paralysis with dark brown urine and renal failure: Russle viper
Grade 0No evidence of envenomationSuspected snake biteFang mark may be presentPain and 1 inch edema & erythemaNo systemic signs- first 12 hoursNo lab changes
Grade 1Minimal envenomationSnake bite suspectedFang wound & moderate pain present1-5 inches of edema or erythemaNo systemic involvement in present after 12
hoursNo lab changes
Grade 3Severe envenomationWithin 12 hours edema spreads to the
extremities and part of trunk.Petechiae and ecchymosis may be
generalizedTachycardiaHypotensionSubnormal temperature
Grade 4Envenomation very severeSudden pain rapidlyProgressive swelling which leads to
ecchymosis all over trunk Bleb formation and necrosis
Grade 4 contd…Systemic manifestations within 15 min after
the bite.Nausea,vomitings,vertigo,Numbness,tingling lips and face, muscle
fasciculations,urinary incontinence,Weak pulseConvulsions, coma
What investigation to do?CBC RFT Coagulation studies Blood grouping & cross matchingSr.electrolytesUrinalysis
20 min whole blood clotting timeA few milliliters of fresh blood are placed in a
new, plain glass receptacle (e.g., test tube) and left undisturbed for 20 min.
Contd…The tube is then tipped once to 45° to
determine whether a clot has formed. If not, coagulopathy is diagnosed
Hess's testBlow up a blood pressure cuff to 80 mm Hg
and leave it on for 5 minutes.If a crop of purpuric spots appears below the
cuff, the test is positive.
First AidFirst Aid
ASVWhen to use ASV?How much to use?What if a reaction occurs?When to stop ASV?
When to use ASVHemostatic abnormalities(lab and clinical)progressive local findings Neurotoxicity Systemic signs and symptomsGeneralised rhabdomyolysis
Polyvalent antivenin
Manufactured by hyper immunizing horses against venoms of four standard snakes
Cobra (naja naja)Krait (B.caerulus)Russel’s viper(V.russelli)Saw scaled viper(Echis carinatus)
Contd..Lyophilised form: stored in a cool
dark place & may last for 5 yearsLiquid form: has to be stored at 4°c
with much shorter life spanEach 1ml of reconstituted serum
neutralise0.6 mg of naja naja0.45 mg of Bungarus caerulus0.6 mg of V.russelli0.45 mg of Echis carinatus
Guide for initial dose of antivenin
Grade Amount of
Antivenin Route
0 None None
1 None None
2 5 vials IV 1:10 dilutions
3 5-10 vials IV 1:10 dilutions
4 10-20 vials IV 1:10 dilutions
Skin testing- Done if patient is stable and time available0.02ml of 1:100 solution of serum is
injected sc
A positive reaction occurs within 5 to 30 mins.
Appearance of wheal & surrounding erythema
What to do in case of anaphylactic reaction to ASV
Adrenaline 0.5 to 1ml IM
If hypotension,severe bronchospasm or laryngeal edema give 0.5 ml of adrenaline diluted in 20 ml of isotonic saline over 20 mins iv.
contd..A histamine anti H1 blocker-chlorpheniramine
maleate-10 mg IV
Pyrogenic reactions-antipyretics
Late reactions-respond to CPM-2 mg, 6 hrly or oral prednisolone-5 mg 6 hrly
What if the patient needs ASV following reactiondose should be further diluted in isotonic
saline and restarted as soon as possible.
concomitant IV infusion of epinephrine may be required to hold allergic sequelae at bay while further antivenom is administered
Serum SicknessCharacterised by fever, chills, urticaria,
myalgias, arthralgias, and possibly renal or neurologic dysfunction developing 1–2 weeks after antivenom administration
systemic glucocorticoids (e.g., oral prednisone, 1–2 mg/kg daily) until all findings resolve
dose is tapered over 1–2 weeks. Oral antihistamines (e.g., diphenhydramine in standard doses) provide additional relief of symptoms
When to stop using ASVBleeding subsidesLab values returns to baselineSigns of neurotoxicity reversesLocal effects halts progression
Supportive treatmentAnticholineesterase have variable but useful role
TrialAtropine sulphate 0.6 mgEdrophonium chloride 10 mg IV (or)
Neostigmine: 1.5–2.0 mg IM (children, 0.025–0.08 mg/kg)
Contd..If objective improvement is evident at 5 min continue neostigmine at a dose of 0.5 mg
(children, 0.01 mg/kg) every 30 min as needed with
atropine by continuous infusion of 0.6 mg over 8 h -children, 0.02 mg/kg over 8 h
Contd Hypotension
administration of crystalloid (20–40 mL/kg)
a trial of 5% albumin (10– 20mL/kg)
CVP guided fluids
Inotropic support and invasive monitoring
Contd..
Oliguria & renal failure- fluids,diuretics, dopamine
no response-fluid restriction, Dialysis
Local infection- TT,antibiotics
Haemostatic disturbances-FFP,fresh whole blood,cryoprecipitates
Cobra spit opthalmiatopical antimicrobial0.1% adrenaline relieves painNo need for ASV
Compartment syndrome If signs of compartment syndrome are
present and compartment pressure > 30 mm Hg:
Elevate limbAdminister Mannitol 1-2 g/kg IV over 30
minSimultaneously administer additional
antivenom, 4-6 vials IV over 60 min If elevated compartment pressure persists
another 60 min, consider fasciotomy
Bee StingHoney bee belong Family- Hymenoptera Sub Family-Apidaeonly the females have adapted a stinger from the
ovipositor on the posterior aspect of the abdomen
VenomHistamine.Melittina –membrane active polypeptide that can
cause degranulation of basophils and mast cells, constitutes more than 50 percent of the dry weight of bee venom
Venom commonly causes pain, slight erythema, edema, and pruritus at the sting site
PresentationsLocal reactionToxic manifestation and anaphylaxisDelayed reaction –Serum sickness
Treatment
Immediate removal is the important principle and the method of removal is irrelevant.
sting site should be washed thoroughly with soap and water to minimize the possibility of infection.
Intermittent ice packs at the site- diminish swelling and delay the absorption of venom while limiting edema.
Oral antihistamines and analgesics may limit discomfort and pruritus.
Nonsteroidal anti-inflammatory drugs (NSAIDs) can be effective in relieving pain
Severe systemic reactionEpinephrine 0.3 to 0.5 mg (0.3 to 0.5 mL of
1:1000 concentration) in adults and 0.01 mg/kg in children (never more than 0.3 mg).
Injected IM and the injection site massaged to hasten absorption
If hypotension,severe bronchospasm or laryngeal edema give 0.5 ml of adrenaline diluted in 20 ml of isotonic saline over 20 mins
Observation for 24 hours in ICU
Contd…Parenteral antihistamines (diphenhydramine 25
to 50 mg IV, IM, or PO) and H2-receptor antagonists (ranitidine 50 mg IV)
Steroids (methylprednisolone 125 mg) -to limit ongoing urticaria and edema and may potentiate the effects of other measures.
Bronchospasm is treated with -agonist
nebulization.
Contd..Hypotension -massive crystalloid infusion, and central
venous pressure monitoring may be helpful in these patients.
-Persistent hypotension require dopamine. -If dopamine is ineffective, an intravenous
infusion of epinephrine can be used
Preventive CareEvery patient who has had a systemic reaction -
insect sting kit containing premeasured epinephrine and be carefully instructed in its use.
patient must inject the epinephrine at the first sign of a systemic reaction.
Medic alert tag
Scorpion sting- C. exilicauda Scorpions have a world-wide distribution.
Highly toxic species are found in the Middle East, India, North Africa, South America, Mexico, and the Caribbean island of Trinidad.
Mechanism of actionVenom can open neuronal sodium channels and
cause prolonged and excessive depolarization
Symptoms and signsomatic and autonomic nerves may be affected
Initial pain and paresthesia at the stung extremity that becomes generalised
Cranial nerve- abnormal roving eye movements, blurred vision, pharyngeal muscle incoordination and drooling and respiratory compromise
Contd…Excessive motor activity
Nausea, vomiting, tachycardia, and severe agitation can also be present.
Cardiac dysfunction, pulmonary edema, pancreatitis, bleeding disorders, skin necrosis, and occasionally death can occur
TreatmentPain Management• Ice pack• Immobilization of limb• Local anaesthetics are better than opiates
Tetanus prophylaxis, wound care and antibiotics
Benzodizepines for motor activity.
Contd..Stabilize Airway Breathing and Circulation
Hyperdynamic circulation• always combination of alpha blocker with beta blocker to
prevent unopposed alpha action causing tachycardia• Nitrates for Hypertension/MI
Contd..Hypodynamic Circulation:• CVP guided fluids• Decrease preload with furosemide (not hypovolumic)• Reduction of afterload improves outcome-Prazosin,
nitroprusside, hydralizine, ACE inhibitor
Dobutamine is the best inotrope, avoid Dopamine
Noradrenaline can be used
Newer modalityInsulin has shown to improve cardiopulmonary status in
case of scorpion envenomation