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Snake Bite Management
Dr Morné Strydom
Department of Pharmacology
University of Pretoria
Who are the main culprits?
Stiletto
Snake
• Most common dangerous bite in SA
• Cytotoxic venom & Sarafotoxin
• NOT INCLUDED in Polyvalent Antivenom
Mozambique
Spitting
Cobra
• Aggressive, bite without being provoked.
• Cytotoxic venom
• INCLUDED in Polyvalent Antivenom
Puff Adder
• Well camouflaged, may strike very rapid!
• Cytotoxic venom
• INCLUDED in Polyvalent Antivenom
Snouted
Cobra
• Neurotoxic Venom
• INCLUDED in Polyvalent
Antivenom
Stiletto Snake
SAVP POLYVALENT ANTIVENOM
1 X Rinkhals
• Rinkhals
2 X Adders
• Puff Adder
• Gaboon
Adder
3 X Mambas
• Black
Mamba
• Green
Mamba
• Jameson’s
Mamba
4 X Cobras
• Snouted
Cobra
• Forest Cobra
• Mozambique
Spitting
Cobra
• Cape Cobra
Rinkhals
Puff Adder
Gaboon Adder
Black Mamba
Green Mamba
Jameson’s Mamba
Snouted Cobra
Forest Cobra
Cape Cobra
Mozambique Spitting Cobra
SAPV MONOVALENT ANTIVENOM
BOOMSLANG
IMMEDIATE FIRST AID
Snake
Transport
Patient
•
•
•
•
Do not attempt to catch or kill the offending snake
Bystanders must contact a snake handler.
Take a digital photo of the snake from a safe distance.
If snake has already been killed:
• Bite reflex may remain intact for several hours, handle dead snake with a long stick.
• Transport to hospital in a safe rigid container for identification.
• Immediately arrange transport to a medical facility.
• Alert the hospital about the arrival of a snake bite victim, so that appropriate
preparations can be made.
• Arrangements should me made to have the SACP Polyvalent Antivenom ready in case it
is needed.
•
•
•
•
•
Keep patient calm and reassured.
Let the patient lie down and discourage any unnecessary movements.
Remove any constricting rings, bracelets or clothing from the bitten limb.
Allow the bitten limb to rest at a level at or slightly lower than the victim’s heart.
Wrap a large crepe bandage snugly around the bitten limb starting at the site of the
bite and working proximally up the full length of the limb.
• Secure a splint to the bandaged limb as rigid and unmoving as possible. Avoid bending
or moving the limb excessively while applying the splint.
IMMEDIATE FIRST AID
DO NOT remove the splint or bandages until the victim has
reached the hospital and is receiving Antivenom if indicated.
DO NOT cut or incise the bite site
DO NOT apply ice to the bite site
HOSPITAL MANAGEMENT
BITES BY SNAKES WITH PREDOMINANTLY CYTOTOXIC VENOM
• Medical emergency and can be fatal if not treated.
• Envenomation may cause severe shock, as well as
haemolytic, coagulopathy, haemorrhagic, and local
reactions.
• Death may ensure rapidly (within hours), but more
commonly occurs in 12-24 hours.
• Make sure at least 12 vials of SAVP Polyvalent
Antivenom are present with the patient.
• If the patient has been envenomated, the treatment is
at least 6 vials of IV Antivenom (to start of with).
IMPORTANT INFO REGARDING THIS TYPE OF
BITE IS ORGANISED INTO THE FOLLOWING
SECTIONS:
1. Signs and Symptoms of Envenomation
2. Medical Management
3. Other Considerations
1. SIGNS & SYMPTOMS OF ENVENOMATION
PAINFUL PROGRESSIVE
SWELLING
LOCAL EFFECTS:
CARDIOVASCULAR:







Pain and swelling: onset almost immediately
Blistering
Haemorrhagic oedema
Tissue necrosis: onset usually days after bite
Ecchymosis
HAEMATOLOGICAL:







Coagulation defects
Spontaneous bleeding: mucosal bleeding
Thrombocytopenia: onset <4hours after bite
Hematemesis, Epistaxis
Ecchymoses / Petechiae
GIT bleeding, Internal haemorrhage
Anaemia: Secondary to bleeding & haemolysis
RENAL / URINARY:


Pulmonary oedema, Tachypnoea, Dyspnoea
Haematuria, Haemoglobinuria, Myoglobinuria,
Renal failure
GENERAL:

PULMONARY:
Severe hypotension: onset often immediately
Cardiac arrhythmias:
 Tachycardia
 Prolonged QT intervals
 Supraventricular tachycardia
 Inverted T waves
 Bradycardia
 Cardiac arrest (*Gaboon viper)
N/V, Fever, Abdominal pain, Regional LA
 FANG MARKS:


1 or 2 punctures, scratches, small lacerations,
no marks!
Single vs. Multiple bites NB TO NOTE!
2. MEDICAL MANAGEMENT
ADMISSION
Admit to a
Trauma Centre
PRIMARY SURVEY
Establish patent airway, WORK UP
adequate breathing &
O2, and Circulation
Begin peripheral IV
infusion (16G) of NS /
Ringers
Type & Cross Match 2X
Units of Whole Blood.
Obtain FFP.
FBC & Diff Count +
Platelets
Clotting Profile: PT, PTT,
INR
If in shock, give fluid
UKE
bolus 20ml/kg, followed
LDH (with isoenzyme
up at rate of 125cc/hr
Children: 4:2:1 Regime
analysis)
Urinalysis: Free protein,
Hemoglobin, Myoglobin
ECG
Continuous Urine Output
Monitoring
Vitals should be
monitored frequently
over the first 48 hours
after the bite
TETANUS
Tetanus Prophylaxis
should be current
Antibiotics are not
recommended
prophylactically
OBSERVATION
Observe for S&S of
Envenomation: 15 minutes
– 2 hours after bite.
If NONE S&S noted after 2
Hours, most likely a dry
bite (no venom injected).
SLOWLY start to remove
bandages and splints
watching carefully for
changes in the patient’s
status.
If ANY changes occur,
assume envenomation and
prepare to give AV stat.
If S&S still fails to manifest,
continue CLOSE observation
of the patient for an
additional 12-24 hours.
2. MEDICAL MANAGEMENT
Severe swelling:
Immediate swelling of more than half
of the affected limb
Swelling that progresses past one joint
in < 1 hour
Severe systemic signs of
envenomation such as:
Swelling that progresses past two joints
in < 4 hours
Any swelling
affecting or
reaching the trunk
of the body
Hypotension
Shock
Cardiac dysrrhythmias
INDICATIONS
FOR
ANTIVENOM
THERAPY
ANTIVENOM ADMINISTRATION
PREPARATION
The patient should be on an ECG, BP & Saturation Monitor
Large bore IV access should be secured
All resus equipment for airway, ventilator and circulatory management
should be prepared
Patients at risk for anaphylactic reactions:
Patients with atopic tendencies
Bronchial asthma
Previous exposure to equine products
Should be pre-treated with 0.3ml of S/C ADRENALINE (1:1000 Sol)
(Avoid Adrenalin pre-treatment in IHD, Uncontrolled HPT, and Arrythmias)
All drugs should be ready for the treatment of anaphylaxis
ADRENALINE 0.5ml (1:1000 Sol) should be drawn up and available for
immediate IM administration in case of severe anaphylaxis.
ANTIVENOM ADMINISTRATION
ADMINISTRATION
Dilute the contents of 6 vials of SAVP Polyvalent Antivenom in NS / Ringers
solution to a total volume of 200ml.
Administer the Antivenom IV over 30 minutes at a rate of 400ml/hour.
Should any signs of ALLERGY / ANAPHYLAXIS develop, immediately
discontinue the administration of the antivenom, and treat symptoms
with ADRENALIN, CORTICOSTEROIDS, and ANTIHISTAMINES.
As soon as the patient is stabilized, continue the antivenom infusion at a
slower rate (100-200ml/hour).
After 15 minutes of Antivenom administration, the splint and bandages
may be removed – VERY SLOWLY over a period of 10 minutes to prevent a
bolus release of venom. If patient’s condition worsens, reapply the crepe
bandage, wait 10 minutes and release the bandage again slowly over 10
minutes while antivenom infusion is continuing.
Antivenom Therapy is the mainstay of treatment of
serious snake envenomation.
Many of the symptoms are ameliorated or entirely
eliminated by the antivenom alone.
Other symptoms will require additional
therapeutic modalities in order to be
corrected.
Additional Therapeutic Modalities:
CARDIOVASCULAR STATUS:
 Gaboon Viper venom known to be cardiotoxic:
causes arrhythmias & hypotension
 Cardiac arrhythmias, specifically prolonged QT
intervals, inverted T waves, and SV Tachycardia my
persist for days after the initial envenomation.
Supportive Rx is indicated.
 Severe bradycardia may require a Temporary
Pacemaker to ensure cardiac output and to prevent
cardiac arrest.
Additional Therapeutic Modalities:
HEMATOLOGICAL SIGNS & SYMPTOMS:
 Gaboon Viper venom has a thrombin-like enzyme:
quickly depletes serum fibrin levels – rendering the
blood incoagulable. In addition, is has hemorrhagic
activity, causes widespread damage to the
microvasculature (lungs & GIT very sensitive).
 Puff Adder venom: Both Pro- and Anticoagulation
activity. May show a variety of responses. Victims
frequently develop thrombocytopenia, ↓Fibrinogen
levels, spontaneous bleeding, DIC, and anaemia.
Death = Internal haemorrhage & Circulatory Shock.
 Rx: Whole blood, Packed RBC’s, Platelets,
Cryoprecipitate, FFP = Should be given when indicated!
Additional Therapeutic Modalities:
RENAL:
 The haemorrhagic activity of the venom may result
in haematuria.
 In addition, haemoglobinuria & myoglobinuria
may likewise affect renal function, and if severe
(ARF), may necessitate peritoneal dialysis.
KEEP VENOM NEUTRALIZATION CURRENT
AND CONTINUOUS
• Monitor patient’s status
• If present condition does not improve, or worsen,
additional antivenom should be administrated!
• Give all additional antivenom in one vial increments.
• Dilute antivenom as before and administer it IV over ±
15 minutes.
BITES WITH ENVENOMATION REQUIRE AT LEAST 6
VIALS, BUT SEVERE ENVENOMATIONS MAY REQUIRE UP
TO 12 VIALS OF ANTIVENOM OR EVEN MORE.
• Patient should be observed in hospital for at least 24
hours after all symptoms abate.
3. OTHER CONSIDERATIONS
PSEUDO-COMPARTMENT SYNDROME:
• True fascial compartment syndromes in these
bites are uncommon.
• Limbs may swell significantly, but rarely involve
specific fascial bound compartments.
• If the bite raise a high index of suspicion for CS,
monitoring with a Stryker needle or appropriate
pressure device may be necessary.
Fasciotomy is rarely, if ever,
recommended in these patients.
HOSPITAL MANAGEMENT
BITES BY SNAKES WITH PREDOMINANTLY NEUROTIXIC VENOM
• Bites by Mambas and Non-spitting Cobras
• Leading to progressive weakness
• A bite from one of these snakes with systemic
envenomation can me rapidly fatal:
Death in 30 – 120 minutes
if untreated
Progressive Weakness:
Neurologic
deterioration
Drowsiness, neurological and
neuromuscular weakness may
develop early
Paralysis
Ventilatory failure
leading to
respiratory arrest
Death (if not treated)
TAKE THE FOLLOWING ACTIONS
1. Be prepared to provide respiratory support
2. Advanced airway management (intubation with
mechanical ventilation) may be needed in severe
cases
3. DO NOT remove crepe bandages & splints until
patient is receiving antivenom, if indicated.
4. Make sure that no less than 8 vials of SAVP
Polyvalent Antivenom are available for initial
treatment of the patient.
5. Treatment of neurotoxic bites from snakes such as
Black Mamba and Cape Cobra may require as many
as 20 vials of Antivenom.
ENVENOMATION IS DX BY THE PRESENCE OF
CHARACTERISTIC SIGNS & SYMPTOMS
IMPORTANT INFO IS GIVEN UNDER THE FOLLOWING HEADINGS:
1. Signs and Symptoms of Envenomation
2. Medical Management
3. Other Considerations
1. SIGNS & SYMPTOMS OF ENVENOMATION
NEUROLOGICAL &
NEUROMUSCULAR:



Progressive weakness of skeletal
muscles, including respiratory
muscles.
Usually, these symptoms manifest
early.
BE ON THE LOOKOUT FOR THE
FOLLOWING:
 Respiratory paralysis or
Dyspnoea
 Excessive salivation
 Drowsiness
 Restlessness
 Sudden LOC
 Ptosis
 Ophthalmoplegia
 Paresthesias
 Palatal paralysis
 Dysphasia
 Vertigo
 Fasciculations
 Limb paralysis
 Ataxia
 Head drooping
 Headache
 Incontinence
 Hyporefelxia or Areflexia
 Local pain or Numbness at
bite site
GENERAL:












Onset of these
symptoms manifest
within 15 minutes to
4 hours following
envenomation:
Shock
Hypotension
Abdominal pain
Nausea & Vomiting
Regional LA
Fever
Epistaxis
Flushing of the face
Warm skin
Increased sweating
Pallor
NEPHROTOXICITY:
 Acute renal failure
has been recorded
in a few cases of
neurotoxic bites.
 Oliguria / Anuria,
dialysis is advised.
CARDIOTOXICITY:


Changes in CVS status result primarily
from the effects of Circulatory Collapse &
Shock, as well as…
Vagal blockade resulting in
Tachydysrrhythmias.
LOCAL SYMPTOMS:

Local tissue damage may range from
minor severity to moderate necrosis and
swelling around the area of the bite site.
FANG MARKS:
 Fang marks of these snakes are
small.
 May be present as 1 or 2 well
defined punctures, or there may
not be any noticeable or obvious
markings where the bite
occurred.
 Single vs. Multiple bites (must be
noted!)
 Probability of dry bites = small,
especially in Black Mambas.
2. MEDICAL MANAGEMENT
ADMISSION
Admit to a
Trauma Centre
PRIMARY SURVEY
Establish patent airway, WORK UP
adequate breathing &
O2, and Circulation
Type & Cross Match 2X
If in respiratory distress, Units of Whole Blood.
perform BM-Ventilation Obtain FFP.
without delay. Consider FBC & Diff Count +
intubation with
Platelets
mechanical ventilation. Clotting Profile: PT, PTT,
Begin peripheral IV
infusion (16G) of NS /
Ringers
INR
UKE
LDH (with isoenzyme
analysis)
Urinalysis: Free protein,
If in shock, give fluid
bolus 20ml/kg, followed Hemoglobin, Myoglobin
up at rate of 125cc/hr
ECG
Children: 4:2:1 Regime
Continuous Urine Output
Monitoring
Vitals should be
monitored frequently
over the first 48 hours
after the bite
TETANUS
Tetanus Prophylaxis
should be current
Antibiotics are not
recommended
prophylactically
OBSERVATION
Observe for S&S of
Envenomation: 15 minutes
– 2 hours after bite.
If NONE S&S noted after 2
Hours, most likely a dry
bite (no venom injected).
SLOWLY start to remove
bandages and splints
watching carefully for
changes in the patient’s
status.
If ANY changes occur,
assume envenomation and
prepare to give AV stat.
If S&S still fails to manifest,
continue CLOSE observation
of the patient for an
additional 12-24 hours.
2. MEDICAL MANAGEMENT
Respiratory
compromise
Declining
Saturation
levels or
ABG Levels
Progressive
muscle
paralysis
INDICATIONS FOR
ANTIVENOM
THERAPY
Difficulty in
swallowing
leading to
salivation
Declining
respiratory
effort
Ptosis,
covering
more than
one third of
the eye
ANTIVENOM ADMINISTRATION
PREPARATION
The patient should be on an ECG, BP & Saturation Monitor
Large bore IV access should be secured
All resus equipment for airway, ventilator and circulatory management
should be prepared
Patients at risk for anaphylactic reactions:
Patients with atopic tendencies
Bronchial asthma
Previous exposure to equine products
Should be pre-treated with 0.3ml of S/C ADRENALINE (1:1000 Sol)
(Avoid Adrenalin pre-treatment in IHD, Uncontrolled HPT, and Arrythmias)
All drugs should be ready for the treatment of anaphylaxis
ADRENALINE 0.5ml (1:1000 Sol) should be drawn up and available for
immediate IM administration in case of severe anaphylaxis.
ANTIVENOM ADMINISTRATION
ADMINISTRATION
Dilute the contents of 8-10 vials of SAVP Polyvalent Antivenom in NS /
Ringers solution to a total volume of 200ml.
Administer the Antivenom IV over 30 minutes at a rate of 400ml/hour.
Should any signs of ALLERGY / ANAPHYLAXIS develop, immediately
discontinue the administration of the antivenom, and treat symptoms
with ADRENALIN, CORTICOSTEROIDS, and ANTIHISTAMINES.
As soon as the patient is stabilized, continue the antivenom infusion at a
slower rate (100-200ml/hour).
After 15 minutes of Antivenom administration, the splint and bandages
may be removed – VERY SLOWLY over a period of 10 minutes to prevent a
bolus release of venom. If patient’s condition worsens, reapply the crepe
bandage, wait 10 minutes and release the bandage again slowly over 10
minutes while antivenom infusion is continuing.
Antivenom Therapy is the mainstay of treatment of Mamba
and Cobra envenomation.
Many of the symptoms are ameliorated or entirely eliminated
by the antivenom alone.
Other symptoms will require additional therapeutic
modalities in order to be corrected.
Local symptoms may take several days to weeks to
completely resolve; their progression, however, may be
controlled with antivenom therapy.
Patient should be observed in hospital for at least 24
hours after all symptoms abate.
ADJUCTIVE THERAPIES
• If severe muscle or respiratory paralysis
persists, or antivenom is not immediately
available, consider:
• Atropine 0.5mg I.V., followed with
• Neostigmine 1mg I.V. every 30 minutes for a
maximum of 5 doses
3. OTHER CONSIDERATIONS
• Berg Adder bites can present with a neurotoxic
progressive weakness syndrome. Don’t give
Antivenom for Berg Adder bites, it will not
neutralize the venom. Rx: Supportive care in
Highcare / ICU Setting.
• Morphine is CONTRAINDICATED due to its
respiratory suppression properties. Alcohol should
also be avoided.
3. OTHER CONSIDERATIONS
MULTIPLE BITES:
• Mambas & Cobras are prone to deliver multiple
bites = INJECT A LARGER VOLUME VENOM
• INITIAL dose = 12 Vials (Diluted to 200ml), infusion
over 30 minutes under direct medical supervision.
• WATCH CLOSELY for signs of allergic response.
CLINICAL CONSIDERATIONS WITH
NEUROTOXIC SNAKE BITES
• Prompt administration of Antivenom has resulted
in remarkably rapid recovery in many cases.
• Delay in administration or insufficient dosages of
antivenom may allow serious neurological
symptoms and respiratory paralysis to manifest,
which may be very difficult to reverse once
established and clinical envenomation is often fatal.
CLINICAL CONSIDERATIONS WITH
NEUROTOXIC SNAKE BITES
• Cape Cobras = Rapid onset in respiratory paralysis, and
difficult to reverse once established even with large
amounts of antivenom.
• Since both antivenom & neostigmine may fail to reverse
fully established paralysis, it is suggested that the toxin
become fixed to a presynaptic target, is unavailable to bind
with the antivenom, and that reversal occurs only after
metabolic degradation has taken place.
• Long-term intubation & ventilation as long as 7-8 days or
more has been necessary in a number of cases.
• Early administration of antivenom before the onset of
respiratory impairment may allow for sufficient binding of
the neurotoxic componants, and avoid the need for
mechanical ventilation.
• Modderfontein Road
Sandringham
Johannesburg
South Africa
(GPS co-ordinates:
S26°07.892
E028°07.106)
P.O Box 28999, Sandringham 2131
Johannesburg, South Africa
After hours emergency
Tel: +27(11) 386-6000
Business hours
Tel: +27(11) 386-6063/2
• SAVP e - mail
Fax: (011) 386-6016
References:
1.
Marsh, N.A., Whaler, B.C., The Gaboon Viper (Bitis gabonica): its biology, venom components and toxinology, Toxicon 22, 669694, 1984.
2.
Warrell, D.A., Ormerod, L.D., Davidson, N. NcD., Bites by Puff-Adder (Bites arietans) in Nigeria, and value of antivenom, British
Medical Journal, 1975, 4:697.
3.
Mebs, D., Pohlman, S., Von Tenspolde, W., Snake venom hemorrhagins: neutralization by commerical antivenoms, Toxicon,
1988, 26:453.
4.
Brink, S., Steytler, J.G., Effects of Puff-Adder venom on coagulation, fibrinolysis and Platelet aggregation in the baboon, South
African Medical Journal, 1974, 48:1205.
5.
Homma, H., Tu, A.T., Morphology of local tissue damage in experimental snake envenomation, British Journal of Experimental
Pathology, 1971, 52:538.
6.
WARRELL, D.A., GREENWOOD, B.M., DAVIDSON, N.M., OMEROD, L.D., PRENTICE, C.R.M.: Necrosis, haemorrhage and
Complement Depletion Following Bites by the Spitting Cobra (Naja nigricollis). Quart. J. Med., n.s., 45(177:1, 1976.
7.
STROVER, H.M.: Observations on Two Cases of Snake-bite by Naja nigricollis ss mossambica. Cent. Afr. J. Med., 19(1):12, 1973.
8.
South African Institute for Medical Research: Anti-Snakebite Serum. (Package Insert with Antivenom), 1980.
9.
SAUNDERS, C.R.: Report on a Black Mamba Bite of a Medical Colleague. Cent. Afr. J. Med., 26:121, 1980.
10.
BLAYLOCK, R.S.: (to the editor) Black Mamba Envenomation. S. Afr. Med. J., 68:293, 1985.
11.
BLAYLOCK, R.S., LICHTMAN, A.R., POTGIETER, P.D.: Clinical Manifestations of Cape Cobra (Naja nivea) Bites. S. Afr. J. Med.,
68:342, 1985.
12.
CRISP, N.G.: (to the editor) Black Mamba Envenomation. S. Afr. Med. J., 68:293, 1985.