The document summarizes information about common venomous snakes in Saudi Arabia and the clinical presentation and management of snake envenomation. It describes 5 common venomous snake species in the region, noting characteristics like size, venom type, and behavior. For clinical presentation, it distinguishes between viper and cobra envenomation, covering local and systemic effects. Management involves first aid, transport, assessment, antivenom administration, monitoring response, wound care, and rehabilitation. Key steps of first aid and indications for antivenom are outlined, along with types of antivenom reactions and administration methods.

1. Snake Envenomation
Prof Hanan Fathy Abd El Aziz
Prof of clinical toxicology
Ain Shams University

2. Common Venomous Snakes In Saudi
Arabia
Levant viper:
Characteristics: it belongs to group of true vipers. it
is large and dangerous. Its length is average 1
meter, maximum 1.5 meters. Its venom is
hemotoxic. Many deaths have been reported from
bites of this species. It is a strong snake with an
irritable disposition; it hisses loudly when ready to
strike.

3. Egyptian cobra (Naja haje):
Characteristics: It is extremely dangerous. It is
responsible for many human deaths. Its length
is average 1.5 meters, maximum 2.5 meters. Once
aroused or threatened, it will attack and continue the
attack until it feels possible escape. Its venom is
neurotoxic and much stronger than the common
cobra. Its venom causes paralysis and death due to
respiratory failure.

4. Common cobra (Naja naja):
Characteristics: A very common species
responsible for many deaths each year. Its length
is average 1.2 meters, maximum 2.1 meters. When
aroused or threatened, the cobra will lift its head off
the ground and spread its hood, making it more
menacing. Its venom is highly neurotoxic, causing
respiratory paralysis with some tissue damage.

5. Puff adder (Bitis arietans ):
Characteristics: it is the second largest of the
dangerous vipers and one of the commonest
snakes. Its length is average 1.2 meters, maximum
1.8 meters. It is largely nocturnal, hunting at night.
It is not shy when approached. It draws its head
close to its coils, makes a loud hissing sound, and
is quick to strike any intruder. Its venom is strongly
hemotoxic.

6. Saw-scaled viper (Echis carinatus):
Characteristics: A small but extremely dangerous
viper. It gets the name saw-scaled from rubbing the
sides of its body together, producing a rasping
sound. Its length is average 45
centimeters, maximum 60 centimeters. This ill-
tempered snake will attack any intruder. Its venom is
highly hemotoxic Many deaths are attributed to this
species.

7. Clinical picture of
Venomenous Snake Bite
Please pay attention to this video

8. I. Viper envenomation(Crotalidae)
Mainly Hematologic
Local manifestations: (Severe )
 Severe progressive pain.
 Petechiae ,oozing from the wound and
formation of blood-filled vesicles.
 Spreading progressive swelling
(edema) and bruising in bite site
(Circumference of the bitten limb
should be measured and observed
every 15 minutes). Edema extends to
cover the whole bitten area.
 Gangrene of the bitten area may occur.

9. Size of bitten area should be
marked every 15 minutes

13. Systemic manifestations:
 Sweating, nausea, vomiting
 Arrhythmias , Hypotension, pulmonary
edema and shock.
 Prolonged clotting and bleeding times.
 Bleeding gums and bleeding per
orifices e.g.
Hematemesis, melena, hematuria
etc….

14. The following manifestations are
more common with Russell viper bite:
• Numbness, tingling, cranial nerve dysfunction
e.g. (abnormal taste and smell), ptosis and
external ophthalmoplegia, paralysis of facial
muscles, aphonia, dysphagia .
• Skeletal muscle flaccid paralysis , respiratory
paralysis and diminished level of
consciousness.
• Loin pain hematuria, haemoglobinuria,
myoglobinuria, oliguria/anuria, hyperkalaemia
and the condition ends by acute renal failure.

15. Grading of Pit Viper Envenomation
Dry Bite:
 bite mark without severe pain or swelling , normal
vital signs , normal coagulation studies and normal
platelet count.
Mild :
 Local pain and swelling, normal vital signs , normal to
mildly abnormal coagulation studies and Platelet
count >100,000.
Moderate :
 Local pain and moderate swelling, normal vital
signs, abnormal coagulation studies (double PT and
PTT) and platelets <100,000.
Severe:
 shock ,altered mental status with or without normal
vital signs, abnormal coagulation studies
, Thrombocytopenia (platelets <20,000)

16. II. Coral snakes (Elapidae)
Mainly Neurotoxic
Local manifestations ( less than those of
viper envenomation) :
 Indistinct fang marks.
 Burning pain (may be absent).
 Mild to moderate swelling (may be absent)
and discoloration.
 Serosanguinous discharge ( may be absent).
 Parasthesias around bitten area.
 Muscular in coordination and weakness in the
bitten limb.

17. Systemic manifestations:
I. Neurotoxicity:
Pre paralytic stage:
 Increased salivation and emesis with or without
headache
Paralytic stage:
 Dysarthria and dysphagia.
 Visual disturbances ( ptosis and external
ophthalmoplegia).
 Respiratory distress ends by respiratory failure.
Most deaths occur from respiratory arrest within
36 hours.
II. Cardiotoxicity:
Cardio toxins affect the cell membranes directly
causing myocardial depression, cardiogenic
shock and systolic cardiac arrest.

18. Management of
Venomenous Snake Bite

19. First Step
The first step is to identify weather snake is
poisonous or not. HOW? The easiest way is to
diagnose from the bite.
In both venomenous and non venomenous bites
there is universal fear - a state of shock. BUT:
In venomenous snake bite:
 Site of the bite shows 2 holes ( refer to canines
injecting venom).
 Spreading pain , numbness and edema.
WHILE in non venomenous snake bite:
 Bite site shows multiple teeth impressions
 ABSENT significant local pain or swelling.

20. After diagnosis of the
venomenous bite
To discuss management of
venomenous snake bite we have to
start by
DON’T DO
Before discussing
WHAT YOU SHOULD DO


21. NEVER TO
 Apply tourniquet or bandage “ All what you do is
to localize all digestive enzymes”.
 Use cut and suck methods. “ Snakebite is an IM
injection. The venom isn’t going to be sucked
out. Cutting increases tissue damage to an area
already infiltrated with digestive enzymes.
 Apply any local chemicals.
 Attempt to bring the venomous snake to the
hospital. “ it has already bitten one person! There
is no medical reason to bring the snake in”. All
local species use the same antivenin”.
 Use ice or cold packs. It does not slow the enzyme
activity. It slows the immune-response.
 Irritate the victim.
 Be anxious.

22. Steps of Management
 First aid management.
 Transport to hospital.
 Assessment and resuscitation.
 ASV.
 Observing response to anti venom and
deciding weather further doses are
needed.
 Treatment of the bitten area.
 Rehabilitation and treatment of
complications.

23. First aid management
Aims of first aid management:
First aid management aims to:
 Retard systemic venom absorption.
 Arrange rapid transport of the victim to
hospital.

24. Steps of First Aid
“Do it R.I.G.H.T.”
(pressure immobilization technique)
Please pay attention to this video

25.  Start by releasing any tight bandage.
 R. = Reassure the patient. Calming the
patient is the actual first aid very to slow the
circulation down.
 I = Immobilize in the same way as a
fractured limb. Use bandages or cloth to
hold the splints, not to block the blood
supply. Do not apply any compression!
 G. H. = Get to Hospital Immediately.
Traditional remedies have NO PROVEN
benefit in treating snakebite.
 T= Tell the doctor of any systemic
symptoms such as ptosis, bleeding
, vomiting etc.. that manifest on the way to
hospital.

26. Clinical Assessment
Factors affecting prognosis:
 Site of the bite. Head and neck and chest are more
dangerous.
 Time passed since the bite.
 Activity at the time of bite.
 Amount of venom injected.
 Previous state of victim’s health.
Clues indicating severe poisoning:
 Rapid early extension of local swelling from the site of
the bite.
 Early tender enlargement of local lymph nodes.
 Early systemic symptoms as
hypotension, nausea, vomiting , severe headache
etc..
 Early spontaneous systemic bleeding and / or passage
of dark brown/black urine.

27. Laboratory Assessment
20 minutes whole blood clotting test 20 WBCT:
 Place 2 ml of fresh venous blood in ordinary glass tube
without any additives and leave it undisturbed for 20
minutes.
 If the blood is still unclotted, this is diagnostic of a viper
bite and rules out an elapid bite.
 N.B : If the used vessel is not made of ordinary glass, or
if it has been cleaned with detergent, the test will be
invalid and should be repeated.
Other hematological tests:
 HB% , hematocrit value and Platelet count.
 Color of Plasma / serum: may be pinkish or brownish if
there is or hemoglobinemia or myoglobinemia.

28. Biochemical abnormalities:
 Elevated Aminotransferases and muscle
enzymes.
 Bilirubin is elevated following massive
hemolysis.
 If renal dysfunction occurs there will be elevated
Urea , creatinine , potassium and decreased
sodium bicarbonate.
 Early hyperkalaemia may be seen following
extensive rhabdomyolysis.
 ABGs : may show evidence of respiratory failure
in neurotoxic envenomation and in case of
acidosis.
Urine examination: urine should be

29. The Anti Snake Venom
(ASV)
Anti venom is the only specific antidote
for snake venom
A most important decision in the
management of a snake-bite victim is
whether or not to administer anti venom

30. Rules of Giving ASV
 Anti venom should be given only to patients in
whom its benefits exceed its risks.
 The risk of reactions should always be taken into
consideration. Patients having +ve history of
atopic diseases (e.g severe asthma) are at high
risk of severe reactions and should be given ASV
under close monitoring during and after treatment.
 Anti venom treatment should be given as soon as
it is indicated. It may reverse systemic
envenoming even after several days up to 2 or
more weeks. It is, should be given as long as
coagulopathy persists.

31. Indications of ASV
Local indications:
 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 within a few
hours of bite on the hands or feet
 Development of an enlarged tender
lymph node draining the bitten area.

32. Systemic indications:
Clinical indications:
 Spontaneous systemic bleeding.
 Neurotoxic signs: ptosis, external
ophthalmoplegia, paralysis etc….
 hypotension, shock, Cardiac arrhythmia and /or
Abnormal ECG
 Oliguria and / or anuria.
 Rhabdomyolysis.
Laboratory indications : Positive 20WBCT .
Prolonged PT. Thrombocytopenia (<100 000/cu
mm). Elevated urea and creatinine and
hyperkalaemia.

33. Types of Reactions to ASV
Usually more than 10% of patients receiving
ASV develop one of the following reactions:
 Early anaphylactic reactions (10 – 180 minutes).
 Pyrogenic ( endotoxic) reactions (1-2 hours).
 Late (serum sickness) reactions (1-12 days
average 7 days).
Risk of reactions is dose-related, except if the
victim has been sensitized e.g. to equine anti
venom or rabies-immune globulin
These reactions may be fatal but fatalities have
probably been under-reported as death is
usually attributed to the venom while patients
may not be monitored carefully after treatment.

34. Prevention of ASV Reactions
There is no prophylactic regimen that has been
effective in clinical trials but there are some
evidences recommend the following:
 Prophylactic drugs e.g. adrenaline , anti H1
blockers and corticosteroids. ( adrenaline is the
best).
 Speed and dilution of ASV administration.
Since no prophylactic regimen has proved
effective, these drugs should be used only in high
risk patients. All patients should be carefully
observed for two hours after the completion of ASV
administration and treated with adrenaline at the
first sign of a reaction.

35. Polyvalent Versus Monovalent
ASV
Polyvalent ASV
Advantages
•No need to waste time
or effort to identify the
exact nature of
venomous snake
•Less expensive
•Easy distribution to all
parts of the country
Disadvantages
•Decreased efficacy
(?)
•Increased
incidence of allergic
reactions

36. Monovalent ASV
Advantages
•Increased efficacy
•Lower incidence of
allergic reactions
Disadvantages
•Identifying the exact
nature of venomous
snake mandatory
•More expensive if all
snakes need to be
covered snake venom
required in various
regions of India.

37. Administration of ASV
Two methods of administration are
recommended
1. Intravenous injection: In this method the
administer must remain with the patient during
time of early reactions (up to 180 minutes).
2. Intravenous infusion over one hour.
Other methods: Not recommended and Not
effective:
 Local administration : It is extremely painful, may
increase intracompartmental pressure.
 Intramuscular injection: ASV have poor
bioavailability , So blood levels never reach the
desired level. Severely painful with risk of

38. ASV Doses
 There is great controversy regarding initial
dose of ASV due to lack of study on this
issue.
 The initial dose should neutralize most of
the of venoms injected.
 WHO recommended, initial dose of
polyvalent ASV is 100 ml. It will neutralize
60 mg of Russell’s viper venom and cobra
venom , 45 mg of krait and saw-scaled
viper.
 The average dose ranges from 5-15 vials.

39. After Administration of ASV
The victim should be observed for:
 General condition.
 Spontaneous systemic bleeding and blood
coagulability (20WBCT).
 Neurological or cardiovascular symptoms.
 Urine color.
 Criteria to repeat the ASV:
 Uncoagulability after 6 hours (20WBCT).
 Persistence or recurrence of bleeding after 1-2
hours
 Deteriorating neurotoxic or cardiovascular signs
after 1-2 hours.

40. Finally
The snake says:
 Don’t threat me
The victim immediately after the bite
says:
 Don’t stress me
The victim during and after administration
of ASV says:
 Don’t leave me
And I say:
 Don’t forget me

41. Thank you