Snake bites

Embu PGH CME by Kariuki
P.M. 1

P.M. 2

 Snakebite- an occupational hazard
 Risk groups - those who work in the fields,
young adventurous children.
 The majority of snakebites occur during the
productive years of life.
 The greater number of snakebite victims in
Kenya take hours to days before they present
in hospital
 This increases the morbidity and mortality of
those affected.
P.M. 3

 The dread of snakes and the fear of their bite is universal
 Affects the reactions of both the patient and the attending
doctor.
 The fright of a rapid and unpleasant death dominates the
clinical picture of most cases of snakebite.
 Emotional symptoms develop rapidly within minutes of the
bite and may be very severe
 This contrasts to symptoms due to systemic snake venom
poisoning which rarely appear within half an hour to two
hours after the bite and only respond to specific
antivenom treatment .
 Contrary to expectations of most people, even without
specific treatment, the mortality from snakebite is low and
in most countries, is less than 1 per 100,000 population
P.M. 4

 Venomous
 Non venomous
 NB:There are no universal distinguishing
features that separate venomous from non-
venomous snakes.
 Most of the world’s snakes are what are
referred to as clinically non-venomous.
 They however do produce toxins that have
toxic effects on their prey.
P.M. 5

Garter snake Rat snake
Speckled sand snake
Egg Eating snake
P.M. 6

 1. Vipers; puff adder, Gaboon viper, Carpet viper
The vipers strike low and most of their bites can be
prevented by the wearing of boots or shoes.
 2. Elapides: Cobras(more numerous+more bites),
Mambas (most deadly) and garter snakes
The spitting cobra is the second snake of
importance in the country and with the puff adder
are responsible for nearly all the snakebite
envenomations in the country.
P.M. 7

Gaboon viper
(deadliest of the vipers)
The puff adder (The puff
adder (Bitis arietans) is
responsible for most cases
of snakebite and deaths in
the country. ]
P.M. 8

BLack mamba Spitting Cobra
P.M. 9

 the clinician who should be able to
distinguish the type and degree of poisoning
and hence decide on the proper line of
management.
 Puff adders, black spitting cobras, black
mambas and the boomslang have been
reported to be behind a majority of the snake
bites in Kenya
P.M. 10

 Dry bites 20% of pit viper bites no venom is injected .
 Local features
1. Fang marks: two puncture wounds -a poisonous
snake.
2. Pain : Burning, bursting or throbbing pain
3. Local swelling : The swelling spreads rapidly from
the site of the bite and may involve the whole limb
and adjacent trunk. If there is no swelling 2 hours
after a viper bite, it is safe to assume that there has
been no envenoming
 Local necrosis: bruising, blistering and necrosis.
 Secondary infection: Bacterial flora in the oral cavity
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P.M. 12

 Clotting defects and haemolysis:. Persistent bleeding from fang puncture
wounds, venepuncture or injection sites, Epistaxis, haematemesis,
cutaneous ecchymoses, haemoptysis, subconjunctival, retroperitoneal
and intracranial haemorrhages ,intravascular haemolysis [2].
 Neurotoxicity: Airway obstruction or paralysis of the intercostal muscles
and diaphragm cause respiratory failure. It is important to note that
these neurotoxins do not cross blood brain barrier and do not alter
consciousness [3]
 Myotoxicity: myotoxins that cause myalgias, myopathy and
rhabdomyolysis. Generalized aching, stiffness and tenderness of
muscles .Trismus is common. Myoglobinuria secondary to
rhabdomyolysis appears 3 to 8 hours after the bite.
 Cardiotoxicity: direct myocardial damage manifesting as arrhythmias,
bradycardia, tachycardia or hypotension
 Nephrotoxicity: Renal failure is secondary to ischaemia in Viper bites
 Shock: A variety of factors contribute to shock. They include fright,
hypovolemia (due to extravasation of fluids and blood loss), myocardial
depression, haemorrhage into the adrenals and pituitary and increased
kinin production (as in Viper bite).
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P.M. 14

 The use of a tourniquet by the general public
is not advised because of the long delays
before arrival in hospital and also because
most snakebites are caused by the vipers.
 Those at high risk should be educated on the
importance of transporting victims to the
nearest hospital as quickly as possible.
 The use of antivenom is not indicated in all
cases of snakebite.
 Those with minimal or no signs of poisoning
should be treated conservatively
P.M. 15

 :Helps in deciding what type of specific treatment is
to be given
 . Most snakes disappear very quickly after an attack,
which is usually at night, and are never identified or
even seen.
 The ability of the average •mwananchi' to name any
but the commonest snakes is very lacking,
 Little reliance should be placed on what is often no
more than an opinion or guess and one should rely
more on the clinical findings.
 A fairly accurate identification of the family of snake
causing a bite can be made from the clinical effects
produced by their venoms if there has been
poisoning.
P.M. 16

 1. Note the Snake's Appearance
 Be ready to describe the snake to emergency staff.
 2. Protect the Person
 Call for help: While waiting for medical help:
 Reassurance - most important
 Move the person beyond striking distance of the
snake.
 Have the person lie down with wound below
the heart.
 Keep the person calm and at rest, remaining as still
as possible to keep venom from spreading.
 Cover the wound with loose, sterile bandage.
 Remove any jewelry from the area that was bitten.
 Remove shoes if the leg or foot was bitten.
P.M. 17

 Cut a bite wound
 Attempt to suck out venom
 Apply tourniquet, ice, or water
 Give the person alcohol or caffeinated drinks
or any other medications
 Waste time trying to find and kill the snake
 Use local concoctions-snake-stone/ viper's
stone/black stone, Herbs
P.M. 18

 airway, breathing, circulatory status, and
consciousness
 Supportive care coupled with antivenom use is
considered most effective
 Supportive care involves:
1. wound disinfection,
2. antibiotic use
3. antihistamines
4. Analgesia
5. a tetanus injection.
6. Limb elevation
P.M. 19

 : Reassurance is the most important.
 Emotional symptoms should be treated with
prophylactic antibiotics, tetanus toxoid or a
placebo injection
 Antivenom has been shown to be the most
effective method of treating systemic snake
venom poisoning.
 They have not been definitively proven to
have a significant effect on local tissue
necrosis.
P.M. 20

 The use of antivenom is not free of adverse
reactions and hence should not be routinely
given to all snake bite victims
 Only those who develop local, systemic, or
laboratory evidence of envenoming.
 The dose of antivenom for children and
adults should be the same.
 Specific antivenom is superior to the
polyvalent antivenom but since most snakes
causing bites are never identified, the
polyvalent antivenom is preferable.
P.M. 21

 Antivenom is given to minimise tissue
destruction in viperine bites in which case it must
be given within two hours of the bite when there
are signs of envenomation
 Antivenom serum should be given to these cases
which present within two hours of the bite and
show local signs of envenomation
 Leading edge of swelling and tenderness should
be marked every 15-30 minutes.
 Elevate and immobilize extremity, treat pain
aggressively with IV opioids, and update tetanus
status as needed.
P.M. 22

 The most important decision in managing a case
of snakebite is to decide whether to administer
antivenom or not.
 There is evidence that in patients with severe
envenomation, the benefits of this therapy far
outweigh the risk of reactions
 If more than two hours have elapsed since the
time of bite and there are no signs of systemic
poisoning no antiserum should be given.
 All cases of snakebite showing minimal or no
clinical signs of poisoning should be treated
symptomatically and antiserum should not be
given.
P.M. 23

 Serum reaction may occur. The immediate
serum reaction is best treated with
adrenaline.
 Steroids are not so effective as adrenaline for
the immediate reactions but are useful for
delayed serum reactions.
 In Kenya the polyvalent antisnake venom
serum (Behringwerke) is in current use.
 It gives protection 30 against the most
lnportant of our vipers, cobras and mambas.
P.M. 24

 Poor supply of antivenom in the health facilities.
 Low demand for antivenom
 High costs of antivenom in privately owned pharmacies.
 Cultural beliefs of victims: traditional healers ,?only
bewitched people were bitten by snakes,the use of herbal
medications in managing bites.
 The period of time taken by victims to seek treatment:
most likely to present to the hospital between 2 and 6
hours after a bite, long distances they had to travel to get
to the hospital. poor infrastructure and poverty
contributed to delays in seeking treatment for snake bites.
 Lack of clinical guidelines on the management of snake
bites in Kenya.
P.M. 25

 seal all holes and crevices,
 keeping lawn short, flower beds to be far
from houses
 Traps to eliminate rodents and mice
 Wear boots and shoes
 Water outside the house
 long trousers -added protection and should
be encouraged for those at risk*
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P.M. 27

P.M. 28

P.M. 29

P.M. 30

P.M. 31

 Antivenom serum is not indicated in majority of
our cases of snakebites* Those with minimal or
no poisoning should be treated conservatively.
 Patients with less severe viper poisoning who are
seen late should be managed conservatively*
 The incidence of snakebite in the country is not
high.
 Worldwide, it is estimated that more than 5
million persons per year are bitten by snakes, out
of which approximately 100,000 (2%) develop
severe sequelae
P.M. 32

P.M. 33

 FORMULA
 Algorithm, as follows:
 Are there signs of envenomation? Signs include:
◦ Swelling, tenderness, redness, ecchymosis, or blebs at bite site.
◦ Elevated protime, decreased fibrinogen or platelets.
◦ Systemic signs (hypotension, bleeding beyond puncture site, refractory vomiting, diarrhea, angioedema, neurotoxicity).
 If YES, proceed to 2.
 If NO, this is an apparent dry bite or no bite. Observe patient ≥8 hours, repeat labs prior to discharge, and do not administer antivenom.
 Check for indications for antivenom:
◦ Swelling that is more than minimal and is progressing.
◦ Elevated protime, decreased fibrinogen or platelets.
◦ Any systemic signs.
 If YES, proceed to 3.
 If NO, this is an apparent minor envenomation. Observe patient 12-24 hours, repeat labs at 4-6 hrs and prior to discharge, and do not
administer antivenom.
 Administer antivenom:
◦ Establish IV access, give IV fluids.
◦ Mix 4-6 vials of crotaline Fab antivenom in 250 mL NS and infuse over 1 hour.
◦ Increase dose to 6-8 vials for patients in shock or with serious active bleeding.
◦ Reexamine after 1 hour, and proceed to 4.
 Check for control of envenomation (after initial antivenom):
◦ Swelling and tenderness not progressing.
◦ Protime, fibrinogen, platelets normal or clearly improving.
◦ Clinically stable.
◦ Neurotoxicity resolved or clearly improving.
 If YES, monitor patient and perform serial examinations and maintenance therapy (2 vials of antivenom every 6 hours x 3 doses (given 6,
12, and 18 hours after initial control). Maintenance therapy may not be needed if close observation by physician expert is available.
 If NO, then repeat antivenom until control is achieved.
P.M. 34

The only action of antivenom is to neutralize circulating venom in
blood and in tissue fluid.
ASV is recommended if and when a patient with proven or
suspected snake develops one or more of the following signs :
 • Haemostatic abnormalities - spontaneous systemic bleeding -
non-coagulable blood in 20 min whole blood clotting test •
 Neurotoxic signs - ptosis, external ophthalmoplegia dysphagia,
paralysis •
 Cardiovascular abnormalities - Shock, cardiac arrhythmia Local
envenoming •
 Local swelling involving more than half of the bitten limb (in the
absence of a tourniquet). •
 Rapid extension of swelling (for example beyond the wrist or
ankle within a few hours of bites on the hands or feet). •
 Development of an enlarged tender lymph node draining the
bitten limb
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P.M. 37

 Hoffman R, Howland MA, Lewin N et al. Goldfrank's
Toxicologic Emergencies, Tenth Edition. McGraw-Hill
Education / Medical; 2014
 Lavonas EJ, Ruha AM, Banner W, et al. Unified treatment
algorithm for the management of crotaline snakebite in
the United States: results of an evidence-informed
consensus workshop. BMC Emerg Med. 2011;11:2.
 SR Mehta, VSM* and VK Sashindran. Clinical Features And
Management Of Snake Bite, 2011.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4925324
/
 Biranchni Narayan Mohapatra, CBK Mohanty, Cuttack.
Guidelines for Anti Snake Venom Therapy. Medicine
Update 2010 Vol. 20
http://www.apiindia.org/pdf/medicine_update_2010/critic
al_care_emergency_medicine_03.pdf
P.M. 38

 Syed Moied Ahmed, Mohib Ahmed, Abu
Nadeem, Jyotsna Mahajan, Adarash
Choudhary, and Jyotishka Pa. Emergency
treatment of a snake bite: Pearls from
literature. J Emerg Trauma Shock. 2008 Jul-
Dec; 1(2): 97–105.
https://www.ncbi.nlm.nih.gov/pmc/articles/P
MC2700615/
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Snake bites

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