Snake Bites
Only 50% of patients bit by a snake will present with signs and symptoms.
Most bites are below the knee.
Venom
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It’s modified saliva
90-95% is made of proteins
Differs among the various snakes
General presentation of a snake bite
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Necrosis
Paralysis
Haemorrhage (eyes, nose, bite site, etc.)
Cardiotoxicity (hypovolaemia, direct damage to the heart)
Myotoxicity
Cytotoxicity (severe hypovolaemia)
Neurotoxicity (headache, vomiting, ptosis, paraesthesia, respiratory paralysis)
Ophthalmia (inflammation of the conjunctiva; red eyes)
Kidney damage
EVERY BITE IS DIFFERENT
Snakes
Puff adder, zebra snake, Mozambique cobra
Dwarf adder,
Mamba, non-spitting cobra
Boom slang, twig snake
Spitting cobra
What they cause
Severe cytotoxicity
Mild cytotoxicity
Neurotoxicity
Haemorrhage
Ophthalmia
First aid
Pre-hospital:
Wrong
Put on a tourniquet
Panic
Consume alcohol
Cut or suck the wound
Stun the wound
Correct
Remain calm
Immobilize the limb and elevate to the level of
the heart
Call for help (ambulance)
Go to hospital
Don’t waste time
Tell doctors what treatment the person already
received, and the signs and symptoms
In the hospital:
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Get expert advice (i.e. snake experts)
Good history. Use the mnemonic BITES
o Bite, site, time it happened
o Identify the snake
o Treatment received thus far
o Extra info (e.g. pt is on anticoagulant medication)
o Signs and symptoms
Red flags:
o Wide spaced bite (then it was a big snake)
o Early onset of signs and symptoms
o No urine or very dark urine
o Paediatric, elderly, and pregnant patients
Examination
o Fang puncture
o Local signs (necrosis, haemorrhage)
o Full systemic exam
Some special investigations
o HGT
o Urine dipstick
o ECG
o FBC
o WCC
o Crossmatch
Tourniquets
o They can cause ischaemia. Thus, WHO does not recommend to apply one after a snake
bite
o If pt comes with one, and it is removed too quickly, it can also cause hypotension. To
remove a tourniquet, have resus ready. Put a new tourniquet, or a BP cuff, above that
one. Deflate 3 times for 10s, then re-inflate for 50s, then totally deflate.
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General: ABCs, tetanus shot, paracetamol, wash and dress wound, elevate limb.
Anti-venom
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Problems it has:
o May not be specific to the snake
o Allergic reaction (anaphylaxis)
o No anti-venom available
o Not enough administered
o Anti-venom doesn’t bind to venom
Dilute 200mL anti-venom, then give IV slowly over 10-15 minutes
Children get an adult dose
Pregnant patients can receive anti-venom too
Patients should be continuously monitored
Surgical intervention
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Debridement
Reconstruction
Fasciotomy only when compartment syndrome is present
Adders
 Cytotoxic (swelling, coagulopathy, necrosis)
 ≥ 6 ampules of polyvalent anti-venom
 Late debridement
Zebra snakes
 They are nocturnal. They love plumbing
 Cytotoxic
 Unique: blue discolouration at the bite site
 Rhabdomyolysis (muscle breaks down and
contents leak into blood)
 Skip lesions if treatment is delayed
 Necrotising fasciitis can occur. Give
Ceftriaxone
 Mx: Early debridement, vacuum dressing
Cape cobra (Geelslang)
 Neurotoxic
 12-15 ampules of polyvalent anti-venom
Spitting cobras
 Cytotoxic
 No anti-venom
 Early debridement
Mamba
 Neurotoxic
 Triad: paraesthesia, profuse sweating and
excessive salivation or metallic taste
 Other Sx: descending paralysis,
fasciculations (like twitching), muscle
spasms
 Mx: 10-15 ampules of polyvalent antivenom, respiratory support
Boom slang
 Large eyes, ‘smiling’ mouth, doesn’t only
come in green
 Haemorrhagic
 2-3 ampules of monovalent anti-venom
Stiletto/burrow snake
 Horizontal fangs, lives in sand burrows
 No anti-venom
 Late debridement
Paediatric patients bitten are an absolute emergency!
Five fingers to remember the 5 types of dangerous snakes
1. Thumb: Adders (short, fat, triangular face)
2. Index: Spitting cobras (pointing the index with the thumb up resembles a water gun which is
squirting/spitting water)
3. Middle: 3 groups (bc the middle finger is 3rd from the left or 3rd from the right)
a. Mambas
b. Boom slang
c. Cobras
4. Ring: Zebra snakes (any snake with rings around its body)
5. Pinkie: Baby snakes (bc the pinkie is littlest of the fingers. Baby snakes have very potent venom)
When you confront a snake
Think of a traffic light
 Red – Stop! Stand completely still if the snake is very close to you
 Yellow – Slowly back away from the snake while still watching it
 Green – Walk away if the snake is far away
Puff adder
They have Chevron markings across their body
It camouflages itself
and is reluctant to
move even if you’re
very close
Triangular head
Zebra snake (cobra)
Cape cobra (Geelslang)
Non-spitting
Dark mark under the
eye
Juveniles have a dark
band on throat
Mozambique spitting cobra
Black mama
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Shy snake
Can bite repeatedly
Can climb trees and swim
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Nocturnal
Black band on chest
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Black markings on the
edges of the scales
Boom slang
Known for their big round eyes
They don’t only come in green