A slide in the management SNAKE BITE.pdf

A detailed slide on management of snake bite

1. MANAGEMENT OF SNAKE
BITE
BY
Muhammad D Adam
Muhammad I Getso
Moderator: DR Z. FAROUK (MBBS, FWCPaed)

2. Introduction
•There are nearly 3000 species of snakes
distributed throughout the world.
•Only 10-16% of these species are venomous
i.e,the bites of which may cause the clinical
spectrum of symptoms characteristic of
venomation.
•M & M are usually low: depending on the size of
the child, the site, the degree of envenomation,
type of snake, and effectiveness of Rx

3. Epidemiology
The highest bite rates occur in
temperate and tropical regions where
people subsist by manual agriculture.
Its largely a rural problem, and patients
usually seek help from herbalist.
(incomplete reporting).
Global estimates suggest that 30,000
to 40,000 persons die each year from
venomous snakebite.
3MD Adam & MI Getso

4. Epidemiology cont’
In Nigeria there are about 500 bites
per 100,000 popln with12%
mortality.
In US: 45 000 bites with 9-14 death
per year.
In UK: Appx 100 admission but no
death reported since 1970.
4MD Adam & MI Getso

5. Snake Anatomy & Identification
Typical Snake-venom
consists of bilat venom glands,
below and behind the eye,
connected by ducts to hollow, ant
maxillary teeth (Fang)
5MD Adam & MI Getso

6. Types of bite
Two types of bite are identified
•Offensive :Snake is after a prey;
more venum is injected (Wet bite).
•Defensive:
trampled upon; less or no venum
may be injected (Dry bite).
pic
6MD Adam & MI Getso

7. Poisonous Vs non poisonous
Poisonous
Head - Triangle; except
Cobra
Fangs - Present
Pupils - Elliptical
nostril pits -present
Anal Plate- Single row of
plates
Bite Mark- Fang Mark;
2punture sing
Non-poisonous
Head - Rounded
Fangs - Not present
Pupils - Rounded
nostril pits- not present
Anal Plate - Double row
of plates
Bite Mark - Row of
small teeth.
7MD Adam & MI Getso

8. 8MD Adam & MI Getso

9. Classification
Snakes are classified based on their
morphological characters like their bone ,
musculature, sense organs, dentition and
the scales on their body.
•Viperidae:
saw-scaled viper.-CVS
•Elapidae:
coral snakes mambas and krait.-CNS
•Hydrophidae: The sea-snakes.-
Myotoxins
9MD Adam & MI Getso

10. Pathophysiology of ophitoxaemia
Snake venom is a mixture of enzymatic and
non-enzymatic compounds as well as other
non-toxic proteins ; CHO & metals.
Enzymatic:PLases, hydrolases, PO4ases,
proteases, esterases, Achase, TAases,
hyaluronidase, PO4DEase, NTase & ATPase.
Non-enzymatic:Neurotoxins,
haemorrhagens (haemotoxins) and
myotoxin.
Constit & prop of wc differ within and inbtw
spp.
Causes disruption of normal cellular
functions by its enzymatic and cytotoxic
activity.
10MD Adam & MI Getso

11. Approach to individual ‘allegedly
bitten’ by a snake
Is it actually a snake bite?
Could it be any thing else?
Is it likely to be a poisonous species?
Which species is involved?
11MD Adam & MI Getso

12. Investigations
No specific lab study is of diagnostic benefit.
However baseline labs are helpful
FBC with differential and peripheral blood
smear
PT and PTTK; (INR).
FDP
Type and cross match
Serum urea and electrolytes
Urinalysis for myoglobinuria
ABG for patients with systemic symptoms
CXR
ECG
12MD Adam & MI Getso

13. MOT
Ophitoxaemia leads to ↑
permiability→
The ↓
enough to compromise circulation →shock.
Direct cytolytic action → local necrosis and 2
o
infection, →death.
Direct neurotoxic action → paralysis and resp
arrest, cardiotoxic effect → cardiac arrest,
myotoxic and nephrotoxic effect.
Ophitoxaemia also causes alteration in the
coagulation activity → to bleeding which may
be severe enough to kill the victim.
13MD Adam & MI Getso

14. The clinical manifestations of snake-bite occur in a
wide spectrum ranging minimal or no symptoms at
all, to severe systemic manifestations→death. Qtty,
toxicity, immunity
Clinical Manifestations
snake Fatal dose Dose per bite
Cobras 12mg 60mg
Russel’s viper 15mg 63mg
Krait 6mg 20mg
Saw-scaled viper 8mg 13mg
•Venom dosage per bite depends on the elapsed time since the last bite, the
degree of threat the snake feels, and the size of the prey.
14MD Adam & MI Getso

15. Common manifestation
blurred vision / dizziness
convulsions /fainting
excessive sweating, thirst and weakness
Fever, nausea and vomiting
increased salivation
Fang marks, localized pain and swelling
burning
muscle contractions
skin discoloration, numbness / tingling
tissue death
15MD Adam & MI Getso

16. Viper: 3% are capable of poisoning.
Local effects: rapid swelling and
necrosis→dry gangrene
Systemic: vasculotoxicity
Abd bleeding, non clotting of bld & CVS
collapse.
Mortality 1-15%;
Death within 48hr
16MD Adam & MI Getso

17. Elapidae:
poisoning
Local effects:
slow swelling and necrosis→wet
gangrene
Systemic: neurotoxicity
Ptosis, CN IX palsy, resp and cardiac
arrest, gen. paresisis.
Mortality 10%;
Death within 24hr
17MD Adam & MI Getso

18. Hydrophidae:
Local effects:
usually no local effects
Systemic: myotoxicity
Severe myoalgia, moving paresis,
myoglobinuria, hyperkalaemia and
renal failure.
Mortality 20%;
Death within 24hr
18MD Adam & MI Getso

19. First aid Care
The most important 1
st

transportation to a med facility.
Reassurance and immobilization of the
affected limb with prompt transfer to a
medical facility are the cornerstones of first
-aid care
NSAIDS particularly aspirin may be
beneficial to relieve local pain
Every effort should be made to capture/kill
it.
Try and keep bitten extremity at body level,
when the person is lying.
19MD Adam & MI Getso

20. Controversial Issues
Incision, excision, cauterization,
amputation.
Suction by mouth, vacuum, or venom
-ex apparatus, cryotheraphy &
electric shock.
Instilation of xcal cmpds. eg KMnO4
The role of toniquet, compression
pads and bandages.
20MD Adam & MI Getso

21. Emergency Unit Care
Assess the patient's airway and breathing.
Aggressively manage any signs of impending
respiratory failure with ETI.
Immediately institute cardiac and pulse
oximetry.
Establish at least one large bore intravenous
line take bld sample and start NS or RL at a
maintenance rate.
Monitor vital signs closely.
Grade the severity of poisoning using the
grading scale.
Consult Toxicologist where available.
21MD Adam & MI Getso

22. Grading scales for snake bite
Mild envenomation:
local swelling pain, with or without
lymphadenopathy, purpura or echymosis.
Moderate envenomation:
presence of coagulation defects or bradycardia
or mild systemic manifestations
severe envenomation:

features, DIC, encephalopathy and
paralysis

22MD Adam & MI Getso

23. Specific therapy
Antivenoms
and purifying the serum of horses
immunized with venom from poisonous
snakes
They can be monovalent (species specific )
or polyvalent (against several species )
Monovalent antivenom is ideal, but the cost
and non-availability makes its use less
common.
Every bite, even if by poisonous species
does not merit its use
23MD Adam & MI Getso

24. Indications for use
Serious manifestations of
envenomation viz coma,
neurotoxicity, hypotension, shock,
bleeding, DIC, ARF, rhabdomyolysis
and ECG changes
Swelling involving more than half the
affected limb
Extensive bruising or blistering and
progression of the local lesions within
30-60 minutes.
24MD Adam & MI Getso

25. Antivenin
Dose
•Conventionally 50 ml (5 vials) is infused for mild manifestations
•Moderate envenomation, use 100 ml (10 vials).
•Severe cases, 150 ml (15 vials) is infused
Administration
A test dose is administered on one forearm with 0.02 ml of 1:10 solution
intradermally. Similar volume of saline in the other forearm serves as
control. Appearance of erythema or wheal greater than 10 mm within 30
min is taken as a positive test.
In this event, desensitization is advised starting with 0.01 ml of 1:100 solution
and increasing concentration gradually at intervals of 15 minutes till 1.0 ml
can be given by 2 hours.
•Infusion is started at 20 ml/kg per hour initially and slowed down later
•Response
Response to infusion of antivenin is often dramatic with comatose patients
sitting up and talking coherently within minutes of administration.
Normalization of blood pressure is another early response [70]. Within 15 to
30 minutes, bleeding stops though coagulation disturbances may take up to
6 hours to normalize.
The intravenous dose can be repeated every 6 hours till the symptoms disappear
25MD Adam & MI Getso

26. Supportive Therapy
Bleeding patients require fresh whole blood transfusion
Volume expanders including plasma and blood are
recommended in shock.in severe shock α-agonist are
used.
Early mechanical ventilation is advocated in respiratory
failure though dramatic responses have also been
observed with edrophonium followed by neostigmine.
Cases of acute renal failure generally respond to
conservative management.
Occasionally peritoneal dialysis may be necessary.
In cases of DIC, use of heparin should be weighed
against risk
intravenous immunoglobulin (IVlg) are of beneficial
effects
26MD Adam & MI Getso

27. Supportive therapy cont’d
If venom is spit into the eyes, immediately and copiously
irrigate them with water, saline solution, or milk.
•Before the antivenin is given, premedicate the patient
with an antihistamine, and continue the antihistamine
for 5 days to prevent anaphylaxis.
•Administer corticosteroids if any history of previous
serum sickness or allergic reaction to the antivenin is
present.
Tetanus prophylaxis
Broad spectrum antibiotics are necessary in patients with
ulceration
Analgesia is essential, and this should be intravenously
administered
urinary catheter inserted so that this balance can be regularly
reassessed
27MD Adam & MI Getso

28. Complications:
Respiratory failure/arrest
Cardiovascular collapse
Prolonged neuromuscular weakness
Tissue necrosis
Antivenom-related complications
Anaphylactoid reactions
Delayed serum sickness
28MD Adam & MI Getso

29. Prevention
Keep landscape or campsite well
manicured.
Wear long pants and boots when in
areas known to have snakes.
Watch where you step and place your
hands when outdoors.
29MD Adam & MI Getso

30. CONCLUSION
Fortunately most snakebite victims
require supportive care only and can
be safely managed in hospitals
without tertiary facilities.
Our traditional healers should be
targeted for education on primary
care as they appear to be consulted
early by many victims.
30MD Adam & MI Getso