Snake Bite

1. Snake Bite
Dr Reem Elshamy
Family Medicine PGY3

2. What is snake bite?
• Potentially life-threatening disease caused by
• toxins in the bite of a venomous snake.
• by having venom sprayed into the eyes by some species.
• Occupational hazard affecting farmers, plantation workers,
herders and fishermen.
• Snake envenomation is a major global health problem,
with the WHO classifying it as a neglected tropical disease
since 2017.​

3. Epidemiology
• According to the World Health Organization, more than 5 million snakebites occur worldwide each
year, resulting in approximately 2.5 million envenomation and 81,000 to 138,000 deaths.
• Underreporting is a major challenge, driven by limited surveillance, reliance on traditional healers,
and lack of access to formal healthcare, especially in rural areas. ​
• Hospital-based data often underestimate true incidence and mortality, as many victims do not seek
or reach medical care. This underreporting impedes accurate burden estimation and resource
allocation.​
• High-risk regions include South Asia (notably India, Bangladesh, Nepal, Pakistan, and Sri Lanka) and
Sub-Saharan Africa, which together account for the majority of global morbidity and mortality.​

4. In 2019, the World Health
Organization (WHO) set a
target to halve the number
of deaths and cases of
snakebite envenoming by
2030

5. VENOMOUS SNAKES FOUND IN UAE
• The venomous snakes found in the United Arab Emirates include several species of medical
importance, primarily from the Viperidae and Elapidae families. The most clinically significant
species are:
Family Common name
Viperidae Arabian horned viper
Saw scaled viper
Hydrophidae Sea snake
Elapidae Desert black snake/black desert cobra
Arabian cobra

8. • Not all bites by venomous snakes are
accompanied by the injection of venom.
• Approximately 20% of pit viper bites
and higher percentages of other
snakebites (up to 75% for sea snakes)
are “dry” bites; i.e., no venom is
released.
• Significant envenomation probably
occurs in ~50% of all venomous
snakebites.

9. CLINICAL
PRESENTATION

10. CLINICAL PICTURE
DEPENDS ON-
• Species involved
• Anatomic location of bite and amount of venom injected
• Area covered or uncovered
• Dry or incomplete bite
• Multiple bites
• Any signs or symptoms and the timing of onset
• Initial treatment and first aid that was provided,
including timing of first aid
• Pertinent past medical history
• Time elapsed between bite and administration of ASV

11. Non venom related symptoms
NON-SPECIFIC SYMPTOMS
RELATED TO ANXIETY
- Palpitations, sweating,
tremulousness, tachycardia,
tachypnoea, elevated BP, cold
extremities and paresthesia
- May have dilated pupils – s/o
sympathetic overactivity
SIGNS AND SYMPTOMS OF
ENVENOMATION
Redness, increased temperature,
persistent bleeding and tenderness
locally

12. There are two different types
of snake bites
• Dry bites: Bites by non-venomous snakes/ bites by venomous species not
accompanied by injection of venom
• Venomous bites: These are much more dangerous. They occur when a
snake transmits venom during a bite.
• Poisonous snakes voluntarily emit venom when they bite. They can control
the amount of venom they discharge, and 50 to 70% of venomous snake
bites result in envenoming or poisoning.

13. Local effects
• Bite site—Swelling, blistering, bruising, necrosis (usual after bites by cobras and vipers, with some
exceptions in each family, and burrowing asps)
• Local pain and local bleeding
• Acute compartment syndrome after deep bite into a limb—Intense pain, abnormal sensations, or a
cold, pulseless, immobile limb
• Venom ophthalmia from entry of venom droplets or spray into the eyes—Intense pain, redness,
blepharitis, blepharospasm, and corneal erosions
• Fang marks
• Lymphangitis (raised red lines tracking up the bitten limb) and lymph node enlargement

15. Systemic
manifestations

16. Systemic manifestations
General manifestations
• Nausea
• Vomiting
• Pain abdomen
• Malaise
• Weakness
• Drowsiness
• Prostration
• Anxiety
• Excessive salivation, etc.

17. • VASCULOTOXIC ( hemotoxic or
Bleeding)
o Bleeding may from venipuncture site,
gums
o Epistaxis and Hemoptysis
o Melena, rectal bleeding
o Hematuria, bleeding from vagina
o Subconjunctival hemorrhage
o Petechiae, purpura, ecchymosis
o Local swelling, blistering and necrosis
o Tender enlargement of local draining
lymph node
o Pain at bite site and severe swelling
leading to compartment syndrome

18. • Neurotoxic
• Ophthalmoplegia
• Pupillary dilatation- often non- responsive to light
• Inability (or limitation) to open mouth
• Numbness around lips and mouths
• 5D’s and 2P’s
• 5D’s – diplopia, dysarthria, dysphonia, dyspnea,
dysphagia
• 2P’s – ptosis, paralysis
• Finally, paralysis of intercostal and skeletal muscles
occur in descending order

19. • MYOTOXIC (sea snake bite)
• Muscle aches, muscle swelling, involuntary contraction of muscles
• Passage of brown urine
• Compartment syndrome, cardiac arrhythmias due to hyperkalemia, acute kidney injury due to
myoglobinuria, and subtle neuroparalytic signs

20. Other systemic symptoms
• Cardiotoxic- (Viperidae & Cobra)
 Manifested by palpitations, hypotension, shock, arrhythmia, pulmonary edema, death
• Renal Toxicity- (Viperidae)
 uncommon with saw-scaled viper
 Multifactorial – Hypotension – ATN, Hb and Myoglobinuria – Rhabdomyolysis, Intravascular hemolysis,
DIC, Vasculitis, Acute Interstitial Nephritis, ultimately leading to AKI
• Gastro-intestinal:- Nausea, Vomiting, abdominal pain

21. LONG TERM COMPLICATIONS
(SEQUELAE)
• Chronic ulceration, infection, osteomyelitis or arthritis
• Physical disability
• Chronic kidney disease due to bilateral renal cortical necrosis
• Chronic pan-hypopituitarism may occur in Russell’s viper envenoming
• Sequelae of intracranial bleeding in hematotoxic envenoming
• Delayed psychological morbidity like depression and anxiety, impaired functioning, post-traumatic
stress disorder

22. Diagnosis

23. INVESTIGATIONS
20-minute whole
blood clotting time
– to diagnose
coagulopathy
Complete blood picture –
to determine degree of
hemorrhage or
hemolysis and to detect
thrombocytopenia
RFT and LFT’s
Coagulation
studies- to diagnose
consumptive
coagulopathy
Measurement of
creatine kinase and
testing of urine for
blood or myoglobin-
for suspected
rhabdomyolysis
ABG, ECG, Chest X Ray – in
severe envenomation or in
pts with significant
comorbidities

24. 20 min
whole blood
clotting
test (20
WBCT)

25. Management

26. Steps for
management
• First aid treatment and transport to the hospital
• Rapid clinical assessment and resuscitation
• Antivenom treatment
• Supportive/ancillary treatment
• Treatment of the bitten part

27. Recommended first aid treatment
• Remove the patient from the snake's territory. Keep the patient calm and at rest, remaining as still
as possible.
• Attempt to identify the snake only if it is safe for the patient and the rescuer, and it will not delay
transport of the patient to definitive medical care.
• Remove any jewelry or footwear from the affected extremity. Clothing that is not tight and does not
cause circulatory compromise can be left in place.
• Immobilize the injured part of the body in a functional position .
• Limited evidence exists regarding the recommended height of the bite wound relative to the level of
the heart. Expert recommendations vary according to the expected degree of local injury compared
with systemic toxicity.

28. First aid Cont.
• Fashion a splint out of any rigid object (eg, padded piece of wood or tree branch, rolled newspaper,
sleeping bag pad, or backpack frame) and apply to the extremity as follows:
 Splint the leg posteriorly in extension immobilizing the ankle and the knee.
 Splint the arm to the elbow and apply a sling.
• Transport the patient to the nearest medical facility as quickly as possible.
• Do not allow the victim to walk because exertion and, with bite wounds on the lower extremity,
local muscle contraction may increase snake venom absorption.
• Do not manipulate the wound except to permit gentle bandaging or, if indicated, pressure
immobilization or placement of a pressure pad. If transport to definitive care will be prolonged and
a venom detection kit will not be used gentle cleansing may be performed.

29. Pressure immobilization
• It is suggested that patients with snakebites from species with venoms that cause paralysis with
little to no local tissue damage in whom transportation to definitive medical treatment will be
prolonged, should receive pressure immobilization rather than immobilization alone.
• Pressure bandage and immobilization (PBI) is not suggested following bites by snake species whose
venom is associated with significant local tissue necrosis (eg, many cobras, adders, pit vipers, and
rattle snakes). In these patients, localization of toxin may worsen tissue damage and could possibly
raise compartment pressures.

31. CAUTION
• Tight arterial tourniquet must never be recommended
• Delay the release of tight tourniquets if patient has
already applied this popular method of first-aid
• Methods to avoid — The following methods, while
used widely in the past and advocated by some, cause
more harm than good and should be avoided :
• Incision and oral suction
• Mechanical suction devices
• Cryotherapy
• Surgery
• Electric shock therapy

32. HOSPITAL MANAGEMENT
• ABC
• Monitoring of vitals , cardiac rhythm , oxygen saturation and urine output
• Secure two large bore iv lines in unaffected extremities
• Fluid resuscitation with isotonic saline 20-40 ml/kg iv ; if hemodynamic instability is present (5%
Albumin can be tried if response to saline is inadequate)
• Vasopressors ( norepinephrine , dopamine) – only if venom induced shock persists after aggressive
volume resuscitation and antivenom administration
• Invasive hemodynamic monitoring ( central venous / continuous arterial pressures ) is helpful but
risky if coagulopathy has developed

33. Antivenom treatment
• Antivenom remains the primary treatment for any patient with serious snake envenomation and in most
patients should be used whenever available
• Although high rates of adverse reactions occur for some antivenoms, patients generally benefit from antivenom
and, for many, antivenom is life-saving.
• All patients who receive antivenom warrant appropriate measures to manage an adverse reaction.
• Antivenoms are whole or fragmented immunoglobulins fractionated from the plasma of domesticated animals
hyper-immunized with venom from one or more snake species over variable periods.
• Early administration of antivenom prevents or limits haemodynamic alterations, progression of coagulopathy to
clinically overt bleeding, postsynaptic neurotoxicity, myotoxicity, acute kidney injury, and local tissue damage.

34. Antivenom treatment Cont.
Monovalent – Most
monovalent antivenoms are
raised against a single genus
or species of snake and
should only be considered
effective for bites by that
snake or group of snakes.
Polyvalent – Polyvalent
antivenoms are developed
against venoms from multiple
different snakes that typically
share a geographical region
and can be used to treat
envenomation by any of the
included species

35. Indications for administering
antivenom
• Evidence of Neurotoxicity
 Ptosis, ophthalmoplegia, broken neck sign, respiratory difficulty, etc.
• Evidence of Coagulopathy
 Evidence of coagulopathy primarily detected by 20 WBCT or visible spontaneous systemic bleeding,
bleeding gums, etc., including myoglobinuria and hemoglobinuria, deranged PT/INR, etc
 Rapid extension of local swelling (more than half of limb) which is not due to tight tourniquet application.
• Evidence of Cardiovascular Collapse
 Shock and hypotension (in case of Russell’s viper bite).
• Evidence Of Acute Kidney Injury
 AKI is an indication for antivenom therapy.

36. Contradictions
• No absolute contraindication to antivenom treatment.
•Prior allergic reaction to antivenom or one of its
components.
• Patients with asthma – These patients may be at higher risk
for immediate allergic reactions with severe respiratory distress.
• Patients receiving beta adrenergic blockers or angiotensin-
converting enzyme inhibitors –These drugs may reduce the
effectiveness of treatment of anaphylaxis.

37. How long after the bite can antivenom be expected to
be effective?
• Antivenom treatment should be given as soon as it is indicated.
• It may reverse systemic envenoming even when this has persisted for several days or, in the case of
hemostatic abnormalities, for two or more weeks.
• It is, therefore, appropriate to give antivenom for as long as evidence of the coagulopathy
persists. Whether antivenom can prevent local necrosis remains controversial, but there is some
clinical evidence that, to be effective in this situation, it must be administered within the first few
hours after the bite

38. ADMINISTRATION
• Choice of antivenom – A list of available antivenoms by snake species available by WHO.
• Dose – Dosing is determined by the snake species and individual patient characteristics. It is based on
the average amount of venom expected from the snakebite, so the size and weight of the patient may
be irrelevant. The dose of antivenom does not differ between adults and children; there is no "pediatric
dose" for antivenom.
• Route of administration – The IV route of administration is preferred to intramuscular (IM) injection
whenever possible to ensure the most effective and rapid neutralization of snake venom. In small
children, if IV access is not possible, IO infusion is appropriate if life-threatening envenomation is likely.
• In general, IV infusion of diluted antivenom is still preferred because it permits slower administration
with an ability to hold the infusion if an adverse reaction occurs and to restart the infusion at a slower
rate after the reaction is treated.
• Do not inject ASV locally at the bite site – not effective, extremely painful and may increase intra
compartmental pressure

39. Response to
treatment
• General symptoms may disappear vary quickly.
• Spontaneous systemic bleeding usually stops within 15-30
min.
• Blood pressure may increase within 30-60 min.
• Neurotoxicity may improve as early as 30 min.
• Blood coagulability is usually restored in 3-9 hrs.

40. Failure to
respond
• May be due to the following reasons:
• Insufficient antivenom
• Wrong antivenom
• Inactive or poor quality antivenom
• Excessive delay in administration after
envenomation
• A venom effect not reversible by
antivenom (eg, presynaptic neurotoxic
paralysis)

41. Criteria for repeating the
initial dose of antivenom
• If the blood remains incoagulable (as measured by
20WBCT) six hours after the initial dose of antivenom,
the same dose should be repeated.
• In patients who continue to bleed briskly, the dose
of antivenom should be repeated within 1-2 hours.
• In case of deteriorating neurotoxicity or
cardiovascular signs, the initial dose of antivenom
should be repeated after 1-2 hours.

42. Premedication
• It is suggested that patients treated in the following settings receive premedication with
subcutaneous epinephrine :
• Use of antivenom is associated with high rates of allergic reactions.
• There is a significant risk of allergic reaction associated with antivenom use and the management of acute
allergic reactions is problematic because of limited staffing or facilities.
• Limited evidence suggests that the use of prophylactic subcutaneous epinephrine prior to the
administration of IV antivenoms in such settings is beneficial.
• Evidence does not support routine pretreatment with either antihistamines or corticosteroids.

44. Treatment other than antivenom
• Neostigmine with atropine is a potentially useful adjunct in patients bitten by snakes such as
some cobras with postsynaptic neurotoxins in their venom.
• Administer a tetanus toxoid booster in all patients except in those with coagulopathy, in which
case injection is postponed until haemostasias is achieved.
• Aspirate large tense bullae to facilitate nursing the bitten limb, pre-empt spontaneous rupture,
and prevent secondary infection.
• Broad spectrum antibiotics are indicated only if the wound has been incised or there are signs of
necrosis, wound infection, or abscess formation.
• Surgical debridement or amputation of gangrenous digits or limbs and skin grafting may be
needed.
• Fasciotomies are rarely justified since compartment pressures usually remain within normal limits.

45. ADDovenom: Novel Snakebite
Therapy Platform of Unparalleled
Efficacy, Safety and Affordability
• Based on a new disruptive protein-
based nanoscaffold called ADDomer –
a megadalton-sized, thermostable
synthetic virus-like particle with 60
high-affinity binding sites to neutralise
and eliminate venom toxins from the
bloodstream.

46. PREVENTION OF SNAKEBITE
• Community based education.
• Keep household clean by cutting grasses, bushes, and plants, remove heaps of rubbish, building
materials etc. from near and around house.
• Bamboo, wood piles should be removed from household so that snake cannot hide.
• Close door, windows properly.
• Try to avoid sleeping on floor. If it is unavoidable, then mosquito net should be used and tucked
well under the mattress or sleeping mat. It not only prevents from krait bite but also from mosquito
bite.
• Keep your granary away from the house, it may attract rodents that snakes will hunt

47. • Use high shoes or boots while walking in paddy field, bushes, long grasses.
• In dark, use light or strike the path using stick.
• Never play with snakes, or irritate them even if they are dead. Never provoke them, they usually do
not bite if not irritated or provoked.
• Never insert hands into long grasses, tree holes or mud holes. Take care while pulling straw.
• Shoes and cloths should be check before wearing, in an area where snakes are abundant.