Snakebite Management Flashcards

What are the first three steps (ABC) in resuscitating a critically ill snakebite victim?

a) Maintain a clear Airway. b) Assess and support Breathing (a weak cough signifies respiratory paralysis). c) Assess Circulation (pulse/BP), establish IV access, and give an IV saline push if hypotensive.

What key parameters should be monitored in all snakebite patients admitted for observation?

Level of consciousness, temperature, pulse rate, blood pressure, respiratory rate & tidal volume, urine output, and fluid balance.

What three types of interventions should be avoided whenever possible in snakebite management?

NSAIDs (including aspirin), intramuscular injections, and narcotics or other respiratory depressants.

What are some early, non-specific signs that suggest systemic envenoming?

Nausea, vomiting, malaise, abdominal pain, weakness, drowsiness, hypotension, and polymorphonuclear leucocytosis.

A patient presents with neurotoxic signs (e.g., ptosis) but has no significant local swelling or coagulopathy. They were bitten at night while sleeping on the floor. What is the likely snake?

Krait.

A patient has neurotoxic signs AND marked local swelling, but no coagulopathy (clotting blood). What is the likely snake?

Cobra.

A patient presents with a combination of neurotoxicity, coagulopathy (non-clotting blood), and marked local swelling. What is the likely snake?

Russell's Viper.

A patient has coagulopathy and marked local swelling but NO neurotoxic signs. What are the two most likely snakes?

Hump-nosed viper or Saw-scaled viper.

What clinical finding suggests rhabdomyolysis and is indicative of envenoming by a sea snake or Russell’s viper?

Muscle movement pain and myoglobinuria (passing deep-red wine-coloured urine).

What is the bedside test used to assess for coagulopathy?

The 20-minute whole blood clotting test (20WBCT).

What does a ‘false negative’ (clotting) 20WBCT result mean?

It may occur in patients with milder coagulopathy or in the early stages of venom-induced consumption coagulopathy, so the test should be repeated frequently.

When should antivenom therapy be started?

As soon as possible following the detection of systemic envenoming.

What premedication is recommended before giving antivenom?

A low-dose of adrenaline given subcutaneously is recommended to prevent or reduce reactions.

Are antihistamines and corticosteroids recommended as premedication before antivenom?

No. Studies show they do not affect the incidence or severity of early antivenom reactions and are NOT advocated for premedication.

What is the mainstay of treatment for an acute anaphylactic reaction to antivenom?

Adrenaline given intramuscularly (0.5 mg for adults, 0.01 mg/kg for children).

How are late reactions to antivenom (serum sickness), which occur 1-12 days after treatment, managed?

First with a 5-day course of an oral antihistamine (chlorphenamine). If there is no response in 24-48 hours, a 5-day course of a corticosteroid (prednisolone) is given.

Is the antivenom dose for a child different from an adult’s?

No, the dose is the same. However, the volume of diluent must be adjusted for the child's smaller body mass to prevent fluid overload.

What is a useful early sign of impending respiratory failure in small children with neurotoxic envenoming?

Progressive reduction of chest expansion. Monitoring respiratory rate alone may be misleading.

When is antivenom indicated for local envenoming *alone*?

Only for cobra bites. It should be given as soon as local envenoming is detected to prevent severe tissue destruction, even without systemic effects.

What are the two primary clinical features of a cobra bite?

Severe local envenoming (leading to tissue necrosis and compartment syndrome) and rapid-onset neurotoxicity that can cause respiratory paralysis.

What is a characteristic early symptom of a Common Krait bite that can indicate the need for antivenom before paralysis starts?

Abdominal pain, which may be associated with vomiting.

Describe the progression of paralysis in a Common Krait bite.

It is a descending paralysis, starting with ptosis and external ophthalmoplegia, followed by facial, bulbar, respiratory, and finally limb paralysis.

What is the life-saving intervention for respiratory paralysis from a krait bite?

Mechanical ventilation. It is the priority, and intubation may be considered before starting antivenom if bulbar paralysis is present.

Why might paralysis persist or worsen after giving antivenom for a krait bite?

Pre-synaptic neurotoxins cause irreversible damage to motor-nerve terminals. Antivenom clears circulating venom but cannot reverse established paralysis.

Is persistent paralysis from a krait bite an indication for more antivenom?

No. The persistence of paralysis is NOT an indication for repeated doses of antivenom.

What are the three most common systemic effects of a Russell’s viper bite?

1. Coagulopathy, 2. Neurotoxicity (limited to ptosis and ophthalmoplegia), and 3. Acute Kidney Injury (AKI).

What is the recommended initial antivenom dose for a Russell’s viper bite?

An initial dose of 20 vials is recommended. If coagulopathy is severe, 30 ampoules should be given as the first dose.

What is the endpoint of antivenom therapy, particularly in viper bites?

The reversal of coagulopathy, as determined by serial performance of the 20WBCT.

Should the Indian polyvalent antivenom be used for a Hump-nosed viper bite?

No. The currently available antivenom is NOT effective for hump-nosed viper envenoming and should not be used.

What are the two most serious systemic complications of a Hump-nosed viper bite?

Venom Induced Consumption Coagulopathy (VICC) and Acute Kidney Injury (AKI).

How long should a patient with a Hump-nosed viper bite be observed in the hospital, and why?

For at least 48 hours, because manifestations of coagulopathy can be delayed.

What is the management approach for a Hump-nosed viper bite?

Expectant and supportive treatment, including monitoring (20WBCT every 6 hours), ensuring hydration, pain management, and considering haemodialysis for severe AKI.

What is the most common systemic manifestation of a Saw-scaled viper bite, and is antivenom effective?

Coagulopathy (incoagulable blood) is the most common manifestation. Yes, Indian polyvalent antivenom is effective.

What are the main clinical features of a Green pit viper bite, and how is coagulopathy managed?

It frequently causes severe local pain and swelling, with rare systemic coagulopathy (VICC). Coagulopathy is managed with fresh frozen plasma (FFP); antivenom should NOT be used.

What are the two distinct clinical syndromes of sea snake envenoming?

1. Myotoxic envenoming (muscle pain, rhabdomyolysis, myoglobinuria, kidney failure) and 2. Dominant flacid paralytic envenoming (neurotoxic).

What is the management for a sea snake bite victim in Sri Lanka?