Snake bites management

Types of Snakes and their Toxins 

       The end of spring, summer, and the beginning of autumn is the period when many people go to the forest for mushrooms and berries. Sometimes it is associated with the danger of being bitten by poisonous animals. According to the WHO (World Health Organization), more than 10 million people are registered annually in the world who are bitten by poisonous animals, about 50 thousand of them die. The toxic danger for children is especially great.   

  How to avoid a snake bite in the forest

First of all, going to the forest, it is best to wear rubber boots and tight trousers. If you decide to sit down and rest, use a stick to check if there is a snake nearby. If you suddenly notice a snake crawling, freeze, give it the opportunity to leave. If the snake has taken a pose of threat, step back slowly. Avoid sudden, snake-scaring movements! It is impossible, defensively, to put your hands forward, turn your back to the snake. Do not run away from the snake you meet — you can step on another unnoticed one. Keep calm in decisions, actions, gestures. Remember, a snake that you do not see is dangerous, a detected snake does not pose a threat.

The clinical picture of snake venom poisoning depends on the amount of venom, the bite site(bites to the head, neck and bites with damage to large vessels are very dangerous when the venom enters the general bloodstream and severe poisoning develops quickly), the age of the victim (in children, the poisoning clinic is more violent and bright), the time of year (severe cases are most often are marked with the onset of heat). The higher the air temperature, the faster intoxication develops.

The bite of the viper immediately causes severe, increasing pain. At the site of the lesion, two scarlet dots are usually visible - traces of poisonous teeth. Soon there are spotty or spotty hemorrhages at the bite site, rapidly progressing swelling of the affected limb. There is increased bleeding in the bite area. The skin acquires a bluish or slate-gray shade. General symptoms of poisoning usually occur after 15-20 minutes. These are general weakness, dizziness, lethargy, drowsiness, nausea, sometimes vomiting, shortness of breath, rapid pulse. Fatalities are very rare.

Snake bite is known as the neglected tropical disease and is an important medical emergency.There are 3000 species of snakes in the world, out of which only 15% are venomous, all others considered non venomous. 

The most common venomous snakes found in South Asia including Pakistan are, 

 1_ Indian cobra 
2_ Common krait
3_ Russell's viper 
4_ Saw scalded viper

Signs and symptoms of snakes bite 

                The snake venom is composed of hundreds of different proteins and enzymes that predominantly maybe, 
1.Neurotoxic
2.Haemotoxic or
3.Combination of  both 
The most common symptom of all snake bites is overwhelming fear with unwarranted thoughts of imminent death that contributes to symptoms secondary to envenomation.These non specific symptoms include,
*Nausea vomiting 
*diarrhoea 
*fainting 
*vertigo 
*tachycardia 
*cold clammy skin 
The signs and symptoms may be localised or systemic 

*Local effects

these depends on the location and severity of snakes bite.There may be mild pain and redness around the bite but in cases of vipers and cobras there may be severe pain and tenderness with marked swelling of the bitten area within five minutes. 

Systemic effects 

  They're of three types 

1_ Haemotoxic 

       Certain venoms can lead to a wide range of haematological effects including severe hemolysis and Disseminated intravascular coagulation (DIC), which can lead to severe anemia and bleeding diathesis.This can manifest as spontaneous bleeding in the form of patechial or purpuric rash, epistaxis, bleeding gums, bleeding from venipuncture or cannula sitesor GI bleed including hematemesis and hematochezia. 

2_ Neurotoxic effects 

             Neurotoxic venoms can result in ptosis, blurred vision, diplopia, dysarthria, dysphagia and also feeling of suffocation.If not handled timely then the patient can die of Respiratory failure. 

3_ Cytolytic effects

             Some venoms produce both hemotoxic and Neurotoxic effects, They can lead to extensive cellular deaths resulting in massive myoglobinuria and shock which can precipitate acute renal failre secondary to acute tubular necrosis.

Management of snakes bite:

        First aid Guide lines 

* Protect the person and others from further bites while snake identification is desirable in certain regions. 

Here this must be added that the locally practiced treatments may cause more harm than good, including making an incision over the bite, mouth suctioning,tourniguet use, ice packs or electric shock. 

* Keep the patient calm and reassure them, as this is most important ( as 70% of all snake bites are from non_venomous species and approximately half of the bites from venomous species are dry bites that rarely poison the person. 

* Washing the wound with soap and copious water and holding the limb still is recommended. 

 Pressure immobilization technique. 

   Immobilise the patient as a whole especially the bitten limb.To do this, use bandages or cloth to hold the splints, with care taken not to apply excessive pressure that might block the blood supply. The objective of PIT is to contain neurotoxic venom within a bitten limb and prevent it from moving through the lymphatic system to the vital organs.

 Remember! First aid should be provided in a timely manner. This will ensure a quick recovery and restoration of the victim's ability to work!

 Hospital management 

   * ABC * 

Maintain Airways, Breathing and Circulation 

* Look for signs of shock ( tachypnea, tachycardia, dry pale skin mental status changes, hypotension)

*Prophylactic antibiotics ( 3rd generation cephalosporins are a good choice)

*Pain management (Paracetamol or norcotic analgesics But avoid NSAIDs and intramuscular injections)

*Administer snake antivenom and then elevate the swollen limb to reduce edema.

*Tetanus prophylaxis

*Keep monitoring until the patients are hemodynamically stable.

 

** The envenomed patients ک must be kept under observation for at least 3_4 days because serum half lives of most of the snake venoms range from 26_95 hours.*

        By Dr Sher jahan 

General Physician at 

Government Hospital Chilas 

Northern Areas Pakistan