Close encounters with a snake

Poisonous snakes are found throughout Thailand and Southeast Asia and while the risk of bites is mainly an occupational hazard for farmers, it is not uncommon in urban areas. In Thailand, there are 7,000 snakebites per year resulting in 20 to 30 deaths, usually the result of late transfer to a medical facility.

Most snakes hunt during the night so it’s wise to avoid walking in the garden after dark. Fifty per cent of the victims are children, who are at higher risk as they are unaware of the dangers and tend to suffer from higher venom toxicity due to their small body size. Snakes usually flee when a person gets close but can become very aggressive if surprised or threatened.

Snakes do not discharge the venom every time. In 25 per cent of cases, the bite is limited to a simple puncture wound but should still be taken seriously. When venom is injected – envenomation, as it’s known – there will be redness, swelling and pain around the bite with varying symptoms felt in other areas of the body 

Thailand is home to several poisonous species that can inflict severe injury and can potentially be fatal. Symptoms vary broadly according to the type of venom. Cobras, among them the feared king cobra, and kraits produce a neurotoxin, which blocks the nerve and leads to paralysis. Symptoms include weakness, dropping of the eyelids and difficulty in swallowing. If left untreated, respiratory failure and general paralysis may occur, possibly leading to death. Coral snakes also have neurotoxic venom. Vipers including the common and particularly aggressive Malayan pit viper, release a venom that’s toxic to the blood (haemotoxic) and to tissue. Fang marks are usually visible at the site of the bite, which is extremely painful. The main symptoms, which can occur hours or days after the bite, are linked to severe blood disorders triggering superficial and internal bleeding and resulting without treatment in potentially fatal cardiovascular shock. 

In any snakebite, first aid during the pre-hospital period is of tremendous importance. It is useful but not vital to know the type of snake involved and no risks should be taken in attempting to identify it.

The main objectives are to organise prompt transfer to hospital, take steps to limit the progression of the venom in the body and not aggravate the condition by using inappropriate measures. To minimise dissemination of the toxin, the heart should beat at normal pace, which means the victim needs to be calm and reassured, preferably lying on the floor with comfortable immobilisation of the affected limb and avoiding any muscular effort. Constrictive items such as jewellery or tight clothing must to be removed due to possible intense swelling. 

The use of an elastic bandage is controversial as it could lead to more damage if not properly applied but is more useful for neurotoxin venom bites. Gentle compression – 5 to 10 cm above the bite area - aims to slow down the drainage of the venom from the lymphatic system and not to stop the blood flow. The bandage needs to be removed at the hospital. 

The bite site should simply be cleaned with soap and water and not be cut, sucked out or covered by icepacks. No alcohol, coffee or tea should be given (water is fine) as it could increase heart rate. Only give paracetamol if the pain is intense though even that is best avoided. At the hospital, the patient may be admitted to receive supportive intensive care treatment and be given antibiotics, tetanus injection and either IV monovalent or polyvalent antivenom when indicated. 

Finally, anyone who suffers a snakebite needs to remember that most injuries are not life threatening and early respiratory and wound care is very effective even in the absence of specific antivenom.

 

Dr Gerard Lalande is managing director of CEO-HEALTH, which provides medical referrals for expatriates and customised executive medical check-ups in Thailand. He can be contacted at |[email protected].