Snakes in the (Indian) Grass

August 12, 2007 at 7:27 am | Posted in antivenin, antivenom, Bungarus, common cobra, common krait, Daboia, Echis, Hypnale, king cobra, Naja, Ophiophagus, Russell's viper, saw scaled viper, snakebite, Trimeresurus, venomous | 3 Comments

A ‘narcissistic’ Indian Cobra

INDIA’S “BIG FOUR

(Naja naja)

The Russell’s Viper

Echis carinatus – the Saw Scaled Viper
Notice how variable the colouring can be.


Saranya, my 19-year-old daughter, just recovered from a snakebite this week. I haven’t really kept myself very up-to-date on the developments in treating snakebites for the last couple of years as my snake rescue work has almost been non-existent of late. It’s very good to see that the next generation is showing an interest in preserving these wonderful, though somewhat dangerous creatures!

Now that I’ve had to brush-up, I thought I would take the opportunity to summarise the steps to be taken when bitten by a snake…

First and foremost, no snakebite should be ignored. Most bites may be from nonpoisonous snakes and sometimes even venomous snakes do not deliver enough venom when biting to prove dangerous, but that is no excuse not to go to the nearest emergency room, get evaluated, and if necessary, have treatment started. Early treatment is the key to preventing complications, and to saving lives, limbs and kidneys!

In India, it is estimated that up to 20,000 people die annually from snakebites. Morbidity is also significant. These are not small numbers, and there seems to have been little improvement in reducing the fatalities over the years in spite of now having good supplies of polyvalent antisnakevenom available in all population centers. The major reason for the high mortality rate (about 5% to 10% of all those reporting bites) is the delay in getting the victim to a well-equipped casualty treatment facility fast enough.

About 80% of the venomous snakebites in India come from the saw scaled viper (Echis carinatus) and this little fellow can cause problems a little more slowly than the others of the “big four” (cobra, krait and Russel’s viper) so it’s probably true that a lot of the fatalities that do occur are in fact preventable.

FIRST AID:
In the absence of a nearby doctor, those accompanying the bitten one need to first calm the victim down and then immobilise the affected limb (if it is a limb). Pressure bandages, tourniquets, and cutting into the site of the bite to suck out the venom (all of which were the mainstays of first aid in my heyday) seem to have fallen out of favour.

Next, get the person to the nearest hospital as fast as possible. Walking and running for the victim are best avoided. The victim should be encouraged to breathe deeply and evenly to bring the pulse rate to a steady state. Those having cell phones should call ahead so that even if antivenom is not available, it will be made available by the time the patient arrives. remember that 5, 10, or even more vials of antivenom may be needed, so ask whoever is at the other end to ensure an adequate supply.

Observe the snakebite victim carefully while taking them to the hospital. Note the time and location of the bite and try to get as much accurate information on the appearance and size of the snake. Any symptoms such as discolouration at the site or of the affected limb, swelling, changes in eyes (e.g. droopy lids), eyesight, speech, breathing, sweating, unusual eye movements, bleeding, lowered level of consciousness or other difficulties should be noted.

TREATMENT:
Mostly, if there are symptoms, the doctors will immediately do a spot test dose in the skin of a forearm to check for allergies to the antivenom. Depending on the symptoms, they may then start the antivenom treatment and then one will most profitably spend one’s time praying that there will be no complications.

On admission, and at relevant intervals afterwards, the doctors will probably check on how well the blood is clotting (bleeding time, clotting time, and sometimes tests like PT and aPTT), kidney function (urine output, blood urea, creatinine and electrolyte levels), and of course the vital signs – pulse, breathing, temperature, blood pressure and the amount of oxygen in the blood (pO2). They may also keep tabs on the patient’s haemoglobin, blood cell counts, and perhaps the blood gasses too.

Sometimes even after a day or two, things can go wrong, with the patient starting bleeding, kidney failure, or even the heart could be affected, so keeping the victim under medical observation even after the antivenom has been administered is important. Most of the time, alert medical staff will successfully deal with the crises as they arise.

Saranya was probably bitten by the Saw Scaled Viper (Echis, see above), but sometimes a non-big-four candidate can cause trouble. In our our area of South India, especially in hilly areas, we do run into bites from the Hump-nosed Pit Viper (Hypnale hypnale)

or the Bamboo Pit Viper (Trimeresurus gramineus) and very, very rarely, the king cobra (Ophiophagus hannah).

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