INDIA’S “BIG FOUR“
Echis carinatus – the Saw Scaled Viper
Notice how variable the colouring can be.
(the three pics below)
Saranya, my 19-year-old daughter, just recovered from a snakebite last month.
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! Naja naja, the Spectacled Cobra
Now that I’ve had to brush-up, I thought I would take the opportunity to summarise the steps to be taken
The Common Krait Bungarus caeruleus
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 conservatively 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 perhaps 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.
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). Tourniquets, applying any sort of chemicals or external medicines, 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.
The use of pressure bandaging is controversial but if done with something like crepe bandage and not too tightly, perhaps combined with a simple splint or sling, it may help to slow the spread of venom through the lymphatic system. Blood supply must NOT be cut off! On the whole, perhaps if the bitten one will be getting to a HOSPITAL within 3 0r 4 hours, it may be better not to attempt any pressure bandaging but advice on this point varies.
Try to remove any jewelery worn on the affected limb like rings, bangles, bracelets, anklets, or metti (toe rings) as these may cause problems if there is swelling or edema associated with the bite.
Next, get the person to the nearest good hospital as fast as possible. Walking and running for the victim are best avoided as is movement of the affected limb. Try to carry the person at least on a pallet or makeshift stretcher if no vehicles are available.
Giving anything by mouth is best avoided except if dehydration is a risk, in which case oral rehydration fluids (clean water mixed with a little salt and sugar will do OK).
Some poisonous snakes have cardiotoxins (poisons that can slow or stop the heart) so if possible try to keep the affected limb below the level of the heart. The victim should be encouraged to breathe deeply and evenly to bring the pulse rate to a steady state.
Particularly as you move towards the closest hospital, keep a watch on breathing and on keeping airways clear. If the person has difficulty breathing first see that there is nothing blocking the airway (like the tongue, secretions, or vomit) and if necessary be prepared to help the person to breathe by doing mouth to mouth. Rarely will the heart be affected so full scale CPR may not be needed.
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, OR in the absence of definite knowledge, try to take the victim to a hospital that is large enough to be likely to have stock of the antivenin. In Tamil Nadu, the government hospitals are expected to have stock of antivenom
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.
If the snakebite victim happens to faint the most important thing is to make sure that they are able to breathe. If possible lean the head backward and depress the tongue to keep the throat open. Do not waste time trying to make them recover from the faint. Make sure that they are breathing and concentrate on getting to the hospital fast. If as you move towards the hospital, you do have access to a phone or mobile, ask the doctors who are waiting for you for advice perticularly in case of fainting as sometimes this may indicate that a medical condition called “shock” is setting in and that is potentially more dangerous than even the effects of snake venom!
Try to get information on what snake it was, appearance, size, etc. but please don’t waste time on this! Getting the person to a competent hospital is the only major priority!
Mostly, if there are symptoms, the doctors will immediately do a spot test dose in the skin 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, 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 gases 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 (my daughter) 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 pic. above))
or the Bamboo Pit Viper Trimeresurus gramineus
and very, very rarely,
the King Cobra (Ophiophagus hannah).
There have been so many hits on this article as well as requests for more information that I thought I would share some of the resources that I found most helpful:
Snakebite Envenomation in India: A Rural Medical Emergency
Indian Pediatrics 2006; 43:553-554
Kraits deliver some powerful neurotoxins that cause few initial symptoms at the site of the bite but can be deadly within a couple of hours.
Detailed Instructions for Krait bites can be found here:
http://www-surgery.ucsd.edu/ent/DAVIDSON/Snake/Bungarus.htm *Note that Indian polyvalent antivenom is effective against Krait venom also.
The University of Adelaide’s toxinology resources website has an excellent database of information on most of the poisonous snakes in the world, first aid, treatment, and antivenins. Use the search engine to find the information you need: http://www.toxinology.com/fusebox.cfm?fuseaction=main.snakes.results&Common_Names_term=&Family_term=&Genus_term=Daboia&Species_term=&countries_terms=®ion_terms=
Snakebite Research Unit, Little Flower Hospital
A helpful interview with Romulus Whittaker in The Hindu: http://www.hindu.com/mag/2004/06/13/stories/2004061300400200.htm