What is a snake bite?
A snake bite is an injury caused by a bite from a snake often resulting in puncture wounds inflicted by the animal’s fangs and sometimes resulting in envenomation.
It is a life-threatening medical emergency when envenomation occurs. Envenomation is the exposure to a poison injected by the bite or sting of a poisonous animal such as venomous snakes, scorpions or spiders.
The victims of snake bites are usually farmers, plantation workers, herdsmen, fishermen, snake restaurant workers and farmfood collectors. Snakebite is therefore a medical problem that has important implications on the nutrition and economy of the countries where it occurs commonly. Despite its importance, there has only been fewer proper clinical studies of snakebite management compared to any other tropical disease.
Determining the species of snake responsible for the bite is important for optimal clinical management. This may be achieved by identifying the dead snake or by inference from the “clinical syndrome” of envenoming.
Most snakebites are not harmful and are delivered by non-venomous species. According to the WHO, out of the over 3000 species of snakes in the world, about 600 are venomous and over 200 are considered to be of medical importance.
Most important venomous snakes responsible for significant mortality and morbidity in Ghana include;
- West African Saw-scaled/carpet viper (Echis ocellatus)
- Puff adders (Bitis arietans)
- Black-necked spitting cobra (Naja nigricollis)
- Night adder (Causus maculatus)
- Western green mamba (Dendroaspis viridis)
Symptoms of a snake bite
Non-venomous snakebites tend to leave a row of several small puncture wounds from the animal’s many teeth. Venomous snakes leave 1 to 4 (usually 2) larger fang marks on the victim. Venomous bites usually bleed a lot more because the fangs penetrate more deeply.
Please do not rely too much on fang marks because the snake can bite at multiple sites leaving multiple fang marks and also a new set of fangs could be coming in while the old set is still in place.
The symptoms of a snake bite depends on the type of envenomation.
Early signs and symptoms of snake bite
Signs and symptoms of snake bite can be classified into local and generalized or systemic. Here are the commonly occurring signs and symptoms following a snake bite;
LOCAL SYMPTOMS AND SIGNS IN THE BITTEN PART:
- fang marks
- local pain
- local bleeding
- lymphangitis (raised red lines tracking up the bitten limb)
- lymph node enlargement
- inflammation (swelling, redness, heat)
- local infection, abscess formation
GENERALIZED (SYSTEMIC) SYMPTOMS AND SIGNS
- Abdominal pain
- Visual disturbances
- cardiac arrhythmias
- pulmonary oedema
- conjunctival oedema (chemosis).
BLEEDING AND CLOTTING DISORDERS (VIPERIDAE)
- Traumatic bleeding from recent wounds
- Spontaneous systemic bleeding from gums
- bleeding into the tears
- intracranial haemorrhage
- rectal bleeding or melaena
- vaginal bleeding
- Ante-partum haemorrhage
- bleeding into the mucosae, skin and retina
NEUROLOGICAL (ELAPIDAE, RUSSELL’S VIPER)
- abnormalities of taste and smell
- “heavy” eyelids
- external ophthalmoplegia
- paralysis of facial muscles and other muscles innervated by the cranial nerves
- nasal voice or aphonia
- regurgitation through the nose
- difficulty in swallowing secretions
- respiratory and generalised flaccid paralysis
SKELETAL MUSCLE BREAKDOWN (SEA SNAKES, SOME KRAIT SPECIES, WESTERN RUSSELL’S VIPER)
- Generalized pain
- stiffness and tenderness of muscles
- cardiac arrest
- acute renal failure.
RENAL (VIPERIDAE, SEA SNAKES)
- Loin (lower back) pain
- symptoms and signs of uraemia (acidotic breathing, hiccups, nausea, pleuritic chest pain etc.)
CEREBRAL ARTERIAL THROMBOSIS (WESTERN RUSSELL’S VIPER)
Thrombotic strokes confirmed by angiography or imaging, are reported rarely after envenoming.
ENDOCRINE (Russell’s viper in Myanmar and South India)
Acute phase: Shock, hypoglycaemia
Chronic phase (months to years after the bite): Weakness, loss of secondary sexual hair, loss of libido, amenorrhoea, testicular atrophy, hypothyroidism etc.
Bites by kraits, sea snakes and Philippine cobras may be virtually painless and may cause negligible local swelling. Someone who is sleeping may not even wake up when bitten by a krait and there may be no detectable fang marks or signs of local envenoming.
Early symptoms include headache, a thick feeling of the tongue, thirst, sweating and vomiting. Generalized aching, stiffness and tenderness of the muscles becomes noticeable between 30 minutes and 3½ hours after the bite.
SYMPTOMS AND SIGNS OF COBRA-SPIT OPHTHALMIA (EYE INJURIES FROM SPITTING COBRAS)
If the “spat” venom enters the eyes, there is immediate and persistent intense burning, stinging pain, followed by profuse watering of the eyes with production of whitish discharge, congested conjunctiva, spasm and swelling of the eyelids, photophobia, clouding of vision and temporary blindness.
Corneal ulceration, permanent corneal scarring and secondary endophthalmitis are recognised complications of African spitting cobra venom.
First aid for snake bite
Most of the familiar methods for first aid treatment of snakebite, both western and “traditional/herbal”, have been found to result in more harm than good.
Their use should be discouraged and they should never be allowed to delay the movement of the patient to medical care at the hospital or dispensary. Since species determination is important, the snake should be taken along to the hospital if it is killed.
However, if the snake is still alive, do not risk further bites and waste time by searching for it.
Recommended first aid methods emphasize reassurance, immobilization of the whole patient and particularly the bitten limb and movement of the patient to a place where they can receive medical care as soon as possible.
Potentially harmful treatments
- Apply a tourniquet. Dangers include ischaemia and gangrene, if applied over 2 hours; damage to peripheral nerves; increased fibrinolytic activity; congestion and swelling; increased bleeding; increased local effects of venom; and, immediately after release, shock, pulmonary embolism or rapidly-evolving life-threatening systemic envenoming.
- Wash, rub, massage or tamper with the bite wound: encourage systemic absorption of venom from the site, may introduce infection.
- Suck bite site by mouth or vacuum pumps. Only a small amount of venom removable, increases tissue necrosis and uncontrolled bleeding.
- Make an incision of the bite site. Only small amount of venom removable, increases risk of infection and tendon damage
- Apply cryotherapy (ice packs): increases tissue damage
- Electric shock
- Instill chemicals e.g. Potassium permanganate
Can you survive a snake bite without treatment?
It depends on the type of snake, if it is a non-venomous snake, as long as you wash the site of the bite and use some antiseptic you should be absolutely fine with no anti venom being administered.
However, a bite from a venomous snake can be fatal if it is not attended to.
How do you administer anti-snake venom?
Antivenom is most effective when given intravenously. IM injection is not ideal and not generally recommended as absorption is very slow. Antivenom can be given by IV injection at a rate of about 5 ml/min, or diluted in isotonic fluid and infused over 30-60 min.
The initial dose of antivenom, however large, may not completely neutralize the depot of venom at the site of injection or prevent redistribution of venom from the tissues. Patients should therefore be observed for several days even if they show a good clinical response to the initial dose of antivenom.
Snake bite treatment protocol
- Presentation with suspected/ confirmed snake bite.
- Initial emergency assessment (ABCD), resuscitate as per standard practice as needed.
- Laboratory investigations; 20WBCT, Full blood count (FBC), Blood Urea and Electrolytes (BUE), Creatinine CR, Liver function test (LFT).
- Check for signs of systemic or severe local envenomation.
- Indication for anti-snake venom (ASV)? Please only give ASV if the patient has more than one indication.
- Give ASV (refer to manufacturer leaflet for dosing) by IV slow push over 5-10 minutes and monitor for an adverse reaction.
- Monitor patients for improvement of symptoms, repeat ASV if 20WBCT does not normalize after 6 hours.
- Give auxiliary treatments such as antibiotics, analgesics, Tetanus toxoid (TT), Flexible fiberoptic bronchoscopy (FFP), etc, if there is the need for it following the standard treatment guidelines.
Does every snakebite require treatment?
No; but all snakebites should always be taken seriously. Though some are non-venomous and very unlikely to result in a fatal outcome, it is a herculean task for the laity to differentiate between a venomous and a non-venomous snake simply by sight or intuition.
The initial absence of symptoms and signs is not ample evidence that the snake bite is harmless. This gives credence to the fact that every case of snakebite should be facilitated to a health facility for the initiation of appropriate management.
Does snakebite treatment for children differ from that of adults?
Antivenom is indicated in all children where there is evidence of envenomation. Children, because of their smaller size (increased venom-to-body mass ratio compared to adults), are more likely to have severe envenomation. There is no weight based calculation for antivenom (the snake delivers the same amount of venom regardless of the size of the child).There is no difference in the management of snakebite in children and in adults.
What are some of the complications of untreated snakebite victims
-Damage to skin and tissue in the bite area
-Heart, lung and kidney damage