Cytotoxic Venom
(Signs and Symptoms)

Cytotoxic venom is cell destroying, attacking both tissue and blood cells.
The majority of snakes possessing this type of venom belong to the family Viperidae.
Cytotoxic bites probably account for 80% of all bites recorded world wide.
This type of venom usually presents itself as painful progressive swelling.
This venom is slow acting.


Immediate symptoms of a Cytotoxic venom:

* Intense local pain at the bite site occuring immediately after envenomation.
* Gradual swelling becoming more pronounced as time goes by.
* Nausea and vomiting.
* A distinct metallic taste occurs shortly after envenomation.
* Loss of conciousness may occur.
* The body usually goes into a state of shock as a result of the envenomation which often leads to panic symptoms in the victim.


Other signs and symptoms of a cytotoxic venom:

* Fang marks. This is usually a good indication of a potential envenomation. This could either be distinct puncture marks at the site, or merely a scratch.
* The pain can be best described as an intense burning sensation at the bite site.
* Edema (swelling) usually occurs shortly after envenomation, progressing further along the affected area. Cytotoxic venom destroys, or weakens the capillary walls. This causes a change in pressure within the capillaries which results in fluids leaking into the surrounding tissue which causes the swelling. The body then senses the loss of fluid and signals the kidneys to hold onto water and sodium. This in turn leads to an increase of fluid volume circulating the blood vessels which leads to additional leakage and so the swelling spreads.
* The swelling usually feels hot to the touch, and is painful and tender.
* The speed at which the swelling occurs is usually a good indication as to the severity of the envenomation.
* The victim will begin to display haemorrhagic spots (Ecchymosis) which is caused by the escape of blood into the tissues from the weakened blood vessels.
* Depending on the severity, the victim may also develop a haematoma (blood filled bruise) around the bite area. Once again this is due to the weakening of the blood vessels which leads to severe internal bleeding around the bite site.
* Blistering around the affected area occurs due to the increased volume of fluid circulating the blood vessels.
* The lymphnodes become enlarged (lymphadenopathy). The accumulation of fluid as well as the body releasing infection-fighting cells to combat the cytotoxic venom causes the lymphnodes to enlarge several times their normal size. These become extremely painful to touch.
* Bleeding from the wound.
* The victim may also experience an increase, or decease in blood pressure (dilation or constricting of blood vessels). A decrease in blood pressure means that not enough oxygenated blood reaches the various body parts which in turn prevents the adequate removal of waste products in the system which in turn leads to shock. An increased blood pressure may lead to a heart attack.
* Muscle twitching.* Victims may also complain from a dry thoat.
* Increased heart rate (Tachycardia). This means that the heart pumps less efficiently and therefore provides less blood flow to the body. This leads to the decrease of oxygen to the heart which may cause a heart attack.
Conversely a victim may also show a decreased heart rate (Brachycardia) which may cause dizziness, lightheadedness, fainting, nausea, and weakness.
* Tissue necrosis. The nature of cytotoxic venom prevents phagocytes (white blood cells that ingest or neutralise foreign particles in the body) from locating the dead cells. This leads to a build up of dead tissue around the bite site.
* Blood in urine (Hematuria).
* Red urine (hemoglobinuria).
* Death


Examples of Cytotoxic snakes that are classified as dangerous and life threatening:

Rattlesnakes (Crotalus).

Lance-headed vipers (Bothrops).

Certain members of the genus Bitis. For example:
Puff adder - Bitis arietans
Gaboon adder - Bitis gabonica

Spitting cobras


The extent of the signs and symptoms exhibited by a ctytotoxic bite victim will vary depending on a number of factors (far too many to mention).
Determining factors that will affect the symptoms shown include:

* Severity of envenomation.
* Locality of bite.
* Type of snake.
* Age of victim.
* Victims overall health/ medical background.

It is important to note that not all cytotoxic venoms are considered life threatening.

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