Snake Bite First Aid
Snake Bite First Aid
South-east Queensland is home to approximately 27 snake species, but only 13 are regarded as medically significant. If you are unlucky enough to be bitten, here is a guide of what and what not to do in the event of a snake bite.
NOTE: All snake bites should be treated as venomous especially in the absence of reliable identification and first aid action should be applied immediately with Pressure Immobilisation Bandaging and call 000.
Signs and Symptoms
In the majority of scenarios bites from venomous snake species are somewhat pain free, even to the point in some cases that unsuspecting people have been unaware of the bite. The bite itself may appear somewhat innocuous more often resembling lacerations or scratches than the two puncture marks synonymous with most peoples expectation of a snake bite.
Occasional bruising may occur however bleeding is generally minimal. A lymphatic response is common and may be quite severe in some cases. Initial symptoms may include headache, nausea, vomiting, diarrhoea, irritability, light sensitivity, disorientation; inconsistent coagulation and potentially a loss of consciousness. Secondary symptoms may include difficulty swallowing, double vision, drooping of the eyelids, blood in the urine, abdominal pain, rapid increase in heart rate. Severe symptoms which may in extreme cases lead to death include marked loss of color or discoloration resulting in circulatory failure, loss of limb function due to paralysis and respiratory muscular apathy leading to respiratory failure.
The consistency of these events is unpredictable and a number of factors must be considered when assessing an individual's response to envenomation. These factors may include:
- Age: In particular the elderly and young children face elevated levels of vulnerability when an envenomation has occurred. This is a reflection of often diminished immunity in the elderly and an under developed immunity in young children.
- General health including current medical condition: Those supporting a pre-existing condition such as a compromised heart, kidney or liver may be at greater risk dependant on the venom constituents specific to a venom type. People with a poor general level of fitness or carrying excess weight may also be more susceptible to the effects of some venom.
- Time between the bite and receipt of first aid: Time is critical when considering the main aim of supportive first aid is to inhibit the progression of venom via lymphatic movement. The application of first aid a soon as possible cannot be overstated.
- Activity of the individual between bite and receipt of first aid: As venom travels via lymphatic movement the absence of muscular activity is paramount. Running to a car for a bandage or to seek assistance may be enough to progress the venom to a point where the benefit of first aid treatment is greatly reduced.
- Activity post first aid application: The key to venom suspension is the absence of movement. Even extremities such as fingers and toes should be kept motionless as these small movements will assist venom progression.
- Species of snake, subsequent toxicity and amount of venom received by the individual: Snake toxicity is highly variable across species represented in Australia. The amount of venom received may vary from cases to case but generally those instances where snakes have been intimidated, harassed or harmed tend to result in greater venom expenditure when a bite is delivered.
- Location of the bite: Envenomation on a limb can be more readily contained with adequate first aid application as opposed to those on the head or torso where the relevant first aid technique is rendered largely ineffective.
The time frame, in which symptoms become evident and escalate, again is highly variable and not easily quantified. Where a number of the factors presented above are adverse symptomatic onset may be rapid in the case of bites from highly toxic species. Anaphylaxis is also a common cause of symptomatic response where although the toxicity of a snake may not be considered of high risk an individual's physiological response may promote an escalated allergic reaction to compounds particular to that venom type.
Lymphatic progression: the vital ingredient.
Before illustrating correct first aid it's of great benefit to understand the mechanism by which venom actually progresses from the bite site and throughout the body. In the vast majority of cases venom moves initially through the secondary circulatory system, otherwise known as the lymphatic system. Where a bite is received directly to a vein or artery progression may be afforded by this means however this event is rare.
The intention of first aid application is to greatly inhibit the progression of venom through the body. To do this, the key ingredients when considering the reduction of lymphatic movement are compression and immobilisation. Pressure applied by a bandage reduces opportunity for lymphatic function and in turn immobilisation disengages voluntary and involuntary muscular movement. The application of correct first aid that implements this strategy has proven to be highly effective and undoubtedly not only saved many lives but has reduced the onset of symptomatic responses prior to receiving increased levels of intervention such as antivenin administration.