Signs and Symptoms of a Tiger snake bite
Tiger snake venom has a wide range of effects on humans. It contains pre-synaptic and post-synaptic neurotoxins, myotoxins and pro-coagulants. Significant envenomation by any species of this group may result in:
* Neurological impairment
* Paralysis
* Incoaguable blood
* Rhabdomyolysis
* Renal failure secondary to myolysis
Headache, nausea and vomiting, abdominal pain, pain and swelling in lymph nodes, common in the first hour or so. Pain such as headache may be due to release of bradykinin an inflammatory media. There ma be an appearcance of bruising locally around the bite sites, and swelling of the affected lymph. Generalized progressive weakness and paralysis can occur due to neurotoxins, this often occurs 1 -3 hours after envenomation. Initially the cranial nerves seem to be affected with drooping eyelids (ptosis) slurred speech, difficulty swallowing, facial paralysis and double vision. There is difficulty walking and standing and in the end there is difficulty breathing, tachycardia and confusion also occur. The urine may become dark because it contains hemoglobin and myoglobin, hemorrhage and renal failure are all possible. Tachycardia (more than 100 heart beat per min), can occur.
http://www.avru.org/health/health_tigers.html
Sorry this is all I could find. I also hope this is my topic as I think it was but didn’t write it down, so apologies if it is not.
Friday, July 25, 2008
PCL 2 – Pharmacological Management for Snakebite
Pharmacological treatment for snakebite is used in about 1 in 10 cases, and involves antivenom.
Before the invention of polyvalent antivenins it was extremely important to identify the snake. This is now less important, as polyvalent antivenin can cover a broad range of snakebite. However, monovalent, snake-specific antivenoms are less likely to cause damage to the body than the broader polyvalent ones. If identification is uncertain, it is very important to treat as though the snake was unidentified, as the use of polyvalent antivenin is preferred to an incorrect monovalent one.
Antivenom should be given to all patients who exhibit signs of systemic spread of the venom; ie. Damage not local to the bite, most often relating to breathing difficulties and twitching of muscles due to damage to nervous system.
In Australia – if Tasmania, use tiger snake antivenin. If Victoria, tiger and brown snake antivenom; polyvalent antivenom in other states. One ampoule (50ml of 17% protein) is usually enough to neutralise the effects of the average yield of a tiger or brown snake, except in most serious cases. If time allows, antivenin should be given slowly.
Pre-treatment includes:
- non-sedating anti-histamine is given, to help prevent allergic reactions
- small amounts of adrenaline can be given subcutaneously, or intravenously to prevent anaphylaxis.
When providing antivenin, it is very important to advise patients about the possibility of serum sickness.
http://www.usyd.edu.au/anaes/venom/snakebite.html#ANTIVENOMS
http://www.snakeshow.net/downloads/snake-snakebitetreatmentinaustralia.pdf
Before the invention of polyvalent antivenins it was extremely important to identify the snake. This is now less important, as polyvalent antivenin can cover a broad range of snakebite. However, monovalent, snake-specific antivenoms are less likely to cause damage to the body than the broader polyvalent ones. If identification is uncertain, it is very important to treat as though the snake was unidentified, as the use of polyvalent antivenin is preferred to an incorrect monovalent one.
Antivenom should be given to all patients who exhibit signs of systemic spread of the venom; ie. Damage not local to the bite, most often relating to breathing difficulties and twitching of muscles due to damage to nervous system.
In Australia – if Tasmania, use tiger snake antivenin. If Victoria, tiger and brown snake antivenom; polyvalent antivenom in other states. One ampoule (50ml of 17% protein) is usually enough to neutralise the effects of the average yield of a tiger or brown snake, except in most serious cases. If time allows, antivenin should be given slowly.
Pre-treatment includes:
- non-sedating anti-histamine is given, to help prevent allergic reactions
- small amounts of adrenaline can be given subcutaneously, or intravenously to prevent anaphylaxis.
When providing antivenin, it is very important to advise patients about the possibility of serum sickness.
http://www.usyd.edu.au/anaes/venom/snakebite.html#ANTIVENOMS
http://www.snakeshow.net/downloads/snake-snakebitetreatmentinaustralia.pdf
Complications and Prognosis:
Serum Sickness
Reaction to proteins found in anti-venom derived from an animal source
Animals are tested on and develop resistance to a particular venom (e.g. horses, rabbits, etc)
Antibodies from animals are used in anti-venom and injected into patient
Patient mounts immune response to foreign animal proteins in body
Anaphylaxis
Acute systemic Type I Hypersensitivity allergic reaction
Induced by administration of anti-venom, very rarely the snake bite itself
Mediated by IgE à histamine released à degranulation of mast cells à vasodilation, constriction of smooth muscles, hypotension, etc
Tetanus
Prophylactic treatment administered
Sometimes as a result of a secondary infection
For signs and symptoms see http://www.medicineau.net.au/resources/handouts/Tetanus.pdf
Others: hypothermia, renal failure, acute myocardial infarction,
Sites:
http://www.medicineau.net.au/resources/handouts/Tetanus.pdf
http://www.allergyfacts.org.au/
http://www.allergy.org.au/aer/infobulletins/bites.htm
http://www.emedicine.com/med/TOPIC2143.HTM
Reaction to proteins found in anti-venom derived from an animal source
Animals are tested on and develop resistance to a particular venom (e.g. horses, rabbits, etc)
Antibodies from animals are used in anti-venom and injected into patient
Patient mounts immune response to foreign animal proteins in body
Anaphylaxis
Acute systemic Type I Hypersensitivity allergic reaction
Induced by administration of anti-venom, very rarely the snake bite itself
Mediated by IgE à histamine released à degranulation of mast cells à vasodilation, constriction of smooth muscles, hypotension, etc
Tetanus
Prophylactic treatment administered
Sometimes as a result of a secondary infection
For signs and symptoms see http://www.medicineau.net.au/resources/handouts/Tetanus.pdf
Others: hypothermia, renal failure, acute myocardial infarction,
Sites:
http://www.medicineau.net.au/resources/handouts/Tetanus.pdf
http://www.allergyfacts.org.au/
http://www.allergy.org.au/aer/infobulletins/bites.htm
http://www.emedicine.com/med/TOPIC2143.HTM
Thursday, July 24, 2008
Anti-venom production
Acquisition of venom in snakes is due to their evolved pancreatic secretion, specialised in immobilising, killing and digesting the prey. Anti-venom, based on the principle of acquired immunity, has long been used worldwide to save patients from, previously fatal, snake bites.
Anti-venom production process
Small amounts of venom are injected into animals (horses, rabbits, sheep, goats and chickens are most used), which are targeted by their immune system producing antibodies. The dosage increases as the animal becomes more immune to the venom, stimulating more production of antibodies in the animals’ bloodstream. The serum is taken from the animal, by removing RBCs, and further purified for human use. The downside of this treatment is that serum sickness can occur which is caused by the human body attacking the proteins in anti-venom.
Anti-venoms can be monovalent (containing only one kind of antibody) or polyvalent (many), and stored up to 3 years if well refrigerated.
Future of anti-venom?
In 2003, Biochemists in VMSRF (Vittal Mallya Scientific Research Foundation) was working on producing anti-venom from chicken eggs. Young chickens are immunised with venom and the dosage is slowly increased. The result is antibodies accumulating in the eggs which can be used, instead of extracting blood from horses or other animals, to make anti-venom. This provides a more humane and cheaper alternative but this technology still requires refining before being used for mass production.
Scientists working at Liverpool School of Tropical Medicine in the UK had made an anti-venom that is not directly derived from snakes.
An analysis of active DNA when a snake (in this experiment, a carpet viper is used) is replenishing its venom leads is done and the genes for the venom are collected. The sequences, coding for the proteins exposed on the outside of the venom molecules, are joined together and are used to produce proteins that are similar to the venom on the outside, but harmless. The manufactured proteins are then injected into animal subjects to produce anti-venom.
The benefits of this technique are that the anti-venom produced is more potent than those made using the original method, and that it can be polyvalent. However, the major drawback is the cost for manipulating the DNA whereas the production method now (though still quite expensive) is more cost effective.
http://www.reptilepark.com.au/venom_snake.asp
http://www.kingsnake.com/elapids/antivenom_manufactures.htm
http://www.newscientist.com/article.ns?id=dn9277&feedId=online-news_rss20
http://news.nationalgeographic.com/news/2003/02/0211_030211_snakeeggs_2.html
And for those who loved the article of the guy from Darwin who got bitten 9 times by the same snake, here’s the link to it:
http://www.darwinawards.com/stupid/stupid1999-18.html
First Aid for Snake Bites
Source: LifeAid Emergency Handbook by Alan Close Pp 190
1. Identify snake, and withdraw to position of safety
2. Keep patient rested and lying down
3. If snake bite is not on limb, apply firm direct pressure to site
4. If bite is on limb, apply Pressure Immobilisation Technique (PIT)
- Using a 7 to 10cm elastic crepe bandage firmly from the fingers or toes, covering the bite site and extending as far as possible up the limb. An alternative is to apply the bandage over the bite site and then another from the extremities to the top of the limb
- Mark the bite site on the bandage
- Apply firmly enough to compress tissue, but do not cut off blood supply to the hand of foot
- Check for circulation to fingers and toes
- Immobilise the limb to minimise movement of the venom due to muscular action
- Do no remove the splint or pressure bandages
5. Call 000 for urgent ambulance attendance
6. If bitten and alone then attempt to apply pressure bandage yourself and call for help
7. Anti venom is available for most dangerous species of snakes in Australia so if possible identify the type of snake and tell emergency operator the time of bite and current condition of patient. Especially important for remote areas.
History Taking
Important to take note of following:
l Identification of snake. If specific species is not known, note size, colour, patterning and other characteristics
l Timing of bite and onset of pain in relation to bite
l Local symptoms – Pain (note intensity), paraesthesia and swelling
l Systemic symptoms – nausea, vomiting, diarrhoea, abdominal pain, difficulty swallowing or breathing
l Previous snakebites/treatments
l Follow up of normal routine history
http://www.patient.co.uk/showdoc/40001328/
Source: LifeAid Emergency Handbook by Alan Close Pp 190
1. Identify snake, and withdraw to position of safety
2. Keep patient rested and lying down
3. If snake bite is not on limb, apply firm direct pressure to site
4. If bite is on limb, apply Pressure Immobilisation Technique (PIT)
- Using a 7 to 10cm elastic crepe bandage firmly from the fingers or toes, covering the bite site and extending as far as possible up the limb. An alternative is to apply the bandage over the bite site and then another from the extremities to the top of the limb
- Mark the bite site on the bandage
- Apply firmly enough to compress tissue, but do not cut off blood supply to the hand of foot
- Check for circulation to fingers and toes
- Immobilise the limb to minimise movement of the venom due to muscular action
- Do no remove the splint or pressure bandages
5. Call 000 for urgent ambulance attendance
6. If bitten and alone then attempt to apply pressure bandage yourself and call for help
7. Anti venom is available for most dangerous species of snakes in Australia so if possible identify the type of snake and tell emergency operator the time of bite and current condition of patient. Especially important for remote areas.
History Taking
Important to take note of following:
l Identification of snake. If specific species is not known, note size, colour, patterning and other characteristics
l Timing of bite and onset of pain in relation to bite
l Local symptoms – Pain (note intensity), paraesthesia and swelling
l Systemic symptoms – nausea, vomiting, diarrhoea, abdominal pain, difficulty swallowing or breathing
l Previous snakebites/treatments
l Follow up of normal routine history
http://www.patient.co.uk/showdoc/40001328/
Wednesday, July 23, 2008
Brown Snake Bite Cinical Symptoms
Hard to diagnose without history of bite due to brown snake bites not causing any local swelling or pain. Patient may complain of neurological symptoms within the hour. Symptomatology (combined symptoms of the disease) will manifest within a few hours with signs of coagulopathy, breathing problems and cardiovascular compromise. One distinct feature of brown snake bites is there is no rhabdomyolysis (rapid break down of skeletal muscles) which is found in most other snake bites.
Symptoms include:
· Early collapse (due to hypotension)
· Fang marks
· Little or no swelling and redness
· Coagulopathy - blood will have prolonged clotting times
· Headache
· Nausea and Vomiting
· Weakness
· Photophobia
· Irritability
· Diplopia – double vision
· Altered mental status
· Dyspnea – shortness of breath
· Epistaxis – nose bleed
· Gingival bleeding – bleeding gums
· Hematemesis – vomiting of blood
· Hematochezia – bloody stools
· Oliguria – no production of urine
· Dysphagia – difficulty in swallowing
Physical symptoms:
· Purpura – red or purple discolorations on the skin
· Petechia – small red or purple spot on the body cause by haemorrhaging
· Ptosis – drooping of upper eyelid
· Trismus – inability to open mouth normally
· Seizures
· Cyanosis – blue colouration of the skin
· Paralysis
· Hypotension
· Tachycardia or bradycardia – fast/slow heart beats
· Cardiac arrest
http://www.emedicine.com/emerg/topic545.htm#section~Clinical
http://www.australianprescriber.com/magazine/29/5/125/9/
http://www.avru.org/health/health_browns.html
Symptoms include:
· Early collapse (due to hypotension)
· Fang marks
· Little or no swelling and redness
· Coagulopathy - blood will have prolonged clotting times
· Headache
· Nausea and Vomiting
· Weakness
· Photophobia
· Irritability
· Diplopia – double vision
· Altered mental status
· Dyspnea – shortness of breath
· Epistaxis – nose bleed
· Gingival bleeding – bleeding gums
· Hematemesis – vomiting of blood
· Hematochezia – bloody stools
· Oliguria – no production of urine
· Dysphagia – difficulty in swallowing
Physical symptoms:
· Purpura – red or purple discolorations on the skin
· Petechia – small red or purple spot on the body cause by haemorrhaging
· Ptosis – drooping of upper eyelid
· Trismus – inability to open mouth normally
· Seizures
· Cyanosis – blue colouration of the skin
· Paralysis
· Hypotension
· Tachycardia or bradycardia – fast/slow heart beats
· Cardiac arrest
http://www.emedicine.com/emerg/topic545.htm#section~Clinical
http://www.australianprescriber.com/magazine/29/5/125/9/
http://www.avru.org/health/health_browns.html
Benefits of snake venom in medicine
Benefits of snake venom in medicine
- Production of anti-venom/anti-venin, using horses or sheep as vectors
- Treatment for breast cancer: in France, an enzyme derived from copperhead venom may possibly be used in treatment
- Dissolving blood clots: ingredients from the venom of a Malayan pit viper could be effective in breaking blood clots, and proteins in venom also prevent blood clotting. This would be very beneficial in treating stroke victims. A “super-aspirin”, Aggrastat, was introduced by Merck & Co. to prevent blood clots and to help prevent heart attacks in people hospitalized with severe chest pain
- Parkinson’s disease and Alzheimer’s disease: enzymes from cobra venom could be used in treatment
- Osteoporosis: a cure could be produced from the venom of certain vipers
- Tumour reduction: a cure could be produced from the venom of certain vipers
- Heart disease: several venom extracts have shown possibilities that could lead to the production of anti-coagulants that would be helpful in treatment
- Hypertension: proteins from certain rattlesnakes’ venom have been used in the production of blood pressure medication
- Leukaemia: ingredients from the red-necked spitting cobra have provided clues as to the mechanism of cell membrane breakdown
- Cancer: ingredients from the red-necked spitting cobra could also be helpful here in a similar way to treatment of leukaemia. A natural compound in the venom also activates the destruction of cells that make up the blood vessels that supply nutrients to tumours , and research shows that some Australian snake venoms target cells that surround tumours, while having less or no effect on other cells and researchers expect the final compound to target only targeted cells
- Analgesics: against chronic pain such as arthritis, and secondary pain caused by other diseases like cancer. Patients with arthritis could get relief using a cream made from chemicals found in venom
- Arrest of bleeding during surgery and trauma: taipan venom has been found to contain large amounts of a blood clotting protein, factor X
- Antimicrobials: envenomation is associated with a low incidence of bacterial infection
- Adhesive for promotion of healing after oral surgery?: stimulates faster tissue repair and may be less infectious than traditional sutures
http://www.annieappleseedproject.org/snakvenpainp.html
http://www.israel21c.org/bin/en.jsp?enZone=Health&enDisplay=view&enPage=BlankPage&enDispWhat=object&enDispWho=Articles%5El1256
http://www.bio-medicine.org/medicine-news/Australian-Snake-Venom-Can-Arrest-Bleeding-During-Surgery-And-Trauma-8283-1/
http://www.bio-medicine.org/medicine-news/Arthritis-Pain-Can-Be-Eased-Using-Snake-Venom-8864-1/
http://ecam.oxfordjournals.org/cgi/reprint/2/1/39
http://www.news-medical.net/?id=229
http://www.associatedcontent.com/article/540977/snake_venom_may_help_heal_your_mouth.html?cat=5
Pathophysiology of Brown Snake Venom
Some Key Facts About Brown Snakes:
-Brown snakes are common throughout mainland Australia (ie. not in Tasmania)
-They are the most common cause of snakebites and snakebites death in Australia.
-Compared to other snakes, they produce little but very potent venom.
-Their bites are either painless or almost painless.
-Brown snake venom includes powerful presynaptic neurotoxins, procoagulants, cardiotoxins and nephrotoxins. There is no myolytic activity.
-Humans are mainly affected by the coagulants which make up 30% of total venom protein.
How do they work?
Neurotoxins
Neurotoxins act on neurons at the motor end plate. Most toxins act by interfering with membrane proteins such as voltage-dependent ion channels. They prevent action potential from occuring thus leading to paralysis and eventually death.
A toxin found in the Australian common brown snake is called the textilotoxin which inhibits the release of acetylcholine presynaptically and/or blocks the postsynaptic nicotinic ACh receptors. This can cause respiratory paralysis.
Procoagulants
Coagulopathy is the hallmark of brown snake envenoming. Procoagulants are prothrombin activators, converting prothrombin into thrombin and fibrinogen into fibrin. This results in consumptive coagulopathy where circulating fibrinogen, plasminogen and other clotting factors are depleted, producing breakdown products which can be detected in a blood test. Platelet count is not affected initially. Thus, the patient is at risk of haermorrhage and intracranial haematomas.
References
http://www.emedicine.com/emerg/byname/Snake-Envenomations--Brown.htm
http://www.toxinology.com/generic_static_files/cslavh_antivenom_brown.html
http://www.kingsnake.com/toxinology/old/snakes/Pseudonaja/Pseudonaja.html
~Michelle
-Brown snakes are common throughout mainland Australia (ie. not in Tasmania)
-They are the most common cause of snakebites and snakebites death in Australia.
-Compared to other snakes, they produce little but very potent venom.
-Their bites are either painless or almost painless.
-Brown snake venom includes powerful presynaptic neurotoxins, procoagulants, cardiotoxins and nephrotoxins. There is no myolytic activity.
-Humans are mainly affected by the coagulants which make up 30% of total venom protein.
How do they work?
Neurotoxins
Neurotoxins act on neurons at the motor end plate. Most toxins act by interfering with membrane proteins such as voltage-dependent ion channels. They prevent action potential from occuring thus leading to paralysis and eventually death.
A toxin found in the Australian common brown snake is called the textilotoxin which inhibits the release of acetylcholine presynaptically and/or blocks the postsynaptic nicotinic ACh receptors. This can cause respiratory paralysis.
Procoagulants
Coagulopathy is the hallmark of brown snake envenoming. Procoagulants are prothrombin activators, converting prothrombin into thrombin and fibrinogen into fibrin. This results in consumptive coagulopathy where circulating fibrinogen, plasminogen and other clotting factors are depleted, producing breakdown products which can be detected in a blood test. Platelet count is not affected initially. Thus, the patient is at risk of haermorrhage and intracranial haematomas.
References
http://www.emedicine.com/emerg/byname/Snake-Envenomations--Brown.htm
http://www.toxinology.com/generic_static_files/cslavh_antivenom_brown.html
http://www.kingsnake.com/toxinology/old/snakes/Pseudonaja/Pseudonaja.html
~Michelle
Tests for snake bite victums
Tests for snake bites
CSL venom detection kit
• Locate the bite site. Alternatively, if there is clearly systemic envenoming and the bite site is of poor quality, test urine.
• Take one of the cotton bud swab sticks provided in the kit and an unused "Yellow Sample Diluent" bottle. Put the swab stick into the sample diluent fluid to thoroughly moisten it.
• Rotate and rub the moistened swab stick vigorously over the bite site and adjacent skin.
• Place the swab stick back in the "Sample Diluent" bottle and twirl it around, to get any venom off into solution, then remove the swab stick and replace the dropper cap.
• Open a pack containing test wells, remove the enclosed set of 8 joined wells and place them in the holder.
• Place 2 drops of the sample diluent you have prepared into each well.
• Leave to stand for 10 minutes.
• Gently wash all wells under gently running water then invert and gently shake out excess water
• Now add the 2 substrate reagents, one drop to each well of the "Peroxide" and the "Chromogen".
• Allow to incubate for 10 minutes, watching the whole time, against a white background, for colour change. It is vital to observe the kit throughout this final phase, as the time sequence of colour change may be crucial.
• There should be a blue colour develop in well 7 (positive control), usually within 2-3 minutes. There should be no colour change in well 6 (negative control). A colour change in any of wells 1 to 5 indicates the presence of snake venom. The number of the well changing colour first indicates the type of snake venom and corresponding CSL snake antivenom. If there is no snake venom detected, then wells 1 to 5 will not change colour.
Meanings of colour changes:
• Only well 7 positive: No snake venom detected. This result does not exclude snakebite.
• If well 1 changes to blue first, then the patient has been bitten by either a tiger snake or rough scaled snake, or possibly a copperhead, broad-headed snake or Stephen's banded snake. Envenoming from all these snakes respond to CSL Tiger Snake Antivenom.
• If well 2 changes to blue first, then the patient has been bitten by a brown snake. CSL Brown Snake Antivenom will then be the right choice.
• If well 3 changes to blue first, then the patient has been bitten by a mulga snake (king brown), red bellied black snake, spotted black snake or Collett's snake. All these respond to CSL Black Snake Antivenom, but this is best reserved for bites by the mulga snake and Collett's snake, as all the others respond well to CSL Tiger Snake Antivenom (which is lower volume and cost effective).
• If well 4 changes to blue first, then the patient has been bitten by a death adder
• If well 5 changes to blue first, then the patient has been bitten by a taipan or inland taipan
• If wells 1 and 3 change to blue at the same time, then the patient has been bitten by either a copperhead, a red bellied black snake, a spotted black snake or possibly a Collett's snake.
• If some other combination occurs please ring CSL for advice
www.toxinology.com/generic_static_files/cslavh_svdk.html
Other tests for patients suspected of being bitten by a snake include:
• Coagulation screen
• Full blood count
• Electrolytes and calcium
• Creatinine kinase levels
• Arterial blood gases
• ECG
aerg.canberra.edu.au/staff/georges/snakebite.pdf
-Ben
CSL venom detection kit
• Locate the bite site. Alternatively, if there is clearly systemic envenoming and the bite site is of poor quality, test urine.
• Take one of the cotton bud swab sticks provided in the kit and an unused "Yellow Sample Diluent" bottle. Put the swab stick into the sample diluent fluid to thoroughly moisten it.
• Rotate and rub the moistened swab stick vigorously over the bite site and adjacent skin.
• Place the swab stick back in the "Sample Diluent" bottle and twirl it around, to get any venom off into solution, then remove the swab stick and replace the dropper cap.
• Open a pack containing test wells, remove the enclosed set of 8 joined wells and place them in the holder.
• Place 2 drops of the sample diluent you have prepared into each well.
• Leave to stand for 10 minutes.
• Gently wash all wells under gently running water then invert and gently shake out excess water
• Now add the 2 substrate reagents, one drop to each well of the "Peroxide" and the "Chromogen".
• Allow to incubate for 10 minutes, watching the whole time, against a white background, for colour change. It is vital to observe the kit throughout this final phase, as the time sequence of colour change may be crucial.
• There should be a blue colour develop in well 7 (positive control), usually within 2-3 minutes. There should be no colour change in well 6 (negative control). A colour change in any of wells 1 to 5 indicates the presence of snake venom. The number of the well changing colour first indicates the type of snake venom and corresponding CSL snake antivenom. If there is no snake venom detected, then wells 1 to 5 will not change colour.
Meanings of colour changes:
• Only well 7 positive: No snake venom detected. This result does not exclude snakebite.
• If well 1 changes to blue first, then the patient has been bitten by either a tiger snake or rough scaled snake, or possibly a copperhead, broad-headed snake or Stephen's banded snake. Envenoming from all these snakes respond to CSL Tiger Snake Antivenom.
• If well 2 changes to blue first, then the patient has been bitten by a brown snake. CSL Brown Snake Antivenom will then be the right choice.
• If well 3 changes to blue first, then the patient has been bitten by a mulga snake (king brown), red bellied black snake, spotted black snake or Collett's snake. All these respond to CSL Black Snake Antivenom, but this is best reserved for bites by the mulga snake and Collett's snake, as all the others respond well to CSL Tiger Snake Antivenom (which is lower volume and cost effective).
• If well 4 changes to blue first, then the patient has been bitten by a death adder
• If well 5 changes to blue first, then the patient has been bitten by a taipan or inland taipan
• If wells 1 and 3 change to blue at the same time, then the patient has been bitten by either a copperhead, a red bellied black snake, a spotted black snake or possibly a Collett's snake.
• If some other combination occurs please ring CSL for advice
www.toxinology.com/generic_static_files/cslavh_svdk.html
Other tests for patients suspected of being bitten by a snake include:
• Coagulation screen
• Full blood count
• Electrolytes and calcium
• Creatinine kinase levels
• Arterial blood gases
• ECG
aerg.canberra.edu.au/staff/georges/snakebite.pdf
-Ben
PCL 2 - DDx for Snake bite
Differential diagnosis of venomous snakebite:
- non-venomous snakebite
- bite or sting by other venomous creature (arthropod (including spider), octopus, jellyfish)
- CVA (Cerebrovascular accident = stroke)
- ascending neuropathy e.g. Guillain-Barre Syndrome
- AMI
- allergic reaction
- hypoglycaemia/hyperglycaemia
- drug overdose
- closed head injury
(Main) Reference: http://www.avru.org/compendium/biogs/A000065b.htm
Pathophysiology of Tiger Snake Venom
Neurotoxins: (Pre-synaptic and post-synaptic)
- cause paralysis or muscle weakness
- pre-synaptic: slow onset, irreversible, only respond to antivenom if given early
- post-synaptic: rapid onset, reversible, respond to anticholinesterases and antivenom
Myotoxins:
- cause muscle damage (myolysis)
Procoagulants:
- interfere with blood clotting by consuming fibrinogen, causing defibrination, which puts the victim at risk of major bleeding
References:
http://www.toxinology.com/about/tiger_snake_snakebite.html
Lecture 15: Envenomation (W. Hodgson)
- cause paralysis or muscle weakness
- pre-synaptic: slow onset, irreversible, only respond to antivenom if given early
- post-synaptic: rapid onset, reversible, respond to anticholinesterases and antivenom
Myotoxins:
- cause muscle damage (myolysis)
Procoagulants:
- interfere with blood clotting by consuming fibrinogen, causing defibrination, which puts the victim at risk of major bleeding
References:
http://www.toxinology.com/about/tiger_snake_snakebite.html
Lecture 15: Envenomation (W. Hodgson)
Epidemiology of Snakebites
As monitoring of snakebites is not mandatory, many go unreported each year and it is hard to accurately determine exact numbers. Globally there are predicted to be 5.4million snakebites each year, half of these will contain venom and 125,000 people will die from them.
In Australia there are about 1000-3000 snakebites each year and 200-500 of these will receive antivenom. In ten years (1981-1991) there was 18 fatal snakebites. 11 were caused by Brown snakes and 4 from tiger snakes.
The number of snakebite caused death each year, roughly 2-4, is similar to the USA. This is a large proportion when you consider Australia has a population about 10% of the US.
Sources:
University of Sydney, "Australian Snake Bites"
http://www.usyd.edu.au/anaes/venom/snakebite.html
Snake-bites: appraisal of the global situation, J.P. Chippaux
http://www.who.int/bloodproducts/publications/en/bulletin_1998_76(5)_515-524.pdf
Deaths from snake bite in Australia, 1981-1991, SK Sutherland
http://www.ncbi.nlm.nih.gov/pubmed/1453996
In Australia there are about 1000-3000 snakebites each year and 200-500 of these will receive antivenom. In ten years (1981-1991) there was 18 fatal snakebites. 11 were caused by Brown snakes and 4 from tiger snakes.
The number of snakebite caused death each year, roughly 2-4, is similar to the USA. This is a large proportion when you consider Australia has a population about 10% of the US.
Sources:
University of Sydney, "Australian Snake Bites"
http://www.usyd.edu.au/anaes/venom/snakebite.html
Snake-bites: appraisal of the global situation, J.P. Chippaux
http://www.who.int/bloodproducts/publications/en/bulletin_1998_76(5)_515-524.pdf
Deaths from snake bite in Australia, 1981-1991, SK Sutherland
http://www.ncbi.nlm.nih.gov/pubmed/1453996
Surgical treatments for snake bite
FASCIOTOMY
Fasciotomy is usually used when compartment syndrome arises, due to the haemolytic toxin present in certain snake venom.
3 types of compartment syndrome:
1. Acute compartment syndrome
2. Sub-acute compartment syndrome
3. Chronic compartment syndrome
For both acute and sub-acute compartment syndrome, fasciotomy is used to treat.
For chronic compartment syndrome, both conservative and surgical methods can be used. Conservative treatment includes rest, anti-inflammatory medications, elevation of the limb and manual decompression. In cases where symptoms persist, the condition should be treated by a surgical procedure, subcutaneous fasciotomy or open fasciotomy. Without treatment chronic compartment syndrome can develop into the acute syndrome. A possible complication of surgical intervention for chronic compartment syndrome can be chronic venous insufficiency.
Fasciotomy in the limbs is usually done by a surgeon under general or regional anaesthesia.
An incision is made in the skin, and a small area of fascia is removed where it will best relieve pressure. Then the incision is closed.
Plantar fasciotomy is an endoscopic (performed with the use of an endoscope) procedure. It is done under local anaesthesia and takes 20 minutes to one hour. The doctor makes two small incisions on either side of the heel. An endoscope is inserted in one to guide the doctor in where to cut. A tiny knife is inserted in the other. A portion of the fascia is cut from near the heel; then the incisions are closed.
In severe cases, amputations are carried out…
AMPUTATION
During an amputation surgery, the surgeon removes a limb, or part of a limb, that is no longer useful and is causing great pain, or threatens the patient’s health because of extensive infection. Amputation is usually used as a last resort.
Procedure:
1) Choosing the incision site is important. If too little tissues are removed, the wound will not heal because unhealthy tissue remains and the circulation at that level may not be sufficient for healing. To determine how much tissue to remove, before the operation, the physician will check for a pulse at a level close to the site. He/she will also compare the skin temperatures in the diseased limb with those in a healthy limb, and note places where the skin appears red, since an incision made through reddish skin may be less likely to heal. Checking that the skin around the proposed incision point still has sensitivity to touch is also important. Finally, during the operation when the surgeon has made the initial cut, he/she may decide that more of the limb needs to be removed if the edges of skin do not bleed enough to allow them to heal.
2) Before the procedure begins, an anaesthesiologist will either put the patient to sleep with a general anaesthetic, or numb the body in the region of the amputation using a regional anaesthetic. The patient is connected to machines that monitor his/her heart rate, blood pressure, temperature, and brain function. When the anaesthetic has taken effect and no pain is felt, the surgeon then makes an incision, leaving enough healthy skin to cover the stump for better healing.
3) When the surgeon divides the muscles, he/she may shape them, to make sure that the stump has a comfortable contour for any artificial limb. The nerves are also protected to prevent exposure and pain.
4) During surgery, clamps are applied to the healthy major blood vessels to minimize bleeding. Stitching of the vessels is carried out, and the clamps are released to ensure that all bleeding points are secure.
5) With a traumatic injury, your surgeon will remove the crushed bone (usually not present in snake bite injuries) and other tissue, a process called "debridement." Then, the surgeon will smooth the uneven areas of the bone to prevent pain upon receiving any artificial limb. If necessary, the surgical team may install temporary drains that will drain blood and other fluids that may accumulate.
6) After the surgeon removes the dead tissue, he/she may decide to leave the site open (open flap amputation) or to close the skin flaps (closed amputation). In an open flap amputation, the skin remains drawn back from the amputation site for several days so that the surgical care team can clean off of any questionable or infected tissue. Once the stump tissue is clean and free of infection, the skin flaps are sewn together to close the wound, a procedure called delayed closure. In a closed amputation, the wound is sewn shut immediately. A closed amputation is usually done if the surgeon is reasonably certain that the chance of infection is small and healing is likely.
7) Finally, a stocking is placed over your stump to hold drainage tubes and wound dressings, or the limb may be placed in traction, or a splint, depending on the circumstances.
www.emedicine.com/med/TOPIC2143.HTM
http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/fasciotomy.jsp
http://www.vascularweb.org/patients/NorthPoint/Amputation.html
Fasciotomy is usually used when compartment syndrome arises, due to the haemolytic toxin present in certain snake venom.
3 types of compartment syndrome:
1. Acute compartment syndrome
2. Sub-acute compartment syndrome
3. Chronic compartment syndrome
For both acute and sub-acute compartment syndrome, fasciotomy is used to treat.
For chronic compartment syndrome, both conservative and surgical methods can be used. Conservative treatment includes rest, anti-inflammatory medications, elevation of the limb and manual decompression. In cases where symptoms persist, the condition should be treated by a surgical procedure, subcutaneous fasciotomy or open fasciotomy. Without treatment chronic compartment syndrome can develop into the acute syndrome. A possible complication of surgical intervention for chronic compartment syndrome can be chronic venous insufficiency.
Fasciotomy in the limbs is usually done by a surgeon under general or regional anaesthesia.
An incision is made in the skin, and a small area of fascia is removed where it will best relieve pressure. Then the incision is closed.
Plantar fasciotomy is an endoscopic (performed with the use of an endoscope) procedure. It is done under local anaesthesia and takes 20 minutes to one hour. The doctor makes two small incisions on either side of the heel. An endoscope is inserted in one to guide the doctor in where to cut. A tiny knife is inserted in the other. A portion of the fascia is cut from near the heel; then the incisions are closed.
In severe cases, amputations are carried out…
AMPUTATION
During an amputation surgery, the surgeon removes a limb, or part of a limb, that is no longer useful and is causing great pain, or threatens the patient’s health because of extensive infection. Amputation is usually used as a last resort.
Procedure:
1) Choosing the incision site is important. If too little tissues are removed, the wound will not heal because unhealthy tissue remains and the circulation at that level may not be sufficient for healing. To determine how much tissue to remove, before the operation, the physician will check for a pulse at a level close to the site. He/she will also compare the skin temperatures in the diseased limb with those in a healthy limb, and note places where the skin appears red, since an incision made through reddish skin may be less likely to heal. Checking that the skin around the proposed incision point still has sensitivity to touch is also important. Finally, during the operation when the surgeon has made the initial cut, he/she may decide that more of the limb needs to be removed if the edges of skin do not bleed enough to allow them to heal.
2) Before the procedure begins, an anaesthesiologist will either put the patient to sleep with a general anaesthetic, or numb the body in the region of the amputation using a regional anaesthetic. The patient is connected to machines that monitor his/her heart rate, blood pressure, temperature, and brain function. When the anaesthetic has taken effect and no pain is felt, the surgeon then makes an incision, leaving enough healthy skin to cover the stump for better healing.
3) When the surgeon divides the muscles, he/she may shape them, to make sure that the stump has a comfortable contour for any artificial limb. The nerves are also protected to prevent exposure and pain.
4) During surgery, clamps are applied to the healthy major blood vessels to minimize bleeding. Stitching of the vessels is carried out, and the clamps are released to ensure that all bleeding points are secure.
5) With a traumatic injury, your surgeon will remove the crushed bone (usually not present in snake bite injuries) and other tissue, a process called "debridement." Then, the surgeon will smooth the uneven areas of the bone to prevent pain upon receiving any artificial limb. If necessary, the surgical team may install temporary drains that will drain blood and other fluids that may accumulate.
6) After the surgeon removes the dead tissue, he/she may decide to leave the site open (open flap amputation) or to close the skin flaps (closed amputation). In an open flap amputation, the skin remains drawn back from the amputation site for several days so that the surgical care team can clean off of any questionable or infected tissue. Once the stump tissue is clean and free of infection, the skin flaps are sewn together to close the wound, a procedure called delayed closure. In a closed amputation, the wound is sewn shut immediately. A closed amputation is usually done if the surgeon is reasonably certain that the chance of infection is small and healing is likely.
7) Finally, a stocking is placed over your stump to hold drainage tubes and wound dressings, or the limb may be placed in traction, or a splint, depending on the circumstances.
www.emedicine.com/med/TOPIC2143.HTM
http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/fasciotomy.jsp
http://www.vascularweb.org/patients/NorthPoint/Amputation.html
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