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35 Cards in this Set
- Front
- Back
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How many snake bites occur per year in Aus? How many require anti venom? And how many deaths from snake bites? |
3000 suspected snake bites 100-200 require antivenom 1-4 deaths annually - mainly from Brown Snakes |
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What are the effects of envenoming? |
Mostly not enough venom to cause problem Local effects - pain, swelling, tissue injury Systemic symptoms- N/V/D, abdo pain, diaphoresis, collapse, headache Major organ effects |
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What are the major organ effects from snake bites? |
Coagulopathy - venom induced coagulopathy, all the fibrinogen is consumed. Neurotoxicity - neuromuscular paralysis, progressive descending flaccid paralysis Myotoxicity - muscle pain, tenderness, weakness, rapid rise CK, myoglobinuria Thrombotic microangiopathy - thrombocytopenia, anaemia, AKI. Kidney damage |
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What are the 7 most venomous snakes in Aus and there major effect? |
Brown - venom induced consumption coagulopathy (VICC). Tiger - VICC Hoplopcephalus - VICC Red-bellied black - systemic symptoms Death adder - neurotoxicity Taipan - VICC Mulga - myotoxicity |
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What is the best first aid for a snake bite? |
A pressure bandage over whole affected limb, Complete immobilisation of the limb/patient Required in all cases of suspected snake bite Do NOT wash the bite site prior to bandaging Urgent transfer to a hospital with critical care, antivenom, pathology on site facilities |
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What are some side effects of antivenom? |
Anaphylaxis - occurs in 25%, severe in 5% cases Serum sickness - occurs 4-14 days post administration, treated with oral prednisolone |
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What are the two essential steps in the diagnosis of a snake bite? |
1. determine if the patient has systemic envenoming 2. determine which group of snakes is responsible - this determines whether antivenom is indicated and which to use. In the majority of cases, envenoming requires antivenom treatment. |
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How do you determine which snake is responsible for the bite? |
1. local geography—knowledge of the local snake fauna 2. clinical syndrome 3. snake venom detection kit - bite site swab collected, stored and then tested if patient appears envenomated |
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Which blood tests are preformed when managing snake bite patients? |
Coagulation studies - INR, APTT, d-dimer, fibrinogen FBE - blood film Biochemistry - UEC, Cr, CK, LDH |
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How frequently are blood samples taken in patients with no evidence of envenomation? |
At admission 1 hr after removal pressure bandage 6 hr after bite 12 hr after bite |
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In non envenomed patients what is the management? |
Observation with Neurological exam, APTT, INR, CK - repeated Until 12 hours post bite Discharge in daylight hours |
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How frequently are blood tests taken in envenomated patients? |
At admission Before antivenom 6 and 12 hours after antivenom Every 12 to 24 hours until discharge |
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How/where is antivenom administered? |
Slow IV infusion over 15minutes following a 1:10 dilution with N.Saline. In a critical care unit, with readily available resus equipment and adrenaline. |
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Which antivenom and what dose should be used? |
Monovalent antivenom - when specific snake Polyvalent antivenom - if doubt about which snake type, however large volume, so avoid if most likely is brown or tiger snake. Instead given 1 vial of brown and 1 vial of tiger antivenom. Dose = 1 vial antivenom Same dose for adults/children |
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Asides from snake antivenom, which other type of antivenoms exist? |
Red back spider Funnel web spider Box jellyfish Stone jellyfish Sea snake |
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What is anaphylaxis? |
A severe, systemic allergic reaction involving the respiratory, cardiovascular systems. Usually occurs within 30minutes of allergen exposure, may take up to 2hours. |
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What are the common features of anaphylaxis? |
1. Respiratory - stridor/wheeze, difficulty swallowing, cough, dyspnoea, hoarse voice, throat or chest tightness 2. Cardiovascular - tachycardia/bradycardia, collapse, LOC, hypotension, pale/floppy in infants 3. Skin - urticaria (hives, wheals), angioedema, flushing, generalised itch 4. GIT - N/V, abdo pain, diarrhoea |
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How is anaphylaxis diagnosed? |
Clinical diagnosis - consider in patients with acute respiratory distress, bronchospasm, and/or cardiac arrest. Sometimes problematic, if no obvious trigger, or if absent skin/mucosal features. Serial serum tryptase levels can sometimes assist in confirming anaphylaxis in unclear cases. |
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What is the lifetime prevalence of anaphylaxis? |
0.05 - 2% international lifetime prevalence |
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What are the most common triggers for anaphylaxis? |
1. Food - most common in children, esp 0-4yrs with a 2nd peak at 15-29yrs. Peanuts, tree nuts, eggs, cows milk, wheat, shellfish, fish, seeds. 2. Medication - common in older adults, antibiotics (esp penicillins), anaesthetic drugs, NSAIDs and opiates. 3. Insect venom - bees, wasps, ants |
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Which anaphylactic triggers have the highest rate of deaths from anaphylaxis? |
Medications = 56% anaphylactic deaths in Aus Food allergies = 6% Insect venom = 18% |
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Which allergy carries the highest risk of anaphylaxis and death from anaphylaxis? |
Nut allergies |
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What are the less common triggers of anaphylaxis? |
Exercise induced - in association food allergy or in isolation Latex Radiocontrast media Idiopathic anaphylaxis |
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What are the risk factors for anaphylaxis? |
Previous anaphylaxis Multiple drug allergies Nut allergy History of asthma (esp if poorly controlled) Factors at time allergen exposure - ETOH, exercise, NSAID use and intercurrent infection. |
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What are the risk factors for increased severity or fatality associated with anaphylaxis? |
Severity underlying allergy, allergen dose, patient age, co-morbidities (asthma/CVD), concurrent medication (beta-blockers, ACEIs). Food - 10-35yrs, active asthma, peanut trigger, ingestion of food not prepared at home. Insect venom - 35-85yrs, male (more exposure). Medication - 55-85yrs, abx or anaesthetic trigger, CV/resp comorbidities, concurrent medications. |
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What is the first aid management of anaphylaxis? |
1. Remove allergen (if still present) 2. Call for assistance 3. Lay patient flat - elevate legs if tolerated 4. Give adrenaline IM (anterolateral thigh) 0.01mg/kg (max 0.5mg) 5. Give high flow oxygen + airway support 6. IV access - if hypotensive give IV N.Saline 20ml/kg rapidly and add second IV line |
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After giving adrenaline, if there is inadequate response, immediate life threatening situation or deterioration, what do you do next? |
Repeat IM adrenaline injection every 5 minutes, as needed, or start an IV adrenaline infusion. Mix 1ml of 1:1000 adrenaline in 1000ml normal saline, start infusion at ~5ml/kg/hr, titrate rate according to response, monitor continuously. |
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Can an adrenaline auto injector be used for anaphylaxis management? |
Adrenaline autoinjector, can be used instead of an adrenaline ampoule and syringe. For children 10-20kg (aged 1-5 years) EpiPen Junior or Anapen Junior should be used. Instructions are on the device label. |
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If adrenaline infusion is ineffective or unavailable, what should be considered next? |
If upper airway obstruction: - Adrenaline neb (5ml i.e. 5ampoules of 1:1000) - Consider intubation If persistent hypotension/shock: - N.Saline max 50ml/kg in the first 30mins - Cardiogenic shock consider IV glucagon 1-2mg i If persistent wheeze: - Salbutamol 8-12puffs via spacer or 5mg sal neb - Oral pred1mg/kg OR IV hydrocortisone |
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How long does the patient need to be observed for post anaphylactic reaction? |
Prolonged and biphasic reactions can occur Observe patient for at least 4hrs after adrenaline Observe longer (overnight) if: - severe reaction e.g. hypotension/hypoxia - required repeated doses adrenaline - hx asthma or protracted anaphylaxis - concomitant illness - lives alone or is remote from medical care |
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What follow up treatment is considered in anaphylaxis? |
Antihistamines - oral non-sedating, for cutaneous symptoms, itch and urticaria. Glucocorticoids - reduce risk biphasic reactions, 2 day course of oral steroid prednisolone 1mg/kg (max50mg daily). Adrenaline auto-injector - prescribes while pending specialist r/v. |
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What are the benefits of IM injection of adrenaline? |
Rapid and effect absorption Avoids time delay in getting IV access Less monitoring needed less potential for significant adverse affects Autoinjectors: Can be safely administered by non-health prof Lower risk of dosing errors |
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What does the long term management of anaphylaxis involve? |
Referral to an allergy specialist Identification of triggers - SPT, IgE RAST testing Avoidance of triggers Prescription of adrenaline auto injector (EpiPen) Written emergency anaphylaxis action plan Annual GP r/v |
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Who should be prescribed an adrenaline auto injector? |
All patient who have experienced an anaphylactic reaction and have continued risk of exposure to an allergen trigger. Food/insect allergy - require EpiPen Medication allergy - can easily avoid. Must include name of consulting clinical immunologist, allergist, paediatrician or respiratory physician. |
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When would you consider repeat f/u with an allergy specialist? |
New symptoms develop Confirmation of allergy resolution Allergies difficult to manage and/or during periods of increased risk (e.g. adolescents, leaving home or travel, changes in health status and comorbidities. |
