General approach to Poisoning and Envenomation Flashcards
What types of poisons may children be exposed to?
POISONS
TYPES
- Therapeutic drugs
- deliberate or iatrogenic
- e.g.
- TCAs
- digoxin (most fatal)
- Lomotil (diphenoxylate with atropine) - can be toxic at therapeutic doses for some children
- recreational drugs e.g. alcohol, solvents
- household products
- plants (more rarely)
- inhalational toxins e.g. chlorine gases (accidents or NAI)
- agricultural products e.g. organophosphates, carbamates
- corrosives - oesophageal burns and complications
What % of children under the age of 5 can open child-resistant containers?
20%
What are some risk factors for accidental poisoning?
ACCIDENTAL POISONING
RISK FACTORS
- maternal depression
- recent change in circumstances e.g. new baby, moving house
Which groups of children are most likely to attempt suicide or parasuicide? What interventions do these children need to have? What is parasuicide?
ATTEMPTED
SUICIDE AND PARASUICIDE
- parasuicide = apparent attempted suicide without the actual intention of killing oneself
- Teens
- may be as young as 8-9 yo
- need PSYCH and SOCIAL assessment
Discuss the primary assessment and resuscitation of poisoning.
POISONING
PRIMARY ASSESSMENT & RESUSCITATION
- A
- patency (P/ U on AVPU –> A at risk)
- airway opening manoeuvres + BVM
- adjuncts
- intubation + ventilation
- Challenges
- corrosive ingestion
- cardiac arrhythmia e.g. TCA
- ++ resp secretion e.g. organophosphate
- B
- high flow O2 - FM w/ reservoir (resp abnormality, shock, decreased GCS)
- Remember CO2 can accumulate despite normal sats if ventilation is inadequate e.g. poisons that depress respiration => ventilate appropriately (BVM or intermittent PPV if intubated)
- RR increased = methanol, cyanide, carbon monoxide, theophylline, ecstacy, ethylene glycol, amphetamines, salicylates (aspirin) (MCC TH.E GAS)
- RR low = barbiturates, opiates, sedatives, ethanol (BOSE - low like the bass)
- Kussmaul breathing (acidotic sighing respirations) + coma = metabolic acidosis e.g. salicylates, ethylene glycol, ethanol, carbon monoxide (SEEM)
- C
- HR
- increased: phenothiazines, cocaine, theophylline, b-agonists (sympathomimetics), ecstacy, amphetamines, TCAs (PHE.CT BEAT)
- low: b-blockers, organophosphates, clonidine, digoxin (BL.O.C.D)
- Rhythm
- Cardiac monitoring IF:
- HR > 200 bpm (infant)
- HR > 150 bpm (child)
- abnormal rhythm
- Dysrhythmias
- TCAs = QRS prolongation / VT
- digoxin
- quinine
- antiarrhythmic drugs
- NB some antiarrhythmic drugs C/I with certain poisons - d/w TOXBASE/ poisons centre
- Tachyarrhythmia + SHOCK
- up to 3 synchronous shocks
- 1-2-2 J
- attempt asynchronous if broad complex and shock not activated by defib
- anaesthetise first if conscious
- NO DC shock in digoxin poisoning
- Cardiac monitoring IF:
- BP
- Hypotension/ SHOCK - serious poisoning, different mechanisms
- = I Can’t Bring The Blood Pressure Back O.P!!!
- Iron poisoning - GI bleeding
- Calcium channel blockers
- Barbiturates - vasodilation
- TCA
- Benzo’s
- Phenothiazines
- b-blockers
- Opiates
- Phenytoin
- NB avoid inotropes (+ poison causing shock = arrhythmias)
- Mx: fluid bolus
- = I Can’t Bring The Blood Pressure Back O.P!!!
- Hypertension - MAOI, ecstacy, cocaine, amphetamines, sympathomimetic agents
- Hypotension/ SHOCK - serious poisoning, different mechanisms
- IV/ IO access
- Bloods
- baseline incl. FBC, U+E
- TOXICOLOGY
- paracetamol + salicylate level
- gas
- GLU - BM/ gas + lab
- Bloods
- HR
- D
- Pupils
- SMALL
- Phenothiazines (Remember Pinpoint)
- Opiates, Organophosphate insecticides - (BOTH O’S - like the tiny little pupils)
- LARGE =
- fun stuff e.g. amphetamines, cocaine, cannabis
- Quite Tremendous And Cute (kawaii eyes) = Quinine, TCAs, Atropine, Carbamazepine
- SMALL
- AVPU / GCS
- GCS reduced –> trial naloxone if also small pupils
- opiates
- sedatives e.g. benzos
- antihistamines
- hypoglycaemic agents
- GCS reduced –> trial naloxone if also small pupils
- Posture
- Hypertonia: theophylline, ecstacy, TCA, amphetamines (TH.E.T.A - think of a tough frat boy flexing his muscles)
- Convulsions –> diazepam/ lorazepam/ midazolam
- hypoglycaemia e.g. ethanol
- This Patient Only Loves Convulsing
- TCA poisoning
- Phenothiazines
- Organophosphate insecticides
- Lindane
- Carbamazepine
- Pupils
- E
- Fever/ Hyperthermia:
- fun stuff: ecstacy, cocaine, amphetamines
- salicylates. phenothiazines
- Hypothermia: ethanol, barbiturates, phenothiazines
- Fever/ Hyperthermia:
- G
- HYPOG
- 10% GLUCOSE 2 ml/ kg
- follow with infusion
- HYPOG
What type of monitoring is needed in cases of poisoning?
MONITORING
POISONING
- Neuro: GCS, temp (core)
- CVS: HR, BP, ECG
- Resp: pulse ox, blood gas
- Renal: U+E
- Gastro: Blood GLU
What assessment must be done at the end of the primary assesment in all cases of poisoning? What information is needed?
LETHALITY ASSESSMENT
- assess the potential lethality of the overdose
- if the nature of the OD is not known, then assume high potential lethality
- NB episods of low lethality often require no Rx
- History:
- age & weight
- which substance?
- what dose? (labelling? description?)
- what time? (& time since exposure)
- single dose or staggered?
- Use findings from examination and investigations
- d/w POISONS CENTRE (complex or life threatening cases)
Do the following agents cause metabolic acidosis, an enlarged anion gap, hypokalaemia, hyperkalaemia or a combination?
- B-agonists
- Carbon monoxide
- Digoxin
- Ecstacy
- Ethanol
- Ethylene glycol
- Iron
- Methanol
- Salicylates
- Theophylline
- TCA’s
CLUES TO THE DIAGNOSIS OF AN UNKNOWN POISON
(SEE IMAGE)
What are the principles of drug elimination in overdose?
IF
high potential lethality
OR
exact nature of OD not known
THEN
need to minimise blood conc. of drug
BY
- Stopping further absorption
- Increasing excretion
- Specific antidote (if available)
- Active elimination e.g. haemoperfusion, plasmapheresis (rarely used, poisons centre to advise)
How does activated charcoal work in cases of poisoning?
POISONING
ACTIVATED CHARCOAL
MOA
- large surface area = 1000 m2 / gram
- give enterally but unpalatable => NGT or lavage tube after gastric washout (NB adding flavouring can decrease its activity)
- can bind certain poisonous substances e.g. barbiturates, aspirin, theophylline (BAT)
- NB can NOT absorb alcohol/ iron
- not systemically absorbed
- promotes drug reabsorption back into the bowel –> excreted (& interrupts enterohepatic cycling)
- dose = 10 x estimated dose of poison ingested, ~ 25 - 50 g
- NB protect the airway esp. if reduced GCS as aspirated charcoal causes lung damage
Describe the use of emesis as a management strategy in the treatment of poisoning? Is it still frequently used? In what cases should it be used?
POISONING
EMESIS
- ipecacuanha
- Dose
- > 2 years = 15 ml with water
- 6 months - 2 years = 10 ml with water
- Repeat once after 20 mins if necessary
- do NOT use if
- depressed conscious level
- corrosive substance ingested
- ONLY use when
- at risk from the poisons ingested
- poisons cannot be bound by activated charcoal
- child will not take charcoal
- present w/i 1 hour of ingestion (only about 30% eliminated even w/i time frame)
Is gastric lavage a frequently used tactic in the management of poisoning? Why not? With which drugs in particular should advice re: gastric lavage be sought?
POISONING
GASTRIC LAVAGE
- Rarely used
- risk outweighs benefit
- if IRON or LITHIUM ingested in the previous hour –> d/w NPIS (national poisons information service)
At what level of iron poisoning (mg/kg) are the following likely:
- Toxicity
- Fatality
IRON POISONING
ELEMENTAL IRON
TOXICITY > 20 mg/ kg
FATALITY > 150 mg/ kg
What are the symptoms of iron poisoning?
IRON POISONING
SYMPTOMS
- D&V
- abdominal pain
- —>
- drowsiness
- convulsions
- circulatory collapse / shock (gut haemorrhage)
Describe the management of iron poisoning.
IRON POISONING
Mx
- A
- secure
- C
- IV access
- BEWARE haemolysed blood samples - high levels of iron can cause haemolysis
- desferrioxamine PO or IV up to 15 mg/ kg/ hr
- IMMEDIATELY in
- shock
- coma
- fits
- IRON level 3 mg/ L at = / > 4 hrs after ingestion AND
- GI Sx
- leucocytosis
- hyperglycaemia
- IMMEDIATELY in
- E
- whole bowel irrigation
- AXR can help identify how much iron remains within
What are the problems associated with TCA poisoning?
TCA POISONING
- Quinidine-like inhibition of fast sodium channels
- BRAIN
- MYOCARDIUM
- intraventricular conduction delay
- prolonged QRS ( > 4 little squares = serious)
- arrhythmias
- Anticholinergic effects
- tachycardia
- dilated pupils
- convulsions
Describe the emergency management of TCA poisoning.
TCA POISONING
Mx
- A
- B
-
ALKALINISE pH (ideally to 7.5 or at least 7.45) – reduces toxic effects on the heart
- hyperventilation
- PCO2 NOT < 3.33
-
ALKALINISE pH (ideally to 7.5 or at least 7.45) – reduces toxic effects on the heart
- C
- ALKALINISE pH
- sodium bicarbonate 1-2 mmol/ kg
- Hypotension - volume expansion
- Inotropes
- noradrenaline is 1st choice
- glucagon
- Antiarrhythmics
- D/W poisons centre
- lidocaine or phenytoin
- do NOT use
- quinidine
- procainamide
- disopyramide
- ALKALINISE pH
- D
- treat convulsions
- E
- F
- G
Describe the emergency management of opiate poisoning, indluding methadone. Why is it important to normalise PCO2 before giving an opiate antagonist?
POISONING Mx
OPIATES incl. METHADONE
- Stablise ABC
- NALOXONE = specific antidote
- 10 mcg/ kg BOLUS
- +/- larger boluses or infusion 5-20 mcg/ hr
- short half life
- relapse often occurs after 20 mins
- NORMALISE CO2 BEFORE GIVING !!!
- opioid and adrenergic system inter-related
- hypercapnia + opioid antagonist
- stimulates sympathetic nervous system
- sudden rise in adrenaline
- arrythmias incl. ventricular arrhythmias, asystole
- flash pulmonary oedema
- seizures
What dose of paracetamol needs to be ingested for toxicity to occur? What does this imply about the method of significant paracetamol poisoning?
PARACETAMOL TOXICITY
> 150 mg/ kg
Can occur with lower doses if hepatic/ renal disease
=> significant paracetamol poisoning is almost always intentional; consider NAI in younger children
Describe the emergency management of paracetamol poisoning.
PARACETAMOL POISONING
Mx
- ACTIVATED CHARCOAL
- within 1 hour of ingestion
- not with liquid preparations (rapid absorption)
- PARACETAMOL LEVEL =/> 4 HOURS POST INGESTION
- use a nomogram –>
- decide whether IV ACETYLSTEINE is needed
- 300 mg/ kg over 24 hours
- contact a poisons centre
Describe the emergency management of salicylate poisoning.
SALICYLATE (ASPIRIN) POISONING
Mx
- SALICYLATE LEVEL
- initially 2 hours post
- repeat measurements
- levels will rise sig. in first 6 hours
- GAS
- resp. alkalosis
- metabolic acidosis
- ALKALINISE
- improves excretion of salicylate
- 1 mmol/ kg sodium bicarbonate over 4 hrs
- GASTRIC LAVAGE
- up to 4 hours post ingestion
- aspirin slows gastric emptying
- ACTIVATED CHARCOAL
- repeated doses if sustained-release preparation
- NB do NOT use forced diuresis
*
What commonly used substances contain ethylene glycol? How does its taste make it attractive to children? What clinical appearance does it cause?
ETHYLENE GLYCOL
Cars: Anti-freeze & De-icer fluid
Sweet tasting
Inebriation
What is the pathophysiology of ethylene glycol poisoning?
PATHOPHYSIOLOGY
ETHYLENE GLYCOL POISONING
- metabolic acidosis (inexplicable ANION GAP)
- cellular damage - widespread, esp kidneys
Describe the management of ethylene glycol poisoning.
ETHYLENE GLYCOL POISONING
Mx
- ETHANOL
- 40% 2.5 ml/ kg = oral loading dose
- aim blood ethanol 100 mg/ dl
- strength of most spirits
- competitive inhibitor of alcohol dehydrogenase
- can block the metabolism of ethylene glycol to poisonous metabolic byproducts
- HAEMODIALYSIS +/- FOMEPIZOLE
- CO-FACTORS
- THIAMINE
- PYRIDOXINE
Describe the pathophysiology of cocaine poisoning.
PATHOPHYSIOLOGY
COCAINE POISONING
- Local accumulation of NEUROTRANSMITTERS
- adrenaline
- noradrenaline
- dopamine
- serotonin
- Adrenaline & Noradrenaline
- @ myocardium
- tachycardia
- increased myocardial oxygen demand
- reduced diastolic time
- reduced time for coronary perfusion
- @ Peripheral b-adrenergic receptors
- vasoconstriction
- hypertesion
- @ myocardium
- Serotonin
- peripheral 5-HT (hydroxytryptamine) receptors
- coronary artery vasospasm
- PLATELET AGGREGATION
- SODIUM CHANNEL INHIBITOR
- similar to a type I antiarrhythmic agent
- prolonged QRS
- impaired myocardial contractility
- tachyarrhythmias incl. VT & VF
- CORONARY EVENT (in children/ adolescents)
- chest pain
- arrhythmias
Describe the emergency management of cocaine poisoning.
COCAINE POISOING
Mx
- ACS
- oxygen
- continuous ECG monitor
- VT
- DC shock
- NOT antiarrhythmic drugs (further pro-arrhythmogenic effects)
- Ventricular arrhythmias
- consider SODIUM BICARBONATE
- 0.5 - 1 mmol/ kg
- counteract sodium channel blockage
- VT
- ASPIRIN
- HEPARIN
- NB b-blocker contraindicated
- BENZODIAZEPINE e.g. diazepam/ lorazepam
- Active cooling for hyperthemia
What is MDMA? What dose of MDMA do most ecstacy tablets contain? What is the half-life of ecstacy?
MDMA & Ecstacy
MDMA = 3,4 - methylene dioxy methamphetamine
Most ecstacy tablets contain
30 - 150 mg MDMA
Half life of ecstacy = 8 hours
What is the pathophysiology of ecstacy poisoning? What adverse effects can be expected at low and high doses?
ECSTACY
PATHOPHYSIOLOGY
- stimulates peripheral and central a- and b- adrenergic receptors
- Adverse effects
- MILD at LOW doses
- General: mild temp elevation
- Neuro: increased muscle tone, agitation, anxiety
- CVS: tachycardia
- HIGHER doses
- Neuro: hypertonia, hyperreflexia, visual disturbance
- CVS: tachycardia
- Resp: tachypnoea
- SEVERE
- General: hypepyrexia
- Neuro: coma, convulsions, increased muscle tone –> rhadbomyolysis, NMS (neuroleptic malignant syndrome) = deaths after 24 hrs
- CVS: cardiac dysrrhythmias = early deaths, DIC
- Renal: metabolic acidosis, acute renal failure
- MILD at LOW doses
Describe the emergency management of ecstacy poisoning.
ECSTACY POISONING
Mx
- ACTIVATED CHARCOAL - conscious
- DIAZEPAM
- for anxiety
- do NOT give major tranquilisers - can exacerbate Sx
- MONITOR
- BP
- Temp > 39
- ACTIVE COOLING
- SODIUM DANTROLENE
- 2-3 mg/ kg
- over 10 - 15 mins
- May need ventilation
Name some of the signs and symptoms suggestive of organophosphate poisoning.
ORGANOPHOSPHATE POISONING
SIGNS AND Sx
- B: SOB
- D: pinpoint pupils
- E: salivation, sweating, rhinorrhoea
Describe the emergency management of organophosphate poisoning.
ORGANOPHOSPHATE POISONING
Mx
- Assess for Sx
- Respiratory
- pinpoint pupils
- salivation
- sweating
- NO –> high flow O2 & observe
- YES
- PRALIDOXIME IV
- 30 mg/ kg over 20 mins
- –> 8 mg/ kg/ hr
- max 12g in 24 hrs
- ATROPINE
- 20 mcg/ kg
- can repeat
- very large doses may be required
- up to 250 mg
- PRALIDOXIME IV
What is envenoming caused by?
ENVENOMING
BITES & STINGS
ANIMALS:
- Snakes
- Spider
- Insects e.g. bees, wasps, ants
- Jellyfish
- Fish
- Ticks
What is the best management of envenoming and why?
Prevention.
Reversal through the use of antidotes may not resolve all medical problems.
What are the symptoms of envenoming the result of?
SYMPTOMS OF ENVENOMING
- VENOM - DIRECTLY
- ALLERGIC RXN TO VENOM
- COMBINATION
What are the principles of management of envenoming?
ENVENOMING
MANAGEMENT PRINCIPLES
- Remove from danger (esp if venomous animals)
-
A,B,C,D,E,F,G - RESUS
- Coagulation factor therapy
- Sedation
- Supportive care to systems affected
- Limit uptake of venom (into circulation)
- Inactivate venom locally
- Antidote/ antivenom - if available
- Pain Mx
- Local injury sites - treat
- Remove from danger (esp if venomous animals)
- ensure it is safe to approach
- avoid further bites/ stings
- some venomous animals can sting repeatedly e.g. jellyfish, other can not e.g. bees
- do not try to catch/ kill the animal, except e.g. removing all ticks in cases of tick paralysis
- A,B,C,D,E,F,G - RESUS (see separate note)
- Supportive care to systems affected
- Limit uptake of venom (into circulation)
- e.g. snakes, funnel web spiders, blue ringed octopus
- PBI first aid = Pressure Bandaging and Immobilisation
- broad bandage over the bite site, then over the rest of the limb and over the top of clothing
- as firm as for a sprain but not so tight as a tourniquet
- crepe bandage or elasticated
- immobilise limb using splint, pt not to move
- only discontinue when child is in a hospital capable of giving antivenom
- limits transport of the venom in the lymphatic system
- do NOT use for red back spider, ticks, stonefish, jelly fish
- broad bandage over the bite site, then over the rest of the limb and over the top of clothing
-
Inactivate venom locally
- for jellyfish and fish stings
- box jellyfish
- inactivate unfired stinging cells on tentactles adherent to the skin
- flood with vinegar
- +/- apply coldpack
- other jellyfish, fish and stingrays
- hot water
- hot shower immersion at 45 degrees (care to avoid thermal injury)
-
Antidote/ antivenom - if available
- IgG Ab’s or fractions
- raised in animals against specific venoms
- each one for a particular species/ group of animals
- can neutralise venom but do not reverse damage
- IV usually - more rapid + effective, dilute in 0.9% saline but avoid fluid overload
- IM - red back spider, stonefish
- Dose depends on quantity of venom injected, not size of pt (same regimen as adults)
- Indications vary based on animal - see separate note
- WHICH antivenom?
- depends on animal
- 5 specific snake antivenoms and 1 polyvalent for all types
- use specific if possible - cost and safety (esp. brown & tiger snake)
- can use snake venom detection test to aid choice of specific antivenom - NB not diagnostic, -ve does not R/O bite
- BEWARE adverse rxn’s => only use when indicated + make sure adrenaline etc to hand
- early: rash, fever, anaphylaxis
- late: serum sickness
-
Pain Mx / ANALGESIA
- HOT WATER (45 degrees), avoid thermal injury - marine stings
- ANTIVENOM - stonefish, red back spider, +/- box jellyfish
- IV OPIOIDS
- REGIONAL NERVE BLOCK - marine stings
-
Local injury sites - treat
- all stings and bites can introduce tetanus or other infections
- TETANUS immune status
- immunisation or booster
- snakebites - only AFTER acute coagulopathy resolved
- ANTIBIOTICS
- NOT as routine prophylaxis
- only in acute infection
- TRAUMA
- Stingrays
- laceration of nerves, tendons and blood vessels
- penetrate abdomen or chest wall
- direct injury to the heart
- local tissue damage/ necrosis
- Wash, debride & control bleeding
- CAREFUL removal of the sting if near heart - incautious removal can be lethal
- Stingrays
- EYES - venom spat into
- NOT likely to cause envenoming
- CAN cause
- intense pain
- temporary blindness
- corneal injury
- Urgent irrigation
- examine the cornea and treat corneal injury
Is enevenoming inevitable after a bite or sting? What kind of factors affect the likelihood of ensuing envenoming after a bite or sting?
ENVENOMING
NOT INEVITABLE - depends on:
- Animal
- can often control how much venom injected
- ‘dry’ snake bites which fail to be effective and do not require antivenom
- NB manage ALL SNAKE BITES as potentially lethal
- Child
- Size:
- smaller –> envenoming more likely as higher concentration of venom
- chances of severe or lethal envenoming also increase as size decreases
- Clothing: may reduce or prevent injection of venom into skin
- Size:
How do you make the diagnosis of envenoming?
DIAGNOSING ENVENOMING
- HISTORY
- EXPOSURE to a bite/ sting
- Type of ANIMAL
- venomous or not
- prediction of potential risks
- targeted therapy
- EXAMINATION
- evidence of ENVENOMING or ALLERGIC RXN to the bite/ sting
- no history of exposure but UNEXPLAINED
- Neuro: paralysis, collapse, convulsions
- MSK: myotoxicity
- CVS: coagulopathy
- Renal: renal failure
- LABORATORY TESTS
- may be useful in indentifying envenoming e.g. snake bites
- coagulopathy (INR, D-dimer, APTT) & myolysis (CK)
With what type of venom are laboratory tests essential for determing the degree of enevnoming? Which tests are these? With which type of venom are laboratory tests NOT helpful in assessing severity?
ASSESSING DEGREE OF ENVENOMING
LABORATORY TESTS
- Useful with SNAKE bites
- examination: look for paralytic features
- Test for:
- Coagulopathy
- INR
- APTT (activate partial thromboplastin time)
- D-dimer
- Myolysis = CK (creatine kinase)
- Coagulopathy
- NOT useful
- spider bites
- tick bites
- marine stings
- insect stings — EXCEPT MASSIVE MULTIPLE
Describe the resuscitation and supportive management of envenoming/ envenomation.
ENVENOMING/ ENVENOMATION
RESUS & SUPPORTIVE Mx
= DANGER + ABCDEFG
- DANGER
- ensure it is safe to approach
- avoid further bites/ stings
- some venomous animals can sting repeatedly e.g. jellyfish, other can not e.g. bees
- do not try to catch/ kill the animal, except e.g. removing all ticks in cases of tick paralysis
- A
- secure - assess frequently
- clear secretions
- may be threatened by
- reduced GCS
- bulbar palsy
- tissues around the airway swollen/ paralysed
- A PARALYSED CHILD MAY BE FULLY CONSCIOUS - ALWAYS ANAESTHETISE BEFORE INTUBATING!!! (Unless GCS is reduced)
- B
- Ventilatory support will be needed for:
- Paralysis
- Severe muscle spasms
- Seizures
- Secretions unmanageable
- Always anaesthetise first as may be fully conscious even if paralysed
- Intubate BEFORE resp. arrest
- Ventilatory support will be needed for:
- C
- SHOCK may occur due to
- cardiac arrhythmia
- bleeding 2ndary to coagulopathy
- massive fluid leak into tissues damaged by cytotoxic venoms
- IV access
- SNAKE BITE - BEWARE coagulopathy - do NOT cannulate / sample from:
- subclavian
- femoral
- jugular
- SNAKE BITE - BEWARE coagulopathy - do NOT cannulate / sample from:
- FLUIDS & ELECTROLYTES
- avoid fluid overload
- beware renal/ electrolyte derangement w/ some venoms
- COAGULATION FACTOR Therapy
- FFP, cryoprecipitate
- give after anti-venom in cases of sig. active bleeding
- venom components e.g. snakebite can attack haemostasis system, causing consumptive coagulopathy incl. defibrination
- anti-venom can neutralise these but it does NOT replace consumed clotting factors - can take hrs to return to safe levels
- SHOCK may occur due to
- D
- Pupils
- GCS/ AVPU
- remember that failure to respond may be due to paralysis and not depressed GCS
- NEURO exam - look for
- ptosis
- opthalmoplegia
- bulbar palsy
- SEDATION
- bites and stings can cause extreme anxiety
- consider sedation and anxiolysis esp. for transportation
- CAUTION in pts at risk of neurotoxic paralysis
- E
- full exposure to identify site of bite/ sting
- stings - check areas covered by hair
- tick bites - check scalp & behind ears
What are the indications for antivenom use in the following:
- Australian snakebites
- Funnel web spider bites
- Red back spider bites
- Stonefish stings
- Box jellyfish stings
INDICATIONS FOR ANTIVENOM
- Australian snakebites
- systemic envenoming incl.
- Neuro: collapse, convulsions, paralysis
- CVS: coagulopathy
- MSK: myolysis
- Renal: renal damage
- NOT if ONLY GENERAL Sx
- headache
- vomiting
- abdo pain
- systemic envenoming incl.
- Funnel web spider bites
- systemic envenoming
- Red back spider bites - controversial
- systemic envenoming
- intractable regional envenoming
- Stonefish stings
- sig. local pain
- Box jellyfish stings - unclear
- life-threatening envenoming
What is the purpose of monitoring in the case of bites and stings? What form does it take?
How long should it go on for in the following:
- Dry/ minor bites/ stings
- Snakebites
- Funnel web spider bites
- Red back spider bites
- Marine envenoming (in general)
- Stingray wounds to the trunk
MONITORING
- Purpose = to detect developing envenoming which may not be the case at presentation
- What type of monitoring = recurrent
- clinical examination
- blood tests (snakebites)
- How long for?
- Dry/ minor bites/ stings
- adequate period so envenoming not missed
- Snakebites
- at least 12 hrs if NO / MINOR envenoming
- longer in remote areas
- Blood tests @:
- 1 hr after PBI removed
- 6 hrs post bite
- 12 hrs post bite
- Funnel web spider bites = BIG BLACK SPIDER
- at least 4 hrs post bite (sig. envenoming will develop within this time frame)
- Red back spider bites
- ONLY symptomatic pts
- Marine envenoming (in general)
- depends on
- bite/ sting
- symptoms
- severe/ life threatening
- within first hr or less - usually
- always w/i 4 hrs – EXCEPT
- depends on
- Stingray wounds to the trunk
- may seem fine initially
- observe for a longer period > 4 hrs
What are button batteries and what devices may they be found in? What metals anf chemicals do they contain? What type of batteries are the most lethal if ingested?
BUTTON BATTERY INGESTION
- Button batteries = small, coin shaped batteries
- Used in
- watches
- calculators
- children’s toys
- Metals
- mercury
- silver
- lithium
- Chemicals
- sodium hydroxide
- potassium hydroxide
- Lithium batteries = most fatal
Describe the pathophysiology of button battery ingestion and the timeframe in which it occurs.
BUTTON BATTERY INGESTION
PATHOPHYSIOLOGY
- not due to leakage
- electric current discharged from battery
- sodium hydroxide generated
- causes liquefaction necrosis of tissues
- Timeframe
- if lodged e.g. in oesophagus –> severe burns w/i 2 hrs
- damage continues for days - weeks due to
- weakened tissues
- residual alkali
What are the complications of button battery ingestion?
BUTTON BATTERY INGESTION
COMPLICATIONS
- Perforation
- Distillation in adjacent structures e.g. trachea, major vessels
- Vocal cord paralysis
- Strictures
Which age group is most at risk of dying from button battery ingestion?
< 4 yo
What percentage of children who ingest button batteries have symptoms? What type of symptoms do they have?
BUTTON BATTERY INGESTION
SYMPTOMS
10%
- vomiting +/- haematemesis
- refusal to take anything orally
- increased salivation
- dysphagia
- airway compromise
What investigations should be done in children who have ingested button batteries? What radiological characteristics suggest button battery ingestion?
BUTTON BATTERY INGESTION
INVESTIGATIONS
- XR of the entire oesophagus and abdomen
- Radiological characteristics
- radiopaque foreign body
- halo effect/ double rim
- lateral XR - step off
Describe the management of button battery ingestion.
BUTTON BATTERY INGESTION
Mx
- REFER TO SURGEONS as an EMERGENCY for removal if
- in the oesophagus
- in the stomach + ingested alone (w/o magnet) + symptomatic
- still in the stomach after 4 days
- if lodged
- REPEAT XR w/i 4 days IF:
- > 15 mm battery AND
- child < 6 yo
- –> if still in the stomach refer for removal
- REFER TO MENTAL HEALTH
- consider self-harm in older children
