Industrial and household toxicology
In Organophosphate poisoning what symptoms do you get? Cholinergic syndrome: wet, slow, Basha: Bradycardia, bronchorrheoa, bronchospasm, diarrhoea, lacrimation, vomiting, miosis
Atropine is given in what doses and what will it not improve? 1.2mg iv, double every 2 mins. end points - Normal HR, secretions dried up, brnchospasm improved.
How do organophosphates cause toxicity? Inhibit acetylcholinesterase = increased ACh @ muscurinic and nicotinic receptors = cholinergic syndrome - wet, slow, Basha, they alos cause ageing
What treatment? Atropine 1.2g double every 2mins, also pralidoxine
What symptoms with the atropine not effect? nicotinic mediated symptoms - tremor, muscle weakness and fasciculations
context herbicide, as little as a mouthful potentially lethal
initial symptoms corrosive injury, metabolic acidosis, renal failure, liver failure, progressive pulm injury
Ix ECG, BSL, para, monitor oxygen, serial ABGs, FBC, EUC, LFT, CXR, urine and serum levels,
Treatment limit oxygen treatment as possible, decontamination is first priority over transport or resus, administer food or soil at scene, activated charcoal immediately, early haemodialysis (only useful within 2hrs)
Sources metallurgy, mining, plastic manufacture, almonds, apple seeds
How does cyandide cause toxicity? Cyanide inhibits ATP production at mitochondrial level (oxidative metabolism) high lactate.
What is the most used cyanide kit in Oz? Dicobalt kit is most used in Australia - it has not been shown to be effective
What are the side effects of dicobalt edentate kit? Hypotension, laryngeal oedema, convulsions - therefore should confirm that there is definitely cyanaide tox - lactic acid >10, decreased LOC
What is a better treatment for cyanide tox? 5g iv hydroxycobalamin repeated x 3 15minutely, is the better, safer kit (with evidence to show it works) as no formation of methaemogobin (formed by amyl nitrite, sodium nitrite and mopped up by the thiosulphate) this is bad if in house fire and already hypoxic
How does hydroxycobalamin work? turns it into B12 and pee it out
What is another cyanide antidote and when would you use? Sodium Thiosulphate - only for mild cases
WRT Oxy/diss curve what does left and right shift mean? Left shift = loaded up/held on Hb/won't let go. Right shift = lets it go and be delivered
How do people go with acute CO poisoning? Deaths occur pre-hospital. At hospital survival is likely, risk assessment concerns risk of long term sequelae.
Risk factors for long term sequelae Low concentration exposure for long duration (accidental); signs of hypoxia (CNS coma, confusion, cerebellar signs; metabolic acidosis; CVS ischaemia); age >55yo; pregnancy (risk to fetus)
COHb levels smokers up to 10%, non specific symptoms (headache, nausea, tachy) up to 40%, initial level not indicative of severity of poisoning
Assessment of severity neuro and CVS symptoms of hypoxia
What tests should you do for CO poisoning? BSL, Para, cyanide if fire, ECG, HCG, lactate, COHb (vbg=abg), FBC< U+E, Trop (worse prognosis if Tn leak), MMSE
Will sats be normal or low on oximetry normal as include COHb in reading
Who should be considered for hyperbaric O2 in CO poisoning? All patients COHb >30%, pregnant woman >15%, comotosed
What are the clearance times for COHb? 240mins - RA, 90mins - 100% O2, 23mins - 100% at 3atm - these are not well established in symptomatic patients
What is it important to remember to arrange for the accidental exposures index them so can contact trace and offer neuropsych follow up in 1-2 months
How do you evaluate a hydrogen peroxide burn? OGD is best way, absence of oropharygeal burns does not mean there is no other lower down (10-15% have only oesophageal or lower injury)
What are the mechanisms of injury H2O2? 1. Direct Gi injury, 2. O2 formation and gas embolus (CNS - cerebral gas embolus); 3. Distend hollow viscera (thus get an AXR and CXR too)
Which is worse acid or alkali? Alkali cause more damage - liquid coagulation, sloughing. Alkaline - oesophageal, acids gastric.
Which household items are bad? Drain and oven cleaners are worse, dishwasher tabs an bleach can cause injury but a lot safer. 3% solutions usually ok, concentrated solutions >10% need assessment.
How should children be managed in ED ? NBM until OGD, can have water if thought not to be significant or large injury as can dilute acids
Where is it unsafe to leave a button battery ?(!) Nose, ears, oesophagus
In what time frame can they cause corrosive damage? by as little as 6 hours
What are the consequences of leaving the battery? Local burns, perforation, haemorrhage +/- stricture formation latterly if don't just die
How do they present? sometime assymptomatics. sometimes with oesophageal pain and dysphagia but these symptoms can be dalyed for some days
How do you investigate? Plain CXR and AXR
If they are below diaphragm how do you manage? expectantly, repeat XR in 24 hours to ensure has passed pylorus, post pylorus no more XR needed and the amount of metal should not cause them serious issue for absorbtion
What is a pathognomic sign? Halo sign
belladonna, angel's trumpet anticholinergic
oleander, foxglove glycosides, treat with digibind
seed kernels - almond, cherry, plum etc cyanide
morning glory, peyote psychosis
castor beans multi organ failure
examples essential oils (eucalyptus!); kerosene, turps; toluene (solvent abuse); carbon tetrachloride
how bad is eucalyptus oil really? as little as 10ml can cause CNS depr and seizures, as little as 5ml can cause coma in a child
clinical features acute toxicity Resp (aspiration pneumonitis - pulm oedema); CVS - dysrrhythmias (due to sensitisation to endogenous catecholamines); Neuro - CNS depr, seizures, coma
chronic solvent abuse effects toluene causes renal tubular acidosis and hyperchloraemic NAGMA, also ataxia, dementia and peripheral neuropathy
Management of acute toxicity resus ABC. BB for arrhythmias. Correct hypokalaemia. Supplemental oxygen and bronchodilators. Benzos for seizures. GI decontamination is CONTRAINDICATED. Charcoal does not bind. Catecholamines avoided if possible.
examples wheel cleaners, glass etching solutions
exposures dermal (most common, delayed severe pain, tissue injury); ingestion (fluorosis - hypocalcaemia, hypoMg, tetany, long QT, arrhythmias); inhalation (ARDS)
Rx fluorosis ACLS, intubate, hyperventilate, iv Ca glu 10% 60ml or CaCl 10% 20ml, rpt q5min; NaHCO 100mEq; MgSO 10mmol
Dermal exposure calcium gluconate gel; calcium gluconate s/c or regional iv or intraarterial [NOT calcium chloride which causes tissue damage]
how do you make calcium gluconate gel 10ml calcium gluconate and 30ml lubricant jelly
examples Drain cleaners, Oven cleaners, Automatic dish washing liquids & powders, Laundry detergents, Ammonia. Acids HCl, HSO4. Alkalis ammonia, KOH, sodium hypochlorite.
clinical corrosive injury to pharynx, upper airway, oes, stomach; not systemically toxic; stridor, drooling or vomiting indicate serious injury. Household bleach < 150ml not significant.
Ix ECG, BSL, para, endoscopy (signs and symptoms do not correlate well with extent of injury), cxr/axr if suspected perforation
Rx airway, endoscopy, charcoal C/I
Question Answer Column 3 Column 4
Lead acute - peripheral neuropathy, abdominal symptoms, encephalopathy, seizures; chronic - poor concentration, abdo pain, impaired coordination ECG, BSL, para, serum lead level, FBC, EUC, LFT, AXR FB removal or WBI, chelation iv EDTA, oral succimer
Arsenic GI haemorrhage, rice water diarrhoea, hypersalivation, garlic odour, acute CMO, multi organ failure, progressive peripheral neuropathy ECG, BSL, para, spot urine arsenic, blds, ABG, cxr/axr (radioopaque) treat hypovolaemia, WBI, succimer
Question Answer Column 3 Column 4 Column 5
ethylene glycol ingestion > 1ml/kg lethal, radiator coolant, antifreeze severe AG (lactate) acidosis, calcium oxalate crystals in tissues, hypocalcaemia, renal failure ECG, BSL, para, EUC, lactate, osmolality intubate, hyperventilate, seizures - benzos, glucose, K, Ca, haemodialysis, ethanol, fomepizole
methanol ingestion > 0.5ml/kg lethal, taste or lick ok but more needs assessment, varnishes, paints, stains formic acid causes aAG acidosis, blindness, headache, vertigo, seizures ECG, BSL, para, EUC, lactate, osmolality, ABG, brain CT dialysis, ethanol, fomepizole
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