dr v p chandrasekaran
TRANSCRIPT
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Pesticide Poisoning – What is new?
Dr.V.P.Chandrasekaran.
M.D., Diploma in Accident & Emergency Medicine
Head. Department of Emergency & Critical care Medicine
Vinayaka Missions Kirupananda Variyar Medical College
Salem
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Poisoning – A global Threat
• Suicidal attempts
• Accidental and occupational exposure to poisons.
• South Asia - Agriculture
• Pesticides – Multipurpose
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Objective
• Newer aspects and controversies
– Organo phosphorous compounds
– Organo chlorine
–Pyrithrines and pyrithrinoids
– Glyphosate
–Aluminum Phosphate
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Organo phosphorus
• Muscular paralysis
• Secretions
• Needs supportive care like Airway, ventilation and treated with charcoal, Atropine and oximes
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Charcoal - Controversies
• Questionable value
• Harmless when handled carefully
• GI obstruction – prevent with Hydration
• Aspiration – Protect airway when in need
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Why Multi dose Activated Charcoal for 48 hrs?
• Direct Adsorption
• Enterohepatic circulation
• Gut Dialysis
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What is new?
• Hypokalemia - needs close monitoring when MAC given.
• Never been reported so for and it is lethal when unnoticed and not corrected
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Atropine
• What is the end point?
–Dilation of pupil and tachycardia are not the real end point
–The real end point of atropinisation should be the drying of secretion.
• Harms – Delerium, Gastro peresis
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Tracheobronchial secretions
Ref: Tintinalli 6th edition
Ref: Harrison’s 17th edition
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How to prevent Delirium?
• The Glycopyrolate can be added to atropine to reduce the delirium as it will not penetrate the blood brain barrier and dry the secretions
• Glycopyrolate should not be used alon as it does not counter th CNS effects of poison
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oximes• Questionable value
• Incidence of Asystole and type 2 respiratory failure is reported
• It is believed harmful by many clinicians.
• Require multicentre studies to clear the dilemma.
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Less Known• OPC induced Parkinsonism
• Malignant neuroleptic syndrome (tremor, rigidity, hyperthermia and increased CPK).
• Precipitated by metaclopromide Needs high index of suspicion, early recognition
and meticulous attention to save the patient.
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Better Outcome
• Magnesium sulphate
• Soda bicarbonate infusion to keep the pH of 7.45 -7.55
it needs to be addressed by researchers seriously.
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Pyrithrines and Pyrithrinoids
• Less lethal poisoning (drowsiness, seizures and the seizures) can be countered by lorazepam and phenobarbitone.
• In combination with OPC - lethal and the incidence of ARDS seen more after this poisoning.
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Organo chlorines
• More dangerous and characterized by refractory seizure (Endosulphan).
• But the newer protocol devised by Vinayaka missions university emergency physicians is promising in saving life.
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Why to intubate electively?
• There will be no aura before the onset of convulsion hence it is mandatory to electively intubate all the patient even when their GCS is 15/15 ( As the airway needs to be protected in refractory seizures).
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Why no Charcoal with out intubation?
• Charcoal should never be instilled unless the intubation is done as the possibility of aspiration when seizures begin with out aura.
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Seizure control
• Phenytoin – No role in seizures secondary to poisoning.
• Though lorazepam and Phenobarbitone –not adequate
• Thiopentone infusion gives good control.
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Refractory Seizure
• Intermittent neuromuscular blocking agents prevent renal failure, hyperkalemia, acidosis and rhabdomyolysis secondary to refractory seizure.
• Episodes of seizures are indirectly reflected as salivation and papillary changes. But bed side EEG monitoring will help us better.
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• Propofol not preferred as propofol infusion syndrome is more when it is used >4mg/kg/hr along with Vasopressors, steroids (Rhabdomyolysis, fever, acidosis and hypotension ). Hence it is not used widely.
•
Refractory Seizure
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Shock management
• Toxin induced cardiac suppression
– Dopamine and Nor Adrenaline
• Central venous catheterization and CVP guided fluid is mandatory.
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Steroids
• Sudden death is possible due to malignant cerebral edema; the role of steroid is not studied. But in our center we are using when no significant contra indication is noted.
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No early declaration of Brain Dead
• Thiopentone coma may continue for days together due to cumulative effect of the Thiopentone when used more ( up to 10 days)
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• Herbicide , Belongs to Bipyridyl group• Severe local irritant and devastating Systemic
toxin• Manufactured – liquids, aerosols & granules• Ingestion – systemic toxicity and deaths• Inhalation - unlikely to cause systemic toxicity
PARAQUAT POISONING
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Acute Exposure
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Toxic Dose
• Ingestion of <20mg/kg - Moderate GI symptoms
• 20-40mg – Results in death from 5th day to several weeks
• >40mg – Usually die within 1-5days
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Clinical Features
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Inhalation
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Multisystem Failure
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Chest Radiograph
Pneumomediastenum
Pneumothorax Corrosive rupture of oesophagus
Diffuse consolidation – indicating Parenchymal injury
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Upper GI Endoscopy
Erosions Ulcers
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Treatment
• ABC
• Low inspired O2 (prevent superoxide radical formation with the goal of reducing pulmonary injury)
• Early and vigorous decontamination• Multi dose activated Charcoal• Steroids• Antioxidents
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What is new?
• Charcoal Haemoperfusion: Instituted as soon as possible and continue Q6H
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What is new?
Plasma Exchange – aggressive , multiple cycles with in 24 hours is promising in saving life
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Glyphosate
• N-phosphonomethyl glycine
• Phosphorous containing organic compound
• A post emergent Herbicide
• Surfactant toxicity
• Concentrations range from 1-41%Emergency Medicine
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Toxicity of Glyphosate
Emergency Medicine
Enhance ATPase Activity
Uncouples Mitochondrial Oxidative phosphorylation
Toxicity of Surfactant
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Factors contributing Toxicity
• Type & concentration of the surfactant
• Salt partner & other adjuvants
• Severe human poisoning 41% glyphosate isopropylamine & 15% polyoxyethylene amine
Emergency Medicine
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NauseaVomiting Diarrhea
Oesophageal corrosion Gastric ulcer Pulmonary edema
On Ingestion – Local effects
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Reduced organ perfusion Renal impairmentHepatic impairment
Myocardial depression
Hypotension
On Ingestion – Systemic effects
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ECG Changes
Broad complex tachycardiaVentricular arrhythmia
Bradycardia
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CNS Effects
Emergency Medicine
Dilated pupil Confusion
ConvulsionsDeep coma
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Inhalation toxicity is fatal due to rapid systemic absorption
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Renal failure requiring dialysis
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Consider in Resistant Hypotension And Acidosis.
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Respiratory insufficiency requiring intubation
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Recurrent convulsionsLoss of consciousness Cardiac arrest
Severe Toxicity
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Prognostic Factors
Old Age High ConcentrationChest infiltrates
ArrhythmiaShock
DialysisLOC
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Mortality Triad
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Management
Emergency Medicine
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Management
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Aluminium & Zinc Phosphide
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Aluminium Phosphide Celphos , Quick pos ,Phosfume
Greyish - white tablets, 3gm each
Garlicky Odour
Fatal dose: 1-3 tablets
High mortality.
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Aluminium phosphide
Filter paper impregnated
with 0.1N silver nitrate
Patient is asked to breathe
through it for 5 to 10min
Filter paper turns black
Breath test
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Silver nitrate test
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Aluminum Phosphide
• Immediate consumption of oil reduces the release of phosphin gas and reduces the complication.
• Water lavage is contraindicated as it can increase the release of phosphin Gas.
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• IABP, Glucose Insulin Potassium infusions , sodium bicarbonate infusion have been used to treat this poison but the outcome is variable and these are not always helpful.
Aluminum Phosphide
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