Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.
Paraquat Poisoning
Introduction
 Paraquat is a rapidly acting, non selective
herbicide ; inexpensive
 Dermal /spray exposure(inhalation)-li...
Pharmacology and cellullar
toxocology
 Chemically- bi pyridyl compounds
 Absorption..concentrated inside cells..redox
cy...
Kinetics
 Highly polar and corrosive
 Ingestion ..rapid absorption..rapid distribution
 Max tissue levels..6hrs
 Activ...
Clinical features:
History
 Formulation , strength and dose are important-
>30ml of 20% paraquat can be lethal.
 Kidney ...
Physical examination and basic
monitoring
 Mouth,pharynx- necrosis, inflammation, ulceration-
maybe delayed to upto 12 ho...
Lab evaluation
 General testing:
 Blood tests- on admission, every 6 to 12th hourly for
first 48 hours, then based on cl...
 Serum electrolytes- may be altered due to
vomiting, diarrhea, acute kidney injury and multi
organ dysfunction.
 Renal f...
 Blood gas-
◦ Alkalemia-vomiting, early in the course
◦ Acidemia- respiratory acidosis( alveolitis,
pneumonitis) and meta...
 Chest radiograph- for assessing acute lung injury(
hypoxia/hyperventilation/crackles)-direct effect of
paraquat(bilatera...
 Specific testing:
 Urine paraquat- inexpensive; based on color
change after addition of dithionite soln to urine-
posit...
 Serum paraquat- nomograms –correlate serum
paraquat concentration with mortality risk
 The proudfoot nomogram, best cut...
 Qualitative serum paraquat- in patients with
positive urinary dithionite test
 soln prepared as before.. But added to 2...
Diagnosis
 h/o ingestion/exposure
 Physical examination-oropharyngeal burns etc
 Subsequent development of: AKI, metabo...
Differential diagnosis
 No other pesticide makes such severe oral burns
 Most corrosives do not cause acute systemic
tox...
Management -overview
 Determined on an individual basis based on
amount ingested, time elapsed since exposure
 None of t...
 GI decontamination to limit systemic exposure
 Hemoperfusion followed by
hemodiafiltration/repeated hemoperfusion may b...
Initial resuscitation
 Follows standard guidelines??
 O2 should not be administered unless SpO2 <90%.
 Hydration -2 to ...
 Gastro intestinal decontamination:
◦ If presented within 2 hrs of exposure: Activated
charcoal 1g/kg in water, max dose ...
Specific treatments and
antidotal therapy:
 Indications for extracorporeal therapies:
◦ Hemoperfusion for 4 hrs if initia...
 Antinflammatory and immunosuppressive therapy:
 Cyclophosphamide+glucocorticoid- not validated
by studies
 Antioxidant...
Ongoing management
 Avoid O2 unless hypoxic
 Correct electrolyte abnormalities
 Monitor blood lactate concentrations, r...
 Renal failure resolves in weeks
 Lung injury becomes progressively more severe for
several weeks.
◦ Lung transplant ine...
 Thankyou
Prochain SlideShare
Chargement dans…5
×

Paraquat poisoning

5 899 vues

Publié le

PARAQUAT POISONING

Publié dans : Santé & Médecine
  • New E-book Reveals Unique Holistic Strategies to Cure candida. Discover How To Quickly And Easily Cure yeast infection Permanently...Even If Everything Else You Tried had Failed...Without Drugs, Without Over The Counters, and Without Nasty Side Effects � Guaranteed! ■■■ http://scamcb.com/index7/pdf
       Répondre 
    Voulez-vous vraiment ?  Oui  Non
    Votre message apparaîtra ici
  • The Yeast Infection No More book has literally saved my life. After years of getting no help from the established "medical profession" and getting sicker and afflicted by pain mood swings and depression, I bought your book and in less than5 weeks my chronic muscle aches and joint pain, caused by my candida yeast infection, have disappeared, and I literally tossed away my cane that I have been using for years. I couldn't believe it, it was nothing short of a miracle. I still can't believe it. Now, months later, the depression has also vanished. I no longer cry with no reason and I feel happier and energized. I am sure the protocols in your book have saved untold thousands of people like me from suffering and pain and "given us our lives back." I will never understand why don�t doctors tell us or investigate more on the subject of candidiasis. Two of my friends, one of them a naturopath had recommended that I try your program. And just like that, I was cured and liberated from years of misery. I have recommended your book to numerous people and all have received a great deal of relief. If only I had been told about it sooner, it would have saved me years of pain and exhaustion. I really tried everything. After 2 months on your program, people say that I look10 years younger, and they are right! Thank you very much for everything you have done for me!  http://ishbv.com/index7/pdf
       Répondre 
    Voulez-vous vraiment ?  Oui  Non
    Votre message apparaîtra ici
  • New E-book Reveals Unique Holistic Strategies to Cure candida. Discover How To Quickly And Easily Cure yeast infection Permanently...Even If Everything Else You Tried had Failed...Without Drugs, Without Over The Counters, and Without Nasty Side Effects � Guaranteed! ◆◆◆ http://ishbv.com/index7/pdf
       Répondre 
    Voulez-vous vraiment ?  Oui  Non
    Votre message apparaîtra ici
  • This program is a must read for anyone suffering from Candida or ones like me who has ever taken antibiotics and is now experiencing any of the many problems that go along with intestinal flora imbalance. I must also add that several people in my church have been following this book and are doing great!  https://tinyurl.com/y4uu6uch
       Répondre 
    Voulez-vous vraiment ?  Oui  Non
    Votre message apparaîtra ici
  • Unique Yeast Infection System, How to get lasting Candida freedom, Candida Cure e-book Reveals All ♥♥♥ https://tinyurl.com/y4uu6uch
       Répondre 
    Voulez-vous vraiment ?  Oui  Non
    Votre message apparaîtra ici

Paraquat poisoning

  1. 1. Paraquat Poisoning
  2. 2. Introduction  Paraquat is a rapidly acting, non selective herbicide ; inexpensive  Dermal /spray exposure(inhalation)-limited localised injury  Ingestion-high case fatality rate  Diquat is a related herbicide-similar mechanism, clinical features, treatment  Coformulated with an antiemetic/alginate to reduce absorption
  3. 3. Pharmacology and cellullar toxocology  Chemically- bi pyridyl compounds  Absorption..concentrated inside cells..redox cycling( repetitive enzyme mediated cycling between paraquat and its radicals)  Byproduct- superoxide radical  Redox cycling –consumes NADPH(antioxidant)  Oxidative stress-cellullar damage  Secondary inflammatory response  Multiorgan failure-organs with high blood flow,oxygen tension and energy requirements- lungs/heart/kidneys/liver
  4. 4. Kinetics  Highly polar and corrosive  Ingestion ..rapid absorption..rapid distribution  Max tissue levels..6hrs  Active uptake by cell membrane transporters(eg: spermidine/putrescine)  High conc: in liver, lungs, kidney,muscle  No significant phase 1/phase 2 biotransformation  Elimination –kidneys  Minor-most ingested will appear in urine by 24 hrs  Severe-kidney function impaired..elimination delayed..elimination half life can exceed 100 hrs
  5. 5. Clinical features: History  Formulation , strength and dose are important- >30ml of 20% paraquat can be lethal.  Kidney disease and age>50yrs- bad prognosis  Time of ingestion  Painful mouth, difficulty in swallowing, nausea, vomiting , abdominal pain  Burning skin sensation  Respiratory complaints-systemic poisoning
  6. 6. Physical examination and basic monitoring  Mouth,pharynx- necrosis, inflammation, ulceration- maybe delayed to upto 12 hours, peak severity in some days later  Dehydration(vomiting)  Monitor respiratory rate, pulse oximetry- O2 only if SpO2<90%  Heart rate, BP- progressive refractory hypotension  Chest-dyspnoeic, tachypnoeic, crackles (alveolitis).subcutaneous emphysema- mediastinitis  Abdominal pain, diffuse tenderness  Topical contact- corneal ulceration, non specific dermatitis
  7. 7. Lab evaluation  General testing:  Blood tests- on admission, every 6 to 12th hourly for first 48 hours, then based on clinical severity- vomiting, diarrhea, kidney injury.  If prognosis is poor - palliative measures
  8. 8.  Serum electrolytes- may be altered due to vomiting, diarrhea, acute kidney injury and multi organ dysfunction.  Renal function- ◦ AKI suggests significant poisoning-acute tubular necrosis/volume depletion-increased mortality ◦ Serum creatinine-rate of increase correlates with survival - <0.034mg% per hr over 5 hrs(survival); >0.049mg% per hr over 6hrs(death) ◦ Serum cystatin C- >0.009mg/L per hr over 6 hrs (death)
  9. 9.  Blood gas- ◦ Alkalemia-vomiting, early in the course ◦ Acidemia- respiratory acidosis( alveolitis, pneumonitis) and metabolic acidosis( diarrhea, AKI, mitochondrial toxicity, hypotension)  Respiratory index >1.5(death)  Arterial Lactate- MODS, hypotension, ARDS. Lactate concentration >40mg%-fatal outcome- helps determine prognosis
  10. 10.  Chest radiograph- for assessing acute lung injury( hypoxia/hyperventilation/crackles)-direct effect of paraquat(bilateral) / aspiration( focal-mostly right lung).  early phase(1-2 weeks)-diffuse alveolar infiltrates-ARDS  late phase-reticulointerstitial infiltrates- progressive fibrosis  Toxicology screen- for patients in altered mental status-usually not caused by paraquat- but by acetaminophen exposure etc
  11. 11.  Specific testing:  Urine paraquat- inexpensive; based on color change after addition of dithionite soln to urine- positive within 6 hrs after large ingestion,remains positive for several days.  Positive test-40% mortality. Negative- 100 % survival  Methods : 100mg sod.dithionite to 10ml of 2M sodium hydroxide- 200ul of this to 2ml urine- blue(paraquat), green(diquat)- darker the color, more the concentration
  12. 12.  Serum paraquat- nomograms –correlate serum paraquat concentration with mortality risk  The proudfoot nomogram, best cut off for the Severity in Paraquat Poisoning(Sipp)  Sipp score-paraquat concentration(mg/dl) x time since poisoning(hrs)..score <10 survival is likely.  Challenges –imprecise time of exposure, paraquat assay within a relevant time frame.
  13. 13.  Qualitative serum paraquat- in patients with positive urinary dithionite test  soln prepared as before.. But added to 2ml of plasma instead of urine- equivocal color change- 50% mortality, definitive color change-100 % mortality  Topical exposure-no need of investigations.  If in doubt- urinary dithionite at 6 and 12 hrs for reassurance.
  14. 14. Diagnosis  h/o ingestion/exposure  Physical examination-oropharyngeal burns etc  Subsequent development of: AKI, metabolic acidosis, or ARDS  Lab confirmation-urine dithionite test
  15. 15. Differential diagnosis  No other pesticide makes such severe oral burns  Most corrosives do not cause acute systemic toxicity  Previously was mistaken for HIV related infections- oral candidiasis/Pneumocystis jiroveci pneumonia
  16. 16. Management -overview  Determined on an individual basis based on amount ingested, time elapsed since exposure  None of the current treatments are effective in severe poisoning  Symptoms/signs manifest in 6 to 12 hrs- need monitoring atleast for this duration.  Negative urinary dithionite test at 6 hrs- minimal exposure.
  17. 17.  GI decontamination to limit systemic exposure  Hemoperfusion followed by hemodiafiltration/repeated hemoperfusion may be beneficial if commenced within 4 hrs of exposure  Antedotes- antiflammatory and antioxidant therapies- limited data to support efficacy.  For severe poisoning- better approach may be palliative care.  Titrated fentanyl/morphine.
  18. 18. Initial resuscitation  Follows standard guidelines??  O2 should not be administered unless SpO2 <90%.  Hydration -2 to 3 L of isotonic crystalloids or more  Continuous pulse oximetry  For severe systemic illness- active management may be futile.but decision can be taken based on history/prognostic tests/clinical signs
  19. 19.  Gastro intestinal decontamination: ◦ If presented within 2 hrs of exposure: Activated charcoal 1g/kg in water, max dose 50g ; per oral or via NG tube ◦ Gastric lavage and forced emesis are contraindicated- caustic injury ◦ NG tube aspiration prior to charcoal administration  Topical/inhalational exposure: ◦ Wash with soap and water for 15 mins. ◦ Staff should use universal precautions ◦ Ocular exposure- standard treatment for corrosive exposure??- rinsing for 30 mins then standard protocol??  Monitoring: pulse oximetry.
  20. 20. Specific treatments and antidotal therapy:  Indications for extracorporeal therapies: ◦ Hemoperfusion for 4 hrs if initiated within 4 hrs of ingestion. ◦ Haemodialysis/hemofiltration may be used –paraquat has less protein binding.??; can also be used in AKI as renal replacement therapy. ◦ Rebound in plasma paraquat following hemoperfusion can be minimised with continuous extracorporeal technique.
  21. 21.  Antinflammatory and immunosuppressive therapy:  Cyclophosphamide+glucocorticoid- not validated by studies  Antioxidant therapy-acetylcysteine, sodium salicylate, deferoxamine, vitamin C, vitamin E.
  22. 22. Ongoing management  Avoid O2 unless hypoxic  Correct electrolyte abnormalities  Monitor blood lactate concentrations, renal function  Acute hepatic injury/pancreatitis- do not influence prognosis  The likely outcome is generally apparent within a day or two: ◦ Either critically ill with severe poisoning ◦ Mild to moderate poisoning but adequately compensated without intervention ◦ Asymptomatic
  23. 23.  Renal failure resolves in weeks  Lung injury becomes progressively more severe for several weeks. ◦ Lung transplant ineffective- paraquat injures the allograft  Diquat- may be associated with MODS and rapid death similar to paraquat. ◦ But survivors are most likely to recover and not experience delayed or progressive respiratory failure
  24. 24.  Thankyou

×