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Carbon monoxide poisoning, its causes and symptoms in a dead body

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Carbon monoxide poisoning, its causes and symptoms in a dead body

  1. 1. Carbon Monoxide Poisoning NAME – MOHIT CLASS – M.Sc. Forensic science(II) Roll no. - 16151027
  2. 2. CONTENTS  Introduction  Sources of CO  Fatal Dose  Toxicokinetics  Mode of Action  Autopsy Features  Forensic Issues  Sample Stability and Storage  Analysis  References
  3. 3. INTRODUCTION  Carbon monoxide is a compound of carbon and oxygen  Synonyms – Carbonic Oxide, Carbon Oxide, Water gas, Flue gas  Chemistry –  Specific gravity-0.967  Colourless  Odourless  Tasteless  Non-Irritating  Lighter than Air  Extremely Stable  Extremely Flammable
  4. 4. SOURCES of CO  Endogenous  Exogenous  Methylene Chloride
  5. 5. ENDOGENOUS  Results from biochemical reaction (Haeme Degradation, Lipid Peroxidation)  Never reach toxic levels on its own  Normal Individual – 1-5%  Smokers – 5-8%  Levels increase in case of :  Haemolytic Anaemia  Sepsis SOURCES(cont.)
  6. 6. SOURCES(cont.) EXOGENOUS  Incomplete combustion of almost any form of fuel or hydrocarbons hydrocarbons (wood, charcoal, gas, kerosene)  Automobile exhaust  Fires  Tobacco smoke  Heaters  Camp stoves
  7. 7. METHYLENE CHLORIDE  Paint and adhesive remover  Used to decaffeinate coffee or tea  Can be absorbed through skin  Converted to CO in liver after inhalation SOURCES(cont.)
  8. 8. FATAL DOSE  COHb level in blood exceeding 50 to 60 % is potentially lethal  A CO concentration of 5000 ppm in air is lethal to humans after five minutes of exposure
  9. 9. TOXICOKINETICS  The lungs avidly absorb CO which combines with haemoglobin(85%) and myoglobin (15%)  Elimination occurs exclusively through the lungs
  10. 10. MODE OF ACTION  CO binds to haemoglobin with an affinity 200-250 times greater then that of oxygen to form Carboxyhaemoglobin (COHb)  CO interfere with cellular respiration by inactivating mitochondrial cytochrome oxidase
  11. 11. SYMPTOMS  Dull headache  Weakness  Nausea  Vomiting  Confusion  Dizziness  Difficult breathing
  12. 12. AUTOPSY FEATURES (A) Lividity of cherry-red or bright pink colour, as a consequence of COHb formation (B) Smoke in the face, nostrils and mouth is suggestive of CO poisoning
  13. 13. Cont. (D) Smoke soot covering the larynx, trachea and bronchi (C) Cutaneous bullae
  14. 14. FORENSIC ISSUES  Circumstances seem to point irrefutably to carbon monoxide poisoning, but the blood analysis shows low or normal COHb levels.  Due to the time gap between analysis, hospital biochemistry laboratory results and forensic science laboratory results do not agree.
  15. 15. SAMPLE STABILITY AND STORAGE  Freezing the samples and thawing them only at the time of analysis  Anti-coagulated blood should ideally be sealed into vials with a minimum of air space  Stored deep frozen or atleast at 3°C prior to assay  Reducing agent – sodium dithionite
  16. 16. ANALYSIS  SPECTROSCOPIC TEST — The spectrum of the blood will show two absorption bands similar to those of oxyhaemoglobin, but placed nearer the violet end. The addition of ammonium sulphide does not alter the spectrum.  HOPPE-SEYLER’S TEST — Caustic Soda of specific gravity 1.3 if added to :  Normal blood - Greenish colour  Blood with Carbon Monoxide – Bright Red colour
  17. 17. ANALYSIS(cont.)  KUNKEL’S TEST — The blood, diluted with 4 volumes of water, is mixed with 3 times its volume of 1% tannic acid solution and shaken well.  Carbon Monoxide blood forms a Crimson-Red coagulum, which retains its colour for several months.  Normal blood forms a coagulum which is at first red, becomes brown in the course of one to two hours and then becomes Grey in in 24 to 48 hours.  The blood saturated even with 10% Carbon Monoxide responds responds to this test.
  18. 18. ANALYSIS(cont.)  POTASSIUM FERROCYANIDE TEST — 15 c.c. Of blood is mixed with an equal amount of 20% potassium ferrocyanide solution solution and 2 c.c. of dil. acetic acid and shaken gently.  Blood with carbon monoxide - bright red coagulum  Normal blood - dark brown coagulum
  19. 19. INSTRUMENTAL METHODS METHODS PRINCIPLE PROBLEMS Derivative spectroscopy Use of derivative spectrometry to eliminate non-specific interference Strict control over timing of reading essential Fourier transform infrared spectrophotometry Absorbance measurement at characteristic bands Not generally available in clinical laboratories GC-TCD Chemical liberation of carbon carbon monoxide from blood blood and direct or indirect measurement of gas Very precise but complex, more time consuming
  20. 20. cont… AVOXIMETER 4000  Allow faster results(in less than 10 sec) to help legal system in closing cases  Low blood volume required  Portable  Accurate analysis of COHb with refrigerated sample(4°C) for at least 6
  21. 21. REFERENCES  Blyth A W, Blyth M W, Poisons: Their Effects And Detection, 4th Edition, Charles Griffin And Company Ltd., 1906  Dinis-olivery R J, Carvalho F, Magalhaes T, Santos A, Postmortem Changes In Carbon Monoxide Poisoning, Clinical Toxicology 2010; 48 : 762-763  Modi J P, A Textbook Of Medical Jurisprudence And Toxicology, 6th Edition, Butter Worth & Co. (India) Ltd., 1940  Penney D G, Carbon Monoxide Toxicity, 2nd Edition, CRC Press LLC, 2000  Pillay V V, Modern Medical Toxicology, 4th Edition Jaypee Brothers Medical Publishers (P) Ltd, 2013

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