Overview

Aims

This module aims to cover the toxicology of the following common or important chemicals:
• Hydrocarbons
• Corrosive chemicals
• Hydrofluoric acid

Objectives

At the end of this module, students should be able to:
• Understand the epidemiology of poisonings by these agents.
• Describe the general management of poisonings by these agents.
• Understand the central nervous system effects common to all hydrocarbons.
• Understand the individual toxicity of the toxic alcohols and how their metabolism affects this.
• Detail specific management required for individual hydrocarbons.
• Describe the local pathological reactions that occur following corrosive poisoning.
• Understand the complications of corrosive poisoning.
• Discuss the appropriate decontamination following corrosive exposure.
• Discuss the role of corticosteroids in the management of corrosive ingestion.
• Understand the toxicology of hydrofluoric acid (HF).
• Be able to evaluate a patient exposed to HF.
• Understand the topical and systemic toxicity of HF
• Understand the options available for treatment of patients exposed to HF.

References

  1. Lee DC. Hydrocarbons. In Marx JA. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th Ed. 2002 Mosby, St Louis, pp 2159-2163.
  2. Lubman DI, Yücel M, Lawrence AJ. Inhalant abuse among adolescents: neurobiological considerations.Br J Pharmacol. 2008 May;154(2):316-26 (fulltext)
  3. Reese E, Kimbrough RD. Acute toxicity of gasoline and some additives. Environ Health Perspect. 1993 Dec;101 (fulltext)
  4. WHO EMRO Pediatric Hydrocarbon Study Group, Cairo, Egypt, Bond GR, Pièche S,Sonicki Z, Gamaluddin H, El Guindi M, Sakr M, El Seddawy A, Abouzaid M, Youssef A. A clinical decision rule for triage of children under 5 years of age with hydrocarbon (kerosene) aspiration in developing countries.Clin Toxicol (Phila). 2008 Mar;46(3):222-9
  5. Patel AL, Shaikh WA, Patel HL, Deshmukh D, Malaviya AP, Janawar P, Londhe V,Dodheja H. Kerosene poisoning--varied systemic manifestations.J Assoc Physicians India. 2004 Jan;52:65-6.(fulltext)
  6. Theis JG, Koren G. Camphorated oil: still endangering the lives of Canadian children.CMAJ. 1995 Jun 1;152(11):1821-4. (fulltext)
  7. Linden CH. Volatile substances of abuse. Emerg Med Clin Nth Amer 1990;8:559-578.
  8. Barceloux DG, Bond GR, Krenzelok EP, et al. American Academy of Clinical Toxicology practice guidelines on the treatment of methanol poisoning. J Toxicol Clin Toxicol. 2002;40(4):415-46. [Medline].
  9. Barceloux DG, Krenzelok EP, Olson K, Watson W. American Academy of Clinical Toxicology Practice Guidelines on the Treatment of Ethylene Glycol Poisoning. J Toxicol Clin Toxicol.1999;37:537-560.
  10. Lynd LD, Richardson KJ, Purssell RA, Abu-Laban RB, Brubacher JR, Lepik KJ,Sivilotti ML. An evaluation of the osmole gap as a screening test for toxic alcohol poisoning.BMC Emerg Med. 2008 Apr 28;8:5. (fulltext)
  11. Brent J, Mc Martin K, Phillips S, Aaron C, Kulif K. Fomepizole for the Treatment of Methanol Poisoning NEJM 2001 Volume 344:424-429 (fulltext)
  12. Mueller-Kronast N, Rabinstein AA, Voung L, Forteza AM. Isopropanol intoxication mimicking basilar artery thrombosis. Neurology. 2003;61:1456-7.
  13. Dowsett RP, Linden CH: Corrosive Poisoning. In Rippe JM, Irwin RS. Intensive Care Medicine. Fifth Edition, Lippincott Williams and Wilkens, Philadelphia, 2003. 1434-1444.
  14. Pelclová D, Navrátil T. Do corticosteroids prevent oesophageal stricture after corrosive ingestion? Toxicol Rev. 2005;24(2):125-9.
  15. Turner A, Robinson P. Respiratory and gastrointestinal complications of caustic ingestion in children.Emerg Med J. 2005 May;22(5):359-61. (fulltext)
  16. Doğan Y, Erkan T, Cokuğraş FC, Kutlu T.Caustic gastroesophageal lesions in childhood: an analysis of 473 cases.Clin Pediatr (Phila). 2006 Jun;45(5):435-8. (fulltext)
  17. Anderson KD, Rouse TM, Randolph JG: A controlled trial of corticosteroids in children with corrosive injury of the esophagus. N Engl J Med 1990;323:637-640.
  18. Graudins A, Burns MJ, Aaron CK. Regional intravenous infusion of calcium gluconate for hydrofluoric acid burns of the upper extremity. Ann Emerg Med. 1997;30:604-7.
  19. Ryan JM, McCarthy GM, Plunkett PK. Regional intravenous calcium--an effective method of treating hydrofluoric acid burns to limb peripheries.J Accid Emerg Med. 1997 Nov;14(6):401-2. (fulltext)
  20. McCulley JP. Ocular hydrofluoric acid burns: animal model, mechanism of injury and therapy. Trans Am Ophthalmol Soc. 1990;88:649-84. (fulltext)
  21. Dale RH.Treatment of hydrofluoric acid burns.Br Med J. 1951 Apr 7;1(4709):728-32 (fulltext) Historical

Resources

WikiTox Ethylene Glycol
WikiTox Methanol
WikiTox Hydrogen Fluoride


Hydrocarbons

Hydrocarbons are a diverse group of organic chemicals that have general sedating effects, like ethanol. Hence there is a risk they may be abused. Occasionally they may be ingested in attempted self-harm.
Of particular concern are hydrocarbons that have systemic toxicity.
The toxic alcohols include methanol and ethylene glycol and, to a lesser extent, ethanol and isopropanol. In addition to their CNS effects, they are metabolised into toxic compounds and, in the case of methanol and ethylene glycol, can be lethal in small amounts.
Other hydrocarbons with inherent systemic toxicity can be remembered by the acronym CHAMP:
• Camphor
• Halogenated hydrocarbons
• Aromatic hydrocarbons
• Metal additives to hydrocarbons
• Pesticides dissolved in a hydrocarbon solvent, eg most organophosphates

Objectives

1. Understand the central nervous system effects common to all hydrocarbons.
2. Understand the individual toxicity of the toxic alcohols and how their metabolism affects this.
3. Understand the general management of patients poisoned by hydrocarbons.
4. Detail specific management required for individual hydrocarbons.

Reading


  1. Lee DC. Hydrocarbons. In Marx JA. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th Ed. 2002 Mosby, St Louis, pp 2159-2163.
  2. Lubman DI, Yücel M, Lawrence AJ. Inhalant abuse among adolescents: neurobiological considerations.Br J Pharmacol. 2008 May;154(2):316-26 (fulltext)
  3. Reese E, Kimbrough RD. Acute toxicity of gasoline and some additives. Environ Health Perspect. 1993 Dec;101 (fulltext)
  4. WHO EMRO Pediatric Hydrocarbon Study Group, Cairo, Egypt, Bond GR, Pièche S,Sonicki Z, Gamaluddin H, El Guindi M, Sakr M, El Seddawy A, Abouzaid M, Youssef A. A clinical decision rule for triage of children under 5 years of age with hydrocarbon (kerosene) aspiration in developing countries.Clin Toxicol (Phila). 2008 Mar;46(3):222-9
  5. Patel AL, Shaikh WA, Patel HL, Deshmukh D, Malaviya AP, Janawar P, Londhe V,Dodheja H. Kerosene poisoning--varied systemic manifestations.J Assoc Physicians India. 2004 Jan;52:65-6.(fulltext)
  6. Theis JG, Koren G. Camphorated oil: still endangering the lives of Canadian children.CMAJ. 1995 Jun 1;152(11):1821-4. (fulltext)
  7. Linden CH. Volatile substances of abuse. Emerg Med Clin Nth Amer 1990;8:559-578.


Alcohols


Reading

  1. Barceloux DG, Bond GR, Krenzelok EP, et al. American Academy of Clinical Toxicology practice guidelines on the treatment of methanol poisoning. J Toxicol Clin Toxicol. 2002;40(4):415-46. [Medline].
  2. Barceloux DG, Krenzelok EP, Olson K, Watson W. American Academy of Clinical Toxicology Practice Guidelines on the Treatment of Ethylene Glycol Poisoning. J Toxicol Clin Toxicol.1999;37:537-560.
  3. Lynd LD, Richardson KJ, Purssell RA, Abu-Laban RB, Brubacher JR, Lepik KJ,Sivilotti ML. An evaluation of the osmole gap as a screening test for toxic alcohol poisoning.BMC Emerg Med. 2008 Apr 28;8:5. (fulltext)
  4. Brent J, Mc Martin K, Phillips S, Aaron C, Kulif K. Fomepizole for the Treatment of Methanol Poisoning NEJM 2001 Volume 344:424-429 (fulltext)
  5. Mueller-Kronast N, Rabinstein AA, Voung L, Forteza AM. Isopropanol intoxication mimicking basilar artery thrombosis. Neurology. 2003;61:1456-7.
  6. WikiTox Ethylene Glycol
  7. WikiTox Methanol

Problem



Corrosive Poisoning

Chemicals capable of causing corrosive injury to tissues constitute a very large group of poisons. Most cause injury by acid-base reactions but damage can also result from hydrocarbon dissolution, re-dox reactions, denaturation, and alkylation reactions.
Small volumes of acids and bases with extremes of pH (<2 or >12) and large amounts of weak acids and bases can produce significant damage to tissues.
Systemic toxicity following corrosive injury is usually secondary to inflammation, acidosis, infection, and necrosis. Chemicals such as phenol, hydrazine, arsenic and other heavy metals, cyanide, acetic acid, formic acid, fluoride, hydrazine, hydrochloric acid, nitrates, sulfuric acid, phosphoric acid and chromic acid can be absorbed after dermal exposure or ingestion and cause systemic toxicity directly.
Organs particularly at risk from corrosive injury include the gastrointestinal tract, the eyes and lungs.
Management of corrosive injury is primarily directed to prompt and thorough decontamination. Evaluation of burns to the gastrointestinal tract may require upper gastro-intestinal endoscopy. Following a significant corrosive exposure local and systemic complications need to be considered.

Objectives

1. Understand the epidemiology of corrosive poisoning.
2. Describe the local pathological reactions that occur.
3. Understand the complications of corrosive poisoning.
4. Discuss the appropriate decontamination following corrosive exposure.
5. Describe the general management of corrosive poisoning.
6. Discuss the role of corticosteroids in the management of corrosive ingestion.

Reading


  1. Dowsett RP, Linden CH: Corrosive Poisoning. In Rippe JM, Irwin RS. Intensive Care Medicine. Fifth Edition, Lippincott Williams and Wilkens, Philadelphia, 2003. 1434-1444.
  2. Pelclová D, Navrátil T. Do corticosteroids prevent oesophageal stricture after corrosive ingestion? Toxicol Rev. 2005;24(2):125-9.
  3. Turner A, Robinson P. Respiratory and gastrointestinal complications of caustic ingestion in children.Emerg Med J. 2005 May;22(5):359-61. (fulltext)
  4. Doğan Y, Erkan T, Cokuğraş FC, Kutlu T.Caustic gastroesophageal lesions in childhood: an analysis of 473 cases.Clin Pediatr (Phila). 2006 Jun;45(5):435-8. (fulltext)
  5. Anderson KD, Rouse TM, Randolph JG: A controlled trial of corticosteroids in children with corrosive injury of the esophagus. N Engl J Med 1990;323:637-640.

Problem



Hydrofluoric Acid

Hydrofluoric acid (HF) is a relatively weak acid with minimal corrosive effects at low concentrations. Tissue damage is primarily related to dissociation of the acid in tissues and combination of free fluoride ions with intracellular divalent cations (calcium and magnesium) resulting in cell death.
It is commonly used in various forms of industry for glass etching, computer silicone chip production, metallurgy and as a cleaning fluid additive. In low concentrations (<10%), it may be bought at hardware stores for domestic use as a tile or car wheel cleaner.
Most exposures to HF are topical. Patients will commonly present following two distinct types of exposures. First, those who have been exposed to low concentrations of HF found in domestic products. Second, patients who have been exposed to higher concentrations of HF following workplace exposures. Uncommonly, patients may present following the ingestion of HF for the purposes of deliberate self-harm.

Objectives

1. Understand the toxicology of hydrofluoric acid (HF).
2. Be able to evaluate a patient exposed to HF.
3. Understand the topical and systemic toxicity of HF.
4. Understand the options available for treatment of patients exposed to HF.

Reading

  1. WikiTox Hydrogen Fluoride
  2. Graudins A, Burns MJ, Aaron CK. Regional intravenous infusion of calcium gluconate for hydrofluoric acid burns of the upper extremity. Ann Emerg Med. 1997;30:604-7.
  3. Ryan JM, McCarthy GM, Plunkett PK. Regional intravenous calcium--an effective method of treating hydrofluoric acid burns to limb peripheries.J Accid Emerg Med. 1997 Nov;14(6):401-2. (fulltext)
  4. McCulley JP. Ocular hydrofluoric acid burns: animal model, mechanism of injury and therapy. Trans Am Ophthalmol Soc. 1990;88:649-84. (fulltext)
  5. Dale RH.Treatment of hydrofluoric acid burns.Br Med J. 1951 Apr 7;1(4709):728-32 (fulltext) Historical



Problem