Organic solvent toxicity

Organic solvents are used in detergents, insecticides, and a number of industrial settings. Most of these substances are highly lipid-soluble and therefore capable of causing CNS disorders and polyneuropathy. Some organic solvents break down into metabolites that are carcinogenic. While the metabolites may be found in urine or blood, the diagnosis is usually established based on clinical features and a history of exposure. Most organic solvents do not have an antidote; therefore, treatment is generally supportive.

For an overview of other types of substance toxicity (e.g., with organophosphates), see the article on poisoning.

Overview of some organic solvents

High lipid solubility

• All organic solvents are highly lipid-soluble (i.e., lipophilic), which can lead to:
  • Degreasing of the skin → eczema
  • Mucosal irritation
  • Permeation of the CNS, with symptoms based on the area affected (e.g, headache)
  • Peripheral neuropathy (e.g., polyneuropathy )

References:^{[1][1][1][1][2]}

• Examples: benzidine, 2-naphthylamine, aniline
• Sources of exposure: occupational sources (dyes, oil refining, rubber production, perfumes, pesticides), pharmaceuticals (e.g., benzocaine), and tobacco smoke
• Effects
  • Carcinogenic → transitional cell carcinoma of the bladder
  • Benzene derivatives (e.g., aniline and benzocaine) → methemoglobinemia

References:^[1][3]

• Sources of exposure: skin contact, ingestion, or inhalation of hexachlorocyclohexane found in insecticides or topical creams for scabies
• Effects
  • CNS: dizziness, vertigo, headache
  • Carcinogenic effects are currently being investigated.

References:[6904;681]

• Sources of exposure: inhalation of or skin/eye contact with polyvinyl chloride, which is found in automotive parts, furniture, packaging materials, pipes, and wire coating
• Effects
  • Neurological changes (e.g., fatigue, dizziness, ataxia, visual disturbances, coma)
  • Eye, mucous membrane, and respiratory tract irritation
  • Chronic exposure: vinyl chloride disease
    • Abdominal pain
      • Liver, esophagus, and stomach injury
      • Splenomegaly
    • Malignant liver tumors (especially hemangiosarcoma)
    • Scleroderma-like skin changes

References:^[1]

Classification and sources of exposure

• Aromatic hydrocarbon : benzene
  • Found in solvents, glues, nail polishes, cigarette smoke, car emissions, paints
  • Benzene derivatives: a hydrocarbon (e.g., xylene, toluene), amine group (e.g., aniline), or a nitro-compound (e.g.,nitrobenzene) attached to a benzene ring
• Aliphatic hydrocarbon
  • Examples: n-hexane; , heptane, methane, ethane, propane, butane, octane
  • Found in gasoline or kerosene (solvents, paraffin wax, lighter fluid, furniture polishes, and lamp oil)
• Halogenated hydrocarbon
  • Examples: methylene chloride, chloroform, carbon tetrachloride, trichloroethylene , tetrachloroethylene
  • From biomass burning or natural production by fungi/bacteria
  • CCl4: formerly widely used in fire extinguishers, refrigerants, dry-cleaning fluids, and propellants
• Terpene hydrocarbon : turpentine in the form of pine/turpentine oil, which is used in the rubber, painting, or welding industries

Effects

• Systemic toxicity
  • Neurotoxicity (e.g., sedation, headache, blurry vision, sensorimotor polyneuropathy; , chronic toxic encephalopathy, coma)
  • Cardiotoxicity (e.g., arrhythmias)
  • Nephrotoxicity (e.g., nephritis, nephrosis, and renal failure)
  • Carbon tetrachloride toxicity: free radical formation → centrilobular fatty change, congestion, and necrosis of the liver
  • Chronic benzene exposure: acute or chronic myeloid leukemia, non-Hodgkin lymphoma
  • Benzene derivatives such as aniline and nitrobenzene: methemoglobin-forming agents → methemoglobinemia
• If aspirated: aspiration pneumonia

Diagnosis and treatment

• Clinical diagnosis
• Treatment is supportive (i.e., monitoring, fluid therapy, supplemental oxygen, intubation if in respiratory failure).
• Gastric lavage may be considered for patients who ingested a large amount of hydrocarbons with significant toxic potential and present within 1 hour of ingestion.

1. Marquardt H, Schäfer SG, McClellan R, Welsch F . Toxicology. Academic Press ; 1999
2. Levine MD. Hydrocarbon Toxicity. In: Miller MA, Hydrocarbon Toxicity. New York, NY: WebMD. http://emedicine.medscape.com/article/821143. Updated: June 6, 2017. Accessed: September 26, 2017.
3. Roberts SM, James RC, Williams PL. Principles of Toxicology: Environmental and Industrial Applications. John Wiley & Sons ; 2014