How Should Patients Exposed to Carbon Tetrachloride Be Treated and Managed?

• Describe treatment strategies for patients with carbon tetrachloride (CCl₄) poisoning.

Treatment for acute or chronic CCl₄ poisoning is primarily symptomatic and supportive.

Because liquid CCl₄ can be absorbed through the skin, remove clothing from persons exposed through this route and clean the skin with copious amounts of soap (or mild detergent) and water. If liquid CCl₄  is splashed in the eyes, irrigate the eyes for at least 15 minutes.

For patients who have ingested CCl₄, the practical value of gastric lavage and administration of activated charcoal is doubtful as absorption from a gastro-intestinal exposure is likely to be nearly complete by the time the patient reaches appropriate medical care. Patients with significant exposure might be clinically unstable and gastric lavage and/or activated charcoal might place the patient at increased risk for complications such as aspiration and chemical pneumonitis.

Induced emesis is contraindicated because of the risk for pulmonary aspiration.

Human case reports from Europe, where antioxidants such as

• Methionine,
• Cysteine, and
• N-acetylcysteine (NAC, Mucomyst, or Acetadote)

were used, suggest that when these free-radical scavengers are given intravenously within 12 to 16 hours after a high-dose acute CCl₄ exposure, they might prevent or decrease hepatic and renal damage [De Ferreyra et al. 1974; De Ferreyra et al. 1977; Prescott et al. 1977; Kearney 2007].

Elevated oxygen concentrations in vitro and in vivo reduce lipid peroxidation and hepatotoxicity. Hyperbaric oxygen (HBO) has been found to play a therapeutic role in human and animal CCl₄ poisoning [Larcan et al. 1973; Truss et al. 1982; Burk et al. 1986; Burkhart et al. 1991]. HBO appears to inhibit the mixed function oxidase system responsible for conversion of CCl₄ to hepatotoxic free radicals. Because there are no proven antidotes for CCl₄  poisoning, HBO may be considered for potentially severe CCl₄  exposures. However, there might be a delicate balance between oxidative processes that are therapeutic and those that mediate hepatotoxicity. Therefore, when HBO is being considered, it should be instituted before the onset of liver function abnormalities [Thom 2006].

Hemodialysis has been used to treat renal failure, but it has not been proven successful in reversing CCl₄ pathology [Meredith 1989; Ruprah 1985].

Patients should be observed for onset of hepatic and renal effects for up to 2 weeks after exposure. To a large extent, survival depends on the patient’s nutritional status and the underlying condition of the hepatorenal system.

Other than removal from the source of exposure and avoidance of other hepatotoxins, there is no specific treatment for patients chronically exposed to CCl₄. The exposure dose along with individual risk factors will contribute to the likelihood of lasting adverse health effects from CCl₄ exposure.

Exposed patients should be instructed to avoid

• Stimulants,
• Ethanol,
• CCl₄ and
• Other hepatotoxicants.

Administration of the hepatitis B vaccine should be considered for unvaccinated persons.

Patients with complaints of persistent mood alteration or cognitive dysfunction, including memory loss, should be referred to a clinical neuropsychologist for evaluation. Those with persistent neurologic complaints, such as

• Numbness,
• Tingling,
• Weakness, or
• Pain,

should be referred for neurologic consultation or electrophysiologic evaluation of peripheral nerve function.

Evaluation of an exposed worker provides an opportunity to reduce exposures and prevent additional health effects for the patient and his or her coworkers. When the results of a clinical evaluation suggest that significant exposure is occurring, the clinician should explore with the worker and the employer avenues of exposure reduction and prevention.

Clinical consultation and referral information can be found in the “Sources of Additional Information” section. This publicly available information pertains to credentialed clinicians with expertise and experience treating patients exposed to hazardous substances including carbon tetrachloride.

• N-acetylcysteine might reduce complications in patients with severe CCl₄ exposure.
• Hyperbaric oxygen treatment has been used as a therapeutic intervention for acute CCl₄ poisoning.
• Other than removal from the source of exposure and avoidance of other hepatotoxins, there is no specific treatment for patients chronically exposed to CCl₄.
• The exposure dose, along with individual risk factors, will contribute to the likelihood of lasting adverse health effects from CCl₄  exposure.