Camphor--a lesser-known killer.

In this issue of the Southern Medical Journal, Ragucci et al (1) describe camphor poisoning in a 10-year-old male who presented to the emergency department. For centuries, camphor has been used as an antiseptic, antipruritic, rubefacient, abortifacient, contraceptive, lactation suppressant and aphrodisiac. (2) The strong aroma associated with camphor has attracted its use in many oils, inhalants and ointments, especially as a remedy for the common cold. It is a component of many preparations available over the counter and has a potential for accidental ingestion by children and infants. The United States Food and Drug Administration in 1983 restricted the use and availability of products containing camphor in a concentration over 11%. (2) However, in most countries, oils and medicaments containing as high as 20% camphor are easily available. In the Indian subcontinent, camphor is an ingredient for many oils and in its solidified form is commonly used in almost all religious events and prayers. In developing countries, compounds do not mention the concentration of camphor as an ingredient. Despite common household usage, camphor poisoning remains a rarely encountered problem in the emergency departments of public hospitals in developing countries, probably because of subclinical effects encountered after ingestion in most patients.

Even in the United States, the knowledge of toxicity of camphor-containing compounds sold over the counter among the general population remains poor. Huott et al found that only 22% of the adolescents surveyed possessed knowledge of the lethal potential of over-the-counter products containing camphor. (3) In a review of the National Poison Center data from 1990 through 2003 in the United States, Manoguerra et al recorded approximately 10,000 annual ingestion exposures to camphor-containing products. (4)

Camphor has been labeled as one of the most toxic poisons for toddlers and children in whom ingestion in small doses might prove fatal. (5) Poisoning presents infrequently in the emergency department as a toxic ingestion. Symptoms appear rapidly after ingestion and seizures have been reported after the ingestion of camphor in 6% of cases. Patients usually present with severe nausea, vomiting, lethargy, ataxia and convulsions. Even dermal application of remedies containing camphor have been reported to cause severe hepatotoxicity. (6) Geller et al, in a study of 80 patients, reported the incidence of seizures and major symptoms at 6%, with no mortality. However, on a literature review of 63 cases, the authors found as many as 6 deaths. They described a mean fatal dose of 199 mg/kg (range 64-570, median 113). (7)

Every exposure does not need a healthcare referral since most effects are benign and self-limited. Decisions regarding patient disposition should take into account the patient's intent, symptoms, and social environment. In addition, individual patient circumstances (eg, pregnancy and comorbidity) need to be considered. Exposures may be dermal, inhalation, ingestion or ocular. It is essential to consider substance composition, whether single or multi-ingredient. (8)

A guideline has been suggested for treatment of camphor poisoning by Manoguerra et al. (4) Patients with suspected self-harm, recipients of malicious administration or those who have accidentally ingested more than 30 mg/kg of a camphor-containing product, and exhibit symptoms of toxicity (eg, convulsions, lethargy, ataxia, severe nausea and vomiting) by any route of exposure should be referred to an emergency department for observation and treatment. A benzodiazepine should be used to control convulsions. Induction of emesis or administration of charcoal should not be attempted. However, charcoal could be considered if there are other ingredients in the product that are effectively adsorbed by activated charcoal or if other substances have been coingested.

Camphor poisoning is seen in emergency rooms across the globe in varying frequency. It can be managed effectively with low mortality rates if the physician maintains a high index of suspicion, is aware of its occurrence and is prepared to confidently diagnose and sensitively treat the cases that present.

References

1. Ragucci KR, Trangmar PR, Bigby JG, et al. Camphor ingestion in 10-year-old male. South Med J 2007;100:204-207.

2. Theis JG, Koren G. Camphorated oil: still endangering the lives of Canadian children. CMAJ 1995;152:1821-1824.

3. Huott MA, Storrow AB. A survey of adolescents' knowledge regarding toxicity of over-the-counter medications. Acad Emerg Med 1997;4:214-218.

4. Manoguerra AS, Erdman AR, Wax PM, et al. Camphor Poisoning: an evidence-based practice guideline for out-of-hospital management. Clin Toxicol (Phila) 2006;44:357-370.

5. Matteucci MJ. One pill can kill: assessing the potential for fatal poisonings in children. Pediatr Ann 2005;34:964-968.

6. Uc A, Bishop WP, Sanders K.D. Camphor hepatotoxicity. South Med J 2000;93:596-598.

7. Geller RJ, Spyker DA, Garrettson LK, et al. Camphor toxicity: development of a triage strategy. Vet Hum Toxicol 1984;26 (Suppl 2):8-10.

8. McGuigan MA. Guideline for the out-of-hospital management of human exposures to minimally toxic substances. J Toxicol Clin Toxicol 2003;41:907-917.

Ashish Goel, MD, and Praveen Aggarwal, MD

From the Division of Emergency Medicine, Department of Medicine, All India Institute of Medical Sciences, New Delhi, India.

Reprint requests to Dr. Ashish Goel, C2/403, Janak Puri, New Delhi, India. Email: [e-mail]

Accepted August 24, 2006.