The pattern of accidental poisoning in children is changing. There is an increasing incidence of poisoning with common house hold insecticides(1,2). Mosquito (Allethrin) coil, a type of pyrethroid is almost ubiquitous in modern households. We report two brothers brought in unconscious state with alleged history of mosquito coil ingestion.

Two cousin brothers 4 yrs and 3 yrs were brought in department of emergency medicine with history of one episode of generalized tonic-clonic convulsion followed by un-consciousness and violent behaviour. Parents suspected the intake of mosquito coils (they were not sure of quantity of coils ingested). There was no history of pica in the children. At admission both were comatosed (E2V2M4) with normal pupillary size and reaction. Vitals were normal. There were no meningeal signs or focal neurological deficits. Routine hematological studies, serum bilirubin, ALT, AST and blood sugar were within normal limits. Stomach wash revealed clear fluid. The older child had two episodes of generalized convulsions, which were managed with intravenous diazepam. Both children regained consciousness in 36 hours with supportive management. They accepted ingestion of one mosquito coil each. On follow up after two weeks both were neurologically normal.

Pyrethroids are common insecticides. There are only few reports of pyrethroid poisoning from India(2,3). Pyrethroids are of two types. Allethrin, present in mosquito coil is a type I pyrethroid which lacks a cyano group and causes repetitive discharges in nerve fibres (by acting on sodium channels) leading to hyperexcitation as compared to Type II pyrethroids (deltamethrin and fenvalerate) which causes nerve membrane depolarization and block leading to paralysis. Allethrin poisoning thus leads to ataxia, loss of coordination, hyperexcitation and convulsions. Recently calcium channels have been also found to be another primary target for allethrin(4). Pyrethroids are generally considered to be safe insecticides in humans because of their rapid biotransformation by ester hydrolysis and hydroxylation to their inactive acids and alcohol components. The fatal dose for allethrin is not known. In our case ingestion of one mosquito coil was sufficient to lead to symptoms. Most cases of acute pyrethroid poisoning recover within 1-6 days with normal neurological out come on follow up. Deaths have been reported in cases where convulsions increase in duration and frequency and do not stop within 2-3 weeks(5). The fatality with insecticides in India has been reported to be 12.5 - 25%(3). No specific antidote is known either for type I (allethrin) or type II pyrethroids. The treat-ment is entirely supportive and symptomatic. In conclusion, mosquito coil (allethrin) poisoning though rarely reported can be much frequent in occurrence due to its easy accessibility in households.

Pankaj Garg,
Prahlad Garg,
Department of Emergency Medicine,
Ram Raghu Hospital,
Church Road, Agra, India.
Correspondence:
Dr. Pankaj Garg,
D-584, Kamla Nagar,
Agra 282 005 (U.P.), India.
E-mail: [email protected]

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3. Ganga N, Rajarajeshwari G. Poisoning in children. Indian Pediatr 2001; 38: 208.

4. Hildebrand ME, McRoy JE, Snutch TP, Stea A. Mammalian-voltage gated calcium channels are potentially blocked by the pyrethroid insecticide Allethrin. J Pharmacol Expo Ther. (in Press).

5. He F, Wang S, Liu L, Chen S, Zhang Z, Sun J. Clinical Manifestations and diagnosis of acute pyrethroid poisoning. Arch Toxicol 1989; 3: 54- 58.