Michael Eddleston

Self-poisoning with pesticides is the cause of an estimated 300,000 deaths annually in rural Asia. The great majority of these deaths are from impulsive acts of self-harm using pesticides that are readily available in the home. The secure storage of pesticides under lock has been emphasized as a possible answer to the problem. This aspect, however, has been poorly researched. In this paper, we report on the design and use, in rural Sri Lanka, of a variety of different lockable storage devices.

Although activated charcoal is widely used for the treatment of self-poisoning, its effectiveness is unknown. An important consideration is patient compliance since poor compliance will limit effectiveness. We aimed to describe compliance in a randomized controlled trial (RCT) performed in Sri Lanka, presuming that this would set the upper limits for compliance in routine clinical use. 1,103 patients randomized to single or multiple (six doses q4h) 50 g doses of superactivated charcoal were prospectively observed. Charcoal was given by study doctors who recorded the amount ingested and the amount of persuasion required for the patients to drink the charcoal. 559 patients were randomized to receive one dose and 544 to receive six doses. Data was available for 1,071 (97%) patients. Eighty-eight were unable to complete their course; 98 required a NG tube, leaving 885 patients that received the first dose by mouth. The mean estimated amount of the prescribed dose of charcoal taken orally as a single or first dose was 83% (95% C.I. 82-84%). For patients receiving multiple doses, this amount fell over the next five doses to 66% (63-69%). While only 3.2% of patients refused the first dose, 12.3% refused the sixth. Relatively less persuasion was required for patients ingesting the first or single dose; 38% of patients required intense persuasion by the sixth dose. Compliance for a single dose of superactivated charcoal among trial patients was good. However, even in the ideal circumstances of a RCT, compliance decreased thereafter for patients taking more than one dose.

In this issue of International Journal of Epidemiology, Gajalakshmi and Peto publish their results from a community study of deaths from injury in a rural district of Tamil Nadu, south India. The results reported are just one component of a large verbal autopsy study in which families were interviewed about the cause of death of 38 836 people. The study adds greatly to our knowledge of the epidemiology of injury in rural South Asia.

Summary: Although the high rate of suicide in elderly people is conventionally explained as being due to greater intent to die, we have noted elderly Sri Lankans dying after relatively mild poisoning. Using data from cases of yellow oleander poisoning, we investigated the effect of age on outcome in 1697 patients, controlling for gender and amount ingested. In fully adjusted models, people over 64 years old were 13.8 (95% CI 3.6–53.0) times more likely to die than those less than 25 years old. The high number of suicides in elderly people globally is likely to be due, in part, to the difficulty they face in surviving the effects of both the poisoning and its treatment.

Background: Acute organophosphorus (OP) pesticide poisoning is a major clinical problem in the developing world. Textbooks ascribe most deaths to respiratory failure occurring in one of two distinct clinical syndromes: acute cholinergic respiratory failure or the intermediate syndrome. Delayed failure appears to be due to respiratory muscle weakness, but its pathophysiology is unclear. Aim: To describe the clinical patterns of OP-induced respiratory failure, and to determine whether the two syndromes are clinically distinct. Design: Prospective study of 376 patients with confirmed OP poisoning. Methods: Patients were observed throughout their admission to three Sri Lankan hospitals. Exposure was confirmed by butyrylcholinesterase and blood OP assays. Results: Ninety of 376 patients (24%) required intubation: 52 (58%) within 2 h of admission while unconscious with cholinergic features. Twenty-nine (32%) were well on admission but then required intubation after 24 h while conscious and without cholinergic features. These two syndromes were not clinically distinct and had much overlap. In particular, some patients who required intubation on arrival subsequently recovered consciousness but could not be extubated, requiring ventilation for up to 6 days. Discussion: Respiratory failure did not occur as two discrete clinical syndromes within distinct time frames. Instead, the pattern of failure was variable and overlapped in some patients. There seemed to be two underlying mechanisms (an early acute mixed central and peripheral respiratory failure, and a late peripheral respiratory failure) rather than two distinct clinical syndromes.

Most data on self-poisoning in rural Asia have come from secondary hospitals. We aimed to: assess how transfers from primary to secondary hospitals affected estimates of case-fatality ratio (CFR); determine whether there was referral bias according to gender or poison; and estimate the annual incidence of all self-poisoning, and of fatal self-poisoning, in a rural developing-world setting. Self-poisoning patients admitted to Anuradhapura General Hospital, Sri Lanka, were reviewed on admission from 1 July to 31 December 2002. We audited medical notes of self-poisoning patients admitted to 17 of the 34 surrounding peripheral hospitals for the same period. A total of 742 patients were admitted with self-poisoning to the secondary hospital; 81 died (CFR 10.9%). 483 patients were admitted to 17 surrounding peripheral hospitals. Six patients (1.2%) died in peripheral hospitals, 249 were discharged home, and 228 were transferred to the secondary hospital. There was no effect of gender or age on likelihood of transfer; however, patients who had ingested oleander or paraquat were more likely to be transferred than were patients who had taken organophosphorus pesticides or other poisons. Estimated annual incidences of self-poisoning and fatal self-poisoning were 363 and 27 per 100,000 population, respectively, with an overall CFR of 7.4% (95% confidence interval 6.0-9.0). Fifty per cent of patients admitted to peripheral hospitals were discharged home, showing that CFRs based on secondary hospital data are inflated. However, while incidence of self-poisoning is similar to that in England, fatal self-poisoning is three times more common in Sri Lanka than fatal self-harm by all methods in England. Population based data are essential for making international comparisons of case fatality and incidence, and for assessing public health interventions.

We read with interest G. Miller's article describing a discrepancy between Chinese rates of suicide and depression (“China: healing the metaphorical heart,” News Focus, 27 Jan., p. [462][1]). However, we feel that Miller, by concentrating on fatal self-harm rather than all acts of self-harm, misses an opportunity to understand the discrepancy he notes. High rates of suicide and low rates of depression are not restricted to China. Many countries of the Asian “suicide belt” have suicide rates higher than those of China ([1][2], [2][3]). Suicide rates result from the incidence of self-harm and the resulting fatality rate among those individuals. Our research in Sri Lanka indicates that high rates of suicide from self-poisoning are due to a high fatality rate rather than a high incidence of self-harm itself ([3][4]). A useful contrast can be made with the UK. Self-poisoning in the UK is very common, with an annual incidence of presentation to hospital of around 300 per 100,000. However, self-poisoning is rarely lethal, with a fatality rate per 1000 incidents normally less than 0.5% ([4][5]). Self-poisoning is also common in Sri Lanka, with an estimated incidence of around 363 per 100,000 in one rural district. However, the fatality rate is significantly higher at ∼7.4%—at least 15 times higher than in the UK ([3][4]). The reason for this higher fatality rate in Sri Lanka, as in China, is the common use of highly toxic poisons such as pesticides. Sri Lankan self-poisoners are not more keen to die—they simply have easier access to pesticides than do the residents of the UK ([5][6]). The high suicide rate in Sri Lanka and China is not due to higher levels of mental illness or rates of self-harm, but to a higher lethality of self-harm acts. Concentrating solely on rates of mental illness in Asia will not explain the high rate of suicide in this region. 1. 1.[↵][7] 1. P. Brown , New Sci., 22 Mar. 1997, p. 34. 2. 2.[↵][8] 1. A. Joseph 2. et al. , Br. Med. J. (2003) 326, 1121. 3. 3.[↵][9] 1. M. Eddleston 2. et al. , Bull. World Health Org., in press. 4. 4.[↵][10] 1. D. Gunnell, 2. D. D. Ho, 3. V. Murray , Emergency Med. J. (2004) 21, 35. 5. 5.[↵][11] 1. M. Eddleston 2. et al. , Clin. Toxicol., in press. [1]: /lookup/doi/10.1126/science.311.5760.462 [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: #ref-4 [6]: #ref-5 [7]: #xref-ref-1-1 "View reference 1. in text" [8]: #xref-ref-2-1 "View reference 2. in text" [9]: #xref-ref-3-1 "View reference 3. in text" [10]: #xref-ref-4-1 "View reference 4. in text" [11]: #xref-ref-5-1 "View reference 5. in text"

Background. Although intentional self-poisoning is a major public health problem in rural parts of the Asia-Pacific region, relatively little is known of its epidemiology. We aimed to determine why Sri Lankan self-poisoning patients choose particular poisons, and whether acts of self-harm with highly dangerous poisons were associated with more premeditation and effort. Methods. We interviewed 268 self-poisoning patients presenting to two district general hospitals in rural Sri Lanka. Results. Eighty-five percent of patients cited easy availability as the basis for their choice of poison. There was little premeditation: more than 50% ingested the poison less than 30 minutes after deciding to self-harm. Patients had little knowledge about treatment options or lethality of the poison chosen. We found no difference in reasons for choice of poison between people ingesting different poisons, despite marked differences in toxicity, and between people who died and those who survived. Conclusions. Poisons were chosen on the basis of availability, often at short notice. There was no evidence that people using highly toxic poisons made a more serious or premeditated attempt. Restrictions on availability of highly toxic poisons in rural communities must be considered in strategies to reduce the number of intentional self-poisoning deaths in the Asia Pacific region.

Summary: We investigated the epidemiology of intentional self-poisoning in rural Sri Lanka by prospectively recording 2189 admissions to two secondary hospitals. Many patients were young (median age 25 years), male (57%) and used pesticides (49%). Of the 198 who died, 156 were men (case fatality 12.4%) and 42 were women (4.5%). Over half of female deaths were in those under 25 years old; male deaths were spread more evenly across age groups. Oleander and paraquat caused 74% of deaths in people under 25 years old; thereafter organophosphorous pesticides caused many deaths. Although the age pattern of self-poisoning was similar to that of industrialised countries, case fatality was more than 15 times higher and the pattern of fatal self-poisoning different.