Abstract
A retrospective analysis of 584 cases of acute poisoning admitted with a medical emergency to the Department of Medicine, GTB Hospital, Delhi, over a three-year period. The patients were analysed with respect to the age, sex, mode of poisoning, type of poison consumed and mortality. Of these, 42.63% were aged 20–30 years. Poisoning was used as a suicidal agent by 63.8% of the patients. The nature of the poison could not be ascertained in 15.92% of patients. Sedatives were involved in 13.36%. Aluminium phosphide poisoning was found in 11.82%. The overall mortality was estimated to be 13.18% with 53.2% being caused by the consumption of aluminium phosphide. There has been a change in the nature of poisons consumed and the number of cases of aluminium phosphide poisoning is declining. However, aluminium phosphide poisoning still remains a major threat as it carries a high mortality rate.
Introduction
Acute poisoning and intoxication is a challenging problem and carries high mortality rates. During the last few decades, there has been rapid growth in the number and variety of industrial compounds, pesticides and new drugs. The poisons used vary between different parts of the world and also within a country depending on cultural and socioeconomic factors. Acute poisoning may be used in suicide attempts, taken accidentally or in attempted homicides. In some developing countries, it is the second most common cause of death after infectious diseases. 1 Earlier studies from North India revealed that substances such as barbiturates, organophosphorus compounds and copper sulphate were the most common causes of acute poisoning. 2 However, during the last two decades aluminium phosphide, a grain preservative has emerged as a common cause of self-poisoning. 3,4 The present analysis was undertaken in order to gain insight into the current trends of poisoning in and around Delhi.
Materials and methods
A total of 584 cases were identified as having been admitted with a diagnosis of acute poisoning or intoxication to the medicine emergency of Guru Teg Bahadur Hospital, Delhi, over a three-year period. These constituted 8.3% of the 7074 patients admitted to our unit during the same period. Notes were made on whether the poisoning was suicidal, accidental or homicidal in nature. We also recorded the number of poisonous agents taken, the type of poison, the age and sex of the patient, the final outcome and the immediate precipitating events or reasons for the patients consuming the poisons. The diagnosis of the nature of poison consumed was based on the history given by the patients or their attendants, the suggestive clinical picture and the presence of wrappers or containers of the poisonous agent. We did not include cases due to snake bite and envenomation.
Results
Demographic data
Figure 1 shows the age distribution of patients admitted with a diagnosis of acute poisoning. Patients aged 14 to 30 years constituted about 73.5% of all cases. The total number of males was 418 compared to 166 females with the overall male to female ratio being 2.5:1. The average age of males was 27.5 years and that of females was 26.3 years.
Distribution of the mode of poisoning according to age groups
Mode of poisoning
Poisoning was used in a suicide attempt by 373 (63.9%) patients but was used accidentally by 211 (35.1%). As shown in Table 1, self-poisoning was much more common among the younger age group and accidental poisoning was more common among the adults. The ratio of suicidal to accidental poisoning was 2.6:1 in the <30 years age group compared to 2:3 in the >30 years age group. The overall mortality was 13.2%.
Distribution of suicidal and accidental cases according to age groups
Nature of poisons
We could not ascertain the poison used by 15.9% of patients. Sedatives were used in 13.4% and organophosphorus agents accounted for 12.0%. Aluminium phosphide was found in 11.8%, alcohol and stupefying agents in 11.8% and 10.3%, respectively, and rat poison (zinc phosphide) in 7.9%. The contribution of the other poisons is shown in Table 2. In patients aged <20 years organophosphates were found to be the most commonly consumed poison (18.9%), whereas in patients aged between 20 and 30 years aluminium phosphide was the most commonly consumed poison (15.3%). Alcohol intoxication was most commonly seen in the >30 years age group. Aluminium phosphide as the agent of poisoning was rarely used by those over 30 years of age and alcohol was rarely used by those under 30 years.
Distribution of type of poison consumed according to age group (30 cases were due to poisoning with multiple agents)
*Figures in parentheses indicate percentage of cases
Poisoning with multiple agents
Poisoning with multiple agents was seen in 30 (4.8%) patients. Of these, 22 (75%) had consumed alcohol, eight (25%) had consumed sedatives and five (16.6%) died.
Deaths
The overall death rate was 13.2% (n = 77). Of these, 53.2% (n = 41) were caused by the consumption of aluminium phosphide. Other agents that caused death were: organophosphates, nine (11.6%); unknown agents, eight (10.3%); aniline dyes, five (6.5%); multiple agents, five (6.5%); acid ingestion, three (3.9%); copper sulphate, two (2.6%); phenyl, two (2.6%); herbal agents, one (1.3%); and alcohol, one (1.3%).
Precipitating events
Academic failure and discord within the family or with loved ones were the most commonly cited reasons for suicidal poisoning in the younger age group. Economic hardships and marital discord were important precipitating causes in the middle aged and endogenous depression or the loss of a spouse in the majority of the elderly.
Discussion
Acute poisoning is an important medical emergency which carries a high mortality rate. Reports from different parts of the world have incriminated various substances that cause acute poisoning. In the West, drugs (sedatives and analgesics) have been reported to be the most common substances of abuse, with mortality rates between 0.4% and 2.0%. 5–8 This is in contrast to reports from developing countries such as India, Pakistan and Uganda where pesticides are more commonly used as agents for self-poisoning. 9–12
Recently, there has been an increase in the incidence of acute poisoning in northern India. Singh et al. reported a steep increase in the incidence of acute poisoning since 1987. 13 They observed an increase in the incidence of poisoning among urban dwellers. In an observation made by Singh et al., 312 patients suffering from poisoning were admitted over a period of 10 years. 2 We admitted 584 cases of poisoning to our medical unit over a period of 39 months, which includes total number of medical emergency admissions due to poisoning. A part of this increase may be attributed to the greater availability of pesticides and medicines and the increase in stress due to modernization.
Data for acute poisoning from our country is scanty. However, it appears from the available literature that there has been a change in the pattern of acute poisoning over the last few decades. Chuttani et al. reported copper sulphate as the most common poison consumed in the 1960s in Delhi. 14 In Chandigarh, Singh et al. reported that barbiturates were the most common agents responsible for acute poisoning followed by organophosphates. 2 This trend seems to have changed since the 1990s, when there were several reports of aluminium phosphide (a grain preservative) being the most commonly consumed poison. 4,2 In an epidemiological survey from Haryana, Siwach et al. observed that 67% cases had ingested aluminium phosphide. 4 This is in contrast to a study from southern India where pesticides still remain the most common mode of deliberate self-poisoning. 15 A few studies from other parts of India have also reported organophosphates to be the most commonly used agents in cases of acute poisoning. 16–18 These differences may be due to differences in the prevailing agricultural practices in the respective areas. In our study sedatives constituted 13.4% of all cases of poisoning followed by organophosphorus agents, which were responsible for 12.0%. Aluminium phosphide was found to be the culprit in 11.8% cases and alcohol and stupefying agents accounted for 11.8% and 10.3% cases, respectively. Copper sulphate was responsible for only 3.8%.
In 63.9% of our cases poisoning was used in an attempted suicide. However, when stratified according to age groups, accidental poisoning was more common among the elderly. This could be attributed to poor vision and the relatively high number of prescribed drugs consumed. Males outnumbered females (2.5:1). Most of the data from northern India shows a male predominance which agrees with our observations. 16–19 This could be partly attributed to the fact that males are exposed to more substances such as pesticides and alcohol and also to the fact that females are socially repressed in our region and do not readily seek medical attention.
The average age of male patients in our study was 27.5 years and that of females was 26.3 years. These figures are consistent with various other reports in which a majority of cases of poisoning were from the younger age group. 16–19 There seems to be a close relationship between these observations and the precipitating events responsible for poisoning. Academic failure and discord with family members or loved ones were the most commonly cited reasons for suicidal poisoning in the younger age group. Economic hardships and marital discord were important precipitating causes in the middle aged. However, endogenous depression or the loss of a spouse was responsible for most of the suicidal cases of poisoning among the elderly.
We observed an overall death rate of 13.2%, and 53.2% of these were caused by the consumption of aluminium phosphide. Another leading agent that caused death was organophosphate ingestion (11.6%). Siwach et al. had reported an overall mortality rate of 32.8% with about 67.7 being caused by aluminium phosphide. 4 Singh et al. had observed that barbiturates (37%) and copper sulphate (22%) were the most common poisons causing mortality between 1972 and 1977; organophosphates (46%) became the most common agents causing mortality between 1977 and 1982; and since 1982 aluminium phosphide (65%) has become the most common agent causing mortality. 13 Thomas et al. conducted a study in southern India and observed a mortality rate of 3.3% with a majority of deaths being caused by pesticides. 15 In northern India aluminium phosphide is commonly used as a grain preservative and is readily available. Ingestion of unexposed tablets causes a high mortality rate. Our study underlines the fact that the percentage of mortality was higher among patients aged >50 years (Figure 2). This can be attributed to the existence of other comorbidities in this age group.
Distribution of cases of poisoning and deaths according to age group
Conclusion
This study seeks to highlight trends in cases of acute poisoning in and around Delhi. It was observed that poisoning and the resultant mortality are often caused by the ingestion of readily available and commonly used substances. Attempts to better educate the general public, provide stress counselling, and promote poison information centres and measures to decrease the over-the-counter availability of many drugs with abuse potential could prevent many of these admissions.