Introduction

Poisoning with alcohol or drugs is defined by the World Health Organization as a state of major disturbance of consciousness level, vital functions, and behavior following the administration in excessive dosage (deliberately or accidentally) of a psychoactive substance [1]. The physiological reaction to poisoning is highly dependent on the type and dose of the substance, and is influenced by the individual’s level of tolerance and organ function. Self-harm is defined as any act of self-poisoning or self-injury carried out by an individual irrespective of motivation [2]. Acute self-poisoning is one of the frequent causes of medical emergencies, and it presents a considerable burden to the health service system. Self-poisoning makes up for 0.6–2.1 % of all emergency department visits [3–5] and up to 17.3 % of intensive care unit (ICU) admissions [6–9]. Causes of self-poisoning are either a suicide attempt or accidental, whereby the latter group includes overdose with recreational drugs or alcohol intoxication, as well as drug overdose for alleviation of pain or discomfort without any suicidal intention. Self-poisoning represents a common method of suicide attempt and deliberate self-harm all over the world [4, 10–16].

The aim of this study is to present data on acute self-poisoning from the emergency department of a university hospital over a period of 8 years and to identify trends relating to epidemiology and substance used.

Methods

This is a retrospective study conducted at the University Hospital Leipzig in Germany. Consent for data acquisition and analysis were given by the Institutional Review Board of the University of Leipzig. Electronic charts of adult patients (≥ 18 years) who presented due to acute self-poisoning to the emergency department of the University Hospital Leipzig between January 2005 and December 2012 were included. Inclusion criterion was presentation with signs of acute poisoning, regardless of the type and amount of substance ingested. We have applied the definition of the World Health Organization regarding poisoning/intoxication versus substance abuse in identifying patients [1]. We have included only those patients who required emergency medical management for proven acute self-poisoning based on history, physical examination and drug screening. Since the physiological reaction to acute poisoning or intoxication is influenced by the individual’s level of tolerance and organ function, the symptoms and signs of acute poisoning or intoxication rather than drug levels were the mainstay of patient inclusion.

Patients treated in the emergency department for other reasons (commonly trauma) and in whom drug abuse was detected in the process were excluded, because these patients did not primarily present with signs of intoxication requiring medical attention by itself. Patients who presented to the emergency department for signs of poisoning despite appropriate intake of prescribed medication and those with accidental poisoning at workplaces or at home were also excluded from the analysis.

The following data were collected: patient characteristics, reason for and mechanisms of self-poisoning, admission time (month, weekday and daytime), repeated admissions, need for ICU admission, and outcome. In those patients with ICU admission, data on the drugs used for self-poisoning, length of ICU stay and ICU management were documented. Identification of drugs used for self-poisoning was based on history (the patient or relatives) and laboratory screening in blood and urine samples.

Depending on the trigger, patients were classified into three groups: suicide attempt (suicide group); intoxication with alcohol or recreational drugs (intoxication group), drug overdose in relation to relief of pain or discomfort (drug overdose group). If the trigger for self-poisoning could not be undoubtedly specified, patients were grouped as “not clearly classified”. This last group was not further analyzed due to the small size, except for mortality.

The data were analyzed using SPSS for Windows, version 20.0. Numerical data were analyzed for homogeneity using Kolmogorov-Smirnov and Shapiro-Wilk tests. Depending on their normal distribution, numerical data are given either as median with interquartile range [IQR] in square brackets or mean with standard deviation. Numerical data comparisons were conducted with either the Student’s t-test or Mann-Whitney U-test depending on their normal distribution. Categorical data comparison was carried out using chi square test. A p value < 0.05 was considered statistically significant.

Results

A total of 3.533 adults with acute self-poisoning (62.6 % males and 37.4 % females) were identified. The number of emergency department presentations continuously increased during the study period, from 305 in the year 2005 up to 624 in 2012 (an increase by 104.6 %). The yearly number of emergency department admissions for the intoxication group showed a continuous rise throughout the study period. During the same period, admission figures for self-poisoning as a suicide attempt showed an increase only in the year 2012, while there was no relevant increase in the drug overdose group (Fig. 1). The proportion of patients with acute self-poisoning in relation to the total emergency department admissions has also increased over the years (Table 1).

Fig. 1
figure 1

Annual number of emergency department presentations for acute self-poisoning

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Table 1 The annual incidence of acute self-poisoning in relation to the total emergency department admissions
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The median age of the study population was 35.0 [IQR 25.0] years for males and 29.0 [24.0] years for females (p < 0.001). 31.7 % of the patients were younger than 25 years, while 21.3 % belonged to the age group 25–34 years. Suicide attempts and drug overdose were more common in females than in males, while intoxication was more common in males than in females. The intoxication group included the youngest population compared to the other two groups (p < 0.001) (Table 2).

Table 2 Age and gender distribution according to the trigger for self-poisoning
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There was no age difference among males and females in the suicide group (median age 42.0 [23] vs. 37 [29] years, p = 0.093) and drug overdose group (36.5 [27] vs. 41.0 [45] years, p = 0.45), while females were significantly younger than males in the intoxication group (25.0 [20] years vs. 34.0 [14.9], p < 0.001).

The monthly distribution did not show any predilection. Presentations due to self-poisoning for suicide attempts were frequent on Mondays and Tuesdays (accounting for 32.7 % of the cases), with a gradual decrease until Saturdays. However, the daily differences were not significant. The most frequent presentation period (65.1 %) throughout the day was between noon and midnight. On the contrary, patients in the intoxication group frequently presented on Fridays (13.6 %), Saturdays (21.3 %) and Sundays (21.2 %), peak time of the day being 8 pm to midnight (21.9 %) and midnight to 4 am (29.8 %).

The means of self-poisoning are presented in Figs. 2, 3, 4. Benzodiazepines and antidepressants were the most common drugs used among the suicide group, while alcohol was the most common substance used in the intoxication group. Intoxication with alcohol only accounted for 81.0 % of the emergency admissions in the intoxication group. Self-poisoning using two or more substances was observed in 333 (52.0 %) cases in the suicide group, 279 (10.3 %) cases in the intoxication group, and 30 (29.7 %) cases in the drug overdose group. An interesting incident was lead poisoning in the years 2007 and 2008 among the intoxication group following consumption of adulterated street marijuana. This particular incident was already reported [17].

Fig. 2
figure 2

Drugs used for self-poisoning with suicidal intention. 32.8 % of these patients additionally consumed alcohol. Chemicals included detergents (18), tenisides (5) and antifreeze (1). Antidiabetics included insulin (14) and oral antidiabetics (6)

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Fig. 3
figure 3

The most common agents of self-poisoning associated with acute intoxication

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Fig. 4
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The most common agents of self-poisoning associated with drug overdose. 17.8 % of these patients also drunk alcohol

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There was no significant trend change for drugs used in the suicide group and the drug overdose group throughout the study period. Regarding the intoxication group, while the yearly admission rate due to the sole alcohol intoxication remained almost unchanged around 80 % throughout the study period, there was a marked increase in the admission rate due to overdose of amphetamines/methamphetamines (“Crystal Meth”), cannabinoids and gamma-hydroxybutyrate (GHB)/gamma butyrolactone (GBL) in the years 2011 and 2012. The admission rate for opioid and benzodiazepine overdose in the intoxication group was the highest in 2007, with a gradual decrease afterwards (Fig. 5).

Fig. 5
figure 5

The annual trend for drugs frequently used among cases of acute intoxication

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Repeated emergency department admissions for acute self-poisoning were observed in 427 cases (12.1 % of the total study population), which involved 7.5 % of the cases in the suicide group, 13.4 % of the intoxication group and 6.9 % of the drug overdose group. Admission to the ICU was considered necessary in 588 cases (16.6 %), with 61.4 % of the suicide group, 4.6 % of the intoxication group and 43.6 % of the drug overdose group being admitted. The top ten drugs that led to ICU admission are shown in Table 3. Acute poisoning with two or more drugs was observed in 48.6 % of the ICU admissions.

Table 3 The top ten drugs that led to ICU admission and the proportion of ICU admissions related to each substance
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The most common reason for ICU admission was the need for vital sign monitoring (75.9 %). A Glasgow coma scale of ≤ 8 (25.2 %), respiratory insufficiency (2.7 %) and hypotension (1.7 %) were further indications. The median length of stay in the ICU was 27 [29.5] hours. The following management procedures were required during the ICU stay: mechanical ventilation (27.0 % of the cases), vasopressor support (9.4 %), administration of an antidote (27.8 %) and hemodialysis (3.6 %).

The need for immediate psychiatric treatment following completion of the medical management was significantly different between the groups (p < 0.001). 82.7 % of the patients in the suicide group, 31.7 % of those in the drug overdose group, but only 6.6 % of those in the intoxication group were transferred for subsequent immediate psychiatric treatment after conclusion of the medical management.

A total of 22 patients died (0.6 % of the total study population), of whom 15 were in the suicide group (2.3 %), four in the intoxication group (0.15 %), while three cases belonged to the not clearly classified group (3.8 %), with a statistically significant difference among the groups (p < 0.001). The causes of death were prolonged hypoxia (10), cardiac arrest (5) and multiple organ dysfunction (13). While 20 patients died in the ICU, two patients (from the intoxication group) died in the emergency department following a refractory cardiac arrest. There were no fatalities in the drug overdose group.

Discussion

This study included a large period of time, which gives an overview on the trend of clinically relevant acute self-poisoning in a German population. Although the presented data were from one center only, the Leipzig university hospital is responsible for the management of patients with acute self-poisoning from a large catchment area with a population of about 1.3 million.

Self-poisoning is a considerable issue in emergency medicine and its incidence is increasing. This is related to suicide attempts as well as intoxications with alcohol and recreational drugs. In our study, the yearly number of presentations for clinically relevant self-poisoning more than doubled between 2005 and 2012, intoxication being the major cause for this increase.

Acute intoxication has become an increasing concern. Similar to a study from the UK, young and male patients represent the majority [18]. Alcohol is still the leading means of intoxication, which is also observed elsewhere [7, 19]. Although the majority of these patients with the sole alcohol intoxication could be discharged after a short stay in the emergency department, alcohol intoxication remains a leading cause of hospital admission [20]. Observational data from emergency units are not uniform and depend on patient selection [7–9, 13, 21].

The increasing use of illegal drugs in the younger population is alarming. In our study, this was the case with amphetamines/methamphetamines, cannabinoids and GHB. Particularly, intoxication with amphetamines/methamphetamines (Crystal Meth) markedly increased since 2011. According to the German drug and addiction report for 2012 and 2013, this issue is strongly related to the German-Czech border regions, mainly affecting the Free State of Saxony, Germany. Since 2009, the number of Crystal Meth consumers in this German state that directly borders with the Czech Republic increased yearly by 25 %, probably because several Crystal Meth laboratories exist in the Czech Republic. The need for counseling of Crystal Meth consumers in 2011 in the State of Saxony was four times more than the German average [22].

The incidence of intoxication with GHB and its precursor GBL in our study cohort is generally not that high. However, this increased rapidly by the year 2012. Although GHB is an illicit drug, its precursor GBL, which is metabolized to GHB in the human body, is legally available as an industrial product. While the drug is a stimulant at lower doses, it results in unconsciousness in higher doses, which is the common cause of emergency department presentation among its consumers. The lack of appropriate laboratory detection methods may have influenced the true incidence of intoxication with GHB.

Although suicidal self-poisoning is not as frequent as intoxication, it is the major cause of ICU admission. The rates of ICU admissions for acute self-poisoning in the literature range from 2.2 to 29.2 % [23–27], with suicidal and parasuicidal self-poisoning being the most frequent cause. Patients in this group are older and the majority are females [12, 13, 21, 28]. The distribution of drugs used for suicidal attempts in our study is not different from previous European reports, with psychotropic drugs, especially benzodiazepines and antidepressants, being the leading substances [12, 13, 21, 23]. Only in the UK was paracetamol the most frequently used drug for suicidal attempts [29, 30]. The use of these drugs is frequently associated with a simultaneous alcohol intoxication [13].

Another concern is the abuse of drugs, particularly analgesics and sedatives, for relief of discomfort, which mainly affects females. Although the incidence of such an abuse leading to emergency consultation did not increase throughout the investigated period of our study, this does not reflect the true dimension of this problem. Appropriate health education and sales control may be necessary preventive measures.

More than 10 % of the patients with self-poisoning were re-admitted at least once during our study period. Figures from other publications vary between 8 and 21 % [31–33]. Risk factors for readmission are young age, past psychiatric admission, drug addiction, abuse of antidepressants and mixed self-poisoning [32, 33].

The Glasgow Coma Scale seems to be a major indication for ICU admission [34]. Future investigations should evaluate whether this scale alone should be taken as a major reason for ICU resource utilization. However, this issue is also dependent on the emergency department organization, such as the capacity to monitor such patients for several hours. The length of ICU stay in our study was similar to the literature report [8, 35].

Emergency management of poisoning mainly involves maintaining vital functions. Primary and secondary poison elimination can be implemented, depending on the type of the drug, the time frame, and organ function (particularly liver and kidney function). Antidotes are available for a few substance groups only [36]. Even then, their use is mostly limited, particularly regarding benzodiazepine and opioid overdose, because their half-life is shorter than that of the toxic drug. However, they can be useful as a differential diagnosis tool, in case the cause of poisoning is not clear. Patients with self-poisoning die in the early stage either due to respiratory or cardiac arrest. Late deaths are mostly due to organ dysfunctions and the resultant complications. Therefore, community education and early identification of a poisoning are essential to prevent tragic consequences.

Psychiatric counseling and therapy is commonly recommended for those patients with suicidal or parasuicidal self-poisoning, which is similar to another German study [13]. However, this figure varies depending on the patient population. In Norway, only 38 % of the patients with suicidal self-poisoning received further psychiatric management [37]. Psychiatric counseling among patients with intoxication is low. Most of these patients left the emergency department and the ICU on their own after stabilization of their acute condition. Another reason for the low psychiatric counseling in this subgroup of our study population may be that the initial psychiatric consultation was targeted to rule out a suicide attempt in order to avoid possible medico-legal issues. The relatively high rate of need for psychiatric counseling among those with self-poisoning for relief of pain or discomfort may indicate an underlying psychiatric disorder.

Mortality following self-poisoning is generally low [7, 19, 26, 38]. In our study, we considered only hospital mortality. A recent study showed a hospital mortality rate of 2.1 % for acute poisoning, with a rise to 9.3 % 24 months after ICU admission [38].

Our study has certain limitations. Firstly, it is retrospective, so that details regarding medical and social history of the patients were not complete. Secondly, this study included only those patients who were brought to the emergency department, thus not representing the true incidence of self-poisoning in the general population. However, it represents the epidemiology of clinically relevant acute self-poisoning.

Conclusion

Acute self-poisoning is a major concern in emergency medicine. Psychotropic drugs are still the leading cause among suicidal self-poisoning. While alcohol is still a major issue, the incidence of illicit drug intake is increasing among those with acute intoxication. The experience in certain European border regions regarding illicit drugs makes the need for international cooperation in preventive measure more than obvious. Self-poisoning related to relief of pain or discomfort implicates the need for appropriate public education, increased psychiatric counseling as a preventive measure and proper drug control.