1 Introduction

Poisoning has consistently been a significant global public health issue, with children being more prone to poisoning incidents due to their immature physiological and psychological development and a lack of awareness about safety. Acute poisoning in children is a major cause of pediatric emergency department visits [1]. While the prognosis for most poisoned children is favorable, severe cases can lead to multi-organ dysfunction and even death, with survivors potentially experiencing long-term consequences. In the United States, drug overdose or poisoning ranks as the sixth leading cause of death among children and adolescents [2]. Surveys in China also indicate that poisoning is a major contributor to accidental injury-related deaths in children [3]. From a global epidemiological perspective, the patterns of childhood acute poisoning exhibit regional variations. In the United States, children aged 1–5 years are most commonly exposed to cosmetics/personal care products [4], while in Italy, pharmaceuticals are reported as the most common exposure in children [5]. Moreover, even within the same region, the etiology and demographics of childhood poisoning may change over time [6].

The prognosis of childhood acute poisoning is related to the type of poison and post-poisoning management. Therefore, real-time understanding by pediatric emergency physicians of common toxic substances, poisoning manifestations, and prompt identification of poisoning types and interventions are crucial for reducing severe injuries and deaths resulting from childhood poisoning.

Several national epidemiological studies have been established in Europe by the European Association Poison Centers and Clinical Toxicologists (EAPCCT) or in North America by the American National Poison Data System (NPDS).However, there is a lack of extensive epidemiological data on childhood poisoning in China. West China Second University Hospital serves as a national pediatric regional medical center, providing treatment for critically ill children in Chengdu city, Sichuan province, and the southwestern region. Therefore, the cases of childhood acute poisoning of this hospital are regionally representative. In this study, we retrospectively analyzed the epidemiological and clinical characteristics of children (≤ 14 years old) who presented to the emergency department of West China Second University Hospital for acute poisoning from January 2019 to December 2022. The aim is to provide reference and basis for the formulation of strategies for the prevention and control of childhood acute poisoning.

2 Methods

This study included children with acute poisoning who sought treatment at the emergency department of West China Second University Hospital, Sichuan University, from 2019 to 2022. Children over 14 years old, those with venomous insect or snake bites, foreign body inhalation, excessive food intake, chronic poisoning, and those without a clear indication of the poisonous substance were excluded. Relevant clinical data, including demographic information (age, gender), types of toxic substances, clinical manifestations, length of hospital stay, presence of underlying diseases, and treatment outcomes (survival or death), were obtained from the hospital information system.

Besides to analyze the incidence of acute poisoning for age, we identified the following categories: < 1 years (infant), 1–3 years (early childhood), 4–6 years (preschool age), 7–11 years (school age) and ≥ 12 years (early adolescence). Microsoft Excel 2019 was used to perform descriptive statistical analyses of the data. The average age was presented as mean ± SD.

3 Results

3.1 General information

From January 1, 2019 to December 31, 2022, 2235 sought medical records for acute poisoning at our pediatric emergency department. Based on inclusion and exclusion criteria, this study included a total of 2036 children with acute poisoning (average age 4.07 years ± 3.92 years), accounting for 0.18% of pediatric emergency department visits. During the 4 years (2019–2022), the number of visits was lowest in 2020. General information included age, gender, onset season, contact type and method, and length of hospital stay, summarized in Table 1.

Table 1 Demographic characteristics of poisoned children admitted to the emergency department from 2019 to 2022
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3.1.1 Age and gender

Among the 2036 cases included in this study, young children accounted for the most of acute poisoning cases (64.1%), followed by preschoolers (11.8%), adolescents (10.1%), infants (7.5%), and school-age children (6.5%). When analyzing different age groups, it was found that the number of poisoned adolescents during the COVID-19 pandemic period (2020–2022) was significantly higher than the pre-pandemic period (2019) (Fig. 1A). The study included 1042 (51.2%) male children and 994 (48.8%) female children, with a male-to-female ratio of 1.05:1. Among children under 12 years old, boys predominated (54.3%), but the gender distribution reversed in the adolescent age group, with girls being the majority (73.3%) (Fig. 1B).

Fig. 1
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A Poisoning of children by age from 2019 to 2022; B Distribution of all poisoning cases by age and gender

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3.1.2 Time distribution

The number of children went to hospital for acute poisoning was lowest in winter (20.6%), followed by spring (24.9%), while the proportions were higher in summer (27.4%) and autumn (26.9%). Specifically, in terms of months, January and February had the fewest cases of poisoning, while July had the most cases (N = 190).

3.1.3 Route of poisoning

The most common form of poison intake was ingestion (99.3%, n = 2022), followed by contact poisoning (0.4%, n = 9), with the least common being inhalation of gases (0.2%, n = 5).

3.1.4 Analysis of poisoning causes

Of the children with acute poisoning, 92.7% were unintentionally ingested, while 7.3% were intentionally ingested. Analysis by age group revealed that infants were often accidentally fed by caregivers (n = 82, 53.6%), early childhood had the highest proportion of unintentional ingestion by themselves (n = 1234, 94.5%), and intentional ingestion of toxic substances was most common in the adolescence group (n = 135, 65.5%).

3.2 Poisonous substance

In this study, toxins were categorized into 10 major groups: medications, pesticides, household cleaners, personal care products, alcohol, plants, mercury, desiccants, gases, and other substances. Simultaneous ingestion of two or more medications was defined as mixed medications.

In this study, the most common substance in childhood acute poisoning was medications, followed by pesticides, household cleaners, personal care products, mercury, desiccants, plants, other substances, with gases being the least common. Among the children, 4.1% ingested two or more medications (2–5 types) (Table 2).

Table 2 Distribution of toxic agents
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Due to the different developmental stages of children in various age groups, the toxic substances showed age-specific distribution characteristics. The highest proportion of poisoned substances in all age groups was medications. In addition to medications, common toxins for infants were household cleaners (n = 21) and desiccants (n = 11), followed by other substances (n = 10) and pesticides (n = 9); for the children of early childhood, pesticides (n = 151) were common, followed by household cleaners (n = 136), personal care products (n = 64), and mercury (n = 59); for preschoolers, pesticides (n = 32), household cleaners (n = 18), other substances (n = 15), and mercury (n = 10) were common; for school-age children, the highest proportion was pesticides (n = 27), followed by household cleaners and plants (n = 8), other substances (n = 7); for adolescents, pesticides (n = 47), household cleaners (n = 7), and alcohol (n = 4) were common (Fig. 2A). From 2019 to 2022, there was an upward trend in children poisoned by medication, while those poisoned by pesticides and desiccants showed a downward trend (Fig. 2B).

Fig. 2
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Poisonous substance in children. A Distribution of toxic agents consumed by different age; B Distribution of toxic substance over 4 years

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3.2.1 Classification of treatment medications

In this study, among all medications, neuro-psychiatric medications were the most prevalent (n = 331), including antidepressants (n = 81), antipsychotics (n = 143), antiepileptic medications (n = 27), and sedatives/hypnotics (n = 80). Vitamins were the second-largest category of ingested medications (n = 157), with vitamin A and D being the most common vitamins, followed by cold and cough medications (n = 132), antihistamines (n = 123), nonsteroidal anti-inflammatory medications (n = 83), beta-adrenergic agonists (n = 58), cardiovascular medications (n = 57), topical medications (n = 54), antibiotics (n = 47), traditional Chinese medicine (n = 40), and endocrine system medications (n = 18). When divided by age, the most ingested drugs for infants were cold medications (n = 16), while for the children aged 1 to 10 years, vitamins were the most common. The most ingested medications for adolescents were antipsychotic medications (n = 106) (Table 3).

Table 3 Distribution of medications
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3.2.2 Classification of pesticides

Pesticides ranked as the second most ingested items, with the most common being pyrethroids, roach baits, etc. (n = 138), followed by anticoagulant rodenticides (n = 65), paraquat (n = 26), diquat (n = 17), and organophosphates (n = 15). The most ingested pesticides for adolescents were diquat (n = 12), while anticoagulant rodenticides were the most common for other age groups.

3.2.3 Other substances

Household cleaners were also a major category of ingested items, with limescale removers containing citric acid being the most common. Mercury thermometers are still widely used in Chinese households, and unintentional ingestion of mercury is not uncommon (n = 72), often resulting from accidental breakage or biting of the mercury thermometer.

3.3 Clinical symptoms and signs

More than half of the t children who exposed to substances did not show obvious clinical manifestations, with only 635 children experiencing clinical symptoms. Gastrointestinal symptoms were the most common, followed by neurological symptoms, and local injuries such as oral ulcers and localized rashes. Respiratory and blood system symptoms were rare (Table 4). Adolescent primarily exhibit neurological symptoms.

Table 4 Clinical manifestation and treatment of acute poisoning children of different ages
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3.4 Treatment and prognosis

Gastric lavage, catharsis, fluid infusion, activated charcoal, and extracorporeal treatment are the main treatment options for poisoning. Only a small number of toxins have corresponding antidotes, such as vitamin K1 for bromadiolone poisoning, flumazenil for benzodiazepine poisoning, and pralidoxime for organophosphate poisoning.

In this study, most children (66.2%) sought medical attention within 4 h of poisoning. Therefore, gastric lavage or induced vomiting (n = 980) or oral activated charcoal (n = 460) was used for most cases. Extracorporeal treatment was used for 5.2% of children (n = 106). Vitamin K1 treatment was given to 49 children who ingested rodenticides, and all children with organophosphate poisoning (n = 18) received atropine and pralidoxime treatment. A total of 272 children were hospitalized, including 40 in the PICU, and the rest were sent home after emergency treatment. Adolescents have the highest hospitalization rate (56.8%), and the highest rate of admission to the Pediatric Intensive Care Unit (PICU) is 10.2%. Adolescents often have underlying health conditions (61.1%), with a predominance of psychiatric disorders. Three deaths occurred, one from ingesting poisonous mushrooms and two from ingesting veterinary medicine containing chloronitrophenol and ivermectin (Table 4).

4 Discussion

Acute poisoning in children is a common reason for emergency department visits [7]. Reported proportions vary worldwide, ranging from 0.27 to 7.6% [8, 9]. In this study, the proportion of pediatric emergency department visits related to poisoning is 0.18%, but some children may not seek medical attention, potentially underestimating the prevalence of acute poisoning in children. The study found that acute poisoning in children is mainly concentrated in children of 1–3 years old, which is related to specific characteristics of this age group, including lower cognitive abilities, curiosity to explore new things, lack of awareness of potential dangers, and a lack of self-protection awareness. In this study, the number of boys is slightly higher than girls, with a ratio of 1.05:1, but during adolescence, the proportion of girls significantly increases, with a male-to-female ratio as high as 1:2.7, like previous reports [10, 11].

The National Poison Data System (NPDS) annual report for 2021 from the American Association of Poison Control Centers reported over 2.08 million cases of toxic substance exposure in 2021, with exposures mainly concentrated in those under 20 years old, accounting for 56.08%, and those under 5 years accounting for 40.68% [4]. The top five substances most commonly exposed to children under 5 years were cosmetics/personal care products (10.8%), household cleaning substances (10.7%), analgesics (8.16%), dietary supplements/herbs/homeopathy (7%), and foreign bodies/toys/miscellaneous (6.51%). Reports from some regions also indicate that children treated in pediatric emergency centers for poisoning are primarily due to medication ingestion [12, 13]. In contrast to the United States, the most common substances in children reported in China were medications, followed by pesticides, household cleaning products, and personal care products [14]. In this study, the most common substance ingested was also medications, followed by pesticides, household cleaning agents, personal care products, mercury, desiccants, plants, and other substances.

There were significant regional and age differences in the types of medications exposed. In New England, the most common substances exposed to children under 12 years old are acetaminophen and ibuprofen [15]. However, in the United States, the most common medications exposed to children are benzodiazepines, opioids, or acetaminophen. In contrast, our study found that the main exposed substances were vitamins, antipsychotic medications, cold medications, antihistamines, etc., with benzodiazepines and opioids being rare. This difference may be related to the strict control of psychotropic medications in China. Younger children often unintentionally ingest a single drug with a small dose, resulting in relatively low harm. Vitamins, cold medications, and antihistamines are over-the-counter drugs in China, easily accessible, and frequently used in children, making them the main types of substances ingested by younger children. For children ≤ 3 years, the ingestion of medications is often related to parental negligence, incorrect dosages, large-packaging that is difficult to accurately divide, and open bottles. The study also found that the proportion of unintentional ingestion of the second-generation antihistamine cetirizine oral solution was significantly higher than that of the cetirizine drops. This may be related to the open packaging of oral solutions, which is easier to overdose compared to drops [16, 17]. This suggests that hospitals and drug manufacturers need to consider the packaging and management of children's medications. Caregivers of young children need to strengthen supervision and the storage and management of household medications to prevent accidental ingestion by children.

Although China regulated pesticides, pesticide poisoning remains a significant cause of childhood poisoning and a major reason for hospitalization. In this study, 12.4% of children sought medical attention for pesticide ingestion, and 34.9% of children ingesting pesticides required hospitalization. Among hospitalized patients, 34.2% were due to pesticide ingestion. Different from previous study [18] which found paraquat was the most common pesticides in poisoned children, rodenticides were the most common pesticides ingested in this study, with anticoagulant rodenticides (bromadiolone, brodifacoum) being the most common. This may be related to prohibition of highly toxic rodenticides and promotion of anticoagulant rodenticides in China. Rodenticide poisoning is often insidious, and some children present with bleeding tendencies without clear exposure history to rodenticides. Most poisoned children are in the younger age group, with 54.3%aged 1 to 3 years, which may be related to rodenticides being mixed with grains, making them difficult to identify.

Mental health problems in adolescents have become a global public health issue, with reported global rates of adolescent mental health problems reaching up to 14% [19]. Emotional and behavioral disorders are common, leading to an increase in self-harm and suicide attempts. Over the past 30 years, mental health problems in Chinese adolescents have also increased, with research reporting positive psychological questionnaire scores in as many as 36% of middle school students [20]. Adolescents with poisoning often have intentional ingestion, high toxicity of ingested substances, a high hospitalization rate, a high likelihood of residual effects, and high costs [21].

Most children in this study received simple emergency treatment and were sent home for observation. Most children showed no lasting effects, indicating a favorable prognosis. This is not only related to the toxicity of the poisoning substance but may also be associated with early medical attention for children. Our emergency department has a high proportion of gastric lavage, induced vomiting, or activated charcoal use, effectively reducing the absorption of toxic substances in the early stages. Additionally, our hospital has a Pediatric Blood Purification Center, allowing for early and timely blood purification treatment.

The limitations of this study is that this study is a retrospective study, and the information may be incomplete. Because our hospital is a specialized hospital for women and children, mainly treating children under the age of 14, those over 14 rarely seek medical treatment in our hospital. Therefore, those under the age of 14 were selected for inclusion. Due to the short emergency reception time, some information may not be recorded.

5 Conclusion

This study provides more epidemiological data on pediatric poisoning in Chengdu. The results indicate that younger children are the most affected, often unintentionally ingesting toxic substances, while the proportion of intentional ingestion significantly increases in adolescents. Our study suggests that medications are the most common toxic substances We advocate for increased awareness of pediatric poisoning across all sectors of society to minimize or prevent such harm.