Introduction

According to the World Health Organization (WHO) there are 2 million suicide attempts and 1 million accidental poisonings worldwide each year.¹ Acute poisoning is one of the most common conditions evaluated in the accident and emergency department (A&E) in Princess Marina Hospital (PMH) in Gaborone, Botswana, accounting for 1.9% of all visits.² Deliberate self-harm is common in developing regions of the world and often takes the form of acute toxic ingestion.

Additionally, the mortality rate from poisonings in these parts of the world is often high due to innate toxicity of compounds, availability of such toxins due to less stringent regulation and decreased access to medical care.³ A 2001 WHO report asserts that 94% of the world’s fatal poisonings occurred in low and middle income countries.¹ A recent investigation in Botswana listed acute poisoning as the third leading cause of non-HIV related admission to PMH.⁴ Due to limited documentation, scarcity of resources and diagnostic challenges, these cases are likely underreported and possibly much more common than described.

Princess Marina Hospital, a public teaching hospital is one of two tertiary referral centers in Botswana which receives patient transfers from other clinics and hospitals throughout the country. PMH has 525 beds and is located in Gaborone, the capital and largest city in Botswana. The A&E has an 18-bed capacity with 2 resuscitation bays and treats both adult and pediatric patients.

Toxic ingestions and exposures are commonly encountered presentations to PMH and contribute significantly to patient morbidity and mortality.⁵ Unfortunately, there is no centralized reporting system for poisonings in Botswana and the overall risk and incidence of such exposures is not yet known. In 2008, Malangu et al.,⁴ published a study which found that acute poisonings in Botswana had a case fatality rate of 2.6% which is significantly higher than most parts of the world. However, from the time of their retrospective review in 2005, no follow-up data has been published on poisonings in Botswana.

Studies from diverse regions of the world demonstrate distinctive temporal patterns of poisonings as well as wide variations among the most commonly exposed toxins.⁶ The goal of this study was to gather information regarding specific toxins, risk factors, frequency, temporal relationships and intentionality as an important initial step to gaining a general understanding of poisonings encountered in Botswana.

Identifying high risk patients and toxic agents may facilitate further, more specified investigations, design of targeted preventive initiatives and development of focused education on individualized treatments which will serve to ultimately advance the overall care of acutely poisoned patients.

Methods

Permission for this study was granted by the Research and Ethics Committee of the Office of Research and Development at the University of Botswana as well as the Ministry of Health and the Research and Ethics Committee at Princess Marina Hospital.

A retrospective review was conducted on the charts of poisoning cases seen in the A&E in PMH from January 1, 2016 to June 30, 2016. Patients were included if they were found to have an acute toxic ingestion, dermal or inhaled chemical exposure or animal envenomation.

Patients were excluded if there was unverifiable data or if the chart was incomplete. Two pre-approved personnel collected data on demographic information including age, sex and month of presentation.

In addition, information about intentionality, specific toxin exposure and disposition was also gathered. Data was entered into a spreadsheet and was analyzed by Microsoft Excel software in order to maintain accurate computations.

We use descriptive statistics to present data. Means are used to present continuous variables and percentages are used to present the categorical data. All information was kept on a password protected hard drive and all identifying patient information was removed to ensure privacy protection.

Results

In the first half of 2016, 289 patients were seen in the A&E at PMH for acute poisonings (Table 1). Of these, 57% were female. Of all the toxic exposures, 58% were intentional. Patients who were age 16-35 were more commonly affected than younger and older patients. While most patients were admitted, only 3 required ICU admission. The case fatality rate among all patients was 0.7%. One of the two deaths resulted from accidental ingestion of a traditional medicine and the other from a scorpion sting.

Table 1: Sex, Age and Disposition by Intentionality.

Source of Information: charts of poisoning cases seen in the A&E.

The five most common toxic exposures presenting to the A&E department from January to June of 2016 were snake bites, paraffin ingestion, paracetamol ingestion, scorpion stings and ingestion cases in which the substance was unknown. The most common exposures seen each month are depicted in Figure 1.

Figure 1: Top 5 Poisonings by Month.
Source of Information: charts of poisoning cases seen in the A&E.

Snake bites occurred more commonly from January to April while there were no cases in May and June. All five of the most common poisonings appeared to present less commonly from the winter months of May through June compared to the warmer months of January through April. In comparison by sex, women were more likely than men to present to the A&E with a toxin exposure, 57.4% and 40.8% respectively (Figure 2).

Figure 2: Poisonings by Sex.
Source of Information: charts of poisoning cases seen in the A&E.

Of patients presenting with toxic ingestions, women were much more likely than men to have consumed the toxin intentionally (Figure 3). While only 43% (51/118) of male cases presenting with toxic ingestions were intentional, 69% (116/166) of female cases of ingestion were intentional. Male ingestions were more commonly accidental events. Most intentional poisonings occurred in patients from 16 to 50 years of age.

Figure 3: Intentionality by Sex.
Source of Information: charts of poisoning cases seen in the A&E.

Women were more likely to intentionally ingest toxic substances than men. Not surprisingly, childhood toxic ingestions before age 11, while common, were all accidental.

Figure 4: Age and Intentionality.
Source of Information: charts of poisoning cases seen in the A&E.

Interestingly, ingestions after the age of 50 were relatively uncommon (Figure 4) and none were intentional up to 80 years of age. However, elderly patients presenting with toxic ingestions after the age of 80 were all intentional (Figure 5).

Figure 5: Intentionality by age.
Source of Information: charts of poisoning cases seen in the A&E.

Women were more likely than men to intentionally ingest toxins in all age groups except age group 11-15 (n=5) in which the reverse was true (Figure 6).

Figure 6: Intentionality by Age and Gender.
Source of Information: charts of poisoning cases seen in the A&E.

Paraffin

Paraffin poisoning was more common in the early years of life. This particular toxin, while common, was accidental in 88% of cases (15/17) (Figure 7 & 8) and common in both sexes. The majority of patients who ingested paraffin were sent home (Fig. 9). Those who were admitted were able to be managed in the ward; none required ICU or surgical intervention.

Figure 7: Paraffin Ingestion by Sex and Age.
Source of Information: charts of poisoning cases seen in the A&E.

Paraffin was common in male and female patients age 0-5, but uncommon after age 5.

Figure 8: Paraffin Intentionality.
Source of Information: charts of poisoning cases seen in the A&E.

Patients with paraffin ingestions were either admitted to the ward or discharged home; none required ICU or surgical intervention (Fig. 9).

Figure 9: Paraffin Disposition.
Source of Information: charts of poisoning cases seen in the A&E.

Paracetamol poisoning

The majority of patients presenting after paracetamol ingestion were ages 16-25 (Figure 10). Patients in this age group were more than twice as likely to be female than male. Ninety percent of paracetamol ingestions were intentional (Figure 11). One patient required ICU, but the majority of paracetamol ingestions were managed in the ward (Figure 12).

Figure 10: Paracetamol Poisoning by Sex and Age.
Source of Information: charts of poisoning cases seen in the A&E.

In ages 16-25, women were more likely to present with paracetamol ingestion. Most patients with paracetamol poisonings were managed in the ward, but 1 patient required ICU admission

Figure 11: Paracetamol Intentionality.
Source of Information: charts of poisoning cases seen in the A&E.

Figure 12: Paracetamol Disposition.
Source of Information: charts of poisoning cases seen in the A&E.

Snake bites

Snake bites were twice as likely to occur in male patients as in female patients (Figure 13). Most patients were admitted to the surgical ward or discharged home. None required care in the ICU (Figure 14).

Figure 13: Snake Bites by Sex and Age.
Source of Information: charts of poisoning cases seen in the A&E.

Figure 14: Snake Bite Disposition.
Source of Information: charts of poisoning cases seen in the A&E.

Discussion

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¹ Emergency Department. University of Botswana.
² University State Island. New York.