Identification of drugs ingested in acute poisoning: correlation of patient history with drug analyses

Critical care management of acute intoxications, dynamics and changes over time: a cohort study

Acute intoxications and poisonings are a relevant cause for ICU admission of critically ill patients. This study aimed to determine the characteristics of intoxicated patients in a tertiary center medical ICU in Austria over time and to investigate parameters associated with ICU mortality. This study was a retrospective data analysis including adult ICU patients from the years 2007 to 2021. In addition to ICU documentation, pre-hospital, and emergency department documents as well as autopsy reports were utilized. In an exploratory subanalysis, we compared these findings to a historical dataset from our facility from 1992 to 1996. We identified 581 cases admitted to the medical ICU because of acute poisoning (2007-2021), of which 45% were female and 46.6% were mixed intoxications. Suicidal intent was the primary cause of intoxication (48.2%) and ICU length of stay was median 1.2 days. The majority of deceased patients received pre-hospital mechanical CPR. Primary and secondary poison/toxin removal modalities were used in 29.9% and 11.7% of cases, whereas antidotes were administered in 54.4%. Comparing the data with a historical cohort (n = 168), we found a shift in primary detoxification away from gastric lavage and an increase in alternative secondary poison/toxin removal techniques. The ICU mortality was 4.1% and 4.2% in the present and historic cohort, respectively. Pre-existing psychiatric illnesses increased from 49% in the historic to 69% in the present cohort. Psychiatric illness predisposes patients to severe intoxications necessitating ICU care, thus increasing prevention measures seems warranted. Females did present with a different spectrum of intoxications compared to males. ICU mortality remained low over time and most deceased patients had a grim prognosis already on ICU arrival.

Accuracy of substance exposure history in patients attending emergency departments after substance misuse; a comparison with biological sample analysis

CONTEXT

Acute toxicity caused by illicit substance use is a common reason for emergency department (ED) presentation. Knowledge of the substances involved is helpful for predicting and managing potential toxicity, but limited information is available about the accuracy of patient-reported substance exposure. This study assessed the accuracy of the history of exposure in those reporting use of a single substance by comparison with those identified by detailed toxicological analysis, focusing on synthetic cannabinoid receptor agonists (SCRA).

METHODS

Adults (≥16 years) presenting between March 2015 and July 2021 to participating UK hospitals with toxicity after reporting use of a single illicit substance were included. Exposure details were documented from medical records and blood and/or urine samples analysed using high-resolution accurate mass liquid chromatography-mass spectrometry (HRAM LCMS). Sensitivity, specificity, and positive and negative predictive values of the exposure history were calculated by comparison with biological sample analysis ("gold standard").

RESULTS

Single substance exposure was reported for 474 (median age 33 years, IQR: 18 range 16-75, 80% males) patients. Analysis commonly identified multiple substances (Median 3, IQR 2-5). A history of exposure was documented for 121 of 151 patients where a SCRA or metabolite was detected on analysis (sensitivity 80.1%, 95% CI 72.9, 86.2%). Corresponding proportions were lower for 3,4-methylenedioxymethamphetamine (MDMA, 44/70, 62.9%., 95% CI 50.5%, 74.1%), heroin 41/108 (38.0% 95% CI 28.8-47.8%) and cocaine (22/56, 31.3%, 95% CI 20.9, 43.6%).

CONCLUSIONS

Multiple undeclared substances were detected analytically in most patients reporting single substance use. Clinicians should be alert to the potential presence and toxicity of unreported substances when managing patients presenting after substance misuse.

Thermal desorption ambient ionization mass spectrometry for emergency toxicology

In the emergency department, it is important to rapidly identify the toxic substances that have led to acute poisoning because different toxicants or toxins cause poisoning through different mechanisms, requiring disparate therapeutic strategies and precautions against contraindicating actions, and diverse directions of clinical course monitoring and prediction of prognosis. Ambient ionization mass spectrometry, a state-of-the-art technology, has been proved to be a fast, accurate, and user-friendly tool for rapidly identifying toxicants like residual pesticides on fruits and vegetables. In view of this, developing an analytical platform that explores the application of such a cutting-edge technology in a novel direction has been initiated a research program, namely, the rapid identification of toxic substances which might have caused acute poisoning in patients who visit the emergency department and requires an accurate diagnosis for correct clinical decision-making to bring about corresponding data-guided management. This review includes (i) a narrative account of the breakthrough in emergency toxicology brought about by the advent of ambient ionization mass spectrometry and (ii) a thorough discussion about the clinical implications and technical limitations of such a promising innovation for promoting toxicological tests from tier two-level to tier one level.

Paracetamol toxicity in mild overdose in combination with opioids: A retrospective observational study

AIMS

Toxicity in paracetamol overdose with opioid co-ingestion is poorly understood. We compared outcomes in both paracetamol-only and paracetamol-opioid overdoses to determine whether toxicity differed significantly between the groups, and to assess the utility of the ratio of measured plasma paracetamol concentration relative to the 4-hour nomogram-adjusted level (APAP_pl /APAP_t ).

METHODS

We conducted a retrospective observational study of all patients (n = 1159) presenting to 2 large UK hospitals between 2005 and 2013 with acute single-dose ingestion paracetamol overdose, with (n = 221) or without (n = 938) opioid co-ingestion. Adverse outcomes included biomarkers of hepatotoxicity and the need for extended treatment. Several outcomes were assessed in relation to the APAP_pl /APAP_t ratio.

RESULTS

Median ingested dose of paracetamol was low in both groups (10 g). Statistical comparison of the median APAP_pl /APAP_t ratios showed a significant difference (0.65 vs. 0.56 for the paracetamol-only and paracetamol-opioid groups respectively, P = .0329). Although there was a trend towards a lower risk of predefined toxic outcomes with opioid co-ingestion, statistical analysis did not show a significant difference, with outcomes for the paracetamol-only and paracetamol-opioid groups including the following: alanine transaminase >2× upper limit of normal, 7.7 vs. 5.7% (P = .6480); alanine transaminase >1000 IU/L, 2.4 vs. 0% (P = .2145); international normalised ratio > 1.3, 8.6 vs. 4.4% (P = .2774); and transfer to tertiary liver unit, 0.2 vs. 0% (P nonsignificant).

CONCLUSION

Our study does not support a change in current clinical practise beyond standard testing at 4 hours or longer post ingestion for mixed low dose paracetamol-opioid overdose.

A clinician's guide to self-poisoning with paracetamol in youth: The what, when and why?

AIM

Deliberate self-poisoning or overdose is a common presentation to the paediatric emergency departments (ED) due to a lack of emergency access to child and adolescent mental health services. We overview medical and psychiatric assessment of overdoses in youth with the most commonly implicated drug, paracetamol, as a case study.

METHODS

A what, when and why framework is adopted to guide clinicians on what information should be ascertained, when overdose treatment should be initiated and how to explore why the overdose occurred.

RESULTS

Presentations are often asymptomatic while gastrointestinal symptoms offer an alarm signal for severe hepatotoxicity. A worst-case exposure amount and time elapsed since ingestion should be calculated to determine whether N-acetylcysteine treatment is indicated. Establishing reasons why the young person took the overdose, along with assessing the degree of remorse or regret, is crucial for discharge planning.

CONCLUSION

Given the importance of timely assessment and treatment, paediatric emergency staff need to be familiar with the protocol for care. Attention needs to be focused on both the medical and psychological risk, and staff need to consider the reasons behind the overdose and following a biopsychosocial assessment, ensure that the young person and family are adequately signposted for future mental health care if needed.

[Medical history taking and clinical examination in emergency and intensive care medicine]

Die Anamnese und die klinische Untersuchung stellen das traditionelle Grundwerkzeug der ärztlichen Tätigkeit bei der Diagnosefindung dar. Sowohl Anamnese als auch klinische Untersuchung haben in der modernen Notfall- und Intensivmedizin zu Unrecht an praktischem Stellenwert verloren. Bei der Diagnosefindung des akut oder kritisch kranken Patienten müssen die Reihenfolge, Technik und Fokussierung der Anamnese und klinischen Untersuchung an die individuelle Situation und den Zustand des Patienten angepasst werden. In diesem Artikel wird die nach wie vor zentrale Bedeutung der Anamnese und klinischen Untersuchung bei der Diagnosefindung des Notfall- und Intensivpatienten praktisch evaluiert und beleuchtet.

Diagnosis of acute intoxications in critically ill patients: focus on biomarkers - part 1: epidemiology, methodology and general overview

Acute intoxications account for a significant proportion of the patient population in intensive care units and sedative medications, ethanol, illicit drugs, inhalable poisons and mixed intoxications are the most common causes. The aim of this article is to describe biomarkers for screening and diagnosis of acute intoxications in critically ill patients. For this purpose, a survey of the relevant literature was conducted, and guidelines, case reports, expert assessments, and scientific publications were reviewed. In critical care, it should always be attempted to identify and quantify the poison or toxin with the assistance of enzyme immunoassay (EIA), chromatography, and mass spectrometry techniques and this section is critically appraised in this publication. The principles for anion gap, osmol gap and lactate gap and their usage in intoxications is shown. Basic rules in test methodology and pre-analytics are reviewed. Biomarkers in general are presented in part one and biomarkers for specific intoxications including ethanol, paracetamol, cardiovascular drugs and many others are presented in part two of these publications.

Substances Involved in Suicidal Poisonings in the United States

OBJECTIVE

This study investigated specific substances most commonly involved in suicidal poisonings, causing severe clinical effects, and leading to intensive treatments.

METHOD

Suicidal poisoning cases for individuals ≥13 years old were obtained from the National Poison Data System for 2011-2015. The most common products involved in single and multiple-product poisonings were identified. Single product cases were used to calculate substances causing the largest numbers of serious clinical effects and leading to intensive treatments.

RESULTS

More than half of reported cases involved only a single product (54.4%), but this frequency was higher at the extremes of age (66.7% in adolescents 13-19 years old and 70.5% in individuals ≥90 years old) and among pregnant women (65.8%). The top three substances involved in single-product poisonings were over-the-counter (OTC) medications, while alcohol and prescription sedatives were most common in multiple-product poisonings. One OTC medication, diphenhydramine, was a frequent cause of several serious clinical effects and intensive treatments.

CONCLUSIONS

Single product suicidal poisonings were more frequent with extremes of age and in pregnancy. OTC products were more frequently used in single product attempts. Products causing serious clinical effects can be targeted for suicide prevention efforts as well as education of health care providers.

[Acute intoxications: markers for screening, diagnosis and therapy monitoring]

Acute poisonings account for a significant proportion of the patient population presenting to intensive care units, whereby mixed drug overdoses and prescription drug overdoses predominate. The aim of this article was to describe indications for screening, diagnosis and therapy monitoring in acute overdoses in the intensive care unit. To conduct this work, a literature search was carried out and a review was written based on guidelines, case reports, expert opinions and scientific publications. Toxidromes are a useful tool for classification of clinical characteristics when the causative agent is initially unknown. Especially in critical care medicine, identifying and quantifying of the causative toxin by enzyme immunoassays, chromatography and mass spectrometry should be attempted. Intensive care treatment of patients with acute overdoses includes not only monitoring and support of vital functions but also methods for primary and secondary elimination of toxins. The indication for the use of extracorporeal procedures should be carefully evaluated and the method should be chosen based on protein binding and molecular size. Lipid emulsion therapy, high-dose insulin euglycaemia therapy and hyperbaric oxygenation are also increasingly used.

Intensive care admissions due to poisoning

BACKGROUND

Poisoning represents a significant part of admissions to intensive care units. The aim of this nationwide study was to describe recent national quality register data of demographics and mortality for these patients.

METHOD

A retrospective national observational study including all patients over 19 years admitted to an ICU in Sweden, between 1 January 2010 and 31 December 2011, with an ICD-10 code for poisoning. The data were collected from three national registers (The Swedish Intensive Care Register, The National Patient Register, and The Cause of Death Register).

RESULTS

The incidence of ICU-treated poisonings was 43/100,000. Twenty-one per cent (n = 8155) of all poisoned patients seeking medical care were admitted to the ICU. Their median age was 38 years (q1-q3: 26-51), as many men as women and 46.5% (n = 3790) had a previous registered poisoning. A mix of different substances was the most common type of suspected poisoning (29.7%, n = 2424). The in-hospital mortality was 1.9% and was correlated to invasive mechanical ventilation (OR 6.91 CI 95% 4.59-10.42), age > 40 (OR 4.54 CI 95% 2.86-7.21) and no previous hospitalisation for poisoning (OR 3.23 CI 95% 2.06-5.07). For 78.3% (n = 119) of the deceased patients, the fatal poisoning was their first diagnosed poisoning. The 30-day mortality was 2.7%, a majority died from poisoning (P < 0.01).

CONCLUSION

In Sweden, patients treated in the ICU due to poisoning represent a fifth of all poisoned patients seeking medical care. Older men with no previous poisoning were considered a high-risk group.

Clinical parameters that predict the need for medium or intensive care admission in intentional drug overdose patients: A retrospective cohort study

INTRODUCTION

Many patients with intentional drug overdose (IDO) are admitted to a medium (MC) or intensive care unit (IC) without ever requiring MC/IC related interventions. The objective of this study was to develop a decision tool, using parameters readily available in the emergency room (ER) for patients with an IDO, to identify patients requiring admission to a monitoring unit.

METHODS

Retrospective cohort study among cases of IDO with drugs having potentially acute effects on neurological, circulatory or ventilatory function, admitted to the MC/IC unit between 2007 and 2013. A decision tool was developed, using 6 criteria, representing intubation, breathing, oxygenation, cardiac conduction, blood pressure, and consciousness. Cases were labeled as 'high acuity' if one or more criteria were present.

RESULTS

Among 255 cases of IDO that met the inclusion criteria, 197 were identified as "high acuity". Only 70 of 255 cases underwent one or more MC/IC related interventions, of which 67 were identified as 'high acuity by the decision tool (sensitivity 95.7%).

CONCLUSION

In a population of patients with intentional drug overdose with agents having potentially acute effect on vital functions, 95.7% of MC/IC interventions could be predicted by clinical assessment, supplemented with electrocardiogram and blood gas analysis, in the ER.

Fatal toxicity index of medicinal drugs based on a comprehensive toxicology database

The fatal toxicity index (FTI) is the absolute number of fatal poisonings caused by a particular drug divided by its consumption figure. Consequently, it is a useful measure in evaluating toxicity of the drug and its relevance in fatal poisonings. In this study, we assessed the FTI of medicinal drugs in 3 years (2005, 2009, and 2013) in Finland. As the measure of drug consumption, we used the number of defined daily doses (DDD) per population in each year. There were 70 medicinal drugs in Finland for which the mean FTI expressed as the number of deaths per million DDD over the three study years was higher or equal to 0.1. The Anatomical Therapeutic Chemical (ATC) classification system was used for the classification of the active ingredients of medicinal drugs according to the organ or system which they act on. Of these 70 drugs, 55 drugs (78.6 %) acted on the nervous system (denoted by ATC code N), 11 (15.7 %) on the cardiovascular system (C), three (4.3 %) on the alimentary tract and metabolism (A), and one (1.4 %) on the musculoskeletal system (M). The nervous system drugs consisted of 20 psycholeptics, (ATC code N05), 20 psychoanaleptics (N06), eight analgesics (N02), six antiepileptics (N03), and one other nervous system drug (N07). The highest individual FTIs were associated with the opioids methadone, dextropropoxyphene, oxycodone, tramadol, and morphine; the antipsychotics levomepromazine and chlorprothixene; and the antidepressants doxepin, amitriptyline, trimipramine, and bupropion. Buprenorphine was not included in the study, because most of the fatal buprenorphine poisonings were due to smuggled tablets. A clearly increasing trend in FTI was observed with pregabalin and possibly with bupropion, both drugs emerging as abused substances.

Rapid identification of pesticides in human oral fluid for emergency management by thermal desorption electrospray ionization/mass spectrometry

Self-poisoning with pesticides accounts for approximately one-third of all suicides worldwide. To expedite rescue in the emergency department, it is essential to develop a point-of-care analytical method for rapid identification of ingested pesticides. In this study, five of the most common pesticides ingested by self-poisoning patients in Taiwan were analyzed from oral fluid samples. Pesticide-oral fluid mixtures were applied on a cotton swab and then transferred into methanol. A metallic probe was used to sample the methanol solution for subsequent thermal desorption-electrospray ionization mass spectrometry analysis. Altogether, pesticide sampling, transfer, desorption, ionization, and detection took less than 1 min. The reproducibility of this method (n = 6) was shown in the observed low-relative standard deviation (<7%) in the detection of pesticide in oral fluid. The detection limits of the pesticides in oral fluid obtained from four human subjects by thermal desorption-electrospray ionization mass spectrometry were between 1-10 ppb with relative standard deviation 10.7%. Moreover, in this study, linear responses of five pesticides in oral fluid with concentrations between 1 ppb-1 ppm (R2 between 0.9938 and 0.9988) were observed. As the whole analytical process is extremely short, this technique allows for early non-invasive point-of-care identification of pesticides in the oral fluid of self-poisoning patients in the emergency room, providing important toxicological information for decision-making during critical resuscitation.

A multicentre programme of clinical and public health research in support of the National Suicide Prevention Strategy for England

Objectives

To carry out a programme of linked research studies aimed at improving the management of self-harm, reducing the incidence of suicide and providing reliable data to evaluate the impact of theNational Suicide Prevention Strategy for England(2002).

Methods

There were four research streams: (1) we studied inquest records from 12 coroners and Ministry of Justice data to assess the accuracy of official suicide statistics; (2) we used Office for National Statistics mortality statistics, data from the Multicentre Study of Self-harm in England, national liver unit data, prescription data and patient interviews to assess (a) the impact of paracetamol (acetaminophen) pack size restrictions (1998), (b) the impact of withdrawal of co-proxamol in 2007 and (c) the relative toxicity in overdose of commonly used antidepressants; (3) we carried out 3-month audits of self-harm management in 32 hospitals to investigate variations between hospitals and the impact of management on repeat self-harm; and (4) we developed and piloted letter-based contact interventions aimed at reducing self-harm.

Key findings

(1) Between 1990 and 2005, the proportion of researcher-defined suicides given a verdict of suicide by the 12 coroners studied decreased by almost 7%, largely because of the increased use of misadventure/accident verdicts for deaths thought, on clinical review, to be suicides. Use of narrative verdicts increased markedly. Coroners who gave more narrative verdicts also gave fewer suicide verdicts, and geographical variations in the use of narrative verdicts appeared to distort reliable assessment of small-area differences in suicide rates. 2(a) UK legislation to reduce pack sizes of paracetamol was followed by a 43% reduction in number of deaths and a 61% reduction in registrations for liver transplantation over the next 11 years. Paracetamol overdoses were often impulsive and some were influenced by media (including the internet); sales outlets appeared mostly to be adhering to sales guidance. Smaller pack sizes of paracetamol for sale in Ireland compared with England did not result in a smaller number of tablets being taken in overdose. There was no clear evidence of an effect of the legislation on prescribing of non-steroidal anti-inflammatory drugs, nor on resulting gastrointestinal bleeds. 2(b) Withdrawal of co-proxamol from use in the UK resulted in approximately 600 fewer deaths than predicted between 2005 and 2010 based on previous trends, with no evidence of substitution by poisoning with other analgesics. 2(c) Of the tricyclic antidepressants, dosulepin and doxepin had the greatest toxicity. Citalopram was more toxic than other selective serotonin reuptake inhibitors. (3) There was marked variation between hospitals in the management of self-harm; effects of this variation on patient outcomes were unclear, although psychosocial assessment may have been associated with reduced repetition. Levels of specialist assessment remained static between 2001–2 and 2010–11, but service quality appeared to improve. (4) Findings of two pilot randomised controlled trials suggested that, although it would be feasible to scale up these interventions to full trials, these interventions might have low generalisability and be of limited benefit to patients.

Conclusion

Within the context of the strengths and limitations of the individual studies, this research programme has made significant additions to the evidence base related to suicide and self-harm prevention in the UK.

Study registration

A pilot study of a contact and information based intervention to reduce repeat self-harm; ISRCTN65171515.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Deliberate drug poisoning with slight symptoms on admission: are there predictive factors for intensive care unit referral? A three-year retrospective study

Deliberate drug poisoning leads to 1% of emergency department (ED) admissions. Even if most patients do not exhibit any significant complication, 5% need to be referred to an intensive care unit (ICU). Emergency physicians should distinguish between low- and high-acuity poisoned patients at an early stage to avoid excess morbidity. Our aim was to identify ICU transfer factors in deliberately self-poisoned patients without life-threatening symptoms on admission. We performed a 3-year retrospective observational study in a university hospital. Patients over 18 years of age with a diagnosis of deliberate drug poisoning were included. Clinical and toxicological data were analysed with univariate tests between groups (ED stay versus ICU transfer). Factors associated with ICU admission were then included in a logistic regression analysis. Two thousand five hundred and sixty-five patients were included. 63.2% were women, and median age was 40 (28-49). 142 patients (5.5%) were transferred to ICU. Cardiac drugs [adjusted OR (aOR) = 19.81; 95% confidence interval (95% CI): 7.93-49.50], neuroleptics (aOR = 2.78; 95% CI: 1.55-4.97) and meprobamate (aOR = 2.71; 95% CI: 1.27-5.81) ingestions were significantly linked to ICU admission. A presumed toxic dose ingestion (aOR = 2.27; 95% CI: 1.28-4.02), number of ingested tablets (aOR = 1.01; 95% CI: 1.01-1.02 for each tablet) and delay between ingestion and ED arrival <2 hr (aOR = 2.85; 95%CI: 1.62-5.03) were also factors for ICU referral. The Glasgow Coma Scale was the only clinical feature associated with ICU admission (aOR = 1.57; 95% CI: 1.44-1.70 for each point loss). These results suggest that emergency physicians should pay particular attention to toxicological data on ED admission to distinguish between low- and high-acuity self-poisoned patients.

Impact of different pack sizes of paracetamol in the United Kingdom and Ireland on intentional overdoses: a comparative study

Background

In order to reduce fatal self-poisoning legislation was introduced in the UK in 1998 to restrict pack sizes of paracetamol sold in pharmacies (maximum 32 tablets) and non-pharmacy outlets (maximum 16 tablets), and in Ireland in 2001, but with smaller maximum pack sizes (24 and 12 tablets). Our aim was to determine whether this resulted in smaller overdoses of paracetamol in Ireland compared with the UK.

Methods

We used data on general hospital presentations for non-fatal self-harm for 2002 - 2007 from the Multicentre Study of Self-harm in England (six hospitals), and from the National Registry of Deliberate Self-harm in Ireland. We compared sizes of overdoses of paracetamol in the two settings.

Results

There were clear peaks in numbers of non-fatal overdoses, associated with maximum pack sizes of paracetamol in pharmacy and non-pharmacy outlets in both England and Ireland. Significantly more pack equivalents (based on maximum non-pharmacy pack sizes) were used in overdoses in Ireland (mean 2.63, 95% CI 2.57-2.69) compared with England (2.07, 95% CI 2.03-2.10). The overall size of overdoses did not differ significantly between England (median 22, interquartile range (IQR) 15-32) and Ireland (median 24, IQR 12-36).

Conclusions

The difference in paracetamol pack size legislation between England and Ireland does not appear to have resulted in a major difference in sizes of overdoses. This is because more pack equivalents are taken in overdoses in Ireland, possibly reflecting differing enforcement of sales advice. Differences in access to clinical services may also be relevant.

Fatal poisonings in Oslo: a one-year observational study

Background

Acute poisonings are common and are treated at different levels of the health care system. Since most fatal poisonings occur outside hospital, these must be included when studying characteristics of such deaths. The pattern of toxic agents differs between fatal and non-fatal poisonings. By including all poisoning episodes, cause-fatality rates can be calculated.

Methods

Fatal and non-fatal acute poisonings in subjects aged ≥16 years in Oslo (428 198 inhabitants) were included consecutively in an observational multi-centre study including the ambulance services, the Oslo Emergency Ward (outpatient clinic), and hospitals, as well as medico-legal autopsies from 1st April 2003 to 31st March 2004. Characteristics of fatal poisonings were examined, and a comparison of toxic agents was made between fatal and non-fatal acute poisoning.

Results

In Oslo, during the one-year period studied, 103 subjects aged ≥16 years died of acute poisoning. The annual mortality rate was 24 per 100 000. The male-female ratio was 2:1, and the mean age was 44 years (range 19-86 years). In 92 cases (89%), death occurred outside hospital. The main toxic agents were opiates or opioids (65% of cases), followed by ethanol (9%), tricyclic anti-depressants (TCAs) (4%), benzodiazepines (4%), and zopiclone (4%). Seventy-one (69%) were evaluated as accidental deaths and 32 (31%) as suicides. In 70% of all cases, and in 34% of suicides, the deceased was classified as drug or alcohol dependent. When compared with the 2981 non-fatal acute poisonings registered during the study period, the case fatality rate was 3% (95% C.I., 0.03-0.04). Methanol, TCAs, and antihistamines had the highest case fatality rates; 33% (95% C.I., 0.008-0.91), 14% (95% C.I., 0.04-0.33), and 10% (95% C.I., 0.02-0.27), respectively.

Conclusions

Three per cent of all acute poisonings were fatal, and nine out of ten deaths by acute poisonings occurred outside hospital. Two-thirds were evaluated as accidental deaths. Although case fatality rates were highest for methanol, TCAs, and antihistamines, most deaths were caused by opiates or opioids.

Reliability of history of acetaminophen ingestion in intentional drug overdose patients

The objective of this study was to determine the reliability of denial of acetaminophen ingestion in intentional drug overdose patients. All intentional drug overdose patients admitted to an emergency department who were able to provide a history were included. A detailed history was obtained on names, timing and number of medications ingested, and serum acetaminophen was assayed. Multidrug ingestion was defined as the reporting of ≥2 medications. Patients were considered ‘reliable’ if they reported acetaminophen ingestion and had detectable acetaminophen levels or the other way around. Validity parameters of acetaminophen history were assessed by sensitivity, specificity and positive and negative predictive values. A total of 154 patients were included. History was significantly more reliable in patients who denied ingestion of acetaminophen (n = 107) compared with patients who reported it (n = 47; 95.3% vs 65.9%, respectively; p < 0.0001, 95% CI of the difference 17.5%—41.2%). No suicidal patient who denied both acetaminophen and multidrug ingestions had a detectable acetaminophen level (negative predictive value 1, 95% CI 0.93—1.0). It is suggested that denial of both acetaminophen and multidrug ingestions by intentional drug overdose patients after a thorough history taking can be considered reliable for acetaminophen history. In facilities with limited resources, these patients may not require routine acetaminophen screening.

Preventing errors in patient management: the emergency department clinician and the toxicology laboratory

Poor communication between the clinical toxicologist and the toxicology laboratory can result in a variety of problems. Clinicians must familiarize themselves with the toxicology assays that are available in their hospital and how to interpret assay results. Toxicology tests ordered in the emergency department should provide useful information for patient management and disposition. Toxicology laboratory personnel should have a good working relationship with emergency department clinicians and clinical toxicologists to maximize the usefulness of the laboratory in patient management.

Presentations of patients of poisoning and predictors of poisoning-related fatality: findings from a hospital-based prospective study

BACKGROUND

Poisoning is a significant public health problem worldwide and is one of the most common reasons for visiting emergency departments (EDs), but factors that help to predict overall poisoning-related fatality have rarely been elucidated. Using 1512 subjects from a hospital-based study, we sought to describe the demographic and clinical characteristics of poisoning patients and to identify predictors for poisoning-related fatality.

METHODS

Between January 2001 and December 2002 we prospectively recruited poisoning patients through the EDs of two medical centers in southwest Taiwan. Interviews were conducted with patients within 24 hours after admission to collect relevant information. We made comparisons between survival and fatality cases, and used logistic regressions to identify predictors of fatality.

RESULTS

A total of 1512 poisoning cases were recorded at the EDs during the study period, corresponding to an average of 4.2 poisonings per 1000 ED visits. These cases involved 828 women and 684 men with a mean age of 38.8 years, although most patients were between 19 and 50 years old (66.8%), and 29.4% were 19 to 30 years. Drugs were the dominant poisoning agents involved (49.9%), followed by pesticides (14.5%). Of the 1512 patients, 63 fatalities (4.2%) occurred. Paraquat exposure was associated with an extremely high fatality rate (72.1%). The significant predictors for fatality included age over 61 years, insufficient respiration, shock status, abnormal heart rate, abnormal body temperature, suicidal intent and paraquat exposure.

CONCLUSION

In addition to well-recognized risk factors for fatality in clinical settings, such as old age and abnormal vital signs, we found that suicidal intent and ingestion of paraquat were significant predictors of poisoning-related fatality. Identification of these predictors may help risk stratification and the development of preventive interventions.

Clinical assessment compared to laboratory screening in acutely poisoned patients

Acute poisonings may require identification of the toxic agents. It is impossible for routine laboratories to provide a full spectrum of toxicological analyses, and clinicians should know the reliability of the clinical diagnoses of toxic agents. We performed a 1-year study of hospitalized acute poisonings to determine the agreement between the clinical assessment on admission and serum laboratory tests for eight common toxic agents. Blood samples were drawn in 665 (70%) of the 947 admissions. The total number of laboratory found agents (967) exceeded the clinically suspected (871) by 11%. The agreement between the clinical assessment and laboratory analyses was good for ethanol and paracetamol ( κ = 0.70 for both), whereas only moderate or fair for other agents ( κ 0.22–0.51). Sensitivities of the clinical assessments compared to the laboratory results were better for common than rare agents, and better for higher than lower serum concentrations. The four most common agents (ethanol, benzodiazepines, paracetamol, and opiates) had overall sensitivity of 82% for higher-than-median serum concentrations, whereas the other agents had sensitivities ranging from 14% to 71% for higher-than-median concentrations. The reliability of the clinical diagnoses varied to such an extent that agents, which are important to recognize for specific treatment, should be tested for.

Fatality after deliberate ingestion of sustained-release ibuprofen: a case report

INTRODUCTION

Ibuprofen is a nonsteroidal anti-inflammatory drug available over the counter and on prescription for the management of pain and inflammation. Severe toxicity is rare following deliberate self-poisoning with ibuprofen, and patients are usually either asymptomatic or develop only mild gastrointestinal toxicity. Although there have been nine other reported fatalities, co-existent factors have probably contributed to all of these deaths. We report here a fatality from isolated toxicity following self-poisoning with sustained-release ibuprofen.

CASE REPORT

A 26-year-old female presented after deliberate ingestion of up to 105 g sustained-release ibuprofen, with a reduced level of consciousness, severe metabolic acidosis and haemodynamic compromise. Despite intensive supportive management, gut decontamination with multidose activated charcoal and correction of the metabolic acidosis with sodium bicarbonate and haemofiltration, the patient did not survive. The ibuprofen concentration ante mortem on presentation in peripheral blood was 760 mg/l and the concentrations post mortem were 518 mg/l in peripheral blood, 74 mg/kg in liver extract and 116 mg/l in the gastric contents.

DISCUSSION

Most patients with ibuprofen poisoning are either asymptomatic or have mild gastrointestinal symptoms; severe poisoning with ibuprofen is rare. We report the first death related to isolated sustained-release ibuprofen poisoning.

Redefining the ACE-inhibitor dose-response relationship: substantial blood pressure lowering after massive doses

OBJECTIVES

The blood pressure-lowering dose-response relationship for angiotensin converting enzyme (ACE) inhibitors is assumed to flatten at doses higher than those conventionally used in clinical practice. However, existing clinical trial data do not adequately address the haemodynamic effects of high ACE inhibitor dosages. Therefore, we examined the blood pressure responses in patients presenting to hospital following a deliberate ACE inhibitor overdose.

METHODS

The study design was a retrospective case review, and included all patients who presented to our hospital in the past 5 years after an ACE inhibitor overdose. The data collected were heart rate and systemic blood pressure at various times after ingestion and maximum haemodynamic derangement; these were compared to baseline or recovered values.

RESULTS

Data from 33 patients (24 men) were evaluated. The median (inter-quartile range, IQR) age of the patients was 49 years (IQR: 42-56 years). The median stated dose ingested was 140 mg (IQR: 60-280 mg), which is 20x (IQR: 7-42) the defined daily dose. The maximum fall in systolic blood pressure was 50 mmHg (IQR: 40-64 mmHg), diastolic blood pressure was 35 mmHg (IQR: 26-43 mmHg) and mean blood pressure was 39 mmHg (IQR: 30-47 mmHg).

CONCLUSIONS

The observed reduction in blood pressure following an overdose of an ACE inhibitor was greater than anticipated based on data from therapeutic doses. We conclude that a blood pressure-lowering dose-response relationship extends to higher ACE inhibitor doses than those conventionally used in clinical practice.

Clinical vs. laboratory identification of drugs of abuse in patients admitted for acute poisoning

OBJECTIVE

The extent of drug abuse in patients admitted for self-poisonings is uncertain. The aim of this study was to assess the pattern of drugs of abuse among patients admitted for acute poisoning according to age and gender, and to study the concordance between the clinical assessments by the physicians on duty and the drug analyses.

METHODS

Prospective cross sectional study of all patients (n = 405, 52% males, median age 31 years) treated for acute poisoning in our department during one year (2001). The physician on-call classified type of drug of abuse by history and clinical assessment. This was later compared to urine and blood samples analysed for ethanol, benzodiazepines, opiates, cocaine, ecstasy, GHB, amphetamine and cannabis.

RESULTS

In 320 admissions (79%), the comparison between clinical diagnosis and laboratory analyses could be performed. A total of 478 drugs were suspected and 621 were found. The main toxic agents found were benzodiazepines (49.7%), ethanol (40.3%), opiates (35.3%), cannabis (23.8%) and amphetamine (21.3%). Ninety-two had used drugs of abuse. The agreement between clinical assessments and laboratory findings was best for GHB and ethanol (kappa = 0.43), and for opiates (k = 0.38). For benzodiazepines and cannabis, the concordance was poor (k = 0.18 and 0.10, respectively). However, the correct clinical evaluation for these substances was 59% and 77%, respectively.

CONCLUSIONS

Drugs of abuse were more frequently found than suspected clinically. Benzodiazepines, ethanol and opiates were most common. The agreement between clinical assessment and drug analyses was moderate to low. Physicians seem to underestimate the use of these drugs.

Change in profile of acute self drug-poisonings over a 10-year period

All acute, deliberate, drug-poisoning-related emergency department visits over two periods of one year, 1992-1993 (P1) and 2001-2002 (P2), were reviewed to investigate trends in substances used for acute self drug-poisonings over a 10-year period. For P1 and P2 respectively, 804 and 830 episodes of acute self drug-poisonings were compared. For the two studied periods, psycholeptic drugs predominated (78 and 77%); however, benzodiazepines declined (67 to 55%; P <0.01) and antidepressants increased (9.5 to 15%; P <0.01). Moreover, the type of antidepressant changed markedly with a decrease of the imipraminic antidepressants (48.4 to 10.7%) and an increase of selective serotonin reuptake inhibitors (31.2 to 74%). The proportion of benzodiazepine-related drugs increased with time (7.9 to 14.1%). The proportion of analgesics was 5.4% for P1 and 7.3% for P2; paracetamol, alone or associated to other compounds, remained the most incriminated. Nevertheless, opioids were more often mentioned during the later period (11.6 to 24.5%). The trend of the different pharmacological families used in acute self drug-poisonings is not fundamentally different over a 10-year period. However, there are some qualitative modifications, which are important for readjusting the emergency physician's toxicological knowledge and public health actions.

Relative Toxicity of Selective Serotonin Reuptake Inhibitors (SSRIs) in Overdose

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) have increasingly replaced tricyclic antidepressants (TCAs) in the treatment of depression. They appear to be safer in overdose, but there is little information on their spectrum of toxicity in overdose, or relative toxicity of each agent.

OBJECTIVE

To determine the effect of SSRIs in overdose, as a group, and the relative toxicity of five different SSRIs.

METHODS

A review of consecutive SSRI poisoning admissions to a single toxicology unit. Outcomes examined were length of stay [LOS], intensive care [ICU] admission rate, coma, seizures, electrocardiographic [ECG] abnormalities, and presence of serotonin syndrome [SS]. Logistic regression was used to model the outcome QTc >440 msec.

RESULTS

There were 469 SSRI poisoning admissions analyzed after exclusions. The median LOS for all SSRI overdose admissions was 15.3 h (IQR: 10.5-21.3) and 30 of 469 (6.4%; 95% CI 4.3-9.0%) cases were admitted to ICU. The incidence of seizures was 1.9% and coma was 2.4%. Serotonin syndrome occurred in 14% of overdoses. Comparison of median QTc intervals of the five SSRIs was significantly different (p=0.0002); citalopram (450 IQR: 436-484) was individually different to fluoxetine (p=0.045), fluvoxamine (p=0.022), paroxetine (p=0.0002), and sertraline (p=0.001). The proportion of citalopram overdoses with a QTc >440 msec was 68%, differing significantly from sertraline (adjusted OR: 5.11 95% CI 2.32-11.27). Comparison of median QT intervals of the five SSRIs was statistically different (p=0.026); citalopram (400 IQR: 380-440) was individually different from sertraline (p=0.023).

CONCLUSIONS

This study shows SSRIs are relatively safe in overdose despite serotonin syndrome being common. The exception was citalopram, which was significantly associated with QTc prolongation. We believe that cardiac monitoring should be considered in citalopram overdose, particularly with large ingestions and patients with associated cardiac disease.

The utility of the history and clinical signs of poisoning in childhood: a prospective study

The authors aimed to evaluate the utility of the history and clinical signs for predicting ingestion of poisons in children. A prospective cohort study was performed of all patients presenting with suspected poisoning to a pediatric emergency department over a 13-month period. Clinical data were collected on a preformatted consultation sheet. Urine drug screens (UDS) were analyzed by gas chromatography/mass spectrometry (GC/MS). Serum toxicologic tests were performed when clinically indicated. The sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) of the history and clinical signs were calculated, first using UDS and, second, using all available toxicologic tests as the gold standards. Of 249 patients, 110 (46%) had a UDS performed. The purported poison ingested was potentially identifiable by GC/MS in 57 (52%) of these UDS. Only the results from these 57 UDS were included in our statistical analysis. Overall, the suspected poison was identified in 33 (58%) of the 57 UDS. Similarly, in the less than 5 years age subgroup, 28 (56%) of 50 UDS were positive. Odor on the breath (PPV 100%), followed by symptoms consistent with poisoning (PPV 92%) and presence of poison on clothes (PPV 86%) were the most useful predictors of a positive UDS. Similar results were obtained when all available toxicologic tests were used as the gold standard. The best clinical predictors of poisonous ingestion in children were found to be odor on the breath, symptoms consistent with poisoning, and presence of poison on the patient's clothes. Approximately 40% of children who present with poisoning have not been exposed to the putative toxin.

Moclobemide poisoning: toxicokinetics and occurrence of serotonin toxicity

AIMS

To investigate the spectrum of toxicity of moclobemide overdose, the occurrence of serotonin toxicity, and to estimate toxicokinetic parameters.

METHODS

All moclobemide overdoses presenting over a 10-year period to the Hunter Area Toxicology Service were reviewed. Clinical features, complications, length of stay (LOS) and intensive care (ICU) admission rate were extracted from a standardized, prospectively collected database. Comparisons were made between moclobemide alone and moclobemide with a serotonergic coingestant poisoning. Serotonin toxicity was defined by a combination of Sternbach's criteria and a clinical toxicologist's diagnosis. In five patients serial moclobemide concentrations were measured. Time to maximal plasma concentration (Tmax), peak plasma concentration (Cmax) and terminal elimination half-lives were estimated.

RESULTS

Of 106 included patients, 33 ingested moclobemide alone, 21 ingested moclobemide with another serotonergic agent (in some cases in therapeutic doses) and 52 ingested moclobemide with a nonserotonergic agent. Eleven (55%) of 21 patients coingesting a serotonergic drug developed serotonin toxicity, which was significantly more than one (3%) of 33 moclobemide-alone overdoses (odds ratio 35, 95% confidence interval 4, 307; P < 0.0001). In six of these 21 cases severe serotonin toxicity developed with temperature >38.5 degrees C and muscle rigidity requiring intubation and paralysis. The 21 patients had a significantly increased LOS (34 h) compared with moclobemide alone overdoses (12 h) (P < 0.0001) and a significantly increased ICU admission rate of 57% vs. 3% (P < 0.0001). Time to peak plasma concentration was delayed in two patients where prepeak samples were obtained. Cmax increased slightly with dose, but all three patients ingesting > or = 6 g vomited or had charcoal. The mean elimination half-life of moclobemide in the five patients in whom serial moclobemide concentrations were measured was 6.3 h and elimination was first order in all cases. There was no evidence of a dose-dependent increase in half-life.

CONCLUSIONS

The effects of moclobemide alone in overdose are minor, even with massive ingestions. However, moclobemide overdose in combination with a serotonergic agent (even in normal therapeutic doses) can cause severe serotonin toxicity. The elimination half-life is prolonged by two to four times in overdose, compared with that found in healthy volunteers given therapeutic doses. This may be a result of wide interindividual variation in overall elimination, also seen with therapeutic doses, but appears not to be due to saturation of normal elimination pathways.

Urine drug screening in the medical setting

BACKGROUND

The term drug screen is a misnomer since it implies screening for all drugs, which is not possible. Current practice is to limit the testing to the examination of serum for several drugs such as ethanol, acetaminophen, salicylate, and of urine for several specific drugs or classes of drugs. In the emergency setting the screen should be performed in less than one hour. Controversies continue to exist regarding the value of urine drug testing in the medical setting. The reasons for these include the drugs involved, the sample, the methods utilized to perform the tests, and the level of understanding of the physician using the data, all of which are closely related to the other.

METHODS

Current automated methods provide rapid results demanded in emergency situations, but are often designed for, or adapted from, workplace testing and are not necessarily optimized for clinical applications. Furthermore, the use of these methods without consideration of the frequency in which the drugs are found in a given area is not cost-effective. The laboratory must understand the limitations of the assays used and provide this information to the physician. Additionally, the laboratory and the physicians using the data must cooperate to determine which drugs are appropriate and necessary to measure for their institution and clinical setting. In doing so it should be remembered that for many drugs, the sample, urine, contains the end product(s) of drug metabolism, not the parent drug. Furthermore, it is necessary to understand the pharmacokinetic parameters of the drug of interest when interpreting data. Finally, while testing for some drugs may not appear cost-effective, the prevention or reduction of morbidity and mortality may offset any laboratory costs.

CONCLUSIONS

While the literature is replete with studies concerning new methods and a few regarding physician understanding, there are none that we could find that thoroughly, objectively, and fully addressed the issues of utility and cost-effectiveness.