Reference values of lithium in postmortem femoral blood.

INTRODUCTION: The main recipients of lithium, people diagnosed with bipolar disorder, show an increased mortality in both natural and unnatural causes of death. Based on international data persons diagnosed with bipolar disorder comprise 2.3-9.6% of all suicidal deaths. In cases of suicide among those suffering from bipolar disorder, 17-53% are due to fatal intoxications. Diagnosing fatal intoxications is often challenging, particularly when the reference information needed to interpret the concentration of a drug is lacking or scarce. AIM: The aim of this study was to establish postmortem femoral blood reference concentrations of lithium, providing both fatal and "normal" postmortem concentrations, as well as to investigate the impact of the mode of intoxication and to study the co-detection of lithium and antidepressant drugs in intoxications and controls. METHOD: In Sweden, forensic autopsies are performed in unnatural and obscure deaths. This study included all autopsies in which lithium was found during the study period (1992-2010). Lithium was not included in the regular drug screen, but analysed upon request using flame photometry, ion-selective electrode detection or atomic absorption spectrophotometry. Each case was evaluated according to an established strategy, with strict inclusion and exclusion criteria followed by a multi-observer manual review (Fig. 1, Table 1). The cases included were classified as single intoxications (group A), multi-drug intoxications (group B) or controls (group C). The control group only included cases where death by intoxication and antemortem incapacitation by drugs could be ruled out. RESULTS AND DISCUSSION: During the study period, lithium was found in 124 cases. After application of inclusion and exclusion criteria and the subsequent manual review, 21 cases were classified as group A (n=4), group B, (n=7) and group C (n=10). The femoral blood lithium concentrations in group A (median 2.69mmol/l) and group B (median 2.10mmol/l) were significantly different (p=0.01) compared to group C (median 0.2mmol/l). There were however no statistically significant difference between the concentrations in groups A and B. The most common mode of death in intoxications was acute-on-chronic (n=10), but the impact of chronic use on the fatal blood concentrations could not be evaluated since there was just one case without previous use. There was no difference in the proportion of co-detections of lithium and antidepressants between intoxication cases and controls.

Antipsychotics - Postmortem fatal and non-fatal reference concentrations.

Making the diagnosis fatal intoxication is a challenging task for the forensic pathologist and toxicologist, particularly when the cases involve substances where reference information is scarce or not at all available. This study presents postmortem femoral blood concentrations for 24 antipsychotic substances, based on samples collected and analyzed from 4949 autopsy cases in Sweden during 1992-2010. In addition our study provides information about the prevalence of different antipsychotics in accidental, suicidal, homicidal and uncertain deaths. The data have been selected and evaluated according to strict inclusion and exclusion criteria as well as a manual, multi-reviewer, case-by-case evaluation. The reference information is subdivided into intoxications by one specific substance only (group A, n=259), multi-substance intoxications (group B, n=614) and postmortem controls, consisting of deaths not involving incapacitation by substances (group C, n=507). Moreover, the results are compared with data based on therapeutic drug monitoring, and data collected from driving under the influence cases. Median concentrations in group A were significantly higher than in group C for all substances evaluated. For 17 of 24 substances, the median concentrations in group B were significantly higher than in group C. In general, the therapeutic drug monitoring and driving under the influence concentrations were similar to, or lower than, the concentrations in group C.