Correlation of antemortem and postmortem digoxin levels.

Postmortem serum digoxin levels from any source routinely exceed antemortem values. Variation resulting from site of sampling gave a mean postmortem to antemortem ratio of 1.96 for heart, 1.63 for subclavian vein, and 1.42 for femoral vein samples. No correlation could be made between the postmortem interval and the increase in post-mortem serum values, irrespective of the site of sampling. A combination of femoral venous serum and vitreous humor values gave the best information for determining possible antemortem digoxin toxicity.     

Digoxin-like immunoreactive substance in postmortem blood of infants and children

A digoxin-like immunoreactive substance (DLIS) has been reported in the serum of infants not receiving digoxin. This study was undertaken to determine if DLIS is present in the postmortem blood and tissues of infants or children and whether the endogenous substance could interfere with forensic toxicological analysis in suspected overdose. Ninety blood specimens taken from the heart at autopsy of children or infants were screened for DLIS using commercial radioimmunoassay kits. The average age at death in these cases was 8.6 months, the median age was 2 months. DLIS equivalent to 0.25 to 2.0 ng/mL digoxin was found in one third of the cases. The incidence of positive findings was 5/6 stillborns, 10/45 Sudden Infant Death Syndrome (SIDS), 10/15 deaths as a result of infection, 4/7 homicides, 1/8 deaths caused by congenital defects, and 0/9 accidental deaths. The body distribution of DLIS was investigated and highest levels were found in the liver. Findings of DLIS in blood were correlated with renal failure, (elevated vitreous urea nitrogen), electrolyte imbalance, and liver trauma. Apparent concentrations were in the equivalent therapeutic range of digoxin and would not be confused with accidental or intentional overdose with digoxin.     

Postmortem redistribution of digoxin in rats

Adult male Wistar rats were treated with either 0.1 or 3 mg/kg body weight X day of digoxin for five days, then killed and stored at 4 degrees C for 12 h in an attempt to mimic the normal preautopsy procedures in our hospital. In rats treated with 0.1 mg/kg body weight X day, the antemortem serum digoxin concentrations (SDC) were 1.1 +/- 0.4 ng/mL while the 12-h postmortem concentration was markedly increased (16.3 +/- 5.9 ng/mL) (P less than 0.01). In rats treated with 3 mg/kg body weight X day, SDC was not changed significantly (11.2 +/- 4.8 ng/mL antemortem and 13.3 +/- 6 ng/mL postmortem). Postmortem redistribution of digoxin was assessed by injection of 125I-labelled digoxin with or without pretreatment with the unlabelled drug. The results indicate that after death passive redistribution of digoxin may take place. When the SDC are within the therapeutic or low toxic range, digoxin may reenter the blood. High antemortem serum concentrations of digoxin may prevent such passive redistribution. Therefore, antemortem digoxin intoxication cannot be reliably inferred on the basis of high postmortem levels of the drug. Digoxin intoxication can be ruled out when postmortem SDC remain within the therapeutic range. The above changes cast doubt on some of the forensic and cardiologic literature, which has in the past been based on incorrect assumptions concerning postmortem behavior of digoxin.     

Fatal cyclobenzaprine overdose with postmortem values

There are only two published cases of overdose with postmortem blood cyclobenzaprine concentrations, both with confounding factors. We report two additional cases of fatal cyclobenzaprine overdose with postmortem values. Case 1: a 56-year-old female was found in full cardiopulmonary arrest after a verbal suicide threat to a friend. Postmortem blood concentrations were cyclobenzaprine 0.96 mg/L and diazepam 0.3 mg/L. Case 2: a 37-year-old male was found in full arrest by a family member after an intentional ingestion of cyclobenzaprine. Postmortem blood concentrations were cyclobenzaprine 0.8 mg/L and ethanol 0.174 gm/dL. The concentrations of diazepam and ethanol reported in these two patients were not found in quantities usually associated with a fatal outcome, suggesting that the cyclobenzaprine was the primary cause of the fatality. Additionally, the blood was drawn from a femoral site, so that postmortem redistribution is not a likely factor. Blood concentration of > or = 0.8 mg/L cyclobenzaprine may be associated with a fatal outcome.     

Serum levels of digoxin in sudden cardiac deaths

Digoxin was determined in postmortem serum samples from 100 patients who died suddenly of cardiac disease. Twenty patients had digoxin levels below the therapeutic range. Twenty-one patients had normal values within the therapeutic range (1.2-2.5 nmol/l). In ten cases there was probably an overdosage. Another 15 patients had markedly elevated levels. No digoxin concentration was found (below 0.5 nmol/l) in 34 patients. The importance of determination of digoxin levels both by the clinician and the pathologist is stressed as well as the necessity of using a correct sampling technique at autopsy.     

The rise and rise of fentanyl in postmortem casework

Forensic toxicology laboratories are navigating a period of time with increasing drug overdose deaths, an opioid epidemic, the impact of the COVID-19 pandemic, and the illicit drug market flooded with novel psychoactive substances. In New York City, the Department of Forensic Toxicology has experienced a 56% increase in postmortem casework in the past decade with fentanyl detected in 80% of all overdose deaths. Over a period of 2.5 years, 15,638 postmortem cases were tested for the presence of fentanyl and fentanyl analogs using liquid-chromatography tandem mass spectrometry (LCMSMS). Fentanyl was detected in approximately one third of cases and of these 4447 cases with femoral blood. A twofold increase in cases with high concentrations of fentanyl (>100 ng/mL) was observed between 2021 and 2022. The minor metabolite and precursor chemical, 4-ANPP (4-anilino-N-phenethylpiperidine) may help differentiate between illicit and licit fentanyl. 4-ANPP blood concentrations were <10 ng/mL in 98% of the cases and the 4-ANPP:fentanyl ratio was <0.67 for 99.1% of blood specimens. Only six cases had 4-ANPP concentrations higher than the corresponding fentanyl blood concentration. This study also highlights, the changing fentanyl analogs found in postmortem cases since 2016 in NYC with the emergence of fluorofentanyl initially identified in 2020 and continuing to dominate in comparison with the prevalence of other analogs, many of which are no longer detected in casework. The detection of one of the latest drugs to be mixed with fentanyl, namely xylazine, has also increased in prevalence by 36.7% in 2022 compared with 2021.     

An autopsy case of combined drug intoxication involving verapamil,metoprolol and digoxin

We present here a fatal poisoning case involving verapamil, metoprolol and digoxin. A 39-year-old male was found dead in his room, and a lot of empty packets of prescribed drugs were found near the corpse. The blood concentrations of verapamil, metoprolol and digoxin were 9.2 microg/ml, 3.6 microg/ml and 3.2 ng/ml, respectively. The cause of death was given as cardiac failure, hypotension and bradycardia due to a mixed drug overdose of verapamil, metoprolol and digoxin, based on the results of the autopsy and toxicological examination. We speculate that the toxicity of verapamil is potentiated by drug interaction with metoprolol and digoxin.     

Classification of digoxin concentrations in blood and tissues in cases under suspicion of poisoning

The clarification of a suspicion of poisoning at all times poses a problem to the forensic toxicologist, when a narrow margin of therapeutic safety and a low dosage coincide as in cases of digoxin poisoning. Statistical methods may serve as an aid. The post mortem digoxin concentration in the tissues of heart, kidney, liver and in blood of 45 patients who had received therapeutic daily doses and of 13 cases of fatal poisoning are compared. After logarithmic transformation of the individual concentration values a two modal distribution is obtained. There is one concentration calculated with equal probability of being classified to "therapeutic or toxic", as well as the probability of observing the "critical" concentrations of 400 ng digoxin/g cardiac tissue, 500 ng/g kidney and 250 ng/g liver after therapeutic dosing. Using the discriminant analysis each of the cases clearly falls into one of the two collectives "therapeutic" and "toxic", when taken as a separate observation. Concentration data of fatal poisonings taken from the literature are as successfully classified as the analytical results of some exhumed bodies under suspicion but not poisoned. As expected the power of discrimination increases with the number of parameters. Because of the relatively slow body distribution of digoxin the blood taken from peripheral vessels is of most important evidence.     

The diagnostic value of postmortem blood glucose determinations in cases of diabetes mellitus

In 24 cases of death in diabetic coma the peripheral venous blood showed glucose levels exceeding 3.5 mg/ml (mean value 7.76 mg/ml). In a control material of deaths of other causes the blood glucose was usually low and often zero, and all values were well below the lower limit of the diabetic concentrations. The acetone contents of the diabetic blood varied widely and were of limited diagnostic value. We conclude that glucose concentrations above 3.5 mg/ml in the peripheral blood indicate that death occurred in diabetic coma.     

Distribution of digoxin, digitoxin and their cardioactive metabolites in human heart and kidney tissue. A postmortem study

A method was developed for the specific determination of digoxin and digitoxin, as well as their semisynthetic derivatives and dependent cardioactive metabolites, in autopsy samples of heart and kidney. A collective of six patients on long-term treatment with therapeutic doses of beta-acetyldigoxin had a mean myocardial digoxin content of 46.1 +/- 25.0 ng/g (SD); kidney: 50.3 +/- 30.3 ng/g. Digoxigenin bisdigitoxoside represented the second most important metabolite in heart and kidney; digoxigenin monodigitoxoside and digoxigenin follow, respectively. In a collective of seven patients on maintenance treatment with digitoxin, the mean tissue levels were higher but the metabolic pattern was similar (myocardial digitoxin content: 78.9 +/- 38.4 ng/g, renal content: 104.1 +/- 44.1 ng/g). The amount of digoxin formed by hydroxylation under long-term treatment with digitoxin in heart and kidney were approximately 10 ng/g. A case of digoxin intoxication differed both in the tissue content and in the metabolic distribution.     

Chloroquine distribution in postmortem cases

Chloroquine concentrations in blood and tissues were examined in overdose and non-overdose cases to determine appropriate ranges for interpretation. Twenty-nine literature overdose cases and 8 non-overdose literature cases were compared with this laboratory's findings. The results indicate significant postmortem redistribution of chloroquine. Combining this laboratory's results and the literature results indicates that using a liver concentration of 150 mg/kg as a cutoff between overdose and non-overdose concentrations properly identified 30 of the 34 published cases containing liver chloroquine and 19 of the 20 presented cases.     

Disposition of quetiapine in biological specimens from postmortem cases

Quetiapine is a new atypical antipsychotic that was approved in 1997 by the U.S. Food and Drug Administration for the treatment of schizophrenia. It possesses a high affinity for 5-HT2 receptors and a low affinity for D1 and D2 dopamine receptors. Because quetiapine has only been released recently to the U.S. market, little information exists regarding therapeutic, toxic, and lethal concentrations. This study reports the detection of quetiapine in 13 postmortem cases. Following a basic liquid-liquid extraction, quetiapine was identified and quantitated by capillary gas chromatography with nitrogen phosphorus detection. Confirmation was accomplished by full scan electron impact gas chromatography/mass spectrometry. Heart blood quetiapine concentrations ranged from 0.07 to 18.37 mg/L (N = 12, mean +/- SD = 3.42 +/- 5.67, median 0.62) and femoral blood concentrations ranged from 0.06 to 19.25 mg/L (N = 10. mean +/- SD = 3.89 +/- 6.12, median 0.81). The average heart blood/femoral blood ratio was 1.31 (range 0.55 to 2.57, N = 10). Urine, bile, and gastric contents were assayed in all cases in which they were submitted. In three cases, the cause of death was determined to be quetiapine toxicity. In these cases heart blood concentrations ranged from 0.72 to 18.37 mg/L (N = 3). These data may provide a basis for establishing levels associated with quetiapine toxicity as well as therapeutic concentrations in postmortem specimens.     

Site-dependent production of gamma-hydroxybutyric acid in the early postmortem period

This study compared endogenous gamma-hydroxybutyric acid (GHB) concentrations in various postmortem fluid samples of 25 autopsy cases. All bodies were stored between 10-20 degrees C until autopsy, and the intervals between death and autopsy were less than 2 days (6-48 h). GHB concentrations were measured by headspace gas chromatography after GHB was converted to gamma-butyrolactone. Endogenous GHB concentrations were significantly higher in femoral venous blood (4.6+/-3.4 microg/ml, n=23) than in cerebrospinal fluid (1.8+/-1.5 microg/ml, n=9), vitreous humor (0.9+/-1.7 microg/ml, n=8), bile (1.0+/-1.1 microg/ml, n=9) and urine (0.6+/-1.2 microg/ml, n=12). GHB concentrations were similar in blood samples taken from different sites. Cut-off limits of 30 and 10 microg/ml are proposed for blood and urine, respectively, to discriminate between exogenous and endogenous GHB in decedents showing no or little putrefaction (postmortem intervals usually 48 h or less). The criterion established for endogenous GHB in postmortem urine may also be applicable to analytical results in cerebrospinal fluid, vitreous humor and bile from deceased persons.     

The use of rapid diagnostic test of procalcitonin serum levels for the postmortem diagnosis of sepsis

Because serum Procalcitonin is reported to be a valid postmortem marker of sepsis, this prospective study was carried out to determine whether the semi-quantitative PCT-Q((R))-Test (B.R.A.H.M.S., Germany) is a reliable indicator of postmortem Procalcitonin (PCT) serum levels, thus enabling a quick "tableside" diagnosis of sepsis. Postmortem PCT-levels of 70 forensic and 78 clinical-pathological autopsy cases (n=148) were examined using the B.R.A.H.M.S-PCT-Q-Test during autopsy. 27 cases were categorized as the cases of sepsis according to the ACCP/SCCM Consensus Conference criteria. 121 cases were assigned to the non-sepsis group. Among the 148 cases, 18 samples could not be analyzed by the reason of strong hemolysis. Using a cut-off point of 2 ng/ml, 20 cases of sepsis were identified (true positive) whereas 3 cases of sepsis were not detected (false negative). In the non-sepsis group (107 cases) 6 cases showed a positive testing (false positive). When applied within 48 h postmortem, the PCT-Q-Test showed a sensitivity of 86.96% and a specificity of 94.39% (at cut-off 2 ng/ml). Likelihood ratios and positive predictive values proved to be lower in the forensic autopsy group (PPV: 59.3% in forensic case vs. 85.1% in clinicopathological cases; NPV: 98.73% in forensic cases vs. 95.2% in clinicopathological cases). The PPVs using a cut-off point of 10 ng/ml were 100% in both groups independent of sepsis prevalences. The results show, that a high NPV for prevalences ranging from 3% to 30% can be reached using a 2 ng/ml cut-off point, whereas a cut-off of 10 ng/ml ensures a high PPV for the respective prevalences in the absence of exclusion criteria. The study provides strong evidence that the introduction of rapid diagnostic test (RDTs) of postmortem PCT serum levels may be useful in achieving rapid distinction between sepsis and non-sepsis-related causes of death, especially in conjunction with the medical case history and further autopsy results. In addition, the use of RDTs enables clinicians to conduct an evidence-based validation of clinical diagnosis, thus facilitating future clinical decision-making.     

Fluvoxamine distribution in postmortem cases

Four postmortem cases are reported in which the selective serotonin re-uptake inhibitor fluvoxamine was identified. Fluvoxamine was detectable using a standard alkaline drug screen, chromatographed well using a HP-1 column, and did not require derivitization for quantitation. Two of the cases reported were drug intoxications; fluvoxamine was only an incidental finding in the other 2 cases. Central and peripheral blood values are reported, as well as antemortem blood, bile, vitreous fluid, and urine values. No solid organs were obtained in any of the cases. Quantitations were performed using both an analytical standard and a fluvoxamine tablet for the preparation of calibrators. A comparison of quantitative values was made to evaluate the feasibility of using a tablet as the drug source for the preparation of calibrators when a pure reference material is unavailable. Postmortem peripheral blood concentrations ranged from approximately 0.5 mg/L in a case of suicidal shooting to approximately 6 mg/L in a case of drug overdose. Evidence of postmortem redistribution was noted in the only case for which both central and peripheral blood were obtained. Quantitations using an extracted drug tablet for the preparation of calibrators correlated well with quantitations using a pure reference material.     

An oxcarbazepine-related fatality with an overview of 26 oxcarbazepine postmortem cases

We present an oxcarbazepine-related fatality together with an overview of 26 postmortem cases involving oxcarbazepine observed during the period 2001-2006. The fatality case concerned a 27-year-old woman with epilepsy, who was found dead in her bed. Oxcarbazepine and its active metabolite, 10-hydroxycarbazepine, were the only compounds detected. The concentrations of oxcarbazepine were as follows: femoral blood, 2.9mg/kg; muscle, 1.8mg/kg; liver, 0.9mg/kg; gastric content (300ml), 860mg/kg; and vitreous humour, not detected. The concentrations of 10-hydroxycarbazepine were as follows: femoral blood, 66mg/kg; muscle, 40mg/kg; liver, 62mg/kg; gastric content, 27mg/kg; and vitreous humour, 25mg/kg. The analyses were performed by HPLC-DAD after liquid-liquid extraction. Oxcarbazepine intoxication was regarded as a possible cause of death. For the other 26 cases, the 10-hydroxycarbazepine concentrations ranged from 2.2 to 48mg/kg with a median of 25mg/kg.     

Cytochrome P450 2D6 (CYP2D6) genotyping on postmortem blood as a supplementary tool for interpretation of forensic toxicological results

Debrisoquine hydroxylase (CYP2D6) is involved in the metabolism of many toxicologically important drugs. The gene encoding for this enzyme displays a polymorphic distribution in all populations examined. We report a study on 46 cases, where analyses of the CYP2D6 gene were conducted on postmortem femoral blood in order to investigate the occurrence of poor metabolizers (PM). A polymerase chain reaction (PCR) method, designed and routinely used for therapeutic drug monitoring, was employed, only slightly modified. Samples from 22 cases, where the parent drug to metabolite ratio was unexpectedly high were analyzed as well as samples from 24 control cases. Genotyping could be carried out in all but one case. Previous freezing or addition of potassium fluoride as preservative did not prevent analysis. Only one PM (from the control group) was discovered, implying an occurrence of only 2.2% as compared to the reported frequency of approx. 7% in Sweden. Among the extensive metabolizers (EM), however, a number of individuals with mutated genes were identified. Although it seems reasonable to suspect a PM genotype in cases with a high concentration of a drug metabolized by CYP2D6, but without suspicion of acute overdose, our study does not support the opinion that this interpretation pitfall is particularly common. This study rather indicates that drug interactions in EMs constitute a more frequent and important problem.     

Biochemical measurements of glucose metabolism in relation to cause of death and postmortem effects

This study was performed to examine the relationship between postmortem biochemical values and cause of death. The follow samples were taken from 399 corpses: cerebrospinal fluid (CSF; n = 376, suboccipital), blood (n = 158, femoral vein), and urine (n = 101, at autopsy). (See Table 1 for causes of death) All samples were stored at -80 degrees C. A further 100 samples of blood were later taken and stored at +4 degrees C before testing. Biochemical determinations made were: glucose in CSF, blood, and urine (hexokinase method); lactate (LDH/GPT) and free acetone (HS-gas chromatography) in CSF; hemoglobin A1 in blood (microcolumn technique). In 34 cases fatal diabetic coma was considered verified by morphological and chemical findings. One hundred cases of sudden cardiac death were chosen as the main control group. In 32 of the 34 cases defined above, the value of the formula of Traub (glucose + lactate in CSF) exceeded 415 mg/dl. It is not influenced significantly by hyperglycemia or hyperlactatemia due to factors other than diabetes (i.e., carbon monoxide, asphyxia). After death the value rose till the 30th hpm, then remained stable for at least 1 week. Fatal coma was defined as the ketoacidotic form if free acetone in CSF ranged above 21 mg/l. In these cases, CSF glucose and free acetone correlated positively. Hemoglobin A1 remained stable after death. Its amount was independent from postmortem blood glucose, postmortem interval and total hemoglobin. Furthermore, the manner of storage (-80 degrees or +4 degrees C) had no significant influence on its values. In 29 of 34 cases of fatal coma, Hb A1 exceeded 12.1%. Analysis of urine glucose showed elevated levels (over 500 mg/dl) in diabetic comas. On conclusion, fatal diabetic coma seems indicated as the cause of death if measured values of postmortem biochemistry exceed the following limits: CSF-Traub 415 mg/dl, free acetone (CSF) 21 mg/l; Hb A1 12.1%; urine glucose 500 mg/dl. Most important are the Traub formula and hemoglobin A1. Usually, in fatal coma both values are elevated. If both of them are normal, diabetic coma can nearly be excluded. Combined evaluation of all values is absolutely necessary. Morphology must also always be taken into account. Consequently, a diagnosis of fatal coma can be obtained by a process of elimination.     

Blood, brain, and hair GHB concentrations following fatal ingestion

Despite the increasing incidence of illicit use of gamma-hydroxybutyrate (GHB), little information is available documenting levels of the drug in GHB fatalities. We measured GHB levels in postmortem blood, brain and hair specimens from a suspected overdose case by gas chromatography/mass spectrometry (GC/MS) following solid phase extraction (SPE) and derivatization with bis(trimethyl-silyl) trifluoroacetamide (BSTFA). Examination found 330 microg/mL GHB in femoral blood and 221 ng/mg GHB in frontal cortex brain tissue, values higher than those typically reported in the literature. The hair shaft was negative for GHB whereas the plucked root bulbs with outer root sheath attached (2,221 ng/mg) and root bulbs after washing and removal of the outer root sheath (47 ng/mg) contained the drug. Our results are consistent with an acute single dose of GHB and, as the toxicology screen was negative for other drugs of abuse, emphasize the significant danger of this drug.     

Interleukin-6 and C-reactive protein serum levels in sepsis-related fatalities during the early postmortem period

Postmortem interleukin-6 (IL-6) and C-reactive protein (CRP) serum levels were investigated prospectively in sepsis-related fatalities and non-septic fatalities by using a linear regression model. At least three blood samples were collected between 0.3 and 139 h postmortem from sepsis-related fatalities (n=8) and non-septic fatalities (n=16). In addition, one antemortem blood sample was collected shortly before death from the septic patients. Antemortem and postmortem IL-6 and CRP levels were highly elevated in all individuals included in the sepsis group. An excessive postmortem increase of IL-6 serum levels associated with progressive time after death was observed in five out of the eight septic patients. Both, IL-6 and CRP serum concentrations seem to be suitable biochemical postmortem markers of sepsis. The determination of IL-6 serum levels above 1500 pg/ml in peripheral venous blood obtained in the early postmortem interval can be considered as a diagnostic hint towards an underlying septic condition. A more precise postmortem discrimination between sepsis and non-septic underlying causes of death is provided by the postmortem measurement of serum CRP in peripheral venous blood: on condition that at least two postmortem CRP values have been determined at different time points postmortem, the CRP level of a deceased at the time of death can be calculated by using linear regression analysis. When assessing postmortem IL-6 and CRP concentrations as biochemical postmortem markers of sepsis, various clinical conditions, such as a preceding trauma or burn injury going along with elevated IL-6 and/or CRP levels prior to death as a result of the systemic inflammatory response syndrome (SIRS) should be taken into consideration, thus adding relevant information for the practical interpretation of the results.