Utility of Postmortem Vitreous Beta-Hydroxybutyrate Testing for Distinguishing Sudden from Prolonged Deaths and for Diagnosing Ketoacidosis

In vitro β-hydroxybutyrate stability evaluation in femoral blood and vitreous humor for integration into forensic toxicology practices

Thanatological biochemistry has gained prominence in determining causes of death, especially when suspected fatal pathologies do not exhibit clear postmortem macroscopic and/or microscopic features, such as in cases of ketoacidosis. Indeed, in these cases, the measurement of β-hydroxybutyrate (BHB) in femoral blood and/or vitreous humor is of particular importance. However, data on its in vitro stability remain scarce, especially in vitreous humor. In this context, the study reported here aims to assess the in vitro stability of BHB. BHB quantification was performed using a liquid chromatography coupled with tandem mass spectrometry method. To investigate BHB stability, two different postmortem matrices were considered: femoral blood and vitreous humor. These matrices were pooled, aliquoted and spiked with BHB at three different concentrations (50 mg/L, 100 mg/L, and 200 mg/L; n = 3). Initial BHB concentrations were established on day 1. Each sample was then divided into two aliquots for storage under two conditions: 20 °C and 4 °C. Analyses were performed on Day 3, 7, 14, and 28. The study revealed no significant degradation of BHB in femoral blood or vitreous humor over time (days 1-28), confirming the robustness and reliability of BHB measurement in these matrices as a postmortem biomarker of ketoacidosis under the tested temperature conditions (+4 °C or -20 °C). These results support a systematic integration of BHB measurement into the routine workflow of forensic toxicology laboratories.

Establishing vitreous glucose and beta-hydroxybutyrate thresholds to assist in the diagnosis of hypothermia

The post-mortem diagnosis of hypothermia is challenging to establish due to the lack of pathognomonic findings and the confounding problem that any comorbidity may account for death. A 4-year retrospective case-control study was performed to compare the vitreous glucose and beta-hydroxybutyrate (BHB) concentrations between hypothermia deaths and controls. Over the study period 34 cases of hypothermia and 39 controls were analyzed. Hypothermia deaths versus controls had higher mean vitreous glucose (2.93 mmol/L vs. 1.14 mmol/L; p < 0.0001), BHB (1.89 mmol/L vs. 1.35 mmol/L; p = 0.01), and combined glucose+BHB (4.83 mmol/L vs. 2.46 mmol/L; p < 0.0001). Receiver operating characteristic (ROC) curves showed that the best model for predicting hypothermia in all cases was a combined vitreous glucose+BHB threshold of 2.03 mmol/L (sensitivity 88.2 %; specificity 56.4 %). A sub-group analysis broken down by detectable levels of blood ethanol showed that cases of hypothermia with and without ethanol maintained higher median vitreous glucose relative to the controls (2.05 vs. 0.35 mmol/L and 2.70 vs. 0.65 mmol/L; p = 0.02), however median BHB was only significantly elevated when ethanol was absent (1.88 vs. 1.42 mmol/L; p < 0.0001). Subsequent ROC curve analysis demonstrated that a better model for predicting hypothermia was in cases when blood ethanol was absent. In those deaths vitreous BHB alone had the best area under the curve, with an optimum threshold of 1.83 mmol/L (sensitivity 83.3 %; specificity 96.3 %). This study shows that post-mortem vitreous glucose and BHB are useful ancillary studies to assist in the diagnosis of hypothermia. Ethanol however is a confounder and can alter the utility of vitreous BHB when diagnosing hypothermia in those who have consumed alcohol prior to death.

Alcoholic ketoacidosis evaluated with a point-of-care capillary beta-hydroxybutyrate measurement device

BACKGROUND

The diagnosis of alcoholic ketoacidosis (AKA) has traditionally been made based only on clinical history and the presence of severe metabolic acidosis with a high anion gap (AG); however, the concentration of beta-hydroxybutyrate (BOHB), a pivotal ketone body in AKA, is not evaluated in most cases. The aim of this study was to clarify the clinical spectrum of AKA in terms of the severity of ketoacidosis by using a point-of-care capillary BOHB measurement device.

METHODS

This retrospective case series was conducted at a Japanese private teaching hospital. Patients with suspected AKA, based on their clinical history, who underwent BOHB measurement using a point-of-care capillary measurement device in the emergency department, were included. Data on their clinical presentations, blood tests, and treatments were collected, described, and compared between patients with a BOHB concentration higher than 3.0 mmol/L (H-BOHB) and those with a concentration less than 3.0 mmol/L (L-BOHB).

RESULTS

A total of 83 patients were included in this study. Sixty-eight patients were categorized as having H-BOHB and 15 as having L-BOHB. Nausea (71%), vomiting (71%), tachycardia (76%), and tachypnea (46%) were commonly observed at presentation. Hyponatremia (46%), hypokalemia (34%), hypomagnesemia (42%), and hyperphosphatemia (41%) were frequent electrolyte abnormalities upon presentation. Rehydration with balanced crystalloids and glucose-containing intravenous fluids, electrolyte supplementation, and thiamine replacement were the major treatments. The mean length of stay in the ICU and hospital were 4.4 and 7.0 days, respectively, with low overall mortality (1%). The H-BOHB and L-BOHB groups did not differ in terms of clinical data. Seventy percent of patients with L-BOHB had severe metabolic acidosis with a high AG due to hyperlactatemia (mean lactate concentration: 8.5 mmol/L).

CONCLUSIONS

We described the clinical features of AKA measured by using a point-of-care capillary BOHB measurement device. Although certain patients diagnosed with AKA based only on their clinical history had predominant lactic acidosis with minor elevations in BOHB concentration, the BOHB concentration had no effect on the clinical spectrum of AKA in this study.

Postmortem survey of haemoglobin A1c, non-alcoholic steatohepatitis and liver fibrosis within a general population

AIMS

Non-alcoholic steatohepatitis (NASH), fatty liver disease and fibrosis are associated with diabetes mellitus and obesity. Previous autopsy series have reported prevalence of fatty liver disease to be 11%-24%. Recent studies, using imaging and serology, suggest a prevalence of 20%-35%, NASH of 5% and advanced fibrosis of 2%-3%. We examined the prevalence of NASH and liver fibrosis in a general autopsy population.

METHODS

A cross-sectional study of consecutive, adult, medicolegal autopsies over a 1-year period was conducted. Liver sections were scored for fibrosis, inflammation and steatosis using a modified NASH scoring system. Stepwise logistic regression was used to identify associations between NASH or moderate/severe fibrosis and several clinicopathological parameters, including postmortem haemoglobin A1c (HbA1c).

RESULTS

Of 376 cases, 86 (22.9%) were classified as NASH. Prevalence of diabetes mellitus, body mass index (BMI) and postmortem HbA1c were significantly higher in NASH cases (39.5%, 32.3 kg/m2 and 6.88%) than non-NASH cases (12.1%, 27.0 kg/m2 and 5.73%). Decedents with moderate/severe fibrosis (6.9%) had higher prevalence of diabetes, BMI and HbA1c (50%, 31.4 kg/m2 and 6.7%) compared with those with no/mild fibrosis (16%, 28 kg/m2 and 5.9%). HbA1c ≥7% was found to be an independent predictor of NASH (OR 5.11, 95% CI 2.61 to 9.98) and advanced fibrosis (OR 3.94, 95% CI 1.63 to 9.53).

CONCLUSIONS

NASH and advanced fibrosis were higher in our general adult autopsy population compared with previously published estimates. This is a large series with histological evaluation showing that HbA1c >7.0% is independently associated with NASH and advanced fibrosis.

Deaths From Alcoholic and Diabetic Ketoacidosis at Autopsy-A Comparison Study

Diabetes mellitus and alcoholism are common disorders that may result in sudden death. Ketoacidosis may occur in both conditions. Diagnosis is based on history, and post-mortem findings including biochemistry and toxicology. This study compares deaths from alcoholic and diabetic ketoacidosis from two centres with large autopsy workloads. In the study period 9332 deaths were autopsies with 151 deaths diagnosed as ketoacidosis (1.6%) with 82 (0.9 %) being diabetic ketoacidosis (DKA) and 48 (0.5%) alcoholic ketoacidosis (AKA) deaths. There were more male deaths in each group. The median age for DKA deaths was 51 years (range 19-79). The median age for AKA deaths was 55 years (range was 34-78). The BMI range in DKA deaths was 12.5 to 40.4 kg/m2, with a median of 21.9. The comparative figures for AKA deaths was a range of 11.3 - 38.3 with a median of 20.2. Acetone concentrations were statistically higher in diabetic compared with alcoholic deaths, mean of 33.7 mg/100 mL in DKA cases versus mean of 16.9 mg/100 mL in AKA cases. Both DKA and AKA deaths are seen more commonly in males than female and are typically people with low BMIs in their 50s.

Utility of a Handheld Blood Ketone Meter as a Postmortem Indicator of Diabetic Ketoacidosis

ABSTRACT

When investigating a death potentially due to diabetic ketoacidosis (DKA), it is challenging to assess the glucose level in the blood, but β-hydroxybutyrate, the most prevalent ketone body in the blood, is relatively stable after death. The aim of this project is to prove that a commercially available ketone meter can be used on postmortem blood samples to aid the diagnosis of DKA in a novel setting (during coroner/medical examiner examination). Samples with acetone detected via gas chromatography were chosen retrospectively to determine whether the meter could detect ketones in postmortem blood (proof-of-concept). In all of the thawed samples, the meter detected an elevated ketone level. Samples were then obtained in a prospective manner to include those with a possible cause of death from DKA along with controls. We correctly identified 16 cases in which death was due to DKA with use of the ketone manner. The ketone levels ranged from 2.6 to 5.4 mmol/L in those cases. The diagnosis was confirmed with a greatly elevated vitreous glucose concentration or glycated hemoglobin concentration. Detecting the presence of ketones while in the autopsy suite allowed for more accurate preliminary diagnoses and utilization of resources.

Postmortem Diagnosis of Ketoacidosis by Determining Beta-Hydroxybutyrate Levels in Three Types of Body Fluids by Two Different Methods

Background: Postmortem assessment of endogenous ketoacidosis is primarily focused on the determination of 3-beta-hydroxybutyrate (BHB). The aim of our study was to identify the most adequate body fluid and postmortem quantification method for assessing ketoacidosis status immediately prior to death. Material and method: We performed a prospective study on 53 cases of sudden death or in-hospital death that were considered forensic cases and could present a state of ketoacidosis prior to death, the autopsies being performed at a post-mortem interval of 24–72 h. BHB analysis was performed by Multi-Functional Monitoring System XPER Technology analyzer (method A—portable analyzer) for peripheral blood, and by BHB Assay MAK041 Kit (method B) for vitreous humor (VH) and cerebrospinal fluid (CSF). Results: We identified 11 ketoacidosis cases using method A and 9 ketoacidosis cases using method B. All nine cases of ketoacidosis identified using the MAK041 kit were confirmed with the portable analyzer. For the 2 cases of ketoacidosis identified only with the portable analyzer, the values obtained by method B were at the diagnostic limit. BHB concentrations determined in VH and CSF by method B were statistically significantly correlated with each other and with peripheral blood BHB concentration. Conclusion: BHB, a marker of ketoacidosis, should be determined post-mortem whenever a metabolic imbalance is suspected irrespective of known risk factors or obvious morphological substrate to help establish the thanatogenic mechanism. BHB quantification can easily be performed using a handheld automatic analyzer and a sample of peripheral blood as BHB levels in various body fluids correlate with each other.

The Importance of BHB Testing on the Post-Mortem Diagnosis of Ketoacidosis

Although beta-hydroxybutyrate (BHB) analysis has proved its importance in forensic pathology, its effects on cause-of-death diagnostics are unaddressed. Therefore, this study aims at evaluating the effects of BHB analysis on the number of deaths by DKA (diabetes ketoacidosis), AKA (alcoholic ketoacidosis), HHS (hyperosmolar hyperglycaemic state), hypothermia, diabetes, alcoholism, and acidosis NOS (not otherwise specified). All 2900 deaths from 2013 through 2019 in which BHB was analysed at the National Board of Forensic Medicine, and 1069 DKA, AKA, HHS, hypothermia, diabetes, alcoholism, and acidosis cases without BHB analysis were included. The prevalence of BHB-positive cases for each cause of death, and trends and proportions of different BHB concentrations, were investigated. The number of BHB analyses/year increased from 13 to 1417. AKA increased from three to 66 and acidosis from one to 20. The deaths from alcoholism, DKA, and hypothermia remained stable. It is unclear why death from alcoholism remained stable while AKA increased. The increase in unspecific acidosis deaths raises the question why a more specific diagnosis had not been used. In conclusion, BHB analysis is instrumental in detecting AKA and acidosis. The scientific basis for the diagnosis of DKA and hypothermia improved, but the number of cases did not change.

The Vital Role of Thanatochemistry in the Postmortem Diagnostic of Diabetic Ketoacidosis-Case Report

Diabetic ketoacidosis (DKA) is a lethal acute hyperglycemic complication of diabetes mellitus (DM) and it represents the initial manifestation of DM in about 15-20% of cases in adults and about 30-40% of cases in children. Postmortem diagnosis of DKA can only be made by applying thanatochemistry. Biochemistry applied postmortem is viewed with skepticism by many practitioners in the forensic field, completely lacking in many forensic services around the world, and especially in the national ones. This article aims to underline the importance of the postmortem application of biochemistry by reviewing the case of a person in the third decade of life who died suddenly at home due to diabetic ketoacidosis (DKA), whose autopsy was performed at an early PMI of approximately 24 h. Routine postmortem examinations (macroscopic, anatomopathological, and toxicological) could not establish a clear cause of death. When attention was turned to biochemical determinations (i.e., determination of glycated hemoglobin, glucose and ketone bodies (acetone, beta-hydroxybutyrate) in the blood, vitreous humor, and cerebrospinal fluid), the identified values clarified the thanatogenic mechanisms by establishing the diagnosis of DKA.