A ruptured thoracic aortic aneurysm and the difficulties of confirming syphilis.

A 43-year-old woman died suddenly and was found at PM to have a ruptured thoracic aortic aneurysm. The endothelial surface of the aorta showed a 'tree-bark' appearance. Histology of the aneurysm wall showed a patchy, mainly perivascular, plasma cell infiltrate. Multiple spirochete-like organisms were identified on T. pallidum IHC. However, PM syphilis serology (screen including rapid plasma reagin (RPR) and T. pallidum particle agglutination (TPPA)) on femoral blood was negative. PCR testing on FFPE aortic wall tissue was negative. Further history revealed routine antenatal syphilis screening tests had been negative, no known history or risk of exposure to syphilis or other treponemes. This case raises the possibility of false negative syphilis testing. While acknowledged in RPR testing, with the modern testing regime using multiple methods, the rate of false negative results is now thought to be markedly reduced, and false positive results are a much greater problem in clinical medicine. The most common cause of false negative results is early in primary infection before an immune response has been mounted and in those patients that are immunocompromised. False negative results are also more often seen in tertiary syphilis, as in this case. Newer testing methods which include 16S rRNA sequencing have become available and early discussion with a microbiologist would be recommended. Strong macroscopic and microscopic suggestion of syphilis as the cause of the aneurysm makes it necessary to include the possibility of infection in the Post Mortem Report to Coroner as this will have implications for her sexual partners and children.

An outbreak of deaths associated with AMB-FUBINACA in Auckland NZ.

BACKGROUND: AMB-FUBINACA is a synthetic cannabinoid that has been associated with periodic outbreaks of acute poisonings, but few fatalities. In late May, June and July 2017 Auckland, New Zealand, experienced an outbreak of deaths associated with AMB-FUBINACA that continued at a rate of about 2-3 per month through February 2019. The aim of this study was to define the demographic, circumstantial, pathological and toxicological characteristics of this outbreak. METHODS: All records of the Northern Forensic Pathology Service, Auckland Hospital, were reviewed in which the word "AMB-FUBINACA" was referenced, including initial police reports, autopsy reports and toxicology reports. Recorded data included age, sex, race/ethnicity, times and locations, cause of death, autopsy and toxicology findings, and a brief summary of the circumstances of death. Descriptive statistics were performed using IBM® SPSS® Statistics Version 24 and Microsoft® Excel® Version 14.7.2. FINDINGS: Sixty-four cases were identified. One sudden infant death and five cases where cause of death was due to trauma were excluded. Of the remaining 58 cases, 88% were male. Mean age was 42 years. In 95% of the deaths, AMB-FUBINACA alone or in combination with alcohol or another drug was listed as the primary or contributory cause of death. In 41 cases postmortem blood concentrations of AMB-FUBINACA acid were available, ranging from <45 ng/mL to >1000 ng/mL, mean 229 ng/mL, median 140 ng/mL. Comorbidities identified included mixed intoxications (29%), heart disease (47%) and obesity (16%). A mental health diagnosis was reported in 50%, and 40% were on antipsychotic medications. INTERPRETATION: This study presents characteristics, comorbidities and toxicological findings in a unique outbreak of deaths associated with the synthetic cannabinoid AMB-FUBINACA in Auckland, NZ. FUNDING: All work was funded as part of the usual employment of the authors in their respective institutions. No special funding sources are reported.

Elevation of Postmortem Cerebrospinal Fluid Sodium and Chloride Levels Is a Potential Adjunct Test in the Diagnosis of Salt Water Drowning.

Postmortem vitreous humor biochemistry is a useful test in the diagnosis of salt water drowning (SWD). A significant limitation of vitreous humor is the potential effect of prolonged immersion. A recent animal study and case report suggested that cerebrospinal fluid biochemistry may be an alternative to vitreous because it is more resistant to the effects of immersion, given its protected anatomical location. This study compared postmortem cerebrospinal fluid sodium and chloride (PMCSC) levels collected via ventricular aspiration (PMCSC_V) and via lumbar puncture (PMCSC_L) in 13 SWD and 31 nonimmersion deaths. It showed a significant elevation in PMCSC levels in SWD deaths for both PMCSC_V and PMCSC_L (P < 0.05). The areas under the curve on the receiver operating characteristic curves for PMCSC_V and PMCSC_L were 0.73 and 0.83, respectively. The optimal cutoff for PMCSC_V was 216 mmol/L (sensitivity, 0.60; specificity, 0.72; likelihood ratio, 1.80; positive predictive value, 0.45) and for PMCSC_L was 241 mmol/L (sensitivity, 0.78; specificity, 0.73; likelihood ratio, 2.89; positive predictive value, 0.46). This study supports PMCSC levels as another biochemical test that can potentially aid in the diagnosis of SWD, particularly in cases where vitreous humor samples are unavailable or uninterpretable.

Differences in Sampling Site on Postmortem Cerebrospinal Fluid Biochemistry: A Preliminary Study.

Cerebrospinal fluid (CSF) is often analyzed at postmortem. The presented preliminary study compared postmortem CSF samples for biochemical analysis from the subarachnoid space around the spinal cord and ventricular space of the brain. This study compared 15 paired CSF samples in which the CSF from the subarachnoid space via lumbar puncture had higher sodium and chloride levels and lower magnesium and potassium levels than CSF from the ventricles. The differences correlated significantly with the deceased's age and had a similar trend with postmortem interval. This study suggests that CSF from different collection sites has different electrolyte concentrations, which are age and possibly postmortem interval dependent. When collecting CSF, the pathologist should document the collection site, age, and postmortem interval, and the mixing of CSF samples from different sites should be avoided. Further studies are warranted to clarify other possible reasons to explain the observed differences.

Combining Postmortem Vitreous Sodium and Chloride and Lung-Body Ratio in Aiding the Diagnosing Saltwater Drowning.

Diagnosing death due to drowning can be difficult, and several postmortem findings have been postulated to aid the diagnosis. Increased lung weights are often seen in drowning deaths. Lung-body (LB) ratio was described to be the best anatomical lung measurement in diagnosing drowning. Postmortem vitreous humor sodium and chloride (PMVSC) was reported to be a useful biochemical test in diagnosing saltwater drowning when the immersion time is less than 1 hour (SWD1). The presented study compared the diagnostic accuracies between LB ratio, PMVSC, and their combination in diagnosing SWD1 in 20 SWD1 and 50 nonimmersion deaths. Classification tree models were used for analysis and revealed that combination of PMVSC and LB ratio was most accurate in diagnosing SWD1 (misclassification rate, 4%), followed by PMVSC (misclassification rate, 10%) and LB ratio (misclassification rate, 24%). A quantifiable diagnostic improvement was established when both LB ratio and PMVSC were used. After adjusting for interlaboratory variations, the developed tree models can be a reliable way in aiding the diagnosis of SWD1.

The Potential Diagnostic Accuracy of Autopsy Lung Weights, Lung-Heart Ratio, and Lung-Body Ratio in Drowning Deaths.

Lung weights are often increased in drowning deaths as well as in other types of deaths. Lung weights may also vary with age, sex, and body weight. A variety of methods have been proposed to utilize lung weight data to assist with the diagnosis of drowning. The present study compared lung weight, lung-heart ratio (LH), and lung-body ratio (LB) between 50 consecutive drowning and 50 nonimmersion deaths in order to assess the accuracy in diagnosing drowning. Analysis revealed both LH and LB to be statistically higher in drowning deaths (P < 0.05), with LB being the most robust measurement. However, the overall diagnostic accuracies of lung weight, LH, and LB were poor to fair, and should therefore be used only in conjunction with the other diagnostic criteria.

Higher Heart Weight in New Zealand Maori and Pacific Islanders.

Heart weight is dependent on sex, age, height, and weight. Although previous autopsy studies showed no differences in heart weight between different ethnic groups, none have examined the New Zealand population of Maori and Pacific Islanders (Polynesians). The presented study compared heart weights between 101 European and 85 Polynesian suicide hanging deaths from New Zealand. Univariate linear regression coefficients for age, male sex, height, body weight, body mass index, and Polynesian ethnicity were positive and significant (P < 0.05). Apart from body mass index, subsequent multivariate analysis showed that all regression coefficients remained positive and significant (P < 0.05). Polynesian ethnicity seemed to be an independent predictor for increased heart weight in the study population. Apart from possible genetic factors, the higher heart weight in Polynesians may have other underlying reasons. Caution is required when interpreting heart weight in cases of sudden natural deaths, especially in this population.

Elevated Postmortem Vitreous Sodium and Chloride Level in a Salt Water Drowning Death During Self-Contained Underwater Breathing Apparatus Diving With Diving Mask in Place: Case Report.

Elevation of postmortem vitreous sodium and chloride (PMVSC) levels in salt water drowning (SWD) is hypothesized to result from electrolyte changes in blood from salt water inhalation/ingestion during drowning. After approximately 1 hour after death, electrolytes may diffuse into the vitreous humor via the eye coverings. This hypothesis was based on a study where bovine eyeballs were immersed in salt water. There is no human study that could confirm that SWD would result in an initial elevation of PMVSC with no effects from immersion. We present an SWD during self-contained underwater breathing apparatus diving in which the face mask remained in its correct position while the deceased was underwater. The face mask would have prevented the orbits from being in direct contact with salt water and therefore stopped any effects of immersion on PMVSC. The PMVSC was 294 mmol/L, above control levels, and the reported cut-off of 259 mmol/L for a diagnosis SWD. The elevated PMVSC would unlikely be owing to immersion but SWD. This case report supports the observation that during SWD PMVSC would initially increase from salt water inhalation and ingestion and not from immersion.

Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion.

Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.