Postmortem diagnosis of hyponatremia: case report and literature review

Do Not Turn a Blind Eye on Forensic Biochemistry: Using Vitreous Electrolytes to Reveal Renal Insufficiency as Cause of Death

ABSTRACT

In both medical and forensic autopsy, the kidneys may be overlooked grossly and histologically. As both acute and chronic kidney dysfunction have major implications on morbidity and mortality, it is essential to consider the kidneys as a pathologic source for both immediate and proximate cause of death. For decades, vitreous humor has been used as a measure of postmortem electrolyte analysis to help understand ionic disturbances carried over from the antemortem period. Renal insufficiency from both acute and chronic kidney dysfunction can be ascertained from vitreous investigations and should be a consideration for cause of death. Here, we present 4 cases in which vitreous analysis was used to determine the cause of death. In highlighting these cases, we support the use of biochemical testing in autopsy while demonstrating how it can help elucidate an often overlooked means of mortality. Importantly, it can help with the formulation of clinicopathologic correlations between antemortem and postmortem findings.

Acute water intoxication in hysteroscopic myomectomy: a rare case report

Water intoxication is rarely seen in forensic practice and is typically associated with excessive water consumption, amphetamine intake, and child abuse. Iatrogenic water intoxication is rare but usually related to medical disputes. Here, we report a 44-year-old female was admitted to the hospital due to a 3-month history of excessive menstrual bleeding. B-ultrasound revealed multiple substantial intrauterine masses, leading to a diagnosis of multiple uterine fibroids. After admission, she underwent submucous myomectomy, endometrial resection, and transcervical resection of endometrial polyps. During the procedure, the patient suffered dizziness and chest tightness, her blood pressure decreased to 89/52 mmHg, and moist rales were heard in her both lungs; she died despite medical efforts. A forensic autopsy was performed and revealed severe pulmonary edema. Considering the patient's clinical history, acute water intoxication was considered to be the cause of death. This highlights the need for forensic pathologists to be vigilant of postoperative water intoxication, a rare complication in obstetrics, to ensure accurate assessments.

Clinical characteristics and outcomes of hyponatraemia associated with oral water intake in adults: a systematic review

INTRODUCTION

Excessive water intake is rarely associated with life-threatening hyponatraemia. The aim of this study was to determine the clinical characteristics and outcomes of hyponatraemia associated with excess water intake.

METHODS

This review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies (case reports, observational or interventional studies) reporting excess water intake and hyponatraemia in adults (1946-2019) were included.

RESULTS

A total of 2970 articles were identified and 177 were included (88.7% case reports), consisting of 590 patients. The mean age was 46±16 years (95% CI 44 to 48 years), 47% female, 52% had a chronic psychiatric disorder and 31% had no underlying condition. The median volume of water consumed and serum sodium at presentation was 8 L/day (95% CI 8.9 to 12.2 L/day) and 118 mmol/L (95% CI 116 to 118 mmol/L), respectively. The motivator for increased water consumption was psychogenic polydipsia (55%); iatrogenic (13%); exercise (12%); habitual/dipsogenic polydipsia (7%) and other reasons (13%). The clinical features on presentation were severe in 53% (seizures, coma); moderate in 35% (confusion, vomiting, agitation) and mild in 5% (dizziness, lethargy, cognitive deficit) and not reported in 5% of studies. Treatment was supportive in 41% of studies (fluid restriction, treatment of the underlying cause, emergency care), and isotonic and hypertonic saline was used in 18% and 28% of cases, respectively. Treatment-related complications included osmotic demyelination (3%) and rhabdomyolysis (7%), and death occurred in 13% of cases.

CONCLUSION

Water intoxication is associated with significant morbidity and mortality and requires daily intake to substantially exceed population-based recommendations. The limitations of this analysis are the low quality and high risk of bias of the included studies.

PROSPERO REGISTRATION NUMBER

A pre-existing protocol in the international prospective register of systematic reviews was updated to incorporate any new amendments and reregistered at http://www.crd.york.ac.uk/PROSPERO (registration no. CRD42019129809).

Health Impacts and Recovery From Prolonged Freshwater Exposure in a Common Bottlenose Dolphin (Tursiops truncatus)

Common bottlenose dolphins (Tursiops truncatus) exposed to freshwater or low salinity (<10 practical salinity units; PSU) for prolonged periods of time have been documented to develop skin lesions, corneal edema and electrolyte abnormalities, and in some instances they have died. Here we review a case of an out-of-habitat subadult, female common bottlenose dolphin that remained in a freshwater lake in Seminole, Alabama for at least 32 days. Due to concerns for the dolphin's health a rescue was initiated. At the time of rescue bloodwork results indicated minor electrolyte abnormalities (hyponatremia, hypochloremia, hypoosmolality). Renal function was not affected (normal creatinine and urea nitrogen) and all other bloodwork parameters (hemogram; serum biochemistry analytes) were within normal limits. The dolphin was deemed healthy enough for immediate relocation and release. A satellite-linked tag was attached to the dorsal fin to track the dolphin following its relocation to a nearby brackish water bay (Perdido Bay, AL), a known habitat for bottlenose dolphins. Twelve weeks following release, the dolphin was found dead as a result of a fisheries interaction (peracute underwater entrapment). A full necropsy was conducted and there was complete resolution of the skin pallor and skin lesions and no evidence of chronic renal or central nervous system lesions. Post-mortem analysis of vitreous humor (used as a proxy for serum analytes and to determine post-mortem interval) was challenging to interpret and has not been validated in dolphins. This supports the need for future research in cetaceans to establish a species-specific approach. Elevated barium (Ba) concentrations in tooth dentin corresponded to increased seasonal freshwater discharge patterns, confirming repeated annual exposure to low salinity conditions prior to death and indicating freshwater exposure may pose an ongoing threat to dolphins in the region. This case provides a unique opportunity to follow the progression of prolonged freshwater exposure and recovery in a bottlenose dolphin and highlights that dolphins in nearshore habitats face a combination of persistent natural and human associated threats.

Vitreous humor endogenous compounds analysis for post-mortem forensic investigation

The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH) has been used as a biofluid for forensic purposes since the 1960s. Due to its established relevance in toxicology, a literature review highlighting the use of VH with an emphasis on endogenous compounds has not yet been undertaken. VH is a chemically complex aqueous solution of carbohydrates, proteins, electrolytes and other small molecules present in living organisms; this biofluid is useful tool for its isolated environment, preserved from bacterial contamination, decomposition, autolysis, and metabolic reactions. The post-mortem analysis of VH provides an important tool for the estimation of the post-mortem interval (PMI), which can be helpful in determining the cause of death. Consequently, the present review evaluates the recent chemical and biochemical advances with particular importance on the endogenous compounds present at the time of death and their modification over time, which are valuable for the PMI prediction and to identify the cause of death.