Another suicide by sodium nitrite and multiple drugs: an alarming trend for “exit”?

Degradation and preservation of nitrites in whole blood

Understanding the factors that influence nitrite degradation in whole blood and developing methods for its stable preservation are crucial for ensuring accurate and reliable forensic identification in cases of nitrite poisoning. This study systematically monitored nitrite degradation and changes in hemoglobin proportions across different initial nitrite concentrations and blood samples. It was revealed that high nitrite concentrations rapidly reduced deoxyhemoglobin levels within the first 15 minutes and subsequently reacted with oxyhemoglobin at a slower rate. Therefore, the proportions of these two hemoglobin forms are key factors in determining nitrite degradation rates. Regarding preservation, the study examined the effects of low temperatures (4°C and -20°C) and various preservatives (potassium ferricyanide, N-ethylmaleimide) on nitrite stability. The results indicate that adding 6.6 g/L potassium ferricyanide can rapidly eliminate all deoxyhemoglobin and reduce oxyhemoglobin proportions to below 60 %, enabling stable preservation of high nitrite concentrations in whole blood for over 30 days at -20°C. The efficacy of potassium ferricyanide was further validated in forensic-acquired postmortem heart blood samples.

Acquired methemoglobinemia in a third trimester puerpera and her premature infant with sodium nitrite poisoning: A case report

BACKGROUND

The common cause of sodium nitrite poisoning has shifted from previous accidental intoxication by exposure or ingestion of contaminated water and food to recent alarming intentional intoxication as an employed method of suicide/exit. The subsequent formation of methemoglobin (MetHb) restricts oxygen transport and utilization in the body, resulting in functional hypoxia at the tissue level. In clinical practice, a mismatch of cyanotic appearance and oxygen partial pressure usually contributes to the identification of methemoglobinemia. Prompt recognition of characteristic mismatch and accurate diagnosis of sodium nitrite poisoning are prerequisites for the implementation of standardized systemic interventions.

CASE SUMMARY

A pregnant woman was admitted to the Department of Critical Care Medicine at the First Affiliated Hospital of Harbin Medical University due to consciousness disorders and drowsiness 2 h before admission. Subsequently, she developed vomiting and cyanotic skin. The woman underwent orotracheal intubation, invasive mechanical ventilation (IMV), and correction of internal environment disturbance in the ICU. Her premature infant was born with a higher-than-normal MetHb level of 3.3%, and received detoxification with methylene blue and vitamin C, supplemental vitamin K1, an infusion of fresh frozen plasma, as well as respiratory support via orotracheal intubation and IMV. On day 3 after admission, the puerpera regained consciousness, evacuated the IMV, and resumed enteral nutrition. She was then transferred to the maternity ward 24 h later. On day 7 after admission, the woman recovered and was discharged without any sequelae.

CONCLUSION

MetHb can cross through the placental barrier. Level of MetHb both reflects severity of the sodium nitrite poisoning and serves as feedback on therapeutic effectiveness.

Special Report from the CDC: Suicide rates, sodium nitrite-related suicides, and online content, United States

BACKGROUND

In 2022, suicide ranked as the 11th leading cause of death in the United States with 49,513 deaths. Provisional mortality data from 2022 indicate a 2.8% increase in the number of suicides compared to 2021. This paper examines overall suicide trends, sodium nitrite ingestion as an emerging suicide method, and the role that online forums play in sharing information about suicide methods (including sodium nitrite ingestion).

METHODS

Suicides were identified from CDC's National Vital Statistics System (2018-July 2023 provisional) multiple cause-of-death mortality files using International Classification of Diseases (ICD), Tenth Revision underlying cause-of-death codes U03, X60-X84, and Y87.0 and T code T50.6 (antidotes and chelating agents). Google search popularity metrics were captured from January 2019 to January 2023. Case reports of sodium nitrite related suicide and suicide attempts (through February 2024) were identified in the medical and forensic literature.

RESULTS

At least 768 suicides involving antidotes and chelating agents (including sodium nitrite) occurred between 2018 and July 2023, set in the context of 268,972 total suicides during that period. Overall, suicides involving antidotes and chelating agents (including sodium nitrite) represent <1% of all suicides, however, numbers are rising.

CONCLUSIONS

Suicide methods are known to change over time. These changes can be influenced by, among other factors, online forums and means accessibility, such as internet purchase availability. CDC remains committed to prevention through comprehensive public health strategies that protect individuals, families, and communities.

PRACTICAL APPLICATIONS

States and community partners might consider leveraging physicians, emergency responders, and other appropriate crisis response groups to disseminate information on sodium nitrite self-poisoning and its antidote, methylene blue. Efforts should be part of a comprehensive public health approach to suicide prevention.

Technical Evaluation of a Paper-Based Electrochemical Strip to Measure Nitrite Ions in the Forensic Field

Nitrite is a compound used as a food additive for its preservative action and coloring capability, as well as an industrial agent for its antifreezing action and for preventing corrosion, and it is also used as a pharmaceutical in cyanide detoxification therapy. However, even recently, because of its high toxicity, it has been used as a murder and suicidal agent due to its affordability and ready availability. In this technical report, we describe an electrochemical paper-based device for selectively determining nitrite in complex biofluids, such as blood, cadaveric blood, vitreous humor, serum, plasma, and urine. The approach was validated in terms of the linearity of response, selectivity, and sensitivity, and the accuracy of the determination was verified by comparing the results with a chromatographic instrumental method. A linear response was observed in the micromolar range; the sensitivity of the method expressed as the limit of detection was 0.4 μM in buffer measurements. The simplicity of use, the portability of the device, and the performance shown make the approach suitable for detecting nitrite in complex biofluids, including contexts of forensic interest, such as murders or suicides in which nitrite is used as a toxic agent. Limits of detection of ca. 1, 2, 4, 5, 3, and 4 μM were obtained in vitreous humor, urine, serum and plasma, blood, and cadaveric blood, also highlighting a satisfactory accuracy comprised between 91 and 112%.

Sodium nitrite suicide and social media influence

ABSTRACT

This article addresses the increase in suicide rates in the US, emphasizing the emergence of sodium nitrite ingestion as a method of self-harm, particularly among adolescents and young adults influenced by social media. Given the rising incidence of sodium nitrite-related suicide attempts, healthcare providers must remain vigilant and prepared to respond effectively.

Nitrites: An Old Poison or a Current Hazard? Epidemiology of Intoxications Covering the Last 100 Years and Evaluation of Analytical Methods

In recent times, there has been a concerning and noteworthy rise in the global use of sodium nitrite for suicidal purposes. This is facilitated either through the employment of specialized "suicide kits" or by acquiring sodium nitrite through alternative means. Additionally, another occurrence contributing to nitrite poisoning is the recreational utilization of nitrites in the form of volatile aliphatic esters of nitrous acid, commonly referred to as "poppers". Based on current available papers and reports on the subject of nitrates, nitrites, and poppers intoxications, an epidemiological analysis and evaluation of analytical methods were performed. A total of 128 papers, documenting a collective count of 492 intoxication cases, were identified. Additionally, in order to complete the epidemiological profile of nitrite poisoning, the authors briefly examined six cases of nitrite intoxication that were under investigation in our laboratory. Furthermore, a review of nitrite poisoning cases over the past 100 years shows that the old poison is still in use and poses a substantial risk to society.

A fatal suicidal sodium nitrite ingestion determined six days after death

Sodium nitrite (SN) is an inorganic salt that appears as a slightly yellowish crystalline solid, odorless, and highly soluble in water at room temperature. It is highly toxic to humans at specific doses because it can oxidize hemoglobin to methemoglobin, causing severe tissue hypoxia. A 20-year-old woman was unconscious in her bedroom and died shortly after that. Two days later, following the discovery of a jar of SN and a paper in which were written instructions on how to take it (and the website from which the procedure was learned) in the same room were death occurred, the Judicial Authority ordered the execution of the autopsy on the exhumed body of the young woman. The autopsy procedure was performed ∼ 2h after exhumation. It showed greyish-purple hypostasis, labial cyanosis, stomach distension and greenish color but empty, subpleural petechiae, brownish fluid in the pleural cavities (∼300 ml), congested and edematous lungs and diffuse visceral congestion. At autopsy, foamy liquid was observed at the lung section and subsequent squeezing. In addition, the autopsy showed edema and hemorrhagic petechiae of the laryngeal, glottal, and tracheal submucosa and green-brownish foamy liquid in the tracheal lumen. The cause of death was attributed tocardiac arrest induced by anoxia resulting from acute methemoglobinemia caused by sodium nitrite poisoning, intensified by severe malnutrition. Manner of death was suicidal.

Suicidal sodium nitrite intoxication: a case report focusing on the postmortem findings and toxicological analyses-review of the literature

Sodium nitrite (NaNO₂) is an inorganic compound that is commonly used as a preservative (E250) in the fish and meat industry. When ingested, sodium nitrite will lead to methemoglobinemia, hypotension, and arrhythmias. An increasing trend in the use of sodium nitrite as a suicide agent has been reported. In Belgium however it remains a rare phenomenon. The ingestion of sodium nitrite is not always apparent from the death scene investigation, especially in cases of covert administration or accidental ingestion. Hence, the forensic pathologist must be aware of this trend and the postmortem changes related to the ingestion of sodium nitrite to effectively identify these cases and determine the cause and manner of death. We describe a case of fatal self-poisoning following the oral ingestion of sodium nitrite with suicidal intent. Postmortem investigations showed signs of methemoglobinemia, such as a gray-brown discoloration of lividity and a chocolate brown discoloration of the blood. Postmortem toxicological investigation revealed methemoglobinemia (35%) in cardiac blood, hypernatremia (159.6 mmol/L) in vitreous humor, and the presence of nitrite in gastric contents (1.15 g/L) and, for the first time in a forensic case, in serum (38 µg/mL). A review of the existing literature regarding cases of sodium nitrite intoxications was performed to correlate these findings.

Sodium nitrite poisoning: A series of 20 fatalities in which post-mortem blood nitrite and nitrate concentrations are reported

Sodium nitrite has several industrial applications however its accidental or intentional ingestion has been associated with severe toxicity and death. We present a series of 20 cases over 2 years in which evidence of sodium nitrite ingestion was found at the scene and supported by biochemical analysis of post-mortem blood nitrite and nitrate levels. Routine toxicological screening was performed on post-mortem blood samples received at University Hospitals of Leicester (UHL) NHS Trust, including ethanol analysis by headspace gas chromatography-flame ionisation detection (HS GC-FID), drug screening by high resolution accurate mass-mass spectrometry (HRAM-MS) and confirmatory drug quantitation by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cases in which the history indicated the possibility of nitrite salts present at the scene, purchase of a suicide kit or a dusky-ash appearance of skin on post-mortem were referred to a specialist laboratory for nitrite and nitrate analysis. Analysis was based upon the gas-phase chemiluminescent reaction between nitric oxide (NO) and ozone; NO levels were determined using an NOA 280A, Sievers NO analyser. Twenty post-mortem cases in which sodium nitrite ingestion was the most probable cause of death were reported between January 2020 and February 2022; mean age was 31 years (range 14-49) with 9/20 (45%) female. 16/20 (80%) of cases had a history of depression and / or mental health issues. In half of the cases, anti-depressant / anti-psychotic drugs were prescribed; these drugs were detected in 8/20 (40%) cases. Ethanol was detected in 4/20 (20%) cases and anti-emetic drugs in 7/20 (35%) cases; anti-emetic drugs may be used to aid retention of sodium nitrite. Illicit drugs (amphetamine, cannabis and cocaine) were present in 3/20 cases (15%). Nitrite was found to be elevated in all but one case (95%), and nitrate was elevated in 17/20 (85%) cases. This paper highlights a surge in numbers of deaths across England and Wales due to sodium nitrite toxicity. Although, nitrite poisoning remains a rare cause of death, it is worthwhile considering its use in individuals with suicidal ideation given its unregulated availability online. The detection and quantitation of nitrite and nitrate requires specialised, highly reliable methodology currently only available in research laboratories. Implication of sodium nitrite ingestion also relies heavily upon circumstantial evidence combined with quantification. The provision of a quantitative nitrite / nitrate analytical service greatly assists in determining the cause of death in these cases.

Sodium Nitrite Intoxication and Death: Summarizing Evidence to Facilitate Diagnosis

BACKGROUND

Over the years, forensic pathology has registered the spread of new methods of suicide, such as the ingestion of sodium nitrite. Sodium nitrite causes increased methemoglobin, resulting in systemic hypoxia, metabolic acidosis, and cyanosis. Since sodium nitrite is a preservative, the ingestion of foods containing an excessive amount of this substance can also cause acute intoxication up to death. The present review is aimed at guiding health professionals in the identification and management of sodium-nitrite-related intoxications and deaths.

METHODS

A systematic literature search was carried out on PubMed by following the PRISMA statement's criteria. A total of 35 studies with 132 cases were enrolled, and the data were cataloged in Microsoft Excel. To establish the causal correlation between sodium nitrite ingestion and death, the Naranjo Adverse Drug Reaction Probability Scale was used.

RESULTS

In addition to the small number of cases that have currently been published, the study demonstrated that there was a general methodological discrepancy in the diagnostic process. However, some interesting results have emerged, especially in post-mortem diagnostics.

CONCLUSION

Sodium-nitrite-related deaths represent a challenge for forensic pathologists; therefore, it is important to promptly recognize the essential features and perform the necessary and unrepeatable examinations for the correct diagnosis of the cause of death.

Four cases of sodium nitrite suicidal ingestion: A new trend and a relevant Forensic Pathology and Toxicology challenge

Sodium nitrite (NaNO₂) is an inorganic compound commonly used as a food additive, antifreeze admixture, and fertilizer. Its toxicity mechanism is mainly represented by the oxidation of ferrous iron to ferric iron of one of the four heme structures in haemoglobin with the onset of methaemoglobin. The mechanism of death by sodium nitrite toxicity is severe hypoxia. We present four cases of suicidal sodium nitrite ingestion that closely occurred within a two months-period. Self-poisoning with sodium nitrite actually represents an increasing trend in nitrates' related deaths. In order to reach a precise diagnosis of NaNO₂ intoxication, a complete toxicological analysis should be carried out including not only MetHb blood levels but also nitrites and nitrites in standard or alternative matrices as a routine procedure. Autopsy should be carefully performed to detect common indicators of hypoxia or more rarely evident typical by themselves-non specific signs of sodium nitrite toxicity. Suicidal manner of death should be carefully considered when circumstantial data support that ingestion of large amounts of NaNO₂ occurred as a consequence of a self-injurious behaviour. Relevant informations include victim's previous Internet or book researches about paths to follow to commit suicide with sodium nitrate, employment and past medical history, with strong regard to psychiatric diseases as well as eventual taking psycotropic drugs. Finally, an accurate integration of autoptic and toxicological results with circumstantial data is necessary to make correct diagnosis of death due to acute respiratory failure secondary to suicidal sodium nitrite ingestion.

Suicide attempt using sodium nitrite ordered on the internet: Two case reports

RATIONALE

Sodium nitrite is a potent oxidizing agent that impairs oxygen transport and delivery through methemoglobin formation. Clinical manifestations are known to induce methemoglobinemia, dysrhythmia, hypotension, and even death. While accidental intoxication of sodium nitrite by contaminated water and food has previously occurred, there has been a substantial upsurge in suicide intoxication in recent years.

PATIENT CONCERNS

We present case reports of 2 patients who attempted suicide by sodium nitrite after ordering a "suicide powder" on the internet market. They were brought to the emergency department after attempting suicide by ingesting sodium nitrite. They experienced dyspnea, cyanosis, and mild nausea.

DIAGNOSIS

Based on their history and blood tests, methemoglobinemia was initially diagnosed.

INTERVENTIONS AND OUTCOMES

The patients received methylene blue antidotal therapy in the emergency department. The patients were discharged after neuropsychiatric evaluation and treatment for mental illness, suicidal ideation, and suicide attempts. They informed us of how simple and easy it was for them to buy sodium nitrite for suicidal purposes.

LESSONS

With widely shared information on the usage of sodium nitrite for suicide and the absence of proper regulation, the incidence of acute poisoning will increase. This increases physicians' chances of encountering unexplained cyanosis and methemoglobinemia. Clinical suspicion of sodium nitrite intoxication is warranted in cases of unexplained cyanosis or methemoglobinemia. We want to highlight how simple and easy it is to buy sodium nitrite for suicidal purposes.

Increasing use of sodium nitrite in suicides-an emerging trend

Sodium nitrite (NaNO₂) is a compound with broad practical applications in food preservation, automotive maintenance, and animal control. Sodium nitrite is also potentially fatal when ingested, as it interferes with the ability of red blood cells to transport oxygen. While incidents of accidental consumption have been reported in the literature, case reports of sodium nitrite being used as a pharmacological suicide agent are becoming more frequent. Therefore, a study was undertaken to evaluate trends in sodium nitrite deaths in South Australia between 2000 and 2019. All cases of fatal sodium nitrite ingestion were identified in the Toxicology database and autopsy reports at Forensic Science SA (FSSA). Ten cases of fatal sodium nitrite ingestion were identified, with the rate of cases increasing significantly over the study period (p > .001). Of the ten deaths attributed to sodium nitrite toxicity, eight were male, and two were female. The age range of decedents was 22-74 years (mean 51.9, SD 21.1), 22-74 years for males (mean 58.4, SD 18.2) and 23-29 years for females (mean 26.0, SD 4.2). Males (80%) and those with a history of depression and/or suicidal ideation (70%) were over-represented within the study population. While autopsy findings were generally consistent with the literature, scene findings emphasized the accessibility of sodium nitrite to the general public. This study highlights both a significant increasing trend in the use of sodium nitrite in suicides and important analytical limitations in the evaluation of suspected cases.

Direct and specific analysis of nitrite and nitrate in biological and non-biological samples by capillary ion analysis for the rapid identification of fatal intoxications with sodium nitrite

In recent years, a significant increase of reports about suicidal cases due to intentional sodium nitrite intake has been described. In the forensic pathology context, the strategy to approach intoxication cases by sodium nitrite, without any preliminary information or hint, is not straightforward. Indeed, in a number of cases the lack of crime scene data and/or specific pathological signs makes difficult the identification of nitrite poisoning. Moreover, the analytical determination of nitrite in blood is challenging, due to its rapid oxidization to nitrate by hemoglobin. Although several methods have been proposed for the clinical analysis of nitrate and/or nitrite in biological samples, none of these is specifically focused on the determination of these ions in cadaveric samples. Consequently, the diagnosis of nitrite fatal intoxication is still based on methemoglobin analysis. The present paper reports the optimization and validation of an analytical method of capillary ion analysis (CIA) with UV detection, for the determination of nitrite and nitrate in biological fluids and its application to two authentic cases of death by nitrite intake. The analyses were carried out in a bare fused-silica capillary (75 µm inner diameter) using 100 mM sodium tetraborate (pH 9.24) as background electrolyte and applying a voltage of - 15 kV between the capillary ends. The detection was obtained by direct UV absorption recorded at 214 nm wavelength. Bromide was used as the internal standard. Linearity was established in the range of 0.25-5 mmol/L). Reproducibility (intraday and day-to-day) was characterized by relative standard deviations (RSDs) 14.7% for peak areas. The method was applied to the determination of nitrite and nitrate in two real forensic cases, where high concentrations of nitrate were found in cadaveric blood samples (6.5 and 4.4 mmol/L, respectively). Nitrite was found only in trace amounts, due to the instability of this ion in cadaveric blood where it is oxidized to nitrate. The present method represents a new tool for the direct and rapid determination of nitrite and nitrate in cases of forensic interest, and thus offers a diagnostic tool more sensitive and precise than the need methemoglobin analysis.

The use of sodium nitrite for deliberate self-harm, and the online suicide market: Should we care?

Sodium nitrite is a common household product with a variety of uses such as curing meat, food additive, colouring agent, anti-freezing agent and disinfectant. We report a case of sodium nitrite intoxication for deliberate self-harm and discuss the increasing number of such cases in recent times.