Fatal methemoglobinemia in three suicidal sodium nitrite poisonings

Abstract

Nitrites are chemicals widely used as preservatives for meat and as anti-microbial agents in other food. They are commonly available as sodium, potassium, or ammonium salts. Nitrites are also abundant in the environment and are naturally occurring in some fruits and vegetables. Nitrates (-NO −3 ) on the surface of food can become nitrites (-NO −2 ) by the action of the bacterial enzyme nitrate reductase. Nitrates and nitrites are water soluble, and the presence of both forms can be minimized by washing food. Peeling the skin from vegetables and blanching them also minimizes nitrate/nitrite ingestion risk. Sodium nitrite as a pharmaceutical can be used to treat cyanide poisoning (Hope Pharmaceutical Sodium Nitrite Injection).Volatile products containing nitrites such as amyl nitrite have been used recreationally as inhalants for a euphoric effect during a state of mild hypoxia. Common exposure to small amounts is harmless.However, nitrites are able to oxidize the iron in hemoglobin from Fe +2 to Fe +3 yielding MetHb, and thereby reducing the oxygen-carrying capability of the blood. As such, when purposefully ingested in large amounts, nitrites can be fatal.

Commentary on: Dean DE, Looman KB, Topmiller RG. Fatal methemoglobinemia in three suicidal sodium nitrite poisonings. J Forensic Sci. doi: 10.1111/1556‐4029.14689. Epub 2021 Feb 17.

“…We read with great interest the recent publication of Dean DE et al [1] entitled "Fatal methemoglobinemia in three suicidal sodium nitrite poisonings." The authors reported 3 fatal cases of ingestion with sodium nitrite (NaNO 2 ) and made a very interesting review regarding the toxicological and pathophysiological mechanisms of toxicity.…”

Increasing use of sodium nitrite in suicides—an emerging trend

“…Between 2000 and recent years, there has been a distinct lack of cases with only 1 case in New Zealand in 2010 identified in the literature [23]. However, since 2019 the number of reported suicides using sodium nitrite has significantly increased compared to previous years [24][25][26][27][28][29][30][31][32].…”

Nitrites: one “click” to suicide

“…Introduction: Nitrites are chemical compounds naturally present in the environment [1]. In addition to endogenous production, human exposure occurs due to multiple applications, e.g.…”

“…in construction and food industry, and also in health [2]. Self-poisoning from ingested nitrites is an uncommon form of suicide [1]. However, several cases have already been reported [1][2][3][4][5].…”

“…Self-poisoning from ingested nitrites is an uncommon form of suicide [1]. However, several cases have already been reported [1][2][3][4][5]. Sodium nitrite shares similar characteristics to typical table salt and is cheap.…”