Pregabalin is a gamma-aminobutyric acid analogue; it has been used clinically as an anticonvulsant and analgesic agent. Few documented reports exist of deaths resulting from pregabalin overdose. This report discusses a case of pregabalin intoxication in a 27-year-old male, who was found unconscious in a prison and later pronounced dead at a local hospital. An autopsy and toxicological analysis revealed the presence of pregabalin, alprazolam, diazepam, escitalopram, fluoxetine, lorazepam, bromazepam, flunitrazepam, zolpidem, and piroxicam. The concentrations of pregabalin and alprazolam were 10.3 mg/L and 0.10 mg/L in heart blood, and 11.4 mg/L and 0.08 mg/L in femoral blood, respectively. The other detected drugs were within therapeutic concentrations. Ethyl alcohol was not detected in the blood. Although the pregabalin concentration was within the therapeutic or toxic range, the concomitant use of other drugs, particularly benzodiazepines and zolpidem, likely enhanced its toxicity. Based on the autopsy findings and toxicological results, the cause of death was determined to be multidrug intoxication, including pregabalin. Although pregabalin is generally considered safe and deaths from its use alone are very rare, it can be fatal at relatively low blood concentrations when combined with opioids or other medications. The rising use of pregabalin in Korea increases the risk of overdose deaths, similar to this case. Therefore, in forensic practice, the possibility of such fatalities should be considered when pregabalin is detected.

Compressive asphyxia is generally defined as a type of asphyxia caused by chest or abdominal compression by a heavy object. It has also been reported that it could be caused by external compression caused by ligatures around the chest or abdomen. However, asphyxia caused by ligature around the thorax has not been reported in suicide cases. We present an unusual case of suicide in which the cause of death was attributed to asphyxia caused by a ligature around the thorax. The deceased was a 41-year-old woman who was found dead and suspended by a rope around the thorax from a rooftop railing on the twelfth floor of a building. On postmortem examination, a ‘C’ shaped ligature mark was identified around the thorax, with a pressure mark in the subcutis and focal intramuscular hemorrhages, which were consistent with the ligature mark. The cause of death was determined to be asphyxia due to external compression of the chest in a suspended position.

Positional asphyxia is a type of asphyxia where the position of an individual compromises the ability to breathe. It is commonly caused by accidents due to alcohol or drug intoxication, diseases, and/or being in a confined space. In this study, the authors reviewed autopsy cases at their institute over the past 5 years where positional asphyxia is suspected as a contributing factor or cause of death. The autopsy cases (n=24) were divided into three groups: positional asphyxia was the cause of death (n=15); unknown cause of death but positional asphyxia was considered (n=4); and positional asphyxia was suspected to be a contributing factor (n=5). All cases of group A included postures that could interfere with breathing, but the typical jackknife or head-down postures were seen in approximately half of the cases; “classic signs of asphyxia” were also observed in approximately half of the cases. They shared features such as high blood alcohol concentration, therapeutic levels of drugs, various disease, minor head trauma, and morbid obesity; however, no definite diagnostic criteria have been established for forensic practice. Positional asphyxia is a form of mechanical asphyxia which must be differentiated from traumatic asphyxia. In addition to a complete autopsy, thorough laboratory tests and understanding of the circumstances of the case and the situation at the death scene are required for diagnosis. Special attention is required for the diagnosis of special types of positional asphyxia such as death during institutional restraint or prone restraint.

This study highlights a new case of an infant death caused by mechanical asphyxia, who was found dead after being wrapped and pressed by a daycare center teacher with the body and beddings. Moreover, we present a comparative review of four similar previously reported cases and the implications for forensic pathologists in the management of such cases from the perspectives of judicial verdicts of the cases. The previous report commented that the four cases could be considered as overlaying as a type of accidental asphyxia. However, a contextual comprehensive review including the whole scenarios of the cases and negative postmortem findings concluded that all the cases were explicitly different from overlaying cases. Furthermore, we followed up the judicial processes and verdicts in all five cases, including the present case and the four previously reported cases. In the four cases, the defendants were incarcerated for violation of ‘Act on Special Cases Concerning the Punishment of Child Abuse Crimes.’ The ruling trend revealed that the prison sentence durations had been prolonged from 4 to 19 years. Therefore, for a pediatric death suspecting mechanical asphyxia involving a daycare center, contextual comprehensive approach is essential to determine the cause of death and to provide appropriate medicolegal interpretation.

Overlaying refers to mechanical asphyxia caused by an adult sleeping on an infant due to deep sleep or external intoxication. We analyzed seven cases (6.6%) of overlaying death out of 106 sleep-related infantile death autopsy cases from January 2018 to March 2021. They were all boys, with an average age of 132.3 (63-244) days, and were sleeping with their inebriated parents. In autopsy, only non-specific findings such as facial congestion, pressure marks, scratches, and froth in the nose and mouth were noted. In the sleep-related infantile death investigation, thorough investigation of the death scene and the previous history are essential for diagnosis, because autopsy findings are minimal or non-specific in most cases. Victims of overlaying and sudden infantile death syndrome show similar clinical and autopsy findings. Therefore, special attention are required for the differential diagnosis.

Pickling salt, also known as curing salt, is a mixture of sodium chloride and sodium nitrite, which is used for color agent and a means to facilitate food preservation. Recently, online purchase of pure sodium nitrite has been restricted, and pickling salts have been used as replacements in cases of suicidal nitrite intoxication. From November 2020 to December 2021, there were four autopsy cases of nitrite poisoning caused by pickling salt, and 10 autopsy cases of nitrite poisoning by pure sodium nitrite. Due to the low nitrite concentration in pickling salts, serum nitrite and nitrate concentration, and methemoglobin levels were relatively low in pickling salts cases. Especially, low methemoglobin levels may cause confusion in the postmortem diagnosis of fatal nitrite intoxication, so caution is required.

For the diagnosis of drowning in immersed bodies, the diatom test has been controversial due to false-negative and false-positive results. Causes of false positive results include antemortem penetration of diatoms, and postmortem contamination during the submersion or the diatom preparation process. Herein, we report a false-positive case in a 30-year-old woman who died from homicidal multiple stab wounds and was thrown into a shallow farm waterway approximately 10 days after her death. In addition, a discussion on the false-positive diatom test results in immersed bodies with penetrating wounds is provided.

Esophageal foreign body impaction may be fatal secondary to occlusion of the glottis or external compression of the membranous portion of the trachea. A 14-year-old adolescent female was admitted to the emergency department for evaluation of sudden dyspnea and cyanosis after she swallowed a food bolus (a part of bachelor radish kimchi) without chewing. Unfortunately, the patient died despite cardiopulmonary resuscitation. Autopsy findings showed an ovoid, firm foreign body (3.5×2.5×2 cm) impacted in the proximal esophagus, with focal narrowing of the tracheal lumen secondary to external compression by esophageal foreign body impaction. Death was attributed to choking caused by an esophageal foreign body.

Histiocytoid cardiomyopathy, an extremely rare heart disease in infants and children, usually occurring in girls under the age of 2 years, is characterized by cardiomegaly, ventricular arrhythmia, and sudden death. In the present study, we report a case of a 2-day-old female neonate who suddenly showed cyanosis and cardiac arrest in the neonatal unit and died without resuscitation. Autopsy revealed multifocal nodular lesions in the left ventricle wall and papillary muscles. Microscopically, these lesions were composed of discohesive round or polygonal cells with eosinophilic cytoplasm and were positive for desmin and negative for CD68. Electron microscopy findings displayed abnormal swollen mitochondria with disorganized cristae, dense granules, and diminished myofibrils in the periphery of the cytoplasm.

Sodium nitrite intoxication is a primary cause of severe methemoglobinemia, which may be fatal. In the past, nitrite-related deaths were rare, but cases of suicide with nitrite have been increasing in number in recent years. We analyzed 14 cases of fatal nitrite intoxication from January 2013 to February 2019. There was a different trend between the cases from the past and those from recent years. The former consisted of older individuals who ingested nitrite accidentally or intentionally, while the latter comprised younger individuals who used nitrite mostly for suicide. Most individuals showed dark purple or dark brown lividity and cherry-pink discoloration of the muscles. Postmortem methemoglobin levels, which were analyzed in 5 cases, were 30%-49%. Most nitrite and nitrate concentrations showed the highest concentration in the stomach contents, and it showed that the nitrite was converted into nitrate in the blood. To conclude, methemoglobin tests using a portable oximeter and quantitative tests of nitrite and nitrate, as well as a thorough investigation of the case and scene may help determine the cause of death.