**2.1. Suicide**

A 44-year-old nondiabetic man was found dead lying on the bed in his flat. Near the body, an ampoule and almost empty syringe were found and taken for further analysis. Two days earlier, the man had called his wife and said that he is going to commit suicide. The forensic autopsy did not reveal the cause of death. The initial stage of putrefaction, blood fluidity, acute blood stagnation (hyperemia) in the internal organs, and two supravital point wounds on the right thigh, which might have been injection sites, were found. Histopathological findings in the main internal organs were the following: brain, hyperemia with numerous petechiae, and edema; heart, adipositas, medium grade of atherosclerosis of the coronary arteries, and local fragmentation of muscle fibers; and lungs, hyperemia with local hemorrhages into alveoli and edema. Additional histochemical staining (Periodic Acid-Schiff, PAS) disclosed low amounts of glycogen in the liver (**Figure 1**). The standard toxicological analysis disclosed no evidence of drug abuse or alcohol, so due to the suspicion of suicide by insulin injection, a directed analysis with immunoradiometric assay (IRMA Kit Immunotech), routinely used for the in vitro determination of insulin in human serum and plasma, was conducted. It revealed a high insulin concentration level—24.42 μIU/ml in the vitreous humor (measuring range, 0.5–300 μIU/ml; the norm for serum, <22 μIU/ml)—and the presence of insulin in the material secured at the crime scene (in the syringe, 1853.91 μIU/ml). All these results (information from the prosecutor about the crime scene, results of medicolegal autopsy, results of histopathological and toxicological studies) clinched the thesis of insulin overdose.

documented case of murder by insulin is dated to the year 1957 (Kenneth Barlow case) [9]. Vincent Marks in his review has analyzed case histories of 66 people alleged or proven to have been poisoned by insulin (murders, manslaughters, attempted murders, Munchausen-

Of course, some insulin overdoses are accidental and associated with incorrect dosage of the drug by the patient [10, 11]. Most of these cases are not clinically serious. It seems, however, that the risk of intentional (suicidal) insulin overdose in patients with diabetes of both types (1 and 2) is underestimated. The population-based study of suicide victims in Northern Finland performed by Löfman et al. revealed that 3.1% of all suicide victims had diabetes (34.6% type 1 and 65.4% type 2) [12]. In victims with type 1 diabetes, insulin as a suicide method covered half of the selfpoisoning cases, while the proportion in type 2 diabetes was 13%. It is known that the risk of depression and attempted suicide is higher in patients with chronic diseases, including diabetes, so physicians who treat diabetic patients should evaluate co-occurring depression and substance

The aim of the author is to present the current state of basic knowledge about the nonmedical use of insulin, with particular emphasis on the possibility of postmortem diagnosis. The study also highlighted the little known, rare clinical problem of insulin abuse for recreational

In order to illustrate the abovementioned problems, I present two typical cases from routine medicolegal practice of the Department of Forensic Medicine and Forensic Toxicology in Katowice, School of Medicine in Katowice, Medical University of Silesia, Poland [15, 16].

A 44-year-old nondiabetic man was found dead lying on the bed in his flat. Near the body, an ampoule and almost empty syringe were found and taken for further analysis. Two days earlier, the man had called his wife and said that he is going to commit suicide. The forensic autopsy did not reveal the cause of death. The initial stage of putrefaction, blood fluidity, acute blood stagnation (hyperemia) in the internal organs, and two supravital point wounds on the right thigh, which might have been injection sites, were found. Histopathological findings in the main internal organs were the following: brain, hyperemia with numerous petechiae, and edema; heart, adipositas, medium grade of atherosclerosis of the coronary arteries, and local fragmentation of muscle fibers; and lungs, hyperemia with local hemorrhages into alveoli and edema. Additional histochemical staining (Periodic Acid-Schiff, PAS) disclosed low amounts of glycogen in the liver (**Figure 1**). The standard toxicological analysis disclosed no evidence of drug abuse or alcohol, so due to the suspicion of suicide by insulin injection, a directed analysis with immunoradiometric assay (IRMA Kit Immunotech), routinely used for the in vitro determination of insulin in human serum and plasma, was conducted. It revealed a high insulin concentration level—24.42 μIU/ml in the vitreous humor (measuring range, 0.5–300 μIU/ml; the norm for serum, <22 μIU/ml)—and the presence of insulin in the material

abuse, both of which are major risk factors of suicide [13, 14].

by-proxy cases) [7].

108 Ultimate Guide to Insulin

purposes.

**2.1. Suicide**

**2. Case reports**

**Figure 1.** Low amounts of glycogen in the liver—50% of control sections taken during autopsy of sudden traumatic death victims.

**Figure 2.** Empty packages after insulin, NovoMix 30 Penfill (a mixture of fast and long-acting insulin analogue), revealed in the apartment of victim. Needles can be analyzed by forensic geneticists for the presence of DNA mixture of the victim and murderer in the case of homicide-suicide death.

#### **2.2. Homicide-suicide**

According to the information of the Prosecutor's Office, a 63-year-old man was supposed to kill his wife and dog and then commit suicide. Such situation in forensic medicine is called homicide-suicide or dyadic death. In the apartment a farewell letter and empty packages after insulin, NovoMix 30 Penfill (a mixture of fast and long-acting insulin analogue), were revealed (**Figure 2**). External medicolegal examination and forensic autopsies carried out at the Department of Forensic Medicine and Forensic Toxicology of the Medical University of Silesia in Katowice did not explain the cause of death. However, potential injection sites on the thighs and the shoulder of woman were revealed (**Figure 3**). Different biological materials for additional tests—biochemical, chemical-toxicological, and histopathological and for forensic genetics—were taken. Due to the inability to quickly determine insulin level in body fluids and the site of injection using the reference chromatographic methods [17–20], the determination of this hormone was ordered to two clinical diagnostic laboratories (by chemiluminometric and immunoradiometric methods). In addition, C-peptide (short 31-amino-acid

> polypeptide that connects insulin's A-chain to its B-chain in the endogenous proinsulin molecule), glycated hemoglobin (HbA1c, a form of hemoglobin that is measured primarily to identify the 2- to 3-month average plasma glucose concentration), glucose, and lactate (it is known that one mole of glucose during the process of glycolysis produces two moles of lactate) were ordered. Incomplete, difficult-to-interpret results were obtained. In addition, a successful attempt of immunohistochemical (IHC) detection of insulin in samples taken from the injection sites was made (**Figure 4**) [21, 22]. The results of the tests carried out in the abovementioned clinical laboratories confirmed our previous experience with the low usefulness of

> **Figure 4.** Positive immunohistochemical (IHC) detection of insulin in the subcutaneous tissue around needle tracts

Insulin in Forensic Medicine and Toxicology http://dx.doi.org/10.5772/intechopen.76691 111

between adipocytes (right) and control section from distant area of the skin with no reaction (left).

insulin determinations in the autopsy hemolyzed blood specimens (article in press).

A classic postmortem macroscopic examination of the corpses (forensic autopsy) usually does not explain the cause and mechanism of death [23, 24]. Typically a feature of acute cardiorespiratory failure and nonspecific lesions related to the age of victim (e.g., atherosclerotic changes in vessels) can be found. For this reason, additional laboratory tests are necessary in each case. In addition to routinely collected sections from internal organs and body fluids (blood and urine), it is worth to take at least the sample of vitreous humor (VH) and the samples from potential injection sites for both histopathological and directed toxicological

A detailed histological examination of all internal organs, especially of the pancreas and liver, aiming at detection of insulinoma (tumor of the pancreas that is derived from β cells and secretes insulin) and morphological symptoms of hypoglycemia, respectively, should

**3. Postmortem diagnostics of fatal insulin poisoning**

**3.2. Forensic histopathology and immunohistochemistry**

**3.1. Medicolegal autopsy**

analyses.

**Figure 3.** Numerous supravital point wounds and surrounding bruises on the thighs—potential insulin injection sites.

**Figure 4.** Positive immunohistochemical (IHC) detection of insulin in the subcutaneous tissue around needle tracts between adipocytes (right) and control section from distant area of the skin with no reaction (left).

polypeptide that connects insulin's A-chain to its B-chain in the endogenous proinsulin molecule), glycated hemoglobin (HbA1c, a form of hemoglobin that is measured primarily to identify the 2- to 3-month average plasma glucose concentration), glucose, and lactate (it is known that one mole of glucose during the process of glycolysis produces two moles of lactate) were ordered. Incomplete, difficult-to-interpret results were obtained. In addition, a successful attempt of immunohistochemical (IHC) detection of insulin in samples taken from the injection sites was made (**Figure 4**) [21, 22]. The results of the tests carried out in the abovementioned clinical laboratories confirmed our previous experience with the low usefulness of insulin determinations in the autopsy hemolyzed blood specimens (article in press).
