Karen Heath’s research while affiliated with Forensic Science South Australia and other places

A 1-week-old girl died suddenly and unexpectedly. At autopsy the major finding was of a right dominant coronary artery circulation with an inapparent left coronary artery ostium. After careful examination, an anomalous origin of the left coronary artery was found with the ostium located in the non-coronary cusp immediately adjacent to the commissure of the non- and left coronary cusps. The ostium was of small caliber with an obliquely oriented artery (<45°) with no ostial ridges. The artery coursed anteriorly past the left coronary cusp between the aorta and the left atrial appendage to then follow its usual course inferiorly along the anterior aspect of the left ventricle. The reminder of the autopsy was unremarkable. Death was, therefore, attributed to an anomalous and hypoplastic left coronary artery (and ostium) with an acute angle of take-off. Tracing coronary arteries in the very young may be technically difficult due to their small size, thus identifying the location of ostia is important. This may be difficult when the ostium was located close to a commissure.

A multitude of conditions may cause acute and unexpected upper airway compromise in both children and adults. These include mechanical blockage of the airways either from internal obstructions due to inhaled food or foreign objects, or from external compression. In addition, kinking of the airway in cases of positional asphyxia may compromise aeration. Infections represent another cause of airway narrowing with the potential for occlusion. The case of a 64-year-old man with acute laryngo-epiglottitis is used to demonstrate that death may occur from infections in previously structurally-normal airways. Infections may compromise respiration due to acute airway occlusion from intraluminal material/mucus, mural abscesses or from acutely inflamed and oedematous mucosa with adherent tenacious mucopurulent secretions. External compression from nearby abscesses may also critically narrow air passages.

Self-immolation suicides refer to lethal situations where a victim has intentionally set themselves on fire using an accelerant, or has deliberately stepped into a fire. These are rare events in Western countries accounting for only 0.6-1% of suicides. Two cases are described of familial self-immolation with features of an anniversary/memorial event: Case 1: The charred body of a 66–year-old woman was found beside a suburban waterway with evidence of self-immolation using methylated spirits. Death was attributed to incineration; Case 2: Twenty five years later the charred body of another 66-year-old woman was found on the banks of a nearby suburban river. Analysis of clothing revealed ethanol, a major component of methylated spirits. Death was due to the combined effects of inhalation of products of combustion and incineration. Review of the history revealed that the decedent in case 2 was the daughter of the victim in case 1. This, therefore, represents an extremely rare event, that of familial self-immolation suicides with the daughter choosing the same method that had been used by her mother, at an identical age and in a similar location. These cases add to the potential complexities of familial suicides.

Two cases of clinically undiagnosed laryngeal squamous cell carcinomas in men aged 57 and 66 years, respectively, are reported that resulted in sudden death from upper airway occlusion. The cause of the terminal event differed between the 2 cases with acute airway narrowing being precipitated by tenacious mucopurulent secretions in case 1 and hemorrhage from surface ulceration with glottic occlusion by blood clot in case 2. At autopsy, the immediate cause of acute airway compromise in cases of space-occupying laryngeal lesions may, therefore, be due to the synergistic effects of different factors.

Analysis of autopsy cases of suicide from Forensic Science South Australia files (2003-2017) where helium, nitrogen or nitrous oxide gas had been used revealed that only 2/58 (3.5%) cases utilised nitrous oxide; the remainder of cases had used helium or nitrogen. The two cases are presented here. In case 1, a 48-year-old man was found completely encased in a plastic bag with a hose connected to an opened cylinder of nitrous oxide. In case 2, a 27-year-old woman was found with a plastic bag over her head, tied around her neck, with a tube connected to a small canister of nitrous oxide. There were approximately 20 empty canisters of nitrous oxide nearby. Death in both cases was due to nitrous oxide augmentation of plastic bag asphyxia, manner suicide. The relative ease with which helium and nitrogen cylinders containing large amounts of gas can be obtained may explain the low numbers of suicides utilising nitrous oxide.

A 29-year-old African immigrant to Australia was found dead in bed. She had no known medical history, except for recent weight loss and hip/leg pain. Autopsy examination revealed extensive tuberculous consolidation with widespread cavitation of the lungs, with multiple caseating granulomas containing large numbers of acid fast bacilli on histology. Similar granulomas were also present in lymph nodes of the porta hepatis, mediastinum and pulmonary hilum, and within the liver, spleen and mesentery. Mycobacterial polymerase chain reaction analysis confirmed tuberculous infection. Her serum was negative for human immunodeficiency virus infection. Death was due to disseminated tuberculosis. In many parts of Africa, there are negative cultural associations attached to tuberculosis, which often leads to a delay in diagnosis. The case demonstrates the extent of active disease that may be uncovered at autopsy in decedents from societies where tuberculosis is stigmatised and therefore concealed. It also emphasises the risk of infection for forensic workers.

A three-year-old boy with mild symptoms of an upper respiratory tract infection and recent onset vomiting collapsed at home. Resuscitative attempts in hospital were eventually unsuccessful. At autopsy an obstruction of the small intestine, with ischemia, was identified. It had been caused by strangulation of the small intestine through a congenital mesenteric defect. Moderate mesenteric lymphadenopathy, with enlarged lymph nodes in the region of the herniated small intestine, were associated with positive testing for human metapneumovirus and enterovirus. Transmesenteric hernias are a very rare form of internal herniation that have the highest risk of strangulation. Unfortunately in children the presentation may be relatively nonspecific with a precipitate decline towards the end. In the reported case it is possible that mesenteric lymphadenopathy may have contributed to intestinal entrapment by preventing spontaneous reduction.

A 47-year-old previously-well woman was found dead on the floor of a shower cubicle on a property in rural South Australia. The impression of the attending doctor and police was of collapse due to natural disease. Although there was significant stenosing coronary artery atherosclerosis found at autopsy, cherry pink discoloration of tissues prompted measurement of the blood carboxyhemoglobin level which was found to be 55%. The source of the gas was a poorly-maintained hot water heater that was mounted on the inside wall of the shower. Construction of the shower using an impermeable concrete rain water tank had caused gas accumulation when the water heater malfunctioned. Had lethal carbon monoxide exposure not been identified others using the same shower unit would also have been at risk.

Suicide pacts usually result in simultaneous deaths by mutual arrangement. While nitrogen and helium gas inhalation are being increasingly used in solitary suicide attempts, for some reason they have been rarely utilised in suicide pacts. A search of autopsy files at Forensic Science SA over a 15-year period (2003–2017) was undertaken to determine how often this method of joint suicide occurs. Only two cases were found. Case 1 comprised a 64-year-old husband and wife (who had a history of multiple sclerosis). They were found deceased in a vehicle with two empty cylinders of nitrogen gas. Case 2 comprised an 87-year-old man (who had a history of ischaemic heart disease) and his 81-year-old wife who were found deceased with plastic bags over their heads, with plastic tubes connecting the bags to opened cylinders of nitrogen. The deaths in all cases were due to nitrogen-induced asphyxiation, in the latter instance augmenting plastic-bag asphyxia. Although suicide pacts have previously usually involved carbon-monoxide toxicity or drug overdose, it is possible that dissemination of information on the use of inert gases in individual suicide attempts may alter the methods used in future.

A 56-year-old man with no previous medical history collapsed and was not able to be resuscitated. The major findings at autopsy were enlargement of the heart (weight = 527 g) which contained an infiltrating firm, homogeneous tumor in an epicardial location adjacent to the left anterior descending and right coronary arteries, with further extension into the right ventricular outflow tract, the interventricular septum and left ventricular free wall. Sections showed sheets of small lymphoid cells with scattered large lymphocytes amounting to a low-grade follicular non-Hodgkin lymphoma, as tumor cells were CD20, CD10, Bcl 2 and LMO 2 positive. This case demonstrates a very rare cause of sudden and unexpected death that resulted from a low-grade follicular lymphoma in an asymptomatic, immunocompetent individual.