Forensic Pathology for Police - Brainshare Public Online Library

208 10 Natural Deaths
the presence of numerous neutrophils (a type of white blood cell). Pus (or “purulence”
or “suppurative inflammation”) is sometimes evident grossly. A Gram stain
can be used to actually visualize bacteria in microscopic tissue sections. If a bacterial
infection is suspected at autopsy, cultures should be collected and sent to the microbiology
laboratory. Mycobacteria (tuberculosis) and fungal infections typically
result in “granulomatous inflammation,” characterized by “granulomas” composed
of lymphocytes and macrophages (two other types of white blood cells). In each
type of infection (tubercular and fungal), special cultures can be collected, and
visualization of the micro-organisms within microscopic tissue sections is possible
using special stains. Viral infections classically cause a lymphocytic inflammatory
reaction. Depending on the virus, there may be specific cellular features (“viral
inclusions”) identified within infected cells, but actual visualization of the viruses
using a light microscope is not possible. Special “immunostains” can help to identify
the infection, along with blood “serology” tests and expensive viral cultures.
Parasite infections, which often involve some type of arthropod or other animal
“vector,” may or may not be readily identified grossly, depending on the organism
involved. Microscopic identification, with or without additional serologic testing, is
used to make the diagnosis.
Infections of specific organ systems will be presented throughout this chapter.
Occasional mention is made of the term “sepsis.” This term should imply
to the reader that an infection (usually bacterial) is widespread throughout the
body. In other words, it represents a “systemic” infection (meaning throughout
the entire body system). The term “septicemia” is similar and implies infection
within the bloodstream. Sepsis and septicemia are very serious conditions which frequently
lead to death. Sepsis can be considered an infectious cause of the “systemic
inflammatory response syndrome,” described above.
By convention, in many deaths due to infectious processes, the manner of death is
considered natural, even though the micro-organism is, strictly speaking, an external
environmental factor. For example, if a child contracts bacterial meningitis and dies,
the death is considered natural. In a similar way, an elderly person who develops a
pneumonia and dies is a natural death. This even holds true for many cases where a
specific external vector is involved, such as West Nile viral encephalitis transmitted
by a mosquito bite or Rocky Mountain spotted fever (caused by a bacteria) transmitted
by a tick bite. Exceptions to this MOD rule regarding infectious diseases occur
when an infection develops at the site of an injury. For example, if a person sustains
a gunshot wound of the abdomen and initially survives, only to die of a bacterial
infection of the abdominal cavity, the death is no longer considered natural, since
the infection was initiated by the gunshot injury.
Cardiovascular System
Strictly speaking, the cardiovascular system is composed of the heart (cardio-) and
the blood vessels (vascular), and therefore this section will deal with diseases of both
the heart and the blood vessels known to result in death. The mechanism of death
in many heart diseases is related to a lethal arrhythmia. The word “arrhythmia”