(1) Pathophysiology of the death in a fire
- The pathophysiological aspects of death in a fire are complex.
The actual cause of death in a fire results from the interplay of many factors.
In rapid deaths,
the possible cause of death is as follow: oxygen deficiency,
carbon monoxide intoxication,
cyanide intoxication,
flash fire,
heatstroke and heat rigor [1].
- Consequently,
it is critically important to obtain a proof that the victim was alive when the fire started and to exclude other causes of death.
(2) The classical autopsy signs of the death in a fire
•Vital reactions
·Respiratory tract mucosa damage due to the inhalation of hot gases
(Edema,
mucosal bleeding,
vasicular detachment)
·Inhalation of soot in the deeper respiratory tract and soot swallowing
·Facial petechial hemorrhages
·High levels of carbon monoxide and carbon cyanide
·Crow’s feet
•Thermal injuries
·Pugilistic attitude
·Thermal fracture and amputation
·Thermal epidural hematoma
·Heat rupture and destruction of skin and soft tissue
·Open mouth with shrunken lips and protrusion of the tongue
(3) Comparison of PMCT findings of burned bodies with autopsy findings
Pugilistic attitude
- Skeletal muscles and tendons contract and shrink from the heat,
resulting in abduction in the shoulder and hip joints and flexion in the elbow,
hip and knee joints [1,
2].
- When the upper extremities are flexed from thermal muscle contraction,
the term pugilistic attitude is applied because the upper body position is that of a boxer holding his hands in front of the body [2].
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600648?maxheight=300&maxwidth=300)
Fig. 1: PMCT shows flexion of the extremities from thermal muscle contraction, which strongly holds the hands and wrists clenched.
Thermal fracture and amputations
- It is difficult to evaluate traumatic fractures and amputations in severely burned bodies because heat-related cortical fractures and amputations are common.
- Thermal fractures are characterized by fine,
linear superficial fracture lines,
which are usually found in areas of severe charring with defect of soft tissue.
In contrast,
morphology and distribution of traumatic fractures are related with mechanical forces,
such as extension,
flexion or compression [2,
3].
- Thermal amputations in the distal extremities have smooth transverse or angulated margins that are not covered by skeletal muscle because of muscle shrinkage and retraction.
In contrast,
traumatic amputations have sharp,
angulated margins or evidence of comminution.
- Another finding indicative of heat-related bone injury is mottled lucency in the marrow space on CT [3,
4].
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600650?maxheight=300&maxwidth=300)
Fig. 2: Charring with distal thermal amputation of upper extremities. PMCT shows defect of the bones with smooth margin and mottled lucency (arrows). Soft tissues are severely damaged.
Thermal epidural hematoma
- Thermal epidural hematoma is a common finding,
which represents accumulation of blood in the epidural space as the brain dehydrates and shrinks from heat [2].
The blood in the hematoma is typically soft and friable,
light brown or reddish,
and has a honeycomb appearance.
- Although thermal epidural hematoma is thought to result from fluid shifting from the diploe and the venous sinuses to the room between the dura and skull,
the exact mechanism is unknown [1,
2].
- Thermal epidural hematoma is usually found under the site of charring of the skull.
The evaporation of brain fluid can also cause the skull to rupture [1].
- Thermal epidural hematoma should be distinguished from traumatic epidural hematoma [2].
While epidural hematomas do not cross over the sutures because the dura firmly attaches to the sutures,
thermal epidural hematomas can cross over the sutures [1].
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600651?maxheight=300&maxwidth=300)
Fig. 3: PMCT shows epidural hematoma (red arrows) and thermal loss of the outer table of the skull (yellow arrows).
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600652?maxheight=300&maxwidth=300)
Fig. 4: PMCT shows epidural hematoma (red arrows) and thermal loss of the posterior part of the skull (yellow arrows).
Heat rupture and destruction of skin and soft tissue
- When the body is exposed to heat,
skin and soft tissues rapidly contract and split.
This phenomenon produces heat rupture,
which appears as linear lacerations of the skin and underlying soft tissue [2].
- Heat ruptures can be distinguished from antemortem injuries because they do not show surrounding edema,
erythema or bruising [2].
- Continued exposure to fire results in thermal destruction of skin and subcutaneous tissue which expose skeletal muscle,
bone and internal organs [2].
For example,
the intestines are forced out of the abdomen [1].
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600653?maxheight=300&maxwidth=300)
Fig. 5: PMCT shows rupture of abdominal wall and protrusion of intestines in a case of severe charred body.
(4) Sample cases and pitfalls
Case 1
73/F: Are all findings due to thermal injuries?
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600655?maxheight=300&maxwidth=300)
Fig. 6: Case 1. A 73-year-old man found dead in a burned-out house.
A: PMCT shows thermal defect in the calvarium, shrinked brain and thermal epidural hematoma. A high-attenuation area is also seen along the surface of the left cerebral hemisphere.
B: The right humerus and clavicle show amputation with smooth margin and mottled lucency typically seen in thermal amputation.
C: The anterior abdominal wall is almost completely lost with exposure of the intraabdominal structures.
D, E: Autopsy photographs show a left-sided antemortem chronic subdural hematoma, which should not be mistaken as postmortem change related with the fire. Note the autopsy photographs have been reversed to correspond with the anatomic orientation of the PMCT images.
Case 2
80/M: Are these clots related to the fire?
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600656?maxheight=300&maxwidth=300)
Fig. 7: Case 2. A 80-year-old man found dead in a burned-out house.
A: Autopsy photograph of resected trachea reveals soot in the airway as a vital reaction.
B: Soft coagulated blood is seen in the aorta, which is not due to heat-coagulation. The reason why there is postmortem clot formation in the aorta despite acute death is considered to be related with alcohol drinking (alcohol concentrations of blood and urine were 1.45mg/dl, 2.29mg/dl, respectively).
C, D: PMCT shows oval-shaped high attenuation areas in the aorta and pulmonary artery (yellow arrows), which is postmortem clot associated with alcohol intake. PMCT also shows hemorrhagic pleural effusion, which is turned out to be an artifact due to blood sampling from the right atrium.
Case 3
67/F: Thermal epidural hematoma?
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600657?maxheight=300&maxwidth=300)
Fig. 8: Case 3. A 67-year-old woman found dead in a burned-out house
A: PMCT shows high-density sediment in the epidural space, which is considered as thermal epidural hematoma (arrows).
B: Autopsy photograph of resected skull shows a small amount of hematoma and massive fluid collection. The latter is fire extinguishing water leaked into the skull; however it is difficult to tell it from thermal epidural hematoma.
Case 4
65/M: Identification of the victim
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600658?maxheight=300&maxwidth=300)
Fig. 9: Case 4. In a burned-out house, a severely charred body was found. It was unsuccessful to identify the victim by fingerprint, DNA analysis or dental work.
A, B: Antemortem CT of the suspected victim was compared with PMCT. The location, shape and size of osteophytes of lumber spine on a scout view of antemortem CT (A) of the suspected victim coincided with that of the volume rendering image obtained by PMCT (B).
![](https://epos.myesr.org/posterimage/esr/ecr2015/126873/media/600659?maxheight=300&maxwidth=300)
Fig. 10: Case 4. In a burned-out house, a severely charred body was found. It was unsuccessful to identify the victim by fingerprint, DNA analysis or dental work.
C-F: Antemortem CT of the suspected victim was compared with PMCT. Bone island of left femoral head and Schmorl node of lumber vertebral body were also identical on antemortem (C, E) and postmortem CT (D, F).