Decomposition

Decomposition of the human body occurs soon after death and is of relevance to radiology in the fields of post mortem and forensic radiology.

Pathology

Decomposition occurs due to two main processes :

• autolysis: degradation by destructive enzymes released by dying cells in the body
• putrefaction: degradation by enzymes released by bacteria. Putrefaction occurs mainly from enteric bacteria originally in the gut but have entered peripheral tissues and organs as a result of the loss of normal tissue integrity and the immune system after death.

Decomposition may be accelerated by infestation by insects and by predation by nearby animals . Other factors affecting the rate and degree of decomposition includes body size, body composition, environmental conditions (e.g. humidity, temperature) and the presence of clothing . Eventually there will be complete skeletalisation of the corpse .

Radiographic features

The earliest signs of decomposition are usually evident in the brain (see Normal postmortem changes in the central nervous system) . Changes in the brain are mostly due to autolysis .

Putrefactive changes however are first visible in the gastrointestinal tract with the formation of intra-mural and intravascular gas as well as increasing intestinal distension from the production of putrefactive gas (see Normal postmortem changes in the gastrointestinal tract) .