Clinical features of

Permanent absence of all ‘vital’ signs: • Spontaneous respiration is absent • Pulses cannot be palpated • Not be able to auscultate breath or heart sounds • The pupils are fixed in diameter and unresponsive to bright light • Corneal reflexes are absent • There is no gag or caugh reflex in response to pharyngeal, laryngeal or tracheal stimulation • There is no motor response within the cranial nerve territory to painful stimuli applied

Postmortem changes

• - cooling of the body • Pallor mortis - paleness of the body • - bluish-red discoloration of the skin and organs • - rigidity (spasm) of the muscles • Postmortem clot • Postmortem Algor mortis - cooling of the body

• The rate of cooling is affected by a variety of factors, such as ambient temperature, airflow across the body, body fat, antemortem hyper- or hypothermia, etc.

• The body will cool at 10 to 1.50 C per hour for the first 12 hours, and subsequently lose 0.50 to 10 C per hour for the next 12 hours

Pallor mortis - paleness of the skin and visible mucosal surfaces

After death, the circulation of blood cessates. The blood passively follows the gravity and pools in the capillaries of deep tissues Antonello da Messina (1476): The dead Christ is supported by an angel (detail).

Postmortem paleness portrayed marvellously by the artist.

Livor mortis - bluish-red discoloration of the skin and organs Result of the blood settling or pooling by gravity in capillaries, which dilate following the cessation of circulation

Back

Belly Livor mortis - bluish-red discoloration of the skin and organs

• Absent where the weight of the body against a supporting object (e.g., mattress, tight fitting diapers) compress the capillaries and prevent them filling with blood • First observed within an hour of death as purple blotches in gravidity dependent points of the body, reaches its peak between 8 and 12 hours: livor due to hypostasis • If the body has not been moved after 8 to 12 hours, the livor will become fixed because the tissues are stained by haemolysed blood: livor due to imbibition Rigor mortis - rigidity (spasm) of the muscles

• At the time of death, the muscles remain flaccid; after 4 to 48 hours, the muscles develop the rigidity, and, after 48 to 72 hours, the rigidity relents • Once rigor becomes fully developed, and has subsequently relented, it will not reform • Rigor starts in the muscles of the eyelids and the muscles of mastication, followed in the muscles of the shoulders and arms, and, finally, in the muscles of legs • Rigor fades in similar sequence Rigor mortis - rigidity of the muscles

• The onset and subsequent development of rigor may be accelerated by severe fever, convulsions, elevated environmental temperature; and can be delayed by the rapid cooling of the body Postmortem clot

• During , it is essential to differentiate between antemortem red thrombus and postmortem red clot

• Antemortem clot: firm, though brittle, and has a dull, matt, striated surface from fibrin lamination; attaches to the vessel wall

• Postmortem clot: dark red, soft, jelly-like, with a shiny, glistening surface; does not attach to the vessel wall

Postmortem decomposition

• Takes two separate forms: autolysis and • Autolysis: fermentative processes that occur without the participation of bacteria. Histologically, disintegration of cellular structures is observed • Occurs very early in enzyme-producing organs, such as the pancreas and adrenals • Autolysis is accelerated if body or environmental temperature is raised, or there is jaundic liver disease

• When a foetus dies in an intact amniotic sac, decomposition, termed maceration begins immediately • Since the amniotic sac does not normally contain bacteria, the decomposition is not putrefactive • Early changes are most obvious in the skin, characterized by the delamination of the epidermis from the dermis  skin slippage • As the RBCs haemolyze, the skin will develop a reddish discoloration, and eventually muscles, connective tissue, viscera, and the umbilical cord will develop a uniform similarity of colour Macerated foetus. Note the reddish discoloration of the skin. The epidermis is detached from the dermis in large laminae.

Courtesy of Kaiser László, MD