| Contusion
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Etiology
•Head trauma
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Pathogenesis
•Blunt head trauma produces contusion in the coup and
contracoup position in the brain. When the brain is
stationary and hit by a moving object, only a coup
lesion at the point of impact is seen. When the
moving head hits a stationary object (usually the ground)
there is a coup injury at the point of impact and a
contracoup injury opposite the point of impact due to
movement of the brain within the head. This is usually
seen when the head hits on the occiput. The brain hits
the posterior part of the head then slides forward and
backward several times. If the anterior part of the skull
was smooth there would be no damage to the brain but
the petrous temporal ridge and orbital frontal skull
are ridged and irregular causing brain to be torn
out as it moves across them causing the contracoup
injury. If the brain hits frontally there is only a large
coup lesion since the posterior part of the skull is
smooth.,
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Epidemiology
•Head trauma caused 1-2% of all deaths and one-third
to one half of all deaths due to trauma are due to
head trauma.
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General Gross Description
•A contusion is a bruise of the brain.
•It appears as
softening with punctate and linear hemorrhages in
crowns of the gyri and can extend into the white
matter in a triangular fashion with the apex in the
white matter.
•Old contusions appear as brownish
stained triangular defects in the cortex and underlying
white matter. They occur on the orbital frontal
surfaces and temporal poles in most instances.
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General Microscopic Description
•Microscopically the contusion looks like a triangular
shaped infarct with pallor and spongy change early
associated with hemorrhages.
•After several days
macrophages are seen picking up dead tissue with
astrocytes walling off the area.
•The old contusion
shows a defect in the cortex and white matter with
an astroglial border and a few macrophages and vessel
remnants in the cavity.
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Clinical Correlation
•Contusions are associated with edema and if large
enough can lead to death from herniation or if the
patient survives there may be some frontal lobe
deficits such as poor judgement.
•Loss of smell due to
damage to the olfactory tracts can also occur.
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References
• Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp.60-62.
• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1304-1305.
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| Contusion
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| Synopsis by: M.L. Grunnet M.D. (TX2000M25420)[373]
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