Head Injury Classification and Pathology Quiz

Classification and Pathology of Head Injuries

• Head injuries can be classified based on impact/non-impact, acceleration/deceleration, direct/indirect, penetrating/non-penetrating, primary/secondary, and focal/diffuse injuries.

• Acceleration/deceleration injuries result from sudden movement or stoppage of head movement and can cause subdural hemorrhage, diffuse axonal injury, or diffuse vascular injury.

• Direct causes of head injury include compression of stationary head, object/missile striking head, blow to stationary head from moving objects, or head in motion striking an object like the ground.

• Indirect causes of head injury include heavy falls on feet or buttocks.

• Penetrating injuries can be caused by missile injuries (e.g. gunshot wounds) or sharp force trauma (e.g. knife stabs).

• Non-penetrating injuries can be caused by falls on flat surfaces or blunt objects hitting a stationary/moving head.

• Primary impact injury occurs at the moment of injury and can cause injury to the scalp, skull fractures, surface contusions, lacerations, diffuse axonal injury, or intra-cranial hemorrhages.

• Secondary damage can be due to complications initiated by or independent of primary damage, including ischemia/hypoxia brain damage, brain swelling/edema, raised intra-cranial pressure, or infection (e.g. meningitis).

• Focal brain injury includes cerebral contusions, brain lacerations, and intracranial hemorrhages, while diffuse brain injury includes diffuse axonal injury, hypoxic brain damage, and brain edema.

• Contact phenomena and movement phenomena are two important mechanisms of head injuries, with contact phenomena resulting from object striking the head and movement phenomena resulting from acceleration/deceleration forces.

• Scalp injuries can indicate a point of contact, and bleeding under the scalp may be mobile under gravity, leading to hematoma/bruise in different locations.

• Intracranial hemorrhages can include extradural/epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, and intracerebral hemorrhage, each with its own causes, pathologies, and mechanisms of death.Types and Pathology of Brain Contusions

• Brain contusions result from a massive force to the head, causing frontal and temporal pole contusions.

• Occipital contusions are uncommon in falls on the frontal region, while contrecoup contusions are relatively common and occur in a variety of falls.

• Contrecoup contusions are often more severe than coup-type contusions, but young children before 4-5 years of age usually do not develop them.

• Individuals over 65 years do not demonstrate contre-coup patterns of contusions with the same frequency as younger adults due to brain atrophy.

• Intermediate coup contusions are intracerebral lesions that occur deep within the neural parenchyma between the impact site and the opposite side of the brain.

• Fracture contusions are seen in association with fracture lines and can be distant from the impact site, with fragments of bone extending into the cortical surface and tearing of leptominges and brain.

• Gliding contusions occur in the parasagittal regions of the cerebrum and are often associated with diffuse axonal injury.

• Herniation contusions involve the medial aspects of temporal lobes and the cerebellar tonsils as the displaced brain impacts against the rigid tentorium cerebelli or the bony margins of the foramen magnum.

• Burst lobe describes a cerebral contusion combined with a hematoma in the white matter deep to the contusion and an overlying SAH from traumatized superficial cortical blood vessels.

• Contusional tears develop hemorrhagic and necrotizing lesions beneath cortex, representing tearing of subcortical matter and are common in infant brains due to their high water content and enclosure in the malleable cranium.

• Contusions appear as a focal discoloration or bruise on the surface of the cortex and typically affect the crests of gyri and involve outer layers of the cortex, usually in association with SAH.

• Brain contusions show a wide spectrum of morphological appearances, ranging from microhemorrhages visible only under the microscope to confluent hemorrhagic lesions extending through the cortex into subcortical white matter, while sulci are spared.

Classification and Pathology of Head Injuries

• Head injuries can be classified based on impact/non-impact, acceleration/deceleration, direct/indirect, penetrating/non-penetrating, primary/secondary, and focal/diffuse injuries.

• Acceleration/deceleration injuries result from sudden movement or stoppage of head movement and can cause subdural hemorrhage, diffuse axonal injury, or diffuse vascular injury.

• Direct causes of head injury include compression of stationary head, object/missile striking head, blow to stationary head from moving objects, or head in motion striking an object like the ground.

• Indirect causes of head injury include heavy falls on feet or buttocks.

• Penetrating injuries can be caused by missile injuries (e.g. gunshot wounds) or sharp force trauma (e.g. knife stabs).

• Non-penetrating injuries can be caused by falls on flat surfaces or blunt objects hitting a stationary/moving head.

• Primary impact injury occurs at the moment of injury and can cause injury to the scalp, skull fractures, surface contusions, lacerations, diffuse axonal injury, or intra-cranial hemorrhages.

• Secondary damage can be due to complications initiated by or independent of primary damage, including ischemia/hypoxia brain damage, brain swelling/edema, raised intra-cranial pressure, or infection (e.g. meningitis).

• Focal brain injury includes cerebral contusions, brain lacerations, and intracranial hemorrhages, while diffuse brain injury includes diffuse axonal injury, hypoxic brain damage, and brain edema.

• Contact phenomena and movement phenomena are two important mechanisms of head injuries, with contact phenomena resulting from object striking the head and movement phenomena resulting from acceleration/deceleration forces.

• Scalp injuries can indicate a point of contact, and bleeding under the scalp may be mobile under gravity, leading to hematoma/bruise in different locations.

• Intracranial hemorrhages can include extradural/epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, and intracerebral hemorrhage, each with its own causes, pathologies, and mechanisms of death.Types and Pathology of Brain Contusions

• Brain contusions result from a massive force to the head, causing frontal and temporal pole contusions.

• Occipital contusions are uncommon in falls on the frontal region, while contrecoup contusions are relatively common and occur in a variety of falls.

• Contrecoup contusions are often more severe than coup-type contusions, but young children before 4-5 years of age usually do not develop them.

• Individuals over 65 years do not demonstrate contre-coup patterns of contusions with the same frequency as younger adults due to brain atrophy.

• Intermediate coup contusions are intracerebral lesions that occur deep within the neural parenchyma between the impact site and the opposite side of the brain.

• Fracture contusions are seen in association with fracture lines and can be distant from the impact site, with fragments of bone extending into the cortical surface and tearing of leptominges and brain.

• Gliding contusions occur in the parasagittal regions of the cerebrum and are often associated with diffuse axonal injury.

• Herniation contusions involve the medial aspects of temporal lobes and the cerebellar tonsils as the displaced brain impacts against the rigid tentorium cerebelli or the bony margins of the foramen magnum.

• Burst lobe describes a cerebral contusion combined with a hematoma in the white matter deep to the contusion and an overlying SAH from traumatized superficial cortical blood vessels.

• Contusional tears develop hemorrhagic and necrotizing lesions beneath cortex, representing tearing of subcortical matter and are common in infant brains due to their high water content and enclosure in the malleable cranium.

• Contusions appear as a focal discoloration or bruise on the surface of the cortex and typically affect the crests of gyri and involve outer layers of the cortex, usually in association with SAH.

• Brain contusions show a wide spectrum of morphological appearances, ranging from microhemorrhages visible only under the microscope to confluent hemorrhagic lesions extending through the cortex into subcortical white matter, while sulci are spared.