Subdural haematoma | Most common haemorrhage following elderly head injury.12 |
Characterised by bleeding into the space between the dura and arachnoid mater following acute arterial or parenchymal injury. | |
Most common aetiology of chronic subdural haematoma is tearing of bridging veins crossing the arachnoid and dura; risk exacerbated by cerebral atrophy | |
Bridging vein tears can also occur with intracranial hypotension (eg following CSF leak).13 | |
Cerebral contusions | Defined as clearly demarcated areas of small-volume focal micro-haemorrhage occurring as a direct result of damage to the small vessels of the brain parenchyma. |
Can be located in proximity to the site of impact, but contrecoup distribution is common. | |
Results in focal neurological deficit.14 | |
Traumatic subarachnoid haemorrhage | Commonly occurs due to direct injury to a blood vessel, or injury secondary to sudden increase in intravascular pressure.15 |
Characterised by bleeding into the CSF-filled subarachnoid space. | |
Can result in secondary obstructing hydrocephalus.15 | |
Intracerebral haemorrhage | Discrete collection of blood within the parenchyma of the brain. |
Classified according to aetiology: trauma is less common than the primary spontaneous causes such as hypertension.16 | |
Results in focal damage due to direct local compression or a more diffuse cerebral injury due to raised intracerebral pressure.16 | |
Full haemorrhage formation can occur due to haemorrhagic progression of contusion.17 | |
Extradural haemorrhage | The least common post-traumatic intracranial haemorrhages.12 |
75–90% of patients co-present with a skull fracture.18 | |
The most common mechanism of injury is rupture of the middle meningeal artery as it passes through the foramen spinosum.19 | |
Commonly accompanied by a characteristic period of lucidity following injury, which often precedes a comatose state. | |
Skull fractures | Classified according to location, appearance and degree of depression.20 |
Can result in damage to brain parenchyma, blood vessels and cranial nerves as they exit the cranial vault. | |
Can also predispose to associated venous sinus thrombosis, especially in occipital fractures crossing the site of the transverse sinus. CT venography may be indicated in the context of persistent headaches or feature of raised intracranial pressure. | |
CSF leakage can result in intracranial hypotension and secondary subdural haemorrhage. | |
Diffuse axonal injury | A syndrome representing microscopic damage to the axons of the neural tract, brainstem and corpus callosum. |
Clinically defined as a coma lasting longer than 6 hours following a traumatic brain injury without other ischemic lesions or swelling identified as the underlying cause.21 |
CSF = cerebrospinal fluid; CT = computed tomography