Which among the following is a secondary brain injury?

.Effects of Brain Injuries - 1. Brain oedema is accumulation of fluid, both intracellular and extracellular. It is due to congestion and dilatation of blood vessels. It may be diffuse or localized. 2. Brain necrosis is of severe variety with destruction and is due to haemorrhagic infarction. 3. Extradural haematoma occurs usually in temporoparietal region. It is commonly due to tear in middle meningeal veins and often middle meningeal aery. It causes intracranial hypeension, displacement, Kernohan's effect and often death. 4. Subdural haematoma is due to tear of veins between cerebrum and dura due to shearing forces. It is diffuse and commonly associated with cerebral injury. 5. Intracerebral haematoma can occur in different pas of cerebrum may be in frontal lobe, temporal lobe. ref:SRB&;s manual of surgery,ed 3,pg no 1038