Hypoxic brain injury, as the name itself suggests, indicates injury to the brain as a result of hypoxia - low oxygen content. This can occur at the time of birth or later. Causes for hypoxic brain injury at later stage in life could be due to accidents such as drowning, electrocution or sudden cardiorespiratory arrest. Some time such damage could occur due to repeated attacks of convulsions (Status Epilepticus) or due to acute massive stroke. Normally small water shed infarcts do not cause hypoxic brain injury. Watershed hypodensity seen in the MRI scan of the brain could be secondary effect of hypoxia. That means it is the result rather than the cause.