The subdural hematoma may be caused by different things but the most common cause of this is a head injury. There are different reasons why people would get head injuries may be because of a fall, a collision with another hard object, or sometimes, an assault. The problem with different types of brain injury is that it can take longer for the brain to heal itself even after the treatment.
There are some who may experience some permanent damage too depending on the severity of what they have gone through. A subdural hematoma is usually small and will not require surgery. Infants are common to get this if they undergo the shaken baby syndrome.