Injuries to head are very frequent as a result of traffic accidents, assaults and falls. If the brain is affected, the injury is serious. Traumatic brain injuries can be classified according to the effect of trauma in two categories: acceleration/deceleration injuries and impact injuries.
Diffuse Neuronal Injuries: This is a result of sudden acceleration/deceleration movement of head and is characterized by diffuse neuronal damage involving the brain stem and brain cells. There is a widespread intracellular disturbance and conduction defects at synaptic junctions.
Diffuse Axonal Injuries: This is encountered in those situations where rotational strains produced during impact to the head damage the blood vessels and axons. There is stretching of the axons due to head motion and therefore loss of functions. They occur in severe head injury and due to repeated jolts as in boxing.
Subdural Hematoma: This is a collection of the blood in the subdural space and is more common in assaults and fall.
Cerebral Concussion: Also called stunning , followed by head injuries is characterized by gross physiological disturbances of brain function due to diffuse neuronal injury but with little or no naked eye lesion or anatomical changes. There is sudden loss of consciousness but tendency to spontaneous recovery is possible. Concussion severity depends on physical stress to neurons or repeated blows so it may wholly or partially be reversible or may prove fetal. Recovery from concussion is sometimes followed by retrograde amnesia which is a condition in which patient losses past memory.
Cerebral Contusions: These result from leakage of blood from traumatically ruptured blood vessels and are most commonly found in frontal and temporal region of the brain. There is small punctate or streak like hemorrhages and associated destruction of brain cells and tissues with or without edema and are mostly associated with skull fracture.
Cerebral Laceration: It is one of the most common causes of raised intracranial pressure and may also be related to diffuse neuronal injury and concussion. Damage brain cells result in leakage and accumulation of fluid within the brain.
- Epidural Hemorrhage: It means bleeding between the dura and skull and is almost invariably traumatic. It is associated with skull fracture also but except in infants and women in which dura is strongly attached to the inner surface of skull. Symptoms are slow in onset.
- Subdural hemorrhages: Subdural hemorrhage occurs between the dura and arachnoid surfaces and may be due to tearing of cortical vein or damage to dural sinuses. It may be acute, sub acute and chronic.
- Subarachnoid Hemorrhages: This is bleeding within the subarachnoid space. Although it is common with natural disease than trauma, the most frequent traumatic causes are explosive blast, asphyxia by strangulation or traumatic asphyxia, prolong hyperextension of head or damage to vertebral arteries.
- Intracerebral hemorrhage: It is though non-traumatic brain injury but physical exertion or emotional excitement may precipitates. It may be the result of laceration and is common in old age.