Traumatic Brain Injury (Head Injury)

– Physical injury to the brain or other structures in the cranium, which may be open with skull fracture or penetration or closed with impact and rapid jarring. Concussion is the least serious injury and is characterized by a transient loss of consciousness with no gross damage to the brain and no neurologic sequelae. Contusions and lacerations indicate a more serious injury, and there is bruising of brain tissue with bleeding and tearing of the cortical surface.

Causes and Incidence

Leading causes of head trauma include falls, industrial accidents, vehicular accidents (particularly involving motorcycles, or automobile accidents with passengers who were not wearing seat belts), assaults, sports injuries (boxing, diving, football), and intrauterine and birth injury. Alcohol use is a common related factor. Traumatic brain injury (TBI) causes more death and disability than any other neurologic disorder in individuals under 50 years of age. It is the leading cause of death in men under age 35. More than 77,000 individuals die of TBI each year in the United States, and 55,000 more are left with permanent neurologic damage.

Disease Process

Damage occurs from skull penetration or rapid brain acceleration and deceleration, which injure brain tissue at the point of impact, at its opposite pole (contrecoup), and diffusely in the frontal and temporal lobes. Blood vessels, meninges, and nerves can be ruptured, sheared, and torn. This results in neural disturbances, ischemia, hemorrhage, and cerebral edema. Laceration of meningeal arteries or sinuses can cause subdural or epidural hematomas and leakage of cerebrospinal fluid (CSF).

Symptoms

Clinical manifestations vary by the structures and brain tissue involved, by whether the injury was open or closed, and by the severity of the injury. The manifestations listed below are all possible.

Level of consciousness
Ranges from anxiety and irritability to restlessness, confusion, delirium, stupor, and coma; posttraumatic and retrograde amnesia

Pain
Mild to severe headache

Cranial nerve injuries
Anosmia; diplopia, strabismus, nystagmus, or blindness; deafness; vertigo; trigeminal paresthesias

Motor function
Weakness, paresis, paralysis; decorticate and decerebrate posturing; areflexia

Meningeal effects
Nuchal rigidity; positive Kernig’s sign; positive Brudzinski’s sign

Fractures
Linear: no bone displacement, possible epidural hematoma Depressed: focal deficits and cranial nerve injuries Basilar: CSF otorrhea or rhinorrhea; periorbital ecchymosis; conjunctival bleeding

Cerebral edema
Increased intracranial pressure (ICP) with slow respirations, bradycardia, nausea, vomiting, altered or loss of consciousness, seizures, weakness

Hematoma
Epidural: ipsilateral pupil dilation, rapidly increasing ICP Subdural: lethargy, headache, seizures, minimal dilation of pupil on affected side; widening pulse pressure; fixed, dilated pupils; hemiplegia; decorticate rigidity

Vital signs
Decreased blood pressure; pulse slow (intracranial hypertension) or rapid and feeble (hemorrhage); shallow respirations with possible CheyneStokes; hyperthermia with hypothalamic injury

Potential Complications

Complications include infection, seizure disorders, hydrocephaly, organic brain syndrome, permanent residual neurologic deficits (memory loss, loss of impulse control, loss of initiation skills, decrease in cognition and abstract reasoning, decrease in judgment and problem solving); physical deficits (paralysis, weakness, spasticity, loss of fine motor abilities); and death.

Diagnostic Tests

Skull xrays
To detect fractures and bone fragments

Computed tomography/ magnetic resonance imaging or angiography
To detect subdural or intracranial hematoma, shift, or cerebral ventricle distortion

Echoencephalography
To detect midline shifts

Cisternography
To detect dural tear

CSF sampling
May be contraindicated with signs of ICP, since it may lead to cerebral herniation; normal findings with cerebral edema and concussion, increased pressure and blood in CSF with laceration and contusion.

Treatments

Surgery
Debridement of open injuries; ventriculostomy or shunting procedures for ICP or hydrocephalus; craniotomy to elevate severe skull depressions, to stop hemorrhage from vessel lacerations or to evacuate hematoma; trephine to relieve pressure from hematoma; bolt placement to monitor ICP pressure; tracheostomy if needed for ventilation.

Drugs
Antiinfective drugs to prevent infection with open injury and leaking CSF; osmotic diuretics to control cerebral edema (corticosteroids are contraindicated, since they may increase seizure potential); polar beta-blockers to control transient hypertension; anticonvulsants for seizures; analgesics for pain (medullary depressants are contraindicated, since they may interfere with level of consciousness); muscle relaxants or paralyzing agents for decorticate and decerebrate posturing and restlessness in coma; stool softeners and suppositories to prevent constipation; artificial tears to prevent corneal damage with coma; histamine antagonists and antacids to control gastric reflux with tube feedings and reduce the chance of ulcers developing.

General
Initially: secure airway, control bleeding, stabilize body on backboard and transport; mechanical ventilation if needed with hyperventilation to control intracranial hypertension; central venous and arterial lines; ICP and cardiac monitoring; blood gases; vital signs and neural vital signs; monitoring of intake and output; enteral feedings or hyperalimentation; indwelling Foley catheter; seizure precautions; passive range-of-motion exercises, turning if comatose; cooling blankets for hyperthermia Long term: comprehensive rehabilitation program, including cognitive therapy to address cognitive, memory, and abstract reasoning deficits; speech therapy for communication deficits; physical therapy for residual weakness, paralysis, gait retraining, ataxia; occupational therapy for relearning activities of daily living; respiratory therapy to retain vital capacity; vocational therapy for learning vocational skills; counseling of individual and family to aid in adaptation to residual disabilities and amelioration of behavioral sequelae; transitional living placement to return individual to independent or supervised community living; long-term medical follow-up to reduce complications; instruction of family about the importance of structure and consistency of environment, safety issues arising from impaired judgment and lack of impulse control; instruction in the use of memory books and other memory aids.