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Brain injury, traumatic
OVERVIEW: Traumatic brain injury (TBI) is a principal cause of death and disability in young adults, at an estimated cost of billion per year in the USA. Frequently related to rapid deceleration such as motor vehicle accidents, diving accidents. May also be due to blunt injury such as with a baseball bat, etc.
• TBI is a dynamic process with initial bleeding followed by secondary injury due to cerebral edema, continued intracranial bleeding, etc.
Predicting outcome initially is difficult and patients may improve for years.
• Consider child abuse in the proper circumstance.
• Categorize patients:
• Mild: Minimal trauma, no loss of consciousness (LOC) or amnesia, alert, oriented, normal GCS, non-focal exam. Vomiting once or twice may occur, especially in children. May have headache. No need for further imaging or intervention.
• Moderate: Evidence of intracranial injury, but non-focal exam. May have had transient loss of consciousness, amnesia, headache, evidence of basilar fracture (Raccoon eyes, Battle's sign, hemotympanum, CSF rhinorrhea). These patients should have a CT scan if practical and should be admitted for serial neurological exams.
• Severe: Continued LOC, focal exam, any decreased level of consciousness. These patients need CT and immediate neurosurgical consultation. Focal exam indicates the possibility of a space-occupying lesion that may need surgical correction. Admit to ICU.
System(s) affected: Nervous, Cardiovascular, Endocrine/Metabolic
Genetics: N/A
Incidence/Prevalence in USA: Incidence: 200/100,000; 500,000 hospitalizations and 75,000 deaths per year
Predominant age: 15-24
Predominant sex: Male > Female
SIGNS AND SYMPTOMS: Variable and dependent on degree of injury:
• Loss of consciousness (transient or persistent)
• External signs of head injury
• Headache
• Vomiting
• Amnesia
• Focal signs and symptoms
• Evidence for increased intracranial hypertension (elevated blood pressure, decreased pulse rate, slow or irregular breathing [Cushing's triad])
• Decorticate or decerebrate positioning (both a bad prognostic sign)
• Seizures
• Raccoon eyes, Battle's sign, hemotympanum
• CSF rhinorrhea (see Special tests)
• Unilateral dilated pupil in an alert patient is not a sign of impending herniation since such patients are always unconscious.
• Epidural hemorrhage from blunt trauma is generally acute, frequently with a lucid interval (initial loss of consciousness followed by recovery of consciousness then loss of consciousness secondary to the intracranial bleed).
• Subdural hemorrhage usually has a slower onset and may present weeks after the initial injury, especially in the elderly.
CAUSES: • Motor vehicle accident (50%)
• Falls
• Assault
RISK FACTORS: • Alcohol
• Prior head injury
• Contact sports
• Recent evidence indicates risk of TBI with heading soccer balls
DIAGNOSIS DIFFERENTIAL DIAGNOSIS: Other causes of coma (e.g., drug overdose, infection, metabolic, vascular causes)
LABORATORY: • Patients may rapidly develop DIC; PT/INR, PTT, CBC (for decreased platelets), fibrin degradation products
• Drug and alcohol screening
Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A
PATHOLOGICAL FINDINGS: • Epidural, subdural or intraparenchymal hemorrhage
• Coup or contra-coup injury
• Evolving, diffuse axonal injury is a principle cause of neurologic sequelae with mild head trauma
SPECIAL TESTS: • Neuropsychometric testing when able
• CSF rhinorrhea contains glucose while nasal mucus does not. Check also for the double-halo sign: put a drop of bloody nasal discharge on filter paper. If it contains both CSF and blood, there will be two rings; a central ring followed by a paler ring.
IMAGING: • CT, C-spine as indicated
• Skull radiographs are not helpful in most cases, but can be done to document child abuse
DIAGNOSTIC PROCEDURES: Placement of intracranial pressure monitor when indicated, serial neurologic exams
TREATMENT APPROPRIATE HEALTH CARE: Outpatient for mild, inpatient or ICU for more severe
GENERAL MEASURES: Acute management depends on severity of injury. Most patients need no interventions. [Note: There is very little evidence to support or refute the use of most of these measures (including hyperventilation and mannitol); further studies are in progress.]
• The immediate goal is to determine who needs further therapy, imaging studies (CT) and hospitalization, and to prevent further injury.
• All penetrating injury should be evaluated by a neurosurgeon.
• C-spine immobilization should be considered in all head trauma. Clear the cervical spine radiographically (AP, lateral showing all 7 cervical vertebrae and the C7/T1 interspace, obliques if indicated).
• ABCs (airway, breathing, circulation) take priority over head injury. Stabilization and prevention of mortality from other injuries is critical to insuring patient survival.
• For the severely injured patient:
• Immediate cardiopulmonary resuscitation, avoid hypotension or hypoxia. Head injury causes increased intracranial pressure secondary to edema and perfusion pressure must be maintained.
• Use normal saline for resuscitation fluid. If unable to obtain good IV access, can use 3% or 7% saline for resuscitation fluid (250cc boluses in adults). This does not seem to change mortality, however. Avoid lactated Ringer's which is slightly hypo-osmolar.
• Keep head of bed elevated at 30 degrees if possible
• Intubate and hyperventilate patients with significant injury to keep the PaCO2 at 25-30 mmHg. This reduces cerebral swelling. However, it also reduces brain circulation and is falling out of favor.
• Start seizure prophylaxis (phenytoin) and continue for a week.
• Manage breakthrough seizures with lorazepam
SURGICAL MEASURES: Dependent on neurological consult
ACTIVITY: See ACTIVITY in topic Post-concussive syndrome for sports activity management.
DIET: As tolerated
PATIENT EDUCATION: • Brain Injury Association help-line: 1-800-444-6443
• Printed patient information: A Chance to Grow, 5034 Oliver Avenue North, Minneapolis, MN 55430, (612)521-2266
• Any patient discharged from your office or the ED should have instructions to watch for any changes in signs or symptoms that might indicate the need for further intervention (changing mental status, worsening headache, focal findings, etc.). Note that these instructions must be given to a competent surrogate who will observe the patient. If the patient deteriorates, it is not likely that he or she will be able to remember or act on any instructions.
MEDICATIONS DRUG(S) OF CHOICE: • Acute management (do not hesitate to use morphine or benzodiazepines as indicated, but remember that they may alter the patient's mental status):
• Morphine 1-2 mg IV prn for pain control up to 15 mg or more per hour as needed
• Increased intracranial pressure:
• Mannitol 0.25-2 gm/kg given over 30-60 minutes. Only for use in patients with adequate renal function. For children, 0.25 -1 gm/kg over 30-60 minutes. Only one dose should be needed since these patients will require neurosurgical consultation.
• Furosemide 20-40 mg IV to promote diuresis and decrease CNS swelling
• Neither furosemide or mannitol should be given to the hypotensive patient
• Seizures: Seizure prophylaxis should be given using phenytoin
• Phenytoin (Dilantin) 15 mg/kg IV (1 mg/kg/min IV not to exceed 50 mg/min). Do not exceed 1 gm in adults. Monitor for QT prolongation and stop infusion if increases by > 50% (risk of torsades de pointes).
• Lorazepam (Ativan) 1-2 mg IV as needed for seizures for adults and 0.1 mg/kg in children. Higher doses may be needed and are OK as long as the patient is ventilated. Preferred over diazepam.
• Diazepam (Valium) 0.1-0.3 mg/kg IV (5-10 mg in adult, but may need 20-30 mg)
• Phenobarbital 15 mg/kg IV at 25-50 mg/min. May give IM.
• For paralysis:
• Vecuronium: 10 mg adults, followed by 2-5 mg IV as needed
• Pancuronium: 4 mg adults, and hourly as needed. Patient should be immediately intubated or airway should otherwise be controlled.
• Avoid succinylcholine which will increase ICP
• To prevent secondary injury from CNS arterial spasm:
• Nimodipine: after acute injury generally in consultation with neurosurgery or neurology
• Corticosteroids: there is no evidence to support their use in acute head injury and they may be detrimental. They should be given, however, if spinal cord injury is also present.
Contraindications: Neither furosemide nor mannitol should be given to the hypotensive patient. Make sure you can manage the airway before paralyzing the patient. Do not use morphine, benzodiazepines or phenobarbital unless you are prepared to manage the patient's airway.
Precautions: Refer to manufacturer's literature
Significant possible interactions: Phenobarbital, morphine and the benzodiazepines can have additive respiratory depression
ALTERNATIVE DRUGS: Diuretics and IV beta-blockers (e.g. esmolol or labetalol) can be used to maintain the systolic pressure less than 170. Labetalol 5-10 mg IV until blood pressure is controlled. Nitroprusside may be helpful. Nitrates may increase intracranial pressure. Antibiotics (e.g., cefazolin) should be given if penetrating trauma is present. Prophylactic antibiotics are not useful in basilar skull fractures.
FOLLOW UP PATIENT MONITORING: • Schedule regular followup
• Gradual return to work or school, even after mild to moderate head injury
• The post-concussion syndrome can follow mild head injury without loss of consciousness and includes headaches, dizziness, fatigue and subtle cognitive or affective changes. Most of these improve within 3 months.
• The most important element of mild TBI management, however, is recognizing the genuine organic basis for the patient's symptoms
• Proper counseling, symptomatic management and gradual return to normal activities is essential to prevent a post-traumatic neurosis which can become refractory to treatment
PREVENTION/AVOIDANCE: • Safety education
• Seat belts, bicycle and motorcycle helmets
• Protective headgear for contact sports
POSSIBLE COMPLICATIONS: • Delayed hematomas
• Chronic subdural hematoma, which may follow even mild head injury, especially in the elderly. Often present with headache, decreased mentation.
• Delayed hydrocephalus
• Emotional disturbances and psychiatric disorders resulting from head injury may be refractory to treatment
• Seizure disorders - in about 50% of penetrating head injuries, in about 20% of severe closed head injuries, and in < 5% of head injuries overall. Hematomas significantly increase risk of epilepsy.
EXPECTED COURSE AND PROGNOSIS: • Gradual improvement for many
• 30-50% of severe head injuries may be fatal
• Prolonged coma may be followed by satisfactory outcome
• Following a significant acute injury, referral for rehabilitation is indicated. This includes involvement of the family in decision making and setting realistic goals for the patient and realistic expectations for the family. Some degree of improvement may continue for some time.
MISCELLANEOUS ASSOCIATED CONDITIONS: Alcohol and drug abuse
AGE-RELATED FACTORS:
Pediatric: Outcome for children more positive, except in severe TBI
Geriatric:
• Poorer prognosis with increasing age
• Subdural hematomas are common after fall or blow; symptoms may be subtle
Others: None
PREGNANCY: N/A
SYNONYMS: • Head injury
• Closed head injury
ICD-9-CM: 800-804 Skull and facial fractures
850 Concussion
851 Cerebral laceration or contusion
852 Hematoma
854 Other cerebral injury of unspecified nature
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Seizure disorders
Post-concussive syndrome
Brain injury - post acute care issues
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