Head Injury

Essentials of Diagnosis

• Grades of traumatic brain injury are traditionally defined by the Glasgow Coma Scale (GCS) measured 30 minutes after injury

• GCS Criteria used are eye opening, verbal response, and motor response

  • 1 Point

    • No eye opening

    • No verbal response

    • No motor response

  • 2 Points

    • Eyes open to pain

    • Patient vocal but not verbal

    • Extension motor response

  • 3 Points

    • Eyes open to voice

    • Patients verbal but not conversational

    • Flexion motor response

  • 4 Points

    • Eyes open spontaneously

    • Patient is conversational but disoriented

    • Patient withdraws from pain

  • 5 Points

    • Eyes open spontaneously

    • Patient is oriented in verbal response

    • Patient localizes pain

  • 6 Points

    • Eyes open spontaneously

    • Patient is oriented in verbal response

    • Obeys commands

  • Total GCS score indicates severity of TBI

    • Mild: 13–15

    • Moderate: 9–12

    • Severe: ≤ 8

General Considerations

• Trauma is the most common cause of death in young people, and head injury accounts for almost half of these trauma-related deaths

• Head injury severity ranges from concussion to severe TBI

• Concussion

  • Broadly defined as an alteration in mental status caused by trauma with or without loss of consciousness

  • The term is often used synonymously with mild TBI

• Head trauma may cause cerebral injury through a variety of mechanisms (Table 24–8)

• Central to management is determination of which patients need head imaging and observation

• Common symptoms of concussion that develop acutely

  • Headache

  • Nausea, vomiting

  • Confusion, disorientation

  • Dizziness and imbalance

• A period of amnesia encompassing the traumatic event and a variable period of time leading up to the trauma is typical

• Loss of consciousness may occur

• Additional symptoms may develop over the following hours to days

  • Photophobia

  • Phonophobia

  • Difficulty concentrating

  • Irritability

  • Sleep and mood disturbances

• Examination is usually normal, although orientation and attention, short-term memory, and reaction time may be impaired

• Persistent or progressive decline in the level of consciousness after the initial injury, or focal neurologic findings, suggests the need for urgent imaging and neurosurgical consultation

• Patients should also be examined for signs of scalp lacerations, facial and skull fracture, and neck injury

• Clinical signs of basilar skull fracture

  • Bruising about the orbit (raccoon sign)

  • Blood in the external auditory meatus (Battle sign)

  • Leakage of cerebrospinal fluid from ear or nose; can be identified by its glucose or beta-2-transferrin content

• Cranial nerve palsies may also occur

• Head CT should be performed in patients with concussion and any of the following:

  • GCS score < 15

  • Focal neurologic deficit

  • Seizure

  • Coagulopathy

  • Aged 65 or older

  • Skull fracture

  • Persistent headache or vomiting

  • Retrograde amnesia exceeding 30 minutes

  • Intoxication

  • Soft tissue injury of the head or neck

• Otherwise, patients can be sent home as long as a responsible caregiver can check the patient at hourly intervals for the next 24 hours

• Cervical spine radiographs (three views) or CT should always be obtained

  • Comatose patients

  • Patients with severe neck pain or a deficit possibly related to cord compression

Conservative measures

• Treatment of mild TBI is aimed at promoting resolution of postconcussive symptoms and preventing recurrent injury

• Simple skull fractures require no specific treatment

• If there is any leakage of cerebrospinal fluid,

  • Elevate the head

  • Restrict fluids

  • Administer acetazolamide, 250 mg orally four times daily

• If the leak continues for more than a few days, lumbar subarachnoid drainage may be necessary

• Antibiotics are given if infection occurs, based on culture and sensitivity studies; vaccination against pneumococcus is recommended

Surgery

• In patients hospitalized with moderate or severe TBI, management often requires a multidisciplinary approach due to multiple concomitant injuries

• Elevated intracranial pressure can result from diffuse axonal injury or a hematoma requiring surgical evacuation, or from a variety of medical causes

• Decompressive craniectomy may reduce otherwise refractory intracranial hypertension but does not improve neurologic outcome

• For patients with subdural hematoma, surgical intervention is indicated if

  • The hematoma is ≥ 10 mm in thickness or there is a midline shift ≥ 5 mm

  • There is a decline in GCS score of 2 or more from injury to hospital admission

  • One or both pupils are fixed and dilated

• Scalp lacerations and depressed skull fractures should be treated surgically as appropriate

Complications

• Cognitive impairment tends to affect frontal and temporal lobe function, causing deficits in attention, memory, judgment, and executive function

• Behavioral dysregulation, depression, and disinhibition can impair social functioning

• Anosmia, presumably due to shearing of fibers from the nasal epithelium, is common

• Epilepsy can develop after TBI, especially with more severe injury

• Normal pressure hydrocephalus may also occur

• Chronic traumatic encephalopathy

  • Repetitive, mild head injury

  • associated with mood and cognitive changes

  • Characterized by the abnormal aggregation of tau or other proteins either focally or globally in the cerebral cortex

Prevention

• Helmets

• Seatbelts

• Other protective equipment

Prognosis

• Moderate and severe TBI may result in permanent cognitive and motor impairment depending on the severity and location of the initial injury

• Initial GCS and head CT findings have prognostic value

• Among patients with a GCS score of 8 or less at presentation, mortality approaches 30% and only one-third of survivors regain functional independence

• Among patients with mild TBI, symptoms of concussion resolve in most patients by 1 month and in the vast majority by 3 months

• Prolonged postconcussive symptoms are uncommon, persisting at 1 year in 10–15% of patients

When to Refer

• Patients with focal neurologic deficits, altered consciousness, or skull fracture

• Patients with late complications of head injury, eg, posttraumatic seizure disorder or normal pressure hydrocephalus

When to Admit

• Patients with concussion and GCS score < 15, predisposition to bleeding, seizure, or no responsible caregiver at home

• Patients with abnormal head CT