Neuro

Head Injury

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Head Injury, Head Trauma, Closed Head Injury, Craniocerebral Trauma, Traumatic Brain Injury

  • Pathophysiology
  1. Intracranial Pressure (ICP) association with injury
    1. Note measurements are in mmHg, not cmH2O
    2. Normal: 10 mmHg ICP
    3. Abnormal: 20 mmHg ICP
    4. Severe: 40 mmHg ICP
    5. Herniation: 50 mmHg ICP
  2. Cushing's Response
    1. Hypertensive response in face of increased ICP
    2. Helps maintain cerebral perfusion
    3. Do not use antihypertensives to lower Blood Pressure
      1. Results in decreased brain perfusion
      2. Exception: Intracranial bleeding (e.g. aneurysmal bleeding)
  • Precautions
  • Respiratory status in Head Injury
  1. Target PaO2: 200-300 mmHg
    1. PaO2 <200 mmHg and PaO2 >300 mmHg are both associated with higher mortality
    2. Option 1: Wean FIO2 to 50%, but still maintain O2Sat at 99-100% or
    3. Option 2:
      1. Wean oxygen to point that O2Sat starts to drop below 99-100% and
      2. Then increase the delivered oxygen by 2-4 L/min above that level
  2. Avoid Hyperventilation following intubation
    1. Hyperventilation is associated with worse outcomes in Traumatic Brain Injury
    2. Monitor End-Tidal CO2 or capnometer following intubation
    3. Maintain pCO2 at 35-40 mmHg
    4. Maintain Respiratory Rate at 10-12 breaths per minute
  3. References
    1. Majoewsky (2012) EM:RAP 12(5): 1-2
    2. Davis (2009) J Neurotrauma 26(12): 2217-23 [PubMed]
  • Evaluation
  • General
  1. Systematic evaluation (unless isolated Minor Head Injury)
    1. See Trauma Evaluation (includes Primary Survey)
    2. See Secondary Trauma Evaluation
  2. Glasgow Coma Scale (GCS)
    1. First GCS at the initial emergency Trauma Evaluation is the best indicator of outcome at one year
    2. Goal in Trauma is to optimize care and allow the best chance for recovery to the initial GCS
  3. Pupil exam
  4. Neurologic Exam
    1. Motor Exam
    2. Sensory Exam
    3. Reflex Exam
  5. Alcohol or drug intake history
  6. Vital Signs
    1. Hypertension is typical response (see Cushing's Response above)
    2. Hypotension seen in pediatric Closed Head Injury
      1. Patrick (2002) Am J Surg 184:555-60 [PubMed]
  7. Signs Skull Fracture
    1. See Skull Fracture
    2. Vault Skull Fracture
    3. Basilar Skull Fracture
      1. CSF Rhinorrhea or Otorrhea
      2. Hemotympanum
      3. Post-auricular Bruising (Battle's Sign)
      4. Orbital Bruising (Raccoon's Eyes)
      5. CN VII palsy (Bell's Palsy)
  8. Signs Intracranial Injury
    1. Focal
      1. Epidural Hemorrhage
      2. Subdural Hemorrhage
      3. Intracerebral Hemorrhage
    2. Diffuse
      1. Mild Concussion
      2. Classic Concussion
      3. Diffuse Axonal Injury
  9. Scalp Lacerations with Hemorrhage
    1. Risk of significant blood loss to the point of Hemorrhagic Shock (especially children)
    2. Apply direct pressure to prevent further bleeding
    3. Close bleeding scalp lesions quickly (even temporarily) with Sutures, staples or Raney Clips
    4. Carefully investigate Laceration for associated complications prior to final closure
      1. Skull Fracture (deformity, bony fragments, CSF leakage)
      2. Subgaleal Hemorrhage may appear similar to Skull Fracture with deformity at the floor of the Laceration
  • Evaluation
  • Age under 2 years
  1. See Head Injury CT Indications in Children
  2. Red Flags suggestive of serious injury
    1. Skull Fracture
    2. Scalp swelling (80-100% of Skull Fracture)
    3. Younger the age, the greater the risk
    4. Non-accidental Trauma (Child Abuse)
    5. No clear history of Trauma
  3. Symptoms that do not predict serious Head Injury
    1. Loss of consciousness
    2. Vomiting
  4. References
    1. Dachs (2012) AAFP Board Review Express, San Jose
  • Imaging
  • Head and Neck
  1. CT Head
    1. Obtain in all cases of moderate or Severe Head Injury
  2. C-Spine imaging indications
    1. See Cervical Spine Imaging in Acute Traumatic Injury
    2. See NEXUS Criteria
  3. Mild Head Injury Imaging Indications
    1. See Head Injury CT Indications in Adults
    2. See Head Injury CT Indications in Children
      1. Consider Head MRI in children in place of Head CT (due to radiation risk)
  4. Coagulopathy or oral Anticoagulant (e.g. Warfarin, Plavix)
    1. Approach based on evidence below
      1. Consider imaging all patients on Anticoagulants regardless of Head Injury severity
      2. Consider repeat CT Head imaging at 24 hours for patients on Warfarin regardless of signs or symptoms
      3. Consider 24 hour observation and repeat CT Head for elderly patients or those with INR >3
      4. Newman in Herbert (2014) EM:Rap 14(1): 6
    2. Even Minor Head Injury on oral Anticoagulants is associated with significant bleeding risk (often without red flags)
      1. Clopidogrel was associated with an initial 12% CNS HemorrhageIncidence, but no delayed bleeding
      2. Warfarin was associated with an initial 6% CNS HemorrhageIncidence with 0.6% having delayed bleeding
      3. Nishijima (2012) Ann Emerg Med 59(6): 460-8 [PubMed]
    3. Warfarin is associated with delayed intracranial bleeding
      1. One study demonstrated 6% of patients at 24 hours
        1. Bleeding may be delayed as long as 1 week after Head Injury
        2. Most patients with CNS Hemorrhage on Warfarin had GCS 14-15 and no focal neurologic changes
        3. Menditto (2012) Ann Emerg Med 59(6): 451-5 [PubMed]
      2. Another study demonstrated a 0.4% risk of delayed Intracranial Hemorrhage
        1. Lim (2016) Am J Emerg Med 34(1): 75-8 +PMID: 26458530 [PubMed]