Rosen & Barkin's 5-Minute Emergency Medicine Consult (246 page)

CODES

324.1 Intraspinal abscess

BASICS

• Direct skull trauma
  
• Inward bending of calvarium causes bleeding when dura separates from skull:
  
  • Middle meningeal artery is involved in bleed >50% of time.
    
  • Meningeal vein is involved in 1/3.
    
• Skull fracture is associated in 75% of cases, less commonly in children.
  
• >50% have epidural hematoma (EDH) as isolated head injury:
  
  • Most commonly associated with subdural hematoma (SDH) and cerebral contusion
    
• Classic CT finding is lenticular, unilateral convexity, usually in temporal region.
  
• It usually does not cross suture lines, but may cross midline.
  

• Accounts for 1.5% of traumatic brain injury (TBI)
  
• Male/female incidence is 3:1.
  
• Peak incidence is 2nd–3rd decade of life.
  
• Motor vehicle accidents (MVAs), assault, and falls are most common causes:
  
  • Of all blunt mechanisms, assault has highest association with intracranial injury requiring neurosurgical intervention.
    
• Uncommon in very young (<5 yr) or elderly patients
  
• Mortality is 12% and is related to preoperative condition.
  

• Head injury is the most common cause of death and acquired disability in childhood.
  
• Falls, pedestrian-struck bicycle accidents are most common causes:
  
  • Most severe head injuries in children are from MVA.
    
  • Always consider possibility of nonaccidental trauma.
    
• <50% have altered level of consciousness (LOC):
  
  • If EDH in differential diagnosis (DD), CT should be obtained.
    
• Bleeding is more likely to be venous.
  
• Good outcome in 95% of children <5 yr
  

DIAGNOSIS

• Altered or deteriorating LOC
  
• LOC: 85% will have at some point in course:
  
  • Only 11–30% will have a lucid interval.
    
• Nausea and vomiting: 40%
  

• Many times the only clinical sign is drop in hematocrit (Hct) of 40% in infants.
  
• Bulging fontanel with vomiting, seizures, or lethargy also suggests EDH in infants.
  
• <50% of children have LOC at time of injury.
  
• Posterior fossa lesions are seen more commonly in children.
  

• Pupillary dilation: 20–40%:
  
  • Usually on same side as lesion (90%)
    
• Hemiparesis >1/3:
  
  • Usually on opposite side from lesion (80%)
    

Head imaging, as below

• ABG, CBC, chemistry, PT/PTT
  
• Blood ETOH and drug screen as appropriate
  

• Noncontrast CT of head:
  
  • Admission perfusion CT may help predict prognosis.
    
  • Lenticular, biconvex hematoma with smooth borders may be seen.
    
  • Mixed density lesion may indicate active bleeding.
    
  • Most commonly seen in temporal parietal region
    
• Plain films may show skull fractures:
  
  • CT with bone windows is more often used.
    
• Spine series
  
• Further workup of trauma as indicated
  

US may be used for diagnosis in infants with open fontanels.

• History of recent head trauma lends itself to the diagnosis:
  
  • Trauma may be minor in infants and toddlers.
    
• Consider other diagnosis:
  
  • SDH
    
  • Cerebral concussion/contusion
    
  • Intracerebral bleed
    
  • Diffuse axonal injury
    
  • Subdural hygroma
    
  • Shaken baby syndrome
    
  • Toxic, metabolic, or infectious causes
    

TREATMENT

• Head-injured patients have 25% improved mortality when triaged to regional trauma centers.
  
• Spinal immobilization is essential.
  
• Ensure adequate oxygenation throughout transport:
  
  • Intubation and airway protection may be necessary.
    

• Prevent hypoxia and hypotension:
  
  • Rapid-sequence intubation for signs of deterioration or increased intracranial pressure (ICP)
    
  • Controlled ventilation to PCO
    ₂
    of 35–40 mm Hg
    
  • Avoid hyperventilation unless signs of brain herniation are present.
    
  • Avoid induction agents, which may increase ICP (e.g., ketamine).
    
• Elevate head of bed 20°–30° after adequate fluid resuscitation.
  
• Perform rapid neurologic assessment:
  
  • Glasgow coma scale (GCS) score:
    
• 14–15; minor head injury
  
• 9–13; moderate head injury
  
• <8; severe:
  
  • Reflexes; pupils, corneal, gag, brainstem reflexes
    
• Secondary survey will reveal coexisting injury in >50%.
  

• Early surgical intervention (<4 hr) in comatose patients with EDH improves meaningful survival:
  
  • Burr hole is placed at fracture site or side with ipsilateral pupillary dilation.
    
  • Rapid craniectomy is occasionally performed if bleeding is not controlled at site of burr hole.
    
• Nonsurgical intervention in asymptomatic patients is associated with high rate of deterioration; >30% require surgical intervention.
  
• Maintain euvolemia with isotonic fluids.
  
• Continuous end tidal CO
  ₂
  monitoring:
  
  • Arterial line placement for close monitoring of MAP, PO
    ₂
    , PCO
    ₂
    
  • Foley catheter to monitor input/output (I/O) status
    
• Control ICP:
  
  • Prevent pain, posturing, and increased respiratory effort:
    
    • Sedation with benzodiazepines
      
    • Neuromuscular blockade with vecuronium or rocuronium in intubated patients
      
    • Etomidate is a good induction agent.
      
    • Barbiturate coma should be initiated for refractory increased ICP in neurosurgical ICU.
      
  • Mannitol may be used once euvolemic:
    
    • Shown to increase MAP greater than coronary perfusion pressure (CPP) and cerebral blood flow (CBF), as well as decrease ICP
      
    • Keep osmolality between 295 and 310.
      
    • Use furosemide (Lasix) as adjunct only if no risk of hypovolemia.
      
• Treat HTN:
  
  • Labetalol or hydralazine
    
• Treat hyperglycemia if present:
  
  • Associated with increased lactic acidosis and mortality in patients with TBI
    
• Treat and prevent seizures:
  
  • Diazepam and Dilantin
    
• Not considered helpful:
  
  • Steroids
    
  • Antibiotic prophylaxis
    
  • Hyperventilation in the absence of herniation
    
  • Fluid restriction
    
  • Calcium channel blockers
    
• Factors associated with poor outcome:
  
  • Age >40 yr
    
  • Increased admission base deficit
    
  • Large hematoma with rapid expansion
    
  • Increased midline shift
    
  • Lower admission GCS or unconsciousness at presentation
    
  • Postoperative ICP >3
    
  • Prolonged anisocoria
    
  • Associated brain injuries or concomitant trauma injuries
    

Hemodynamically significant blood loss can result from scalp lacerations and subgaleal hematomas: Direct pressure and control of bleeding is indicated.

• Diazepam: 5–10 mg (peds: 0.1–0.2 mg/kg) IV
  
• Dilantin: Adult/peds: Load 18 mg/kg at 25–50 mg/min
  
• Etomidate: 0.3 mg/kg IV
  
• Fentanyl: 2–4 Ug/kg IV
  
• Furosemide (Lasix): Adults/peds: 0.5 mg/kg IV
  
• Hydralazine: 10 mg/h IV (peds: 0.1–0.5 mg/kg IV) q3–4h PRN
  
• Labetalol: 15–30 mg/h IV (peds: 0.4–1 mg/kg/h IV continuous infusion; max. 3 mg/kg/h)
  
• Levetiracetam: 1,500 mg IV/PO q12h
  
• Lidocaine: As preinduction agent, 1.5 mg/kg IV
  
• Mannitol: Adults/peds: 0.25–1 g/kg IV q4h
  
• Midazolam: 1–2 mg (peds: 0.15 mg/kg IV × 1) IV q10min PRN
  
• Pentobarbital: 1–5 mg IV q6h
  
• Prothrombin complex concentrate 50 U/ kg IV
  
• Rocuronium: 1 mg/kg IV
  
• Thiopental: As induction agent, 20 mg/kg IV