Rosen & Barkin's 5-Minute Emergency Medicine Consult (683 page)

• All patients with SAH should be admitted to an ICU.
  
• Patients with negative CT findings and equivocal LP findings should be admitted for observation.
  

• Patients with negative CT and LP findings and onset of symptoms <2 wk
  
• Outpatient follow-up for headache treatment and further evaluation
  

Early referral to center with access to neurosurgeons and endovascular specialists (if none at practicing institution)

• Mortality is 12% before arrival to hospital.
  
• Ultimately fatal in more than 50%.
  
• In cases of “sentinel bleed” or early detection of aneurysmal rupture, outcomes are improved with early surgical or interventional approaches.
  

• Failure to consider SAH in differential diagnosis for new, acute headache
  
• Failure to assess previous headache workup as complete (CT and LP)
  

• Bederson JB, Connolly ES Jr, Batjer HH, et al. Guidelines for the management of aneurysmal subarachnoid hemorrhage: A statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association.
  Stroke
  . 2009;40:994–1025.
  
• Edlow JA, Malek AM, Ogilvy CS. Aneurysmal subarachnoid hemorrhage: Update for emergency physicians.
  J Emerg Med
  . 2008;34(3):237–251.
  
• Rabinstein AA. The AHA Guidelines for the Management of SAH: What we know and so much we need to learn.
  Neurocrit Care
  . 2009;10(3):414–417.
  
• Uysal E, Yanbuloğlu B, Ertürk M, et al. Spiral CT angiography in diagnosis of cerebral aneurysms of cases with acute subarachnoid hemorrhage.
  Diagn Interv Radiol
  . 2005;11(2):77–82.
  
• Wolfson A. Blunt neck trauma. In: Wolfson AB, Hendey GW, Hendry PL, et al., eds.
  Harwood-Nuss’ Clinical Practice of Emergency Medicine
  . Philadelphia, PA: Lippincott Williams & Wilkins; 2005.
  

CODES

• 430 Subarachnoid hemorrhage
  
• 852.00 Subarachnoid hemorrhage following injury without mention of open intracranial wound, unspecified state of consciousness
  

BASICS

• Classification of subdural hematoma (SDH):
  
  • Acute: Diagnosis within the 1st 3 days
    
  • Subacute: Diagnosis 3 days–3 wk
    
  • Chronic: Diagnosis after 3 wk
    
• CT description:
  
  • Rarely crosses midline
    
  • Does cross suture lines
    
  • Inner margins are often seen to be irregular.
    
• Acute:
  
  • Most commonly due to acceleration–deceleration forces and less commonly from direct trauma
    
  • Sagittal movement of the head causes stretch of parasagittal bridging veins.
    
  • Other bleeding sites include:
    
    • Laceration of dura
      
    • Venous sinus injury
      
    • Cortical arteries
      
    • Nontraumatic injuries: Intracerebral aneurysm rupture, arteriovenous malformation, coagulation disorder, arterial HTN, drug or alcohol abuse
      
• Chronic:
  
  • Encapsulated hematoma most likely caused by repeated small hemorrhages of bridging veins.
    

• Acute:
  
  • Most common type of intracranial hematoma (66–70%)
    
  • Occurs most commonly at cerebral complexities > falx cerebri > tentorium cerebelli
    
  • Peak incidence 15–24 yr, 2nd peak >75 yr
    
  • Represents 26–63% of blunt head injury
    
  • Motor vehicle crash (MVC) is most common cause overall.
    
  • Falls and assault more commonly result in isolated SDH (72%) than do MVCs (24%).
    
  • Elderly patients and those with seizure disorders are at increased risk.
    
  • Mortality is related to presenting signs and symptoms as well as comorbidities:
    
    • Mortality is 50% for age >70
      
    • Less than 1/2 present as
      simple extra-axial collection
      (22% mortality rate)
      
    • ∼40% of patients will have
      complicated SDH
      : Parenchymal laceration or intracerebral hematoma (mortality rate >50%)
      
    • 3rd group
      associated with contusion
      (30% mortality rate with functional recovery of 20%)
      
• Coagulopathy: INR >2 increases risk of bleed ×2, INR >3 is associated with larger initial volume and increased expansion
  
• Chronic:
  
  • Most common in babies or elderly with atrophy:
    
    • Associated with infarction in underlying brain
      
• 75% of patients are >50
  
• <50% have history of trauma
  
• 50% are alcoholic
  
• Epilepsy and shunting procedures
  

• May occur secondary to trauma at birth
  
• Nonaccidental trauma more common
  

DIAGNOSIS

• Acute:
  
  • 1/5 have diagnosis discovered at autopsy.
    
  • Most commonly misdiagnosed as intoxication or cerebrovascular accident (CVA)
    
  • Headache and altered mental status:
    
    • 50% unconscious at discovery
      
• Subacute/chronic:
  
  • Headaches, nausea, vomiting, and seizures are frequent symptoms.
    
  • Presentation varied:
    
    • Fluctuating mental status
      
    • Unsteady gait
      
    • Slow progression of deficits
      

Imaging is necessary in infants with persistent vomiting, new seizures, lethargy, irritability, bulging, or tense fontanels.

• Acute:
  
  • Headache and altered mental status
    
  • Most common clinical signs are hemiparesis or hemiplegia:
    
    • Seen in 40–65%
      
    • SDH opposite motor deficit in 60–85%
      
  • Pupillary abnormality seen in 28–79%:
    
    • SDH will be on same side of pupillary abnormality in 70–90%.
      
  • Seizures may be seen in ∼10% initially.
    
  • Papilledema in <1/3
    
• Chronic:
  
  • Presentation is varied and mimics other diseases.
    

Obtain directed history:

• Mechanism of injury kinetics
  
• Neurologic status: Baseline and at-scene
  
• Complicating factors:
  
  • Past medical history, medications
    
  • Allergies, drug use
    
  • Rapid neurologic assessment:
    
• Glasgow Coma scale ([GCS] after fluid resuscitation most important)
  
• Brainstem reflexes:
  
  • Anisocoria
    
  • Pupillary light reflex
    
  • Corneal, gag, oculocephalic/oculovestibular
    
  • Head imaging
    

• ABG, CBC, electrolytes with glucose, prothrombin time (PT), partial thromboplastin time (PTT)
  
• Blood ethyl alcohol, drug screen
  

• Head CT in coordination with other necessary trauma workup
  
• Acute:
  
  • Characteristic CT finding is crescent-shaped clot overlying hemispheric convexity.
    
  • May have irregular medial border of hematoma
    
  • Mixed density of clot may represent active bleeding
    
  • Most (60%) associated with other intracranial lesions
    
  • Intracranial volume of hematoma >2% predicts poor prognosis
    
• Chronic:
  
  • MRI is a better choice, as lesion may be isodense on CT from 2–3 wk.
    
  • MRI volume in diffusion-weighted images correlates with Rankin disability score.
    
  • CT may show hypodense lesion after 3 wk.
    
  • Spinal radiographs
    

US can be used to visualize cerebral structures if fontanelles are patent.

• Acute:
  
  • Diffuse axonal injury
    
  • Cerebral contusion
    
  • Intracerebral bleed
    
  • Subdural hygroma
    
  • Epidural hematoma
    
  • Shaken baby/battered child syndrome
    
• Chronic:
  
  • Pseudotumor cerebri
    
  • Brain tumor
    
  • Dementia
    
  • Meningitis
    
  • CVA/transient ischemic attack
    
  • Cerebral atherosclerosis
    
  • Toxic, metabolic, respiratory, or circulatory causes
    

TREATMENT

• Manage airway and resuscitate as indicated:
  
  • Hypoxia is a strong predictor of outcome.
    
  • Maintain SaO
    ₂
    >95%.
    
  • Rapid-sequence intubation (RSI) is indicated for GCS <9 or for evidence of increased intracranial pressure (ICP).
    
  • RSI for PaCO
    ₂
    >45, anisocoria, drop of GCS by 3, loss of gag reflex, C-spine injury
    
• Routine hyperventilation is no longer recommended due to resultant diminished cerebral perfusion pressure.
  
• Controlled ventilation to maintain PCO
  ₂
  35–40 mm Hg:
  
  • NS to maintain mean arterial pressure (MAP) 100–110 is necessary:
    
    • A single episode of systolic BP <90 is associated with poor outcome.
      
  • Spine precautions
    
  • Elevate head of bed 20–30° (only after adequate fluid resuscitation to avoid resultant decrease in cerebral blood flow [CBF]).
    
• Not considered helpful:
  
  • Steroids
    
  • Antibiotic prophylaxis
    
  • Hyperventilation (unless herniation is imminent)
    
  • Fluid restriction
    
  • Calcium channel blockers
    
  • Hypothermia not proven
    
  • NaCl 3% not yet proven helpful