II. Risk Factors

III. Pathophysiology

  1. Cranial Trauma results in Subdural Hemorrhage
  2. Tear of bridging veins between dura and surface of the brain
  3. Six times more common than Epidural Hematoma

IV. Precautions: Acute Subdural Hematoma

  1. Acute Subdural Hematomas are vastly different than chronic subdurals
  2. Acute Subdural Hematoma has a 60-80% mortality rate
  3. Requires rapid assessment and management (surgical decompression)

V. Causes: Acute Subdural Hematoma

  1. Severe Closed Head Injury
  2. Rapid Deceleration Injury

VI. Associated Conditions: Acute Subdural Hematoma

  1. Comorbid Brain Contusion

VII. Symptoms

  1. Acute (Rapid progression of symptoms)
    1. Headache
    2. Irritability
  2. Chronic (Insidious symptom progression)
    1. Intermittent Headache
    2. Variable levels of Decreased Level of Consciousness

VIII. Signs

  1. Acute (<24 hours)
    1. Fluctuating levels of consciousness
    2. Dilated pupils
    3. Hemiplegia
    4. Hyperreflexia
    5. Babinski's Sign
    6. Convulsions
  2. Subacute (24 hours to 2 weeks)
  3. Chronic (>2 weeks)
    1. Progressively impaired intellect
    2. Agitation
    3. Impulsive behavior
    4. Hemiparesis
    5. Stupor
    6. Variable Level of Consciousness

IX. Imaging: CT Head

  1. Subdural Hematoma appears as crescent-shaped Hematoma
    1. As this is below the dura, the Subdural Hematoma follows the surface of the brain
    2. Gyri are absent in region of Subdural Hematoma
      1. Helps identify subacute Subdural Hematoma which is isodense and more difficult to distinguish
  2. Appearance varies based on timing
    1. Acute: White blood collection
    2. Subacute: Isodense blood collection (may be subtle)
    3. Chronic: Dark blood collection

X. Labs: Cerebrospinal fluid

  1. Increased CSF Opening Pressure
  2. CSF Protein increased
  3. CSF Bloody or xanthochromic fluid

XI. Diagnostic Testing: EEG

  1. Localized disturbance

XII. Management

  1. Admit all patients with chronic or acute Subdural Hematoma (SDH)
  2. Anticoagulation and antiplatelet agent use predisposes to subdural expansion
  3. Manage systolic Blood Pressure, targets per neurosurgery, but typically <180 mmHg
  4. Surgical decompression
    1. Emergency surgical decompression if acute Subdural Hematoma with signs of Herniation
      1. See Skull Trephination
    2. Over age 65 years old, are unlikely to need surgical intervention if
      1. Midline shift <=1 mm
      2. Width <= 10 mm
      3. Evans (2015) Injury 46(91): 76-9 [PubMed]

XIII. Prognosis

  1. Worse prognosis than Epidural Hematoma (given decompression)
    1. Subdural Hematomas are associated with greater brain parenchymal injury than Epidural Hematomas

XIV. References

  1. Dreis (2020) Crit Dec Emerg Med 34(7):3-21
  2. Marcolini and Swaminathan in Swadron (2023) EM:Rap 23(5): 13-14

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