วันเสาร์ที่ 28 กุมภาพันธ์ พ.ศ. 2569

Skull Fracture

Skull Fracture

1. Overview & Clinical Significance

Skull fracture เกิดเมื่อแรงกระแทกต่อศีรษะเกิน mechanical integrity ของ calvarium และมักสัมพันธ์กับ traumatic brain injury (TBI) ระดับปานกลางถึงรุนแรง รวมถึง extracranial injuries (เช่น cervical spine, thoracoabdominal trauma)

จุดสำคัญ:

  • ไม่ใช่ทุก skull fracture = severe TBI
  • แต่บางชนิดมี morbidity/mortality สูง ได้แก่
    • Depressed skull fracture
    • Basilar skull fracture + CSF leak
    • Fracture ข้าม middle meningeal artery / venous sinus

2. Epidemiology (Clinical relevance)

  • พบบ่อยในผู้บาดเจ็บศีรษะจาก:
    • Falls (พบบ่อยสุด โดยเฉพาะผู้สูงอายุ)
    • MVC
    • Assault
    • Penetrating trauma
  • กระดูกที่ fracture บ่อย:
    • Parietal > Temporal > Occipital > Frontal
  • Linear fracture = ชนิดที่พบบ่อยที่สุด

ประมาณ 5–27% ของผู้ป่วย skull fracture มีร่วมกับ cervical spine injury → ต้อง rule out เสมอ

3. Anatomy & Mechanism (High-yield)

Skull structure

  • Outer table
  • Diploë (cancellous bone)
  • Inner table
    ความหนาเฉลี่ย 2–6 mm
    Temporal bone บางที่สุด → fracture ง่าย → เสี่ยง epidural hematoma

Mechanism

  • Direct blunt trauma
  • Energy + surface area ของแรงกระแทกกำหนดชนิด fracture
    • Large area → Linear fracture
    • Small high-energy focal impact → Depressed fracture

4. Initial & Prehospital Management (Trauma Priority)

Prehospital

  • Assume skull fracture ใน high-energy head injury
  • Full spinal immobilization (C-spine + thoracic spine)
  • Scalp bleeding → direct pressure (≥15 min)
  • Circumferential bandage มักไม่พอหยุดเลือด

Primary Survey (ABCDE)

  • Airway protection (GCS ↓)
  • Control scalp hemorrhage (bleeding มากได้)
  • Avoid probing scalp wound

Secondary Survey — Clues to Skull Fracture

  • Depressed mental status
  • Focal neurologic deficit
  • Scalp laceration/contusion
  • Bony step-off
  • Periorbital ecchymosis (raccoon eyes)
  • Retroauricular ecchymosis (Battle sign)

5. Diagnostic Imaging (Key Clinical Practice)

First-line: Noncontrast CT brain + bone window

Gold standard for:

  • Skull fracture
  • Intracranial hemorrhage (EDH, SDH, contusion)
  • Pneumocephalus

MDCT thin-slice + 3D reconstruction → sensitivity สูงมาก

When to add CT Angiography (CTA)

พิจารณาเมื่อ:

  • Basilar skull fracture (petrous temporal bone)
  • Fracture near carotid canal
  • Suspected vascular injury
    (มี cerebrovascular injury ~3–20% ใน cranio-cervical trauma)

MRI

ใช้เมื่อ:

  • Suspected ligamentous injury
  • Vascular injury (adjunct)
  • Persistent neurologic deficit

Skull X-ray

  • ไม่มีประโยชน์ถ้ามี CT
  • ใช้เฉพาะ CT unavailable

6. Classification of Skull Fractures (High-yield for Exams & Practice)

6.1 Linear Skull Fracture

Most common

  • Single fracture line ผ่าน full thickness calvarium
  • มักไม่มี neurologic deficit
  • Clinical:
    • Local swelling
    • Mild headache
    • Often asymptomatic
      ⚠ Red flag: fracture crossing
  • Middle meningeal groove → risk epidural hematoma
  • Venous dural sinus → delayed bleeding

6.2 Depressed Skull Fracture (DSK)

Segment of skull displaced below adjacent skull

Key risks:

  • Brain parenchymal injury
  • CNS infection
  • Seizures
  • Death

Types:

  • Open (compound) — most common
  • Closed (simple)

Clinical clues:

  • Scalp wound over fracture
  • Palpable depression (limited by swelling)
  • LOC (~25%)
  • Focal deficits (depending brain injury)

Mechanism:

  • High-energy focal impact (bat, club, heavy object)

6.3 Basilar Skull Fracture (Very High Clinical Importance)

Involves skull base bones:

  • Ethmoid (cribriform plate)
  • Frontal (orbital plate)
  • Temporal (petrous/squamous)
  • Sphenoid
  • Occipital

Most common: temporal bone → risk epidural hematoma

Classic Clinical Signs (Highly Predictive)

  • Battle sign (mastoid ecchymosis) — delayed 1–3 days
  • Raccoon eyes (periorbital ecchymosis)
  • Hemotympanum
  • CSF otorrhea / rhinorrhea (pathognomonic)

Associated complications:

  • Cranial nerve palsy (III, IV, VI, VII, VIII)
  • Hearing loss
  • Facial nerve palsy
  • TCCF (traumatic carotid-cavernous fistula) ~3–4%
  • CSF leak (4–45%)

6.4 Other Types (Less common)

  • Elevated skull fracture (fragment elevated)
  • Penetrating skull fracture (GSW, stab, blast)
  • Tangential fracture (high risk intracranial hemorrhage)

7. Management (Type-based Clinical Approach)

7.1 Linear Skull Fracture

No intervention required if:

  • Normal CT
  • No ICH
  • Neurologically intact

Observation:

  • ED observation 4–6 hours
  • Discharge if stable + good supervision 24 hr

Admit if:

  • Suspected brain injury
  • ICH on CT
  • Fracture over venous sinus or middle meningeal artery

7.2 Depressed Skull Fracture (Neurosurgical disease)

Immediate actions

  • Neurosurgery consult (urgent)
  • Tetanus prophylaxis
  • Prophylactic antibiotics 5–7 days (especially open fracture)
  • Consider anticonvulsants (post-traumatic seizure prevention)

Surgical indications (Brain Trauma Foundation)

  • Depression > skull thickness
  • 5–10 mm depression
  • Dural tear
  • Pneumocephalus
  • Intracranial hematoma
  • Gross contamination
  • Frontal sinus involvement

บางกรณี uncomplicated closed DSK → conservative management ได้ (case-by-case)

7.3 Basilar Skull Fracture (Must Admit)

Mandatory:

  • Hospital admission + close neuro monitoring
  • Immediate CT brain
  • Neurosurgical consultation

CSF Leak Management

Diagnosis:

  • β2-transferrin / β-trace protein (specific)
  • Halo sign (supportive but nonspecific)

Treatment:

  • Conservative first (most resolve within 7 days)
  • Avoid routine prophylactic antibiotics (controversial)
  • Persistent >7 days → neurosurgical repair + ID consult
  • Consider pneumococcal vaccination

8. Special Situations

Anticoagulated Patients (Very High Risk)

  • Higher delayed ICH risk
  • Recommend observation ≥24 hr
  • Serial neurologic exam
  • Repeat CT if deterioration
  • Consider anticoagulant reversal (case dependent)

Penetrating Skull Fracture

  • IV antibiotics (meningitis coverage)
  • Immediate neurosurgical consultation
  • Usually severe brain injury

9. Complications (Clinically Important)

Early:

  • Epidural hematoma
  • Subdural hematoma
  • Contusion
  • Massive scalp hemorrhage

Delayed:

  • Post-traumatic seizures
  • CNS infection
  • Meningitis (especially persistent CSF leak)
  • Cranial nerve palsy (2–3 days post-injury)
  • TCCF (rare but serious)

10. High-Yield Red Flags in ER (Should NOT Miss)

  • Battle sign / raccoon eyes
  • CSF rhinorrhea/otorrhea
  • Hemotympanum
  • Depressed GCS
  • Focal neurologic deficit
  • Anticoagulant use + head trauma
  • Fracture crossing middle meningeal artery
  • Suspected cervical spine injury

11. Practical ER Algorithm (Quick Use)

1.       ABCDE + C-spine immobilization

2.       Noncontrast CT brain (bone window)

3.       Classify fracture type

4.       Screen for:

o   ICH

o   CSF leak

o   CN deficit

o   Spine injury

5.       Consult neurosurgery if:

o   Depressed fracture

o   Basilar fracture

o   ICH

o   Open fracture

6.       Observe vs Admit based on risk

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