How to diagnose a basilar skull fracture?

Assessment for Basilar Skull Fracture

CT scan is the gold standard for diagnosing basilar skull fractures, but specific clinical signs should be evaluated to determine the need for imaging.

Clinical Signs of Basilar Skull Fracture

The following clinical signs should be systematically assessed when suspecting a basilar skull fracture:

Primary Signs (Battle's Sign and Raccoon Eyes)

• Raccoon eyes (periorbital ecchymosis): Bruising around the eyes
• Battle's sign (retroauricular ecchymosis): Bruising behind the ear

Other Important Clinical Signs

• CSF otorrhea: Clear fluid draining from the ear
• CSF rhinorrhea: Clear fluid draining from the nose
• Hemotympanum: Blood behind the tympanic membrane
• Bleeding from ear canals
• Cranial nerve deficits: Particularly facial nerve (CN VII) paralysis

Diagnostic Algorithm

1. Initial Assessment:

   • Evaluate for clinical signs listed above
   • Assess Glasgow Coma Scale (GCS)
   • Evaluate for focal neurological deficits

2. Imaging Decision:

   • Obtain CT scan if any of the following are present 1:
     • Any clinical sign of basilar skull fracture
     • GCS ≤ 13
     • Focal neurological deficit
     • Anticoagulant use
     • Age > 60 years
     • Loss of consciousness
     • Severe headache
     • Vomiting (especially persistent)

3. CT Scan Interpretation:

   • Evaluate for fracture lines in:
     • Anterior cranial fossa (cribriform plate, orbital roof)
     • Middle cranial fossa (temporal bone, sphenoid)
     • Posterior cranial fossa (occipital bone)

Clinical Pearls and Pitfalls

• Timing of clinical signs: Battle's sign and raccoon eyes may take hours to develop after injury, so their absence on initial examination does not rule out basilar skull fracture 2

• Diagnostic accuracy: Clinical signs have low specificity (30.5-52.8%) and accuracy (43.4-55.9%) for basilar skull fracture, but high sensitivity in late stages (within 48 hours) 2

• Correlation with injury severity: The presence of clinical signs correlates with head injury severity as indicated by GCS and Maximum Abbreviated Injury Scale-Head region 2

• Contraindications: Avoid nasogastric tube placement and nasal intubation in patients with suspected basilar skull fracture due to risk of intracranial penetration 2

• Monitoring requirements: Patients with basilar skull fracture who have a GCS ≥13 and no intracranial pathology on CT may be managed without intensive care monitoring 3

• Pediatric considerations: In children, the most common physical findings are hemotympanum (58%) and bleeding in ear canals (47%), with CSF otorrhea in 26% and facial nerve paralysis in 13% 4

Complications to Monitor

• CSF leak: May lead to meningitis if persistent
• Cranial nerve injuries: Particularly facial and vestibulocochlear nerves
• Vascular injuries: Carotid-cavernous fistula, venous sinus thrombosis
• Hearing loss: Present in approximately 34% of pediatric cases 4

Outcome Considerations

• Patients with isolated basilar skull fractures (no other intracranial injuries) have low risk for acute adverse outcomes 5

• Patients with basilar skull fractures on CT have higher risk of adverse outcomes than those with only clinical signs 5

• The presence of other intracranial injuries significantly increases morbidity and mortality 3

Remember that while clinical signs are important for initial assessment, CT imaging is necessary for definitive diagnosis and risk stratification of patients with suspected basilar skull fracture 1.