Extradural hematoma and base of skull fracture

Discussion:

Base of skull fractures are commonly seen in craniofacial trauma. Up to 24% of patients with blunt head trauma sustain a skull base fracture1

Base of skull fractures are clinically relevant due to the possibility of endangerment of nearby structures including:

  • Cranial nerves
  • Internal carotid artery
  • Cavernous sinus

Definitive management for skull base fracture depends on the degree of fracture and the clinical state of the patient. Indications for operative management include:

  • Neurological deficits - facial nerve paralysis, hearing loss or blindness
  • CSF fistula - manifests as rinorrhea and otorrhea
  • Temporal bone fracture

Operative management includes a subtotal petrosectomy. This involves exenteration of the temporal bone air cell tracts and obliteration of the eustachian tube. Once the injured structures are repaired, the remaining cavity is obliterated with an endogenous fat graft and temporalis muscle flap. 

In the absence of the above features, conservative, expectant management is carried out. This includes a 5 day course of intravenous antibiotics.

Another point to note, is that nasogastric tube placement is to be avoided in patients with confirmed or suspected base of skull fracture. This is due to the risk of intracranial nasogastric tube placement, whereby the tube traverses into the cranium via a fractured cribriform plate2.

This patient has a petrous temporal bone fracture. He underwent operative management as described above.

Extradural hematoma (EDH) has a reported incidence of 2.7-4% of traumatic brain injuries3. In particular, blunt trauma due to traffic accidents, falls and assaults account for over 90% of causes.
Pathologically, extradural hematoma has traditionally been reported due to middle meningeal artery hemorrhage - a branch of the maxillary artery.

Clinically, the characteristic 'lucid interval' where a patient becomes unconscious after the initial insult, then wakes up and then deteroriates again was found in 47% of patients. Other clinical changes noted include pupillary abnormalities, focal deficits and seizures.

CT is the imaging modality of choice for diagnosis of extradural hematoma. The characteristic appearance of EDH is a hyperdense, lentiform lesion which represents acute hemorrhage building up between the dura and the skull. In particular, the following factors are associated with a poor outcome:

  • Hematoma volume greater than 30cm3
  • Midline shift (MLS) greater than 5mm
  • Clot thickness greater than 15mm on initial CT

Management is invariably with urgent decompressive craniectomy. That being said, there has been one study where the authors treated a subset of EDH cases conservatively4.

Case contributed by A/Prof. Pramit Phal.

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