Epidural Hematoma

A patient walks, talks, then rapidly deteriorates into unconsciousness — the lucid interval of an epidural hematoma is a neurosurgical emergency hiding behind a deceptively normal exam.

An epidural hematoma (EDH) is arterial bleeding — typically from the middle meningeal artery — that collects between the skull and the dura mater after a temporal bone fracture. Because it is arterial, pressure builds fast. The hallmark presentation is a lucid interval: the patient sustains a head injury, may lose consciousness briefly, then appears to recover and seems neurologically intact for minutes to hours. As the hematoma expands, intracranial pressure rises rapidly, causing sudden deterioration — worsening headache, decreasing level of consciousness, ipsilateral fixed and dilated pupil (from uncal herniation compressing CN III on the same side as the bleed), and contralateral hemiparesis. On CT scan, an EDH appears as a biconvex (lens-shaped) hyperdense collection that does not cross suture lines, because the dura is tightly adhered at sutures. This is a surgical emergency requiring emergent craniotomy for evacuation. Without intervention, brain herniation progresses to death. Nursing priority is serial neuro checks — GCS every 15-30 minutes — to catch the transition from lucid interval to rapid decline. Any decrease in GCS of 2 or more points warrants immediate provider notification.

Key Distinctions

Don't confuse epidural (arterial, lucid interval, lens-shaped on CT, doesn't cross suture lines) with subdural (venous, gradual onset, crescent-shaped on CT, crosses suture lines). Students mistake the lucid interval for clinical improvement — it signals danger, not recovery. The dilated pupil is ipsilateral to the hematoma (same side), while motor weakness is contralateral (opposite side) — mixing these up is a common exam trap.

Clinical Pearl

Lucid doesn't mean safe. A patient who 'looks better' after a temporal blow and then starts to decline has an epidural hematoma until proven otherwise — call neurosurgery, not the floor charge nurse.