Review Question - QID 214616

This patient has a history of head trauma, loss of consciousness followed by a lucid interval, and subsequent signs of increased intracranial pressure (headache and vomiting). The noncontrast head CT demonstrates an epidural hematoma, which is likely from a middle meningeal artery (branch of the maxillary artery) hemorrhage.

Epidural hematomas occur as the result of head trauma causing hemorrhage between the skull and dura mater. Classically, the patient has a lucid interval after initial loss of consciousness followed by sings of increased intracranial pressure (e.g., headache, vomiting, decreased mental status, anisocoria, and Cushing reflex). The source of hemorrhage is most often the middle meningeal artery, which is a branch of the maxillary artery. Epidural hematomas are diagnosed with noncontrast CT scans and demonstrate biconvex, hyperdense masses confined to the suture lines between the dura mater and the skull. Rapidly expanding epidural hematomas can cause mass effect leading to CN III palsy and herniation. Treatment includes urgent craniotomy and hematoma evacuation.

Figure/Illustration A demonstrates an epidural hematoma on head CT without contrast. An epidural hematoma appears as biconvex (yellow and green curved lines), hyperdense lesion (blue arrow) most often in the temporoparietal junction that is limited by suture lines.

Incorrect Answers:
Answer 1: Bridging vein rupture causes a subdural hematoma which presents as increasing headaches over several days or weeks with possible changes in mental status. On nonconstrast CT, subdural hematomas appear as crescent-shaped, hyperdense lesions between the brain and skull not limited by suture lines.

Answer 2: Deep temporal artery rupture results in hemorrhage outside the calvarium and would not cause an intracranial hemorrhage. The deep temporal artery branches off the maxillary artery and ascends between the temporalis and the pericranium.

Answer 3: Internal carotid artery rupture can occur at the site of an aneurysm and would result in a subarachnoid hemorrhage, which would present as a sudden, severe headache (i.e., worst headache of life). On noncontrast head CT, subarachnoid hemorrhage appears as an extensive hyperdense network around the circle of Willis.

Answer 5: Middle temporal artery rupture results in hemorrhage outside the calvarium and would not cause an intracranial hemorrhage. The middle temporal artery branches off the superficial temporal artery above the zygomatic arch and perforates the temporal fascia to supply the temporalis muscle.

Bullet Summary:
Epidural hematomas are most often the result of hemorrhage from the middle meningeal artery, which is a terminal branch of the maxillary artery.