A young man is brought to the emergency department in an unconscious state following a road traffic accident (RTA). Physical examination reveals no external injuries. A CT scan is performed and shows a characteristic biconvex lesion.
What is the most likely diagnosis?
A. Subarachnoid hemorrhage
B. Extradural hematoma
C. Subdural hematoma
D. Cerebral laceration
The Correct Answer is: B. Extradural hematoma
Explanation:
Extradural hematoma (B):
– An extradural (or epidural) hematoma is a collection of blood between the inner surface of the skull and the dura mater. It is typically caused by a traumatic injury that leads to the tearing of an artery, most commonly the middle meningeal artery.
– On a CT scan, an extradural hematoma often appears as a characteristic biconvex (lens-shaped) lesion.
– Patients with extradural hematoma may have a “lucid interval” where they regain consciousness before deteriorating neurologically, but in severe cases, they may remain unconscious.
Explanation of Incorrect Options:
Subarachnoid hemorrhage (A):
– Subarachnoid hemorrhage involves bleeding into the subarachnoid space, often due to the rupture of an aneurysm or trauma. It appears as diffuse bleeding in the subarachnoid spaces on a CT scan, not as a biconvex lesion.
Subdural hematoma (C):
– Subdural hematomas occur when blood collects between the dura mater and the arachnoid mater, usually due to the tearing of bridging veins. On a CT scan, subdural hematomas typically appear as crescent-shaped lesions, which can cross suture lines.
Cerebral laceration (D):
– Cerebral laceration involves tearing of brain tissue, usually associated with severe traumatic brain injury. It can lead to various patterns of bleeding and damage on a CT scan, but it does not present as a biconvex lesion.
In conclusion, the presence of a characteristic biconvex lesion on a CT scan in a patient with head trauma is most indicative of an extradural hematoma, making option B the correct answer.