Neuropathology — MCQs

Question 1: A 19-year-old man is admitted to the emergency room following a motorcycle accident. He is alert and fully oriented, but witnesses to the accident report an interval of unresponsiveness following the injury. Skull films show a fracture of the left temporal bone. Following x-ray, the patient suddenly loses consciousness and dilation of the left pupil is noted. What condition should this patient be considered to have?

• A. Ruptured berry aneurysm
• B. Epidural hematoma (Correct Answer)
• C. Acute subdural hematoma
• D. Intra-abdominal hemorrhage

Explanation: ### Explanation **Correct Answer: B. Epidural Hematoma** The clinical presentation is a classic textbook case of an **Epidural Hematoma (EDH)** [1]. The underlying medical concept involves a traumatic injury to the **temporal bone**, which leads to the rupture of the **middle meningeal artery** (a branch of the maxillary artery) [1]. The hallmark of EDH is the **"Lucid Interval"**: a period where the patient is initially unconscious, regains consciousness and appears normal (as seen when he was alert and oriented), followed by a rapid neurological deterioration [1]. The sudden loss of consciousness and **ipsilateral pupillary dilation** (left pupil) indicate an expanding hematoma causing uncal herniation and compression of the **third cranial nerve (Oculomotor nerve)** [2]. **Why the other options are incorrect:** * **A. Ruptured berry aneurysm:** This typically presents as a sudden "thunderclap headache" (Subarachnoid Hemorrhage) in the absence of trauma, usually located in the Circle of Willis. * **C. Acute subdural hematoma:** This results from the tearing of **bridging veins**. It usually presents with a more gradual onset of symptoms and is common in elderly patients or those with brain atrophy; it does not typically feature a lucid interval. * **D. Intra-abdominal hemorrhage:** While possible in trauma, it would present with signs of hypovolemic shock (tachycardia, hypotension) rather than focal neurological signs like pupillary dilation. **NEET-PG High-Yield Pearls:** * **Radiology:** On CT, EDH appears as a **biconvex (lentiform)**, hyperdense lesion that does not cross suture lines. * **Source of Bleed:** Middle meningeal artery (most common) entering through the **foramen spinosum** [1]. * **Anatomy:** The injury usually occurs at the **Pterion**, the weakest point of the skull where the frontal, parietal, temporal, and sphenoid bones join. * **Triad:** Trauma → Lucid Interval → Rapid Deterioration. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 701-702. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 699-700.