Question

A male patient with recent history of RTA was brought to hospital. His CT scan was normal, but he died within three hours of admission. Autopsy revealed retraction ball appearance and petechial hemorrhages in the corpus callosum. What is the most likely diagnosis?

• A. Diffuse vascular injury
• B. Diffuse axonal injury
• C. Intracerebral hemorrhage
• D. None of the above

Hint:

RTA with normal CT but fatal coma and axonal retraction balls = diffuse axonal injury.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The clinical triad presented is: High-energy trauma (RTA) + Normal CT scan + Significant neurological deterioration/death + Specific autopsy findings (retraction balls, corpus callosum petechiae).
Step 2: Detailed Explanation:

Diffuse Axonal Injury (DAI): This is a severe form of traumatic brain injury caused by shearing forces (acceleration-deceleration or rotational) that disrupt axons at a microscopic level. It usually occurs during high-impact accidents.

The CT Paradox: One of the hallmark clinical features of DAI is that the initial CT scan often appears normal, yet the patient may be in a deep coma. This is because the damage is diffuse and microscopic rather than a large focal hematoma.

Pathology - Retraction Balls: When an axon is severed or severely damaged, the transport of axoplasm is interrupted. The axoplasm accumulates at the site of the break, causing the end of the axon to swell into a bulbous shape called a "retraction ball." This is visible on histology with silver stains or Beta-APP immunohistochemistry.

Anatomy of Lesions: DAI characteristically involves the gray-white matter junction, the corpus callosum, and the brainstem. Petechial hemorrhages in the corpus callosum are a classic macroscopic indicator of high-grade DAI.
- Diffuse Vascular Injury (A): Usually involves more widespread small vessel rupture and is associated with immediate death and multiple hemorrhages on CT.

Step 3: Final Answer:
The "retraction ball appearance" and specific hemorrhages in the corpus callosum are the pathognomonic findings for Diffuse Axonal Injury.