Which of the following is feature of Diffuse axonal injury: September 2010
**Core Concept**
Diffuse axonal injury (DAI) is a type of traumatic brain injury characterized by widespread damage to axons in the brain, leading to disruption of neural function. This occurs due to shearing forces during rapid deceleration or acceleration, causing micro-tears in the axonal membranes.
**Why the Correct Answer is Right**
The key feature of DAI is the presence of micro-hemorrhages and axonal retraction balls, which are visible on magnetic resonance imaging (MRI). These micro-hemorrhages are a result of the shearing forces that cause disruption of the blood-brain barrier, leading to bleeding into the surrounding tissue. The axonal retraction balls are formed due to the retraction of axonal fragments after the injury. This damage to the axons disrupts neural function, leading to symptoms such as altered consciousness, seizures, and focal neurological deficits.
**Why Each Wrong Option is Incorrect**
* **Option A:** is incorrect because it does not specify a key feature of DAI.
* **Option B:** is incorrect because it does not accurately describe the pathophysiology of DAI.
* **Option C:** is incorrect because it is not a characteristic of DAI.
**Clinical Pearl / High-Yield Fact**
DAI is often associated with high-speed motor vehicle accidents, falls from a height, and other types of traumatic brain injuries that involve rapid deceleration or acceleration. It is essential to recognize the characteristic features of DAI on imaging studies to diagnose this condition accurately.
**Correct Answer: C. Micro-hemorrhages and axonal retraction balls on MRI are characteristic of Diffuse Axonal Injury.**