Certified Neuroscience Registered Nurse (CNRN) Practice Exam

How is the diagnosis of diffuse axonal injury (DAI) confirmed?

1. CT scan

2. Clinical diagnosis

3. MRI

4. Microscopic examination of the brain tissue

The correct answer is: Clinical diagnosis

The diagnosis of diffuse axonal injury (DAI) is primarily considered to be a clinical diagnosis rather than one solely reliant on imaging techniques or tissue examination. DAI typically occurs due to acceleration-deceleration forces, often seen in traumatic brain injuries, and is characterized by widespread damage to the axons within the brain. Clinical diagnosis involves assessing the patient's neurological status, including consciousness level, motor responses, and cognitive function, often aided by the history of trauma. While CT and MRI scans may show associated findings of brain injury, such as small hemorrhages or edema, they do not specifically confirm DAI due to their inability to visualize the extensive microscopic damage to axonal fibers. Microscopic examination of brain tissue can reveal axonal damage but is not practical for routine clinical diagnosis and typically requires post-mortem analysis or specific surgical procedures. Thus, the confirmation of DAI is best made through a thorough clinical evaluation that takes into account the patient's symptoms and the circumstances surrounding the injury, rather than relying solely on imaging or tissue samples.