CAISS Head and Neck Injuries 4 — Questions and Answers
Question 1: For AIS coding purposes, which criterion distinguishes an epidural hematoma (EDH) coded AIS 4 from one coded AIS 5?
- Hematoma location (temporal vs. parietal)
- Volume of hematoma and associated brain shift (Correct answer)
- Patient age
- Time to surgical evacuation
Correct answer: Volume of hematoma and associated brain shift
AIS severity for EDH escalates with larger hematoma volume and significant midline shift indicating greater mass effect.
Question 2: Under the AIS 2015 update, subarachnoid hemorrhage (SAH) is primarily coded based on which factor?
- Fisher grade
- Hunt-Hess scale
- Traumatic vs. spontaneous origin (Correct answer)
- Location relative to the Sylvian fissure
Correct answer: Traumatic vs. spontaneous origin
AIS distinguishes traumatic SAH from spontaneous SAH because the AIS dictionary covers only traumatic injuries.
Question 3: A pedestrian struck by a car has a depressed skull fracture with underlying dural laceration but no parenchymal injury on MRI. What AIS severity applies?
- AIS 2
- AIS 3
- AIS 4 (Correct answer)
- AIS 5
Correct answer: AIS 4
A depressed skull fracture with dural disruption but no brain parenchymal injury codes to AIS 4 due to the structural significance.
Question 4: Which structure, when lacerated in a neck injury, most likely elevates the AIS severity to 4 or 5?
- Sternocleidomastoid muscle
- External jugular vein
- Common carotid artery (Correct answer)
- Platysma muscle
Correct answer: Common carotid artery
Laceration of the common carotid artery is a major vascular injury that elevates AIS neck injury severity to 4 or 5.
Question 5: In AIS, the 'masked injury' rule states that if a more severe brain injury is identified later, the coder should:
- Keep the original code
- Add a supplemental code
- Revise the AIS code to the higher severity injury (Correct answer)
- Code both with equal weight
Correct answer: Revise the AIS code to the higher severity injury
AIS coding is updated to reflect the most accurate diagnosis; the code is revised upward when a more severe injury is subsequently identified.
Question 6: A cyclist falls and sustains loss of consciousness of 15 minutes with a GCS on arrival of 14. No CT abnormality is found. What is the AIS code?
- AIS 1
- AIS 2 (Correct answer)
- AIS 3
- AIS 4
Correct answer: AIS 2
LOC of 1–30 minutes with GCS ≥14 and no structural finding is coded AIS 2 (Moderate concussion).
Question 7: An AIS code ending in '.4' as the final digit represents which component of the 7-digit AIS predot code system?
- Body region
- Anatomical structure
- Specific injury level (Correct answer)
- Severity qualifier
Correct answer: Specific injury level
In the AIS 7-digit predot coding system, the sixth digit represents the specific injury level or type, refining the injury within the anatomical structure.
CAISS Head and Neck Injuries 4
For AIS coding purposes, which criterion distinguishes an epidural hematoma (EDH) coded AIS 4 from one coded AIS 5?