From the Guidelines
Yes, nystagmus after a head strike warrants a CT scan. Nystagmus, characterized by involuntary eye movements, can indicate damage to the brain stem, cerebellum, or vestibular system following head trauma. This finding is concerning for potential intracranial injury such as hemorrhage, contusion, or diffuse axonal injury that may require urgent intervention. The CT scan should be performed promptly to identify any structural abnormalities, bleeding, or swelling that might explain the nystagmus. According to the American College of Radiology Appropriateness Criteria 1, Head CT is useful for the evaluation of any trauma patient with neurologic deterioration, especially in the acute setting and regardless of whether the initial imaging was positive or negative.
Key Points to Consider
- Nystagmus can be a sign of serious head injury, including damage to the brain stem, cerebellum, or vestibular system 1.
- CT scan is the initial imaging modality of choice due to its speed and availability in emergency settings 1.
- Other symptoms that might accompany nystagmus and further necessitate imaging include headache, vomiting, altered mental status, loss of consciousness, or other neurological deficits.
- While CT is the initial imaging modality of choice, an MRI may be considered later for more detailed evaluation, especially if symptoms persist despite normal CT findings 1.
- The patient should be monitored closely for any deterioration in neurological status while awaiting and following imaging, as some intracranial injuries can evolve over time.
Imaging Recommendations
- Noncontrast head CT is usually appropriate for the initial imaging of patients with acute head trauma that is mild (GCS 13–15) when imaging is indicated by clinical decision rule 1.
- Noncontrast head CT is usually appropriate for the short-term follow-up imaging of patients with acute head trauma who have new or progressive neurologic deficit(s) 1.
- Brain MRI may be indicated as a second-line study when there are persistent neurologic deficits that remain unexplained after the head CT 1.
From the Research
Nystagmus after a Head Strike
- Nystagmus is a symptom that can occur after a head strike, and its presence may warrant further investigation, including imaging studies like CT scans.
- According to 2, CT scanning is the current first imaging technique to be used after head injury, and it is useful for demonstrating scalp, bone, extra-axial hematomas, and parenchymal injury.
Use of CT Scans in Head Injury
- The use of CT scans in head injury is guided by various factors, including the mechanism of injury, neurological evaluation, and Glasgow Coma Scale (GCS) score 3.
- A study found that only a small proportion of patients with head injury require neurosurgical intervention, and the majority of CT scans performed as emergency procedures have no pathological findings 3.
- CT scans are excellent for evaluating facial and skull fractures, and they can detect neurosurgically significant lesions such as epidural hematomas, subdural hematomas, or depressed skull fractures 4.
Timing of CT Scans
- National Institute for Health and Care Excellence guidelines for triaging patients with head injury to CT imaging are based on research conducted in populations presenting within 24 hours of injury 5.
- A study found that the sensitivity of these guidelines for intracranial injuries was lower in patients presenting after 24 hours of injury, suggesting that existing guidelines may not be sufficient for patients presenting after this time period 5.
Predictors of CT Scan Use
- A study found that significant predictors of CT scan prescription in patients with suspected mild traumatic brain injury included urban location of hospital, loss of consciousness and/or post-traumatic amnesia, vomiting, arrival by ambulance, nausea, and older age 6.
- These findings suggest that the management patterns for acute mild traumatic brain injury are inconsistent, and that geographical location of hospital and arrival mode are significant predictors of CT use 6.