What is the workup for a patient with severe Traumatic Brain Injury (TBI) who develops new nystagmus?

Workup for New Nystagmus in a Patient with Severe TBI

A patient with severe traumatic brain injury (TBI) who develops new nystagmus requires urgent neuroimaging with brain MRI to evaluate for structural lesions, vascular injuries, or progression of TBI-related damage. 1

Initial Assessment

Immediate Evaluation

• Perform detailed neurological examination focusing on:
  • Complete eye movement assessment (horizontal, vertical, rotatory movements)
  • Characterization of nystagmus (direction, amplitude, frequency, triggers)
  • Pupillary responses and fundoscopic examination
  • Cranial nerve function, particularly CN III, IV, VI, and VIII
  • Cerebellar function (coordination, ataxia)
  • Level of consciousness (any deterioration from baseline)

Imaging Studies

1. Brain MRI with contrast (first-line imaging for new neurological findings with normal initial CT) 2

   • T1, T2, FLAIR, DWI, and SWI sequences
   • SWI is particularly sensitive for detecting microhemorrhages not visible on CT
   • Focus on brainstem, cerebellum, and vestibular pathways

2. CT angiography of supra-aortic and intracranial vessels 2

   • Indicated to evaluate for vascular injury, particularly with:
     • Skull base fractures
     • Cervical spine injuries
     • Focal neurological deficits

3. Repeat non-contrast head CT 2

   • If MRI is not immediately available
   • To evaluate for new hemorrhage, hydrocephalus, or mass effect
   • Particularly important if neurological deterioration is present

Specialized Testing

Vestibular Assessment

• Transcranial Doppler (TCD) 2
  • Evaluate cerebral blood flow velocities and pulsatility index
  • Abnormal values: mean velocity <28 cm/s or diastolic velocity <20 cm/s with PI >1.4

Neurophysiological Testing

• Electrooculography (EOG) or video-oculography
  • For quantitative measurement of eye movements
  • Helps characterize nystagmus pattern (pendular vs. jerk)

Additional Considerations

• Visual and vestibular examination for all TBI patients 3
• Consider evaluation for benign paroxysmal positional vertigo (BPPV), which is common after head trauma 3

Differential Diagnosis

Central Causes (Higher Priority)

• Brainstem or cerebellar contusion/hemorrhage
• Post-traumatic hydrocephalus
• Vascular injury (dissection, stroke)
• Cerebellar edema
• Brainstem compression
• Medication effect (particularly sedatives, anticonvulsants)

Peripheral Causes

• Labyrinthine concussion
• Perilymphatic fistula
• Post-traumatic BPPV
• Vestibular nerve injury

Management Considerations

• Transfer to a specialized center with neurosurgical facilities if not already there 2
• Maintain adequate cerebral perfusion (systolic BP >110 mmHg, CPP ≥60 mmHg) 2
• Monitor for signs of increased intracranial pressure
• Consider neurosurgical consultation if structural abnormalities are identified
• Avoid medications that may worsen nystagmus or mask neurological deterioration

Red Flags Requiring Immediate Action

• Nystagmus accompanied by:
  • Decreased level of consciousness
  • New cranial nerve deficits
  • Ataxia or strabismus (strongly associated with urgent conditions) 4
  • Progressive headache
  • Vomiting
  • Papilledema

Follow-up

• Serial neurological examinations to monitor for progression
• Repeat imaging if symptoms worsen or fail to improve
• Consider neuro-ophthalmology or neuro-otology consultation for persistent nystagmus

The presence of new nystagmus in a patient with severe TBI represents a significant finding that warrants thorough investigation, as it may indicate progression of injury or new pathology requiring intervention to prevent further morbidity and mortality.