Management and Treatment of Bruns Nystagmus
Bruns nystagmus is a neurological emergency requiring immediate neuroimaging with MRI brain to identify the underlying structural lesion—most commonly a large cerebellopontine angle tumor (≥3 cm) causing significant brainstem compression—followed by urgent neurosurgical consultation for definitive treatment. 1, 2, 3
Immediate Diagnostic Workup
Neuroimaging (First Priority)
- MRI of the brain without and with IV contrast is mandatory to identify the causative lesion, as Bruns nystagmus indicates significant mass effect and brainstem distortion 4, 1
- CT imaging has no role in evaluation, as it provides inadequate visualization of posterior fossa structures 5
- In 92% of cases with tumors >3.5 cm diameter, nystagmus is present, with 67% specifically demonstrating Bruns nystagmus 6
Clinical Characteristics to Document
- Gaze-dependent bidirectional pattern: coarse, high-amplitude, low-frequency horizontal nystagmus when looking toward the lesion side, and fine, low-amplitude, high-frequency nystagmus when looking away from the lesion 2, 3
- This pattern does not fatigue and is not suppressed by visual fixation, confirming its central origin 1, 7
- Associated balance impairment is present in 95% of patients with Bruns nystagmus 6
Underlying Pathology
Most Common Causes
- Large cerebellopontine angle tumors (particularly vestibular schwannomas ≥3 cm) are the classic etiology, occurring in 11-16% of patients with these tumors 3, 6
- All cases demonstrate significant brainstem distortion and compression of the flocculus and/or vestibulocerebellum 2, 3
- Fourth ventricle displacement is present in 89% of cases where visualized on imaging 3
Alternative Etiologies (Less Common)
- Paramedian pontine base infarction can rarely cause Bruns-Cushing nystagmus, particularly in hypertensive patients 8
- Other structural lesions causing significant brainstem compression should be considered 9
Definitive Treatment
Surgical Management
- Urgent neurosurgical referral for tumor resection is the definitive treatment for cerebellopontine angle masses 2, 6
- Complete surgical resection typically resolves the nystagmus, though rare cases of persistent postoperative Bruns nystagmus have been reported 2
- Patients with preoperative Bruns nystagmus show relatively greater improvement in balance status postoperatively compared to those without nystagmus 6
Vestibular Rehabilitation
- Comprehensive vestibular function testing should be performed to guide rehabilitation, including vestibulo-ocular reflex assessment and vestibular evoked myogenic potentials 5
- Long-term balance outcomes after surgery are similar across all nystagmus groups, despite greater preoperative impairment in Bruns nystagmus patients 6
Critical Pitfalls to Avoid
- Do not mistake Bruns nystagmus for benign peripheral vestibular disorders, as it definitively indicates central pathology requiring urgent intervention 1, 7
- Do not delay imaging based on symptom severity alone, as the presence of Bruns nystagmus itself indicates a large structural lesion regardless of symptom intensity 3, 6
- Do not rely on brainstem auditory evoked potentials as the primary assessment tool, as they are less sensitive (47% abnormal) than neuroanatomical imaging for detecting brainstem compression 3
- Bruns nystagmus can occur postoperatively as a new finding despite complete resection, requiring continued monitoring 2