Differential Diagnosis for Nystagmus to the Right
- Single most likely diagnosis:
- Benign paroxysmal positional vertigo (BPPV) - This condition is characterized by brief, episodic vertigo triggered by head movements, and nystagmus can be a presenting feature. The direction of nystagmus can vary but often corresponds to the direction of the fast phase, which in BPPV, is typically rotational and to the right in right-sided BPPV.
- Other Likely diagnoses:
- Vestibular neuritis - This is an inner ear disorder that can cause vertigo, dizziness, and nystagmus. The nystagmus is usually unidirectional and can be to the right if the right vestibular nerve is affected.
- Labyrinthitis - Similar to vestibular neuritis but involves both the vestibular and cochlear portions of the inner ear, leading to vertigo, hearing loss, and potentially nystagmus to the right.
- Meniere's disease - A disorder of the inner ear that causes episodes of vertigo, tinnitus, hearing loss, and aural fullness. Nystagmus can occur during acute attacks and may be directed to the right.
- Do Not Miss diagnoses:
- Stroke or cerebellar infarction - Although less common, a stroke in the posterior circulation can cause nystagmus, among other symptoms like vertigo, ataxia, and dysarthria. It's crucial to rule out a stroke due to its high morbidity and mortality.
- Multiple sclerosis - This demyelinating disease can present with a wide range of neurological symptoms, including nystagmus. While not the most common cause, its potential for significant disability makes it a "do not miss" diagnosis.
- Rare diagnoses:
- Congenital nystagmus - Although present from birth, some forms may not be diagnosed until later in life. It's characterized by involuntary, rhythmic eye movements that can be horizontal, vertical, or rotational.
- Medication-induced nystagmus - Certain medications, such as anticonvulsants, sedatives, and alcohol, can cause nystagmus as a side effect.
- Brain tumors or cysts - Rarely, tumors or cysts in the brainstem or cerebellum can cause nystagmus due to their location affecting the vestibular pathways.