Differential Diagnosis for Internuclear Ophthalmoplegia with Negative MRI
Single Most Likely Diagnosis
- Multiple Sclerosis (MS): This is the most common cause of internuclear ophthalmoplegia (INO), especially in young adults. A negative MRI does not rule out MS, as lesions may not always be visible, especially early in the disease course.
Other Likely Diagnoses
- Stroke or Small Vessel Disease: Although less common than MS, small vessel disease or stroke can cause INO, particularly in older adults. A negative MRI might not capture small infarcts or ischemic changes.
- Infectious or Inflammatory Conditions: Conditions like Lyme disease, syphilis, or sarcoidosis can cause INO. These diagnoses might not be immediately apparent on MRI, especially if the infection or inflammation is not primarily affecting the brainstem or medial longitudinal fasciculus.
Do Not Miss Diagnoses
- Wernicke's Encephalopathy: This condition, caused by thiamine deficiency, can present with ophthalmoplegia, among other symptoms. It's crucial to consider this diagnosis due to its potential for severe consequences if left untreated, including death.
- Brainstem Glioma: Although rare, a brainstem glioma could cause INO. A negative initial MRI does not entirely rule out this possibility, as some tumors may not be visible or may be mistaken for other conditions.
Rare Diagnoses
- Chiari Malformation: While more commonly associated with other symptoms, a Chiari malformation could potentially cause INO, especially if there's significant brainstem compression or syringomyelia.
- Neurodegenerative Diseases (e.g., Progressive Supranuclear Palsy): Certain neurodegenerative diseases can present with ophthalmoplegia, though INO is less common. These conditions are rare and typically have a broader range of symptoms.
- Trauma: Traumatic brain injury can result in INO, especially if there's damage to the brainstem or medial longitudinal fasciculus. This might be considered if there's a relevant history of trauma.