Differential Diagnosis for a Patient with Intact Extraocular Movements

Given that the patient's extraocular movements are intact, the differential diagnosis can be refined to focus on conditions that do not primarily affect the cranial nerves responsible for eye movement (III, IV, and VI) or their pathways. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis
  • Ischemic Stroke: Intact extraocular movements suggest that the brainstem, where the cranial nerve nuclei for these movements are located, is not primarily affected. However, a stroke in other areas, such as the cerebral cortex or the anterior circulation, could still occur without affecting eye movements.
• Other Likely Diagnoses
  • Migraine: Migraines can cause a variety of neurological symptoms, including visual disturbances, without necessarily affecting extraocular movements.
  • Seizure: Certain types of seizures, especially those not involving the brainstem, might not affect extraocular movements.
  • Multiple Sclerosis: While multiple sclerosis can affect any part of the central nervous system, including areas responsible for eye movements, some presentations might spare these functions.
• Do Not Miss Diagnoses
  • Pituitary Apoplexy: Although less likely, pituitary apoplexy is a medical emergency that can present with sudden headache and visual disturbances but might initially spare extraocular movements.
  • Cavernous Sinus Thrombosis: This condition can affect the cranial nerves but might present with other symptoms initially, making it crucial not to miss.
  • Giant Cell Arteritis: This condition can cause visual disturbances and is a medical emergency due to the risk of blindness, but it might not initially affect extraocular movements.
• Rare Diagnoses
  • Mitochondrial Myopathies: Certain mitochondrial disorders can affect the nervous system and muscles, potentially sparing extraocular movements in some cases.
  • Whipple's Disease: A rare infectious disease that can affect the central nervous system, potentially causing a variety of neurological symptoms without necessarily affecting eye movements.

Each of these diagnoses is considered based on the premise that intact extraocular movements suggest that the pathology might not be primarily located in the brainstem or in the direct pathways of the cranial nerves controlling eye movements. However, a thorough clinical evaluation, including history, physical examination, and appropriate diagnostic tests, is essential to narrow down the differential diagnosis and establish a definitive diagnosis.