Which statement about Multiple Sclerosis is true?

Which statement about Multiple Sclerosis is true?

• A. It never involves the optic nerve
• B. Bilateral INO is commonly associated
• C. Lhermitte's phenomenon is never seen
• D. Uhtoff's phenomenon never occurs

Answer: (B)

Multiple Sclerosis involves demyelination in the CNS and can affect pathways like the optic nerve and the medial longitudinal fasciculus (MLF). The MLF coordinates horizontal eye movements, so demyelination there leads to internuclear ophthalmoplegia. When both MLFs are involved, you get bilateral INO, which MS patients can exhibit due to widespread demyelinating plaques. Optic neuritis is a well-known feature in MS, so it’s not true that the optic nerve is never involved. Lhermitte's phenomenon, an electric shock-like sensation with neck flexion, is a common MS symptom, and Uhthoff's phenomenon, transient worsening with heat, is also commonly seen. Therefore, bilateral INO being commonly associated with MS is the correct statement.

Multiple Sclerosis involves demyelination in the CNS and can affect pathways like the optic nerve and the medial longitudinal fasciculus (MLF). The MLF coordinates horizontal eye movements, so demyelination there leads to internuclear ophthalmoplegia. When both MLFs are involved, you get bilateral INO, which MS patients can exhibit due to widespread demyelinating plaques. Optic neuritis is a well-known feature in MS, so it’s not true that the optic nerve is never involved. Lhermitte's phenomenon, an electric shock-like sensation with neck flexion, is a common MS symptom, and Uhthoff's phenomenon, transient worsening with heat, is also commonly seen. Therefore, bilateral INO being commonly associated with MS is the correct statement.