Review Question - QID 221218

This patient with painful, monocular vision loss and a previous history of unilateral motor weakness most likely has multiple sclerosis. This condition can also present with the Lhermitte sign, which is an electric shock-like sensation radiating down the spine with neck flexion.

Multiple sclerosis (MS) is caused by autoantibodies that target oligodendrocytes in the central nervous system. Patients present with focal neurological findings such as optic neuritis, diplopia, Lhermitte sign, and brainstem syndromes. Lhermitte sign is an electric shock-like sensation radiating down the spine with neck flexion. Diagnosis of this disease requires the demonstration of lesions across both space and time, which can be demonstrated clinically or via imaging. Lesions on MRI typically occur in the white matter as ovoid lesions; sometimes, lesions are seen oriented perpendicularly to and radiating from the corpus callosum. Disease-modifying treatment for MS includes interferon beta, glatiramer acetate, and biologics such as natalizumab.

Khare and Seth review the evidence regarding Lhermitte sign. They discuss how demyelination and hyperexcitability are the main causes of this sign. They recommended that clinicians be aware of the inverse and reverse presentations of the Lhermitte sign, in which neck flexion causes paresthesias shooting from caudad to cephalad or neck extension causes paresthesias shooting in the cephalocaudal direction, respectively.

Figure/Illustration A is a brain MRI that demonstrates white matter lesions near the corpus callosum (red circle). This finding is classically seen in patients with multiple sclerosis.

Incorrect Answers:
Answer 2: Protein deposits in the lens are the cause of cataracts, which present with progressive vision loss. Patients often report seeing bright “halos” around lights at night. Cataracts do not cause a relative afferent pupillary defect or motor weakness.

Answer 3: Pupils that accommodate but do not react describe the Argyll Robertson pupil, which is seen in tertiary syphilis. Tertiary syphilis presents with cardiovascular symptoms such as aortic regurgitation or heart failure and tabes dorsalis. Tabes dorsalis presents with sensory ataxia and sudden, brief stabs of pain. Tertiary syphilis does not usually cause a relative afferent pupillary defect.

Answer 4: Symptomatic improvement in warm weather is incorrect because MS symptoms typically worsen in the heat. Symptoms can improve in cold weather instead.

Answer 5: Temporal scalp tenderness is seen in temporal giant cell arteritis, which can present with acute, painless monocular vision loss due to optic nerve ischemia. It also causes jaw claudication.

Bullet Summary:
Patients with multiple sclerosis can present with the Lhermitte sign, which is an electric shock-like sensation that radiates down the spine with neck flexion.