Rare Presentation of Midbrain Infarction: Isolated Medial Rectus Palsy

Abstract

A 69-year-old woman presented with sudden onset of diplopia. In neurologic examination left medial rectus palsy without abduction nystagmus was detected. Brain magnetic resonance imaging revealed acute ischemic lesion in mesencephalon on diffusion-weighted images. Sponteneous resolution was observed after 1 month. Medial rectus palsy is a rare presention of acute ischemic stroke and early neuroimaging is important to establish such lesions.

Aetiology, clinical features and surgical outcomes of isolated medial rectus palsy

“…In extraocular muscle palsy, CN VI represents the most common type of paralytic strabismus, accounting for 33% to 63% of cases, followed by CN III palsy (22%‐41.2%) and CN IV palsy (11%‐36%) 1‐4 . Isolated medial rectus palsy (MRP) is extremely rare in clinical practice, with only 59 cases being reported in the English literature, often involving single case presentations 5‐14 . Possible aetiologies may include damage of the medial rectus nucleus or terminal branches of the oculomotor nerve serving only the medial rectus, or direct medial rectus muscle injury, such as orbital trauma or surgical complications of endoscopic sinus surgery.…”

Medial Rectus Nuclear Palsy as a Sole Feature of Midbrain Infarction Secondary to Stenosis of Posterior Cerebral Artery

“…[12] In our report, the patient was characterized by right, pure medial rectus nuclear palsy due to acute mesencephalon infarction. To our knowledge, the oculomotor nuclear is situated at the superior colliculus level of the midbrain, which is composed of two parts: the main motor nucleus and the accessory parasympathetic nucleus.…”

“…It is fairly rare that midbrain infarction only manifests as isolated medial rectus nuclear palsy. [1] Here, we provided such an uncommon case and discussed the possible etiology.…”

“…Hence, isolated medial rectus nuclear palsy without other extraocular muscles, pupil, and convergence reflex involved is extremely rare. As far as we know, there are only a few similar cases reported,[12345] and the comparison of six cases is shown in Supplementary Table 1.…”

“…;[1] Case 2: Rabadi and Beltmann;[2] Case 3: Al-Sofiani and Lee Kwen;[3] Case 4: Lee et al . ;[4] Case 5: Bal et al .…”