Wernekink Commissure Syndrome Secondary to Bilateral Caudal Paramedian Midbrain Infarction Presenting with a Unique "Heart or V" Appearance Sign: Case Report and Review of the Literature

Abstract

Wernekink commissure syndrome secondary to caudal paramedian midbrain infarction (CPMI) is a rare midbrain syndrome involving the decussation of the superior cerebellar peduncle in the caudal paramedian midbrain tegmentum. The central characteristics are constant bilateral cerebellar dysfunction, variable eye movement disorders, and rare delayed palatal myoclonus. Following is a description of the case of a 60-year-old man who presented with dizziness, slurred speech, and difficulty walking. Neurological examination revealed bilateral cerebellar dysfunction and bilateral internuclear ophthalmoplegia (bilateral INO). Serial magnetic resonance imaging (MRI) revealed a lesion in the caudal paramedian midbrain with a "heart-shaped" sign on fluid-attenuation inversion recovery images and a "V-shaped" appearance on diffusion-weighted imaging (DWI). An acute CPMI with a "heart or V" appearance sign was diagnosed. Upon follow-up evaluation 3 months later, a palatal tremor accompanied by involuntary head tremor was discovered. Hypertrophy and increased signal of the bilateral inferior olivary nucleus, compatible with hypertropic olivary degeneration (HOD) were revealed during a subsequent MRI study.

Keywords: Palatal myoclonus; Wernekink commissure syndrome; bilateral internuclear ophthalmolegia; caudal paramedian midbrain infarction; hypertrophic olivary degeneration; “heart-shaped” sign.

Figure 1

The axial brain fluid-attenuation inversion recovery (FLAIR) images (A) and sagittal T2-weighted images (B), demonstrating a “heart-shaped” appearance area of hyperintensity located in the tegmentum of the caudal midbrain.

Figure 2

(A) The brain diffusion-weighted image (DWI) of the patient is shown. Note the “heart or V”-shaped lesion showing increased intensity in the tegmentum of the caudal midbrain. (B) The brain apparent diffusion coefficient map MRI (ADC) of the patient is shown. The “heart or V”-shaped lesion shows low intensity on ADC, consistent with acute infarction.

Figure 3

1.5T Brain MRI, axial T2-weighted images (A) and coronal T2-weighted images (B) shows the symmetric enlargement and increased signal intensity of both inferior olives (arrow).

Figure 4

Transverse section of the lower midbrain at the level of the inferior colliculus. This schematic diagram of the midbrain depicts its arterial supply and some of the important structures within it. (A) Anteromedial, (B) anterolateral, (C) lateral, and (D) dorsal.