Journal of the Neurological Sciences 332 (2013) 154–155 Contents lists available at SciVerse ScienceDirect Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns Short communication Pure ipsilateral central facial palsy and contralateral hemiparesis secondary to ventro-medial medullary stroke R. Ahdab a,⁎, H.S. Saade a, R. Kikano b, J. Ferzli b, W. Tarcha c, N. Riachi a a b c Division of Neurology, University Medical Center Rizk Hospital, Beirut, Lebanon Radiology Department, University Medical Center Rizk Hospital, Beirut, Lebanon Cardiology Department, University Medical Center Rizk Hospital, Beirut, Lebanon a r t i c l e i n f o Article history: Received 25 April 2013 Received in revised form 13 June 2013 Accepted 20 June 2013 Available online 9 July 2013 Keywords: Medial medullary infarct Facial corticobulbar fibers Crossed paresis Central facial palsy Millard Gubler syndrome Stroke a b s t r a c t Medullary infarcts are occasionally associated with facial palsy of the central type (C-FP). This finding can be explained by the course of the facial corticobulbar (F-CB) fibers. It is believed that fibers that project to the upper facial muscles decussate at the level of the facial nucleus, whereas those destined to the lower facial muscles decussate more caudally, at the level of the mid or upper medulla. It has been proposed that the lower F-CB fibers descend ventromedially near the corticospinal tract to the upper medulla where they cross midline and ascend dorsolaterally. Accordingly, ventromedial medullary infarcts are expected to result in contralateral facial and limb weakness. We report a patient with a medial medullary infarct restricted to the right pyramid and associated with ipsilateral C-FP and contralateral hemiparesis. The neurological findings are discussed in light of the hypothetical course of the F-CB fibers in the medulla. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Brainstem infarcts caudal to the facial nucleus are occasionally associated with facial palsy [1,2]. As opposed to pontine lesions, facial palsy is typical of the central type. To explain this finding, it is essential to consider the course and distribution of the facial corticobulbar fibers. It is believed that fibers that project to the upper facial muscles decussate at the level of the facial nucleus, whereas those destined to the lower facial muscles decussate more caudally, at the level of the mid or upper medulla [3,4]. We report a patient with a medial medullary infarct restricted to the right pyramid and associated with ipsilateral central facial palsy and contralateral hemiparesis. The neurological findings are discussed in light of the hypothetical course of the facial cortico-bulbar fibers in the medulla. 2. Case report A 63 year old diabetic and hypertensive man presented for acute onset left hemiparesis and facial asymmetry. Cranial nerve examination demonstrated right facial palsy involving the lower facial muscles and the orbicularis oculi but sparing the frontalis muscle. The other cranial ⁎ Corresponding author at: Division of Neurology, University Medical Center Rizk Hospital, P.O. Box 11-3288, Beirut, Lebanon. Tel.: +961 1 200800; fax: +961 1 200816. E-mail address: rechdi.ahdab@gmail.com (R. Ahdab). 0022-510X/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jns.2013.06.028 nerves were normal including intact facial sensation. His motor exam displayed Medical Research Council (MRC) grade 4 weakness of the left upper and lower extremities with intact sensation. Limb coordination was normal. MRI done 24 h after symptom onset revealed an area of restriction on the Diffusion-Weighted images (DWI b = 1000) in the ventro-medial aspect of the medulla and limited to the right pyramid, corresponding to increased signal on the fluid attenuation inversion recovery ( FLAIR)-weighted images (Fig. 1). 3D time of flight (TOAF 3 SLAB ASSET) MR angiogram was performed without contrast and demonstrated diffuse atherosclerotic changes of the basilar trunk with multisegmental mild to moderate narrowing, especially in the distal third. Limb weakness rapidly improved and the patient was discharged 3 days after admission. He was left with mild residual right upper extremity weakness and left facial palsy. 3. Discussion Crossed motor weakness, known as the Millard Gubler syndrome, is classically attributed to lesions in the pons [5]. In this setting, facial weakness is due to lower motor neuron injury at the nucleus level and is frequently associated with abducens nerve palsy, contralateral cerebellar ataxia and one-and-a half syndrome [6,7]. On the other hand, crossed motor weakness is a rare manifestation of lateral medullary stroke [4]. As opposed to its pontine counterpart, facial weakness is of the central type and attributed to injury to the corticobulbar fibers destined to the lower facial muscles [4]. Associated symptoms are more suggestive of lateral medullary dysfunction [4]. R. Ahdab et al. / Journal of the Neurological Sciences 332 (2013) 154–155 155 Fig. 1. Multilevel Fluid Attenuation Inversion Recovery (FLAIR) weighted images show a longitudinal area of increased signal seen, and limited to, the right parasagittal ventro-medial medulla extending from the lower pons/ponto-medullar junction (image A) to the medullo-cervical junction (image C). Although rare, crossed paresis can also complicate medial medullary stroke [8]. To the best of our knowledge, only one patient has been previously published. As opposed to our case, the infarct extended beyond the pyramids and the patient had additional signs suggestive of medial lemniscus injury [8]. Pure hemiparesis affecting the lower facial muscles is a rare manifestation of medullary infarcts restricted to the pyramids [3,9,10]. However in all previous reports, central type facial palsy was contralateral to the lesion [3,9,10]. These cases are in line with the hypothetical facial cortico-bulbar pathway proposed by Terao and associates [4]. Based on a group of patients with medullary stroke and facial palsy, the authors concluded that the lower facial cortico-bulbar fibers descend near the corticospinal tract to the upper medulla where they cross midline and ascend in the dorsolateral medulla. According to the proposed scheme, our patient's facial weakness should be contralateral to the lesion, and ipsilateral to the paretic limb. Terao and associates' findings did suggest that ascending facial cortico-bulbar fibers were dispersed in the medulla but remained restricted to its dorsolateral aspect. Our case suggests that these tracts follow a more variable course. In a subset of people, ascending rather than descending facial cortico-bulbar pathways seem to accompany the pyramids in the medulla. How the descending facial cortico-bulbar fibers reach the facial nucleus in such cases remains to be determined. Further work is needed to better clarify the course of the facial cortico-bulbar fibers in the medulla and their relation to the pyramidal tracts. Conflict of interest The authors report no conflict of interest related to this work. References [1] Kim JS, Lee JH, Suh DC, Lee MC. Spectrum of lateral medullary syndrome. Correlation between clinical findings and magnetic resonance imaging in 33 subjects. Stroke 1994;25:1405-10. [2] Kameda W, Kawanami T, Kurita K, Daimon M, Kayama T, Hosoya T, et al. Lateral and medial medullary infarction. A comparative analysis of 214 patients. Stroke 2004;35:694-9. [3] Cavazos JE, Bulsara K, Caress J, Osumi A, Glass JP. Pure motor hemiplegia including the face induced by an infarct of the medullary pyramid. Clin Neurol Neurosurg 1996;98:21-3. [4] Terao S, Miura N, Takeda A, Takahashi A, Mitsuma T, Sobue G. Course and distribution of facial corticobulbar tract fibres in the lower brain stem. J Neurol Neurosurg Psychiatry 2000;69:262-5. [5] Onbas O, Kantarci M, Alper F, Karaca L, Okur A. Millard–Gubler syndrome: MR findings. Neuroradiology 2005;47:35-7. [6] Gandhavadi B. Millard–Gubler syndrome: electrophysiologic findings. Arch Phys Med Rehabil 1988;69:980-2. [7] Yasuda Y, Matsuda I, Sakagami T, Kobayashi H, Kameyama M. Pontine infarction with pure Millard–Gubler syndrome: precise localization with magnetic resonance imaging. Eur Neurol 1993;33:331-4. [8] Yamana T, Hasegawa Y, Dei R, Saitou, Takagi S. Ipsilateral central-type facial palsy and contralateral hemiparesis associated with unilateral medial medullary infarction: a case report. Rinsho Shinkeigaku 1998;38:750-3. [9] Chokroverty S, Rubino FA, Haller C. Pure motor hemiplegia due to pyramidal infarction. Arch Neurol 1975;32:647-8. [10] Leestma JE, Noronha A. Pure motor hemiplegia, medullary pyramid lesion, and olivary hypertrophy. J Neurol Neurosurg Psychiatry 1976;39:877-84.