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Table of Contents    
Year : 2021  |  Volume : 69  |  Issue : 6  |  Page : 1831-1834

An Atypical Presentation of Left Lateral Medullary Syndrome – A Case Report

1 Department of Neurology, Institute of Neurosciences, Indraprastha Apollo Hospitals, Delhi, India
2 Department of Internal Medicine, Institute of Neurosciences, Indraprastha Apollo Hospitals, Delhi, India

Date of Submission02-Feb-2021
Date of Decision11-Apr-2021
Date of Acceptance25-Jul-2021
Date of Web Publication23-Dec-2021

Correspondence Address:
Dr. Pushpendra N Renjen
C-85, Anand Niketan, New Delhi - 110 021
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.333445

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 » Abstract 

Lateral medullary syndrome (LMS), known as Wallenberg's syndrome and posterior inferior cerebellar artery syndrome, is a rare cause of stroke. It often results from thrombosis or emboli of the vertebral artery or posterior inferior cerebellar artery. The triad of Horner's syndrome, ipsilateral ataxia, and ipsilateral hyperalgesia clinically identify patients with LMS. We report a case of a 62-year-old diabetic, hypertensive male who presented with symptoms involving the left lateral dorsal medulla along with partial Horner's syndrome, left lateral rectus palsy, and left lower motor neuron–type facial palsy. Atypical presentation in LMS could be explained by infraction of left facial colliculus in addition to the left lateral medulla. Association of these entities with Wallenberg's syndrome is atypical features in our case, which questioned the diagnosis of a simple LMS.

Keywords: Ataxia, Horner's, Wallenberg's syndrome
Key Message: Multiple variants of Lateral Medullary Syndrome exist which need careful examination and neuroanatomical correlation. Clinical presentations of brainstem infarcts may vary accordingly.

How to cite this article:
Renjen PN, Krishnan R, Chaudhari D, Ahmad K. An Atypical Presentation of Left Lateral Medullary Syndrome – A Case Report. Neurol India 2021;69:1831-4

How to cite this URL:
Renjen PN, Krishnan R, Chaudhari D, Ahmad K. An Atypical Presentation of Left Lateral Medullary Syndrome – A Case Report. Neurol India [serial online] 2021 [cited 2022 Jan 28];69:1831-4. Available from: https://www.neurologyindia.com/text.asp?2021/69/6/1831/333445

The lateral medullary syndrome (LMS) was first described in 1808 by Gaspard Vieussux.[1] The first descriptions by Wallenberg were in 1895 (clinical) and 1901 (autopsy findings). Wallenberg's syndrome or lateral medullary syndrome is associated with a variety of symptoms due to the involvement of the lateral segment of the medulla. It is caused most commonly due to atherothrombotic vertebral artery occlusion, followed by posterior inferior cerebellar artery (PICA) and medullary arteries. Hypertension, diabetes, and smoking are the common risk factors. Among other causes, vertebral artery dissection due to neck manipulation/injury, Marfan's syndrome, Ehler–Danlos syndrome, and fibromuscular dysplasia may be attributed to LMS.[2] The syndrome is characterized by loss of pain and temperature sensation on the contralateral side of the body and ipsilateral side of the face.[3] If spinal trigeminal nucleus is affected, this causes absence of pain on the ipsilateral side of the face as well as absence of corneal reflex. If spinothalamic tract is affected, it leads to hemisensory loss on the contralateral trunk and extremities. Involvement of nucleus ambiguous causes dysphagia and dysarthria. The damage to the cerebellum or the inferior cerebellar peduncle causes ataxia. Damage to the hypothalamo-spinal fibers disrupts the sympathetic nervous system giving rise to Horner's syndrome. Nystagmus and vertigo are the results of the involvement of vestibular nuclei. Apart from these classical clinical features, Wallenberg's syndrome may present with some atypical manifestations as well.

 » Case Report Top

A 62-year-old gentleman recently diagnosed with Type 2 diabetes mellitus and hypertension presented with a sudden onset giddiness, vertigo, dizziness, and a tendency to fall to his left side for 2 days for which he was admitted to another hospital. Magnetic resonance imaging (MRI) was done there, which revealed a normal scan with no changes on DWI (diffusion-weighted images) [Figure 1]a. He was managed conservatively with antiplatelets and supportive care. The same day, in the evening, he developed left facial weakness and dysarthria; gradually, he noticed that he was unable to feel any pain or change in temperature on that half of his face. His symptoms aggravated over the next few hours, and he started to experience vertical diplopia. A repeat CEMRI brain (contrast-enhanced MRI) was done, which showed hypoperfusion in the middle cerebellar peduncle [Figure 1]b. A day later, he developed a slowly evolving hemisensory loss of pain and temperature on the right half of the body. An lower motor neuron (LMN)–type facial palsy with partial ptosis on the left half of his face. He started experiencing bulbar symptoms, namely, nasal regurgitation/intonation, difficulty in swallowing, slurred speech, hoarseness of voice, and impaired cough reflex. He had also complained of gait disturbance with swaying to the left with left-sided incoordination. In view of the progression of his symptoms, he was referred to our hospital. A detailed neurological examination revealed left horizontal nystagmus with a partial ptosis of the left eye [Figure 2]a. There was deviation of mouth toward the right side with absence of furrows on the left forehead [Figure 2]b. Cough reflex was absent, and left-sided cerebellar signs were positive with an abnormal vestibulo-ocular reflex on the left. There was sensory disturbance of the right upper and lower limb and left facial territory.
Figure 1: (a) – MRI brain suggestive of normal scan with no changes on DWI (diffusion-weighted images); (b) – Repeat CEMRI (contrast-enhanced MRI) brain showing hypoperfusion in middle cerebellar peduncle

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Figure 2: (a) – Left horizontal nystagmus with a partial ptosis of left eye; (b) – Deviation of mouth toward right side with the absence of furrows on the left forehead

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Immediate MRI brain was done, which revealed diffusion restriction in left pontomedullary junction suggestive of acute infarct with diffusion restriction on DWI sequence and reversal on apparent diffusion coefficient sequence [Figure 3]. CT (computed tomography) angiography of the brain (four vessels) and neck vessels did not reveal any significant abnormality. Electrocardiography and echocardiography findings were within normal limits. The patient was started on dual antiplatelet therapy (aspirin and clopidogrel), high-dose statin (atorvastatin), and neuromuscular electrical stimulation (NMES Vital Stim) for swallowing difficulty. He recovered gradually over the next 2 to 3 weeks with mild residual cerebellar symptoms.
Figure 3: MRI brain showing diffusion restriction in the left pontomedullary junction suggestive of acute infarct

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 » Discussion Top

Atypical features in our case, which questioned the diagnosis of a simple LMS, were as follows:

  • Partial Horner's syndrome
  • LMN-type facial palsy
  • Left lateral rectus muscle palsy.

In classical cases of LMS, Horner's syndrome is quite evident due to the involvement of descending oculo-sympathetic tracts. But in our case, only partial ptosis was present, whereas the other features of Horner's syndrome (e.g., miosis, anhydrosis) were absent. This may be attributed to parts of the descending sympathetic tracts that are located more deeply; hence, they may be spared in a more dorsal medullary lesion leading to this differential involvement.[4]

Ipsilateral LMN-type facial palsy may result from lower pontine inferomedial tegmentum lesion where the facial nerve passes. The left PICA might supply the inferolateral tegmentum of the lower pons, which is usually supplied from the anterior inferior cerebellar artery. LMN-type facial palsy in our patient may have resulted from facial infranuclear involvement of the caudal pons extended from the dorsolateral upper medullary lesion in the ascending pathway of the corticobulbar tract fibers[5],[6] [Figure 4]a.
Figure 4: (a) Schematic diagram of brainstem showing pathway of facial fibers and site of lesion with types of facial involvement. (A) Produces contralateral central facial palsy (CFP) (B) nuclear lesion; ipsilateral peripheral facial palsy, (C) hypothetical loop before decussation; contralateral CFP, (D) hypothetical loop in dorsolateral medulla; ipsilateral CFP [(1) Corticospinal tract, (2) corticobulbar tract (corticofacial fibers), (3) bilateral innervation to upper face, (4) hypothetical looping of supranuclear corticobulbar tract fibers].[5],[6] (b) The schematic figures of the axial and coronal planes depict the classic (e and f) and common (g and h) types of Raymond syndrome.[11],[12],[13]

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The involvement of ipsilateral left lateral rectus muscles could be explained by the lesion in the medial caudal pons, which could produce Raymond syndrome.[7],[8] Clinical manifestation of simultaneous ipsilateral abducens nerve palsy with contralateral central facial paresis seen in the classic Raymond syndrome results from a lesion in the pons involving the corticofacial decussation at the level of abducens nerve. A lesion in the more dorsal area may produce an isolated abducens nerve palsy,[9] whereas the lesion in the ventral caudal pons may produce Millard–Gubler syndrome consisting of both ipsilateral abducens and facial paralysis, and contralateral hemiplegia[8],[10],[11],[12],[13] [Figure 4]b. All relevant variants of LMS and corresponding anatomical involvements have been mentioned in [Table 1].
Table 1: Different Variants of LMS with corresponding anatomical involvements

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Although Wallenberg's syndrome is commonly known as PICA syndrome, the commonest cause of this syndrome is atherothrombotic occlusion of the vertebral artery.[14] The left PICA might supply the inferolateral tegmentum of the lower pons, which is usually supplied from the anterior inferior cerebellar artery, could explain LMN-type facial palsy. The mechanism of stroke in our case is arguable in the presence of poorly controlled diabetes as a risk factor.

 » Conclusion Top

It is evident from the above-mentioned scenario that LMS may present with atypical findings such as the presence of LMN facial palsy, absence of classical Horner's syndrome, and left lateral rectus muscle palsy due to variation in the involvement of neuroanatomical structures. Neuroanatomical correlation is suggestive of a diagnosis of pontomedullary syndrome; hence, clinicians should always be aware of the atypical presentation of brain stem strokes.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

 » References Top

Kim H, Chung CS, Lee KH, Robbins J. Aspiration subsequent to apure medullary infarction: lesion site, clinical variables and outcome. Arch Neurol 2005;57:478-83.  Back to cited text no. 1
Ogawa K, Suzuki Y, Oishi M, Kamei S. Clinical study of 46 patients with lateral medullary infarction. J Stroke Cerebrovasc Dis 2015;24:1065-74.  Back to cited text no. 2
Saha R, Alam S, Hossain MA. Lateral medullary syndrome (Wallenberg'S syndrome) - A case report. Faridpur Med Coll J 2010;5:35-6.  Back to cited text no. 3
Kim JS. Pure lateral medullary infarction: Clinical - radiological correlation of 130 acute, consecutive patients. Brain 2003;126:1864-72.  Back to cited text no. 4
Terao S, Takatsu S, Izumi M, Takagi J, Mitsuma T, Takahashi A, et al. Central facial weakness due to medial medullary infarction: The course of facial corticobulbar fibres. J Neurol Neurosurg Psychiatry 1997;63:391-3.  Back to cited text no. 5
Urban PP, Wicht S, Vucorevic G, Fitzek S, Marx J, Thömke F, et al. The course of corticofacial projections in the human brainstem. Brain 2001;124:1866-76.  Back to cited text no. 6
Kuypers HG. Corticobulbar connections to the pons and lower brain-stem in man: An anatomical study. Brain 1958;81:364-88.  Back to cited text no. 7
Marx JJ, Thömke F. Classical crossed brain stem syndromes: Myth or reality? J Neurol 2009;256:898-903.  Back to cited text no. 8
Donaldson D, Rosenberg NL. Infarction of abducens nerve fascicle as cause of isolated sixth nerve palsy related to hypertension. Neurology 1988;;38:1654. doi: 10.1212/wnl. 38.10.1654.  Back to cited text no. 9
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;33:333-4.  Back to cited text no. 10
Ogawa K, Tougou M, Oishi M, Kamei S, Mizutani T. A case of pontine infarction causing alternating hemiplegia with ipsilateral abducens nerve palsy and contralateral supranuclear facial nerve palsy. Clin Neurol 2008;;48:135-8.  Back to cited text no. 11
Ogawa K, Suzuki Y, Kamei S. Two patients with abducens nerve palsy and crossed hemiplegia (Raymond syndrome). Acta Neurologica Belgica 2010;110:270-1.  Back to cited text no. 12
Satake M, Kira JI, Yamada T, Kobayashi T. Raymond syndrome (alternating abducent hemiplegia) caused by a small haematoma at the medial pontomedullary junction. J Neurol Neurosurg Psychiatry 1995;58:261. doi: 10.1136/jnnp. 58.2.261.  Back to cited text no. 13
Lui F, Tadi P, Anilkumar AC. Wallenberg syndrome. [Updated 2019 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019. Available from: https://www.ncbi. nlm.nih.gov/books/NBK470174.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]


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