Formation of a Large Fusiform Aneurysm near a Medullary Infarction Caused by Dissection of the Posterior Inferior Cerebellar Artery.

Infarction of the posterior inferior cerebellar artery (PICA) can lead to ischemic stroke in the lateral medullary oblongata. PICA dissection can also elicit an ischemic event in this region, but its detection on radiological images is difficult because of the small diameter of the vessel. We report a case of Wallenberg syndrome due to PICA dissection in a 48-year-old man, which was difficult to diagnose on first admission. He reported sudden onset of sensory disturbance on the right side of his face, ataxic gait, and headache. Brain magnetic resonance imaging (MRI) revealed a fresh cerebral infarct in the right lateral medulla oblongata. Magnetic resonance angiography (MRA) performed at the time of his admission showed no cerebral vessel abnormalities. An MRI study 18 months after the event revealed a fusiform aneurysm on the lateral medullary segment of the PICA, which was extremely close to the cerebral infarct. We concluded that the infarct was due to PICA dissection because of the sudden onset of symptoms and because the infarcted territory of the occluded penetrating branch of the dissecting aneurysm was consistent with Wallenberg syndrome. The aneurysm was trapped and an occipital artery-PICA bypass was placed. At the latest follow-up, 1 year after the procedure, he had no neurological symptoms. Imaging findings at the time of his first admission indicated that the PICA was intact. However, 18 months later, MRI revealed enlargement of an aneurysm at the site of the dissection. A cerebral infarct with headache may indicate PICA dissection.

Topographic Consideration on the Occurrence of Ipsilesional Facial Paresis in Lateral Medullary Infarction.

INTRODUCTION: The purpose of this study was to identify course of the corticobulbar tract and factors associated with the occurrence of facial paresis (FP) in lateral medullary infarction (LMI). METHODS: Patients diagnosed with LMI who were admitted to tertiary hospital were retrospectively investigated and divided into two groups based on the presence of FP. FP was defined as grade 2 or more by the House-Brackmann scale. Differences between the two groups were analyzed with respect to anatomical location of the lesions, demographic data (age, sex), risk factors (diabetes, hypertension, smoking, prior stroke, atrial fibrillation, and other cardiac risk factors for stroke), large vessel involvement on magnetic resonance angiography, other symptoms and signs (sensory symptoms, gait ataxia, limb ataxia, dizziness, Horner syndrome, hoarseness, dysphagia, dysarthria, nystagmus, nausea/vomiting, headache, neck pain, diplopia, and hiccup). RESULTS: Among 44 LMI patients, 15 patients (34%) had FP, and all of them had ipsilesional central-type FP. The FP group tended to involve upper (p < 0.0001) and relative ventral (p = 0.019) part of the lateral medulla. Horizontally large lesion was also related to the presence of FP (p = 0.044). Dysphagia (p = 0.001), dysarthria (p = 0.003), and hiccups (p = 0.034) were more likely to be accompanied by FP. Otherwise, there were no significant differences. CONCLUSION: The results of present study indicate that the corticobulbar fibers innervating the lower face decussate at the upper level of the medulla and ascend through the dorsolateral medulla, where the concentration of the fibers is densest near the nucleus ambiguus.

Sinus arrest following acute lateral medullary infarction.

Lateral medullary syndrome (LMS) is an ischemic stroke of the medulla oblongata that involves the territory of the posterior inferior cerebellar artery. LMS is often missed as the cause of autonomic dysregulation in patients with recent brain stem stroke. Due to the location of the nucleus tractus solitarius (NTS), the dorsal vagal nucleus, and the nucleus ambiguous in the lateral medulla oblongata, patients with LMS occasionally have autonomic dysregulation-associated clinical manifestations. We report a case of LMS-associated autonomic dysregulation. The case presented by recurrent syncope, requiring permanent pacemaker placement. This case shows the importance of recognizing LMS as a potential cause of life-threatening arrhythmias, heart block, and symptomatic bradycardia. Extended cardiac monitoring should be considered for patients with medullary strokes.

Vocal cord paresis on CTA - A novel tool for the diagnosis of lateral medullary syndrome.

BACKGROUND: Diagnosis of lateral medullary syndrome (LMS) is often delayed due to elusive clinical presentations and frequently non-revealing neuroimaging tests. We aimed to investigate the use of ipsilateral vocal cord paresis (VCP) identified on neck computed tomography angiography (CTA) as an early diagnostic sign for LMS. METHODS: Medical records were queried for patients admitted with LMS between 1/2012 and 10/2020. A control group of patients undergoing CTA for transient or no neurological symptoms was matched for sex and age. Clinical data were collected by a stroke neurologist. Two neuroradiologists independently and blindly assessed CTA images for radiological signs of VCP. RESULTS: Fifteen LMS and 15 control patients were included in the analysis. Median time from arrival to LMS diagnosis was 29.4 h [IQR 7,47] and twice as long in patients who suffered aspiration pneumonia. Thrombolysis rate was 0% in LMS patients versus 14.5% in general stroke patients. Dysphonia was noted in the emergency department in three (20%) patients, whereas all 15 patients had radiological signs of VCP on CTA. Medialization of a true vocal cord was the most sensitive (100%) and specific (80-87%) sign for LMS, with good inter-rater agreement (kappa 0.66). Timely detection of VCP on CTA could have shortened median time to LMS diagnosis by 14 h and enabled thrombolytic therapy in 3 (20%) patients. CONCLUSIONS: VCP on CTA is a valuable sign for the diagnosis of LMS. If detected early, it may enable reperfusion therapy and prevent aspiration pneumonia, consequently saving life and diminishing disability.

Clinical and Radiological Characteristics Associated with Respiratory Failure in Unilateral Lateral Medullary Infarction.

BACKGROUND: The prognosis for unilateral lateral medullary infarction (ULMI) is generally good but may be aggravated by respiratory failure with fatal outcome. Respiratory failure has been reported in patients with severe bulbar dysfunction and large rostral medullary lesions, but its associated factors have not been systematically studied. We aimed to assess clinical and radiological characteristics associated with respiratory failure in patients with pure acute ULMI. MATERIALS AND METHODS: Seventy-one patients (median age 55 years, 59 males) with MRI-confirmed acute pure ULMI were studied retrospectively. Clinical characteristics were assessed and bulbar symptoms were scored using a scale developed for this study. MRI lesions were classified into 4 groups based on their vertical extent (localized/extensive) and the involvement of the open and/or closed medulla. Clinical characteristics, bulbar scores and MRI lesion characteristics were compared between patients with and without respiratory failure. RESULTS: Respiratory failure occurred in 8(11%) patients. All patients with respiratory failure were male (p = 0.336), had extensive lesions involving the open medulla (p = 0.061), progression of bulbar symptoms (p=0.002) and aspiration pneumonia (p < 0.001). Peak bulbar score (OR, 7.9 [95% CI, 2.3-160.0]; p < 0.001) and older age (OR, 1.2 [95%CI, 1.0-1.6]; p=0.006) were independently associated with respiratory failure. CONCLUSIONS: Extensive damage involving the open/rostral medulla, clinically presenting with severe bulbar dysfunction, in conjunction with factors such as aspiration pneumonia and older age appears to be crucial for the development of respiratory failure in pure ULMI. Further prospective studies are needed to identify other potential risk factors, pathophysiology, and effective preventive measures for respiratory failure in these patients.

Severe Unilateral Proprioceptive Loss in Medullary- Rostral Spinal Cord Infarction. A Posterior Spinal Artery Syndrome.

We draw attention to a unique presentation, severe unilateral loss of limb proprioception, in patients with medullary and rostral spinal cord infarction. Two patients developed acute severe proprioceptive loss in the limbs ipsilateral to infarcts that involved the caudal medulla and rostral spinal cord. They also had symptoms and signs often found in lateral medullary infarction. The proprioceptive loss is attributable to injury to the gracile and cuneate nuclei and/or their projections to the medial lemniscus. The infarct territory is supplied by the posterior spinal branches of the vertebral artery near its penetration into the posterior fossa. The presence of severe ipsilateral proprioceptive loss in a patient with features of lateral medullary infarction indicates involvement of the rostral spinal cord.

Posterior circulation stroke presenting as a new continuous cough: not always COVID-19.

A 19-year-old man was admitted with a 2-week history of continuous cough along with a day history of acute onset unsteadiness and hiccups. Given the current pandemic, he was initially suspected to have COVID-19, however he tested negative on two occasions. Subsequent brain magnetic resonance imaging (MRI)confirmed a small left acute and subacute lateral medullary infarction with chest X-ray suggesting aspiration pneumonia with right lower lobe collapse. This is a distinctive case of posterior circulation stroke presenting with a new continuous cough in this era of COVID-19 pandemic. We anticipate based on MRI findings that his persistent cough was likely due to silent aspiration from dysphagia because of the subacute medullary infarction. It is therefore imperative that healthcare workers evaluate people who present with new continuous cough thoroughly to exclude any other sinister pathology. We should also be familiar with the possible presentations of posterior circulation stroke in this pandemic era.

An Atypical Presentation of Left Lateral Medullary Syndrome - A Case Report.

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.

Lateral Medullary Syndrome Following Injury of Lateral Vestibulospinal Tract: Diffusion Tensor Imaging Study.

BACKGROUND: Unilateral lesions of vestibular nucleus can cause lateral medullary syndrome. Little is known about injury of medial and lateral vestibulospinal tract (VST) after dorsolateral medullary infarct. We investigated injury of the lateral VST in patients with typical central vestibular disorder using diffusion tensor tractography (DTT). METHODS: Seven patients with lateral medullary syndrome and ten control subjects were recruited. For the medial VST, we determined seed region of interest (ROI) as medial vestibular nuclei of pons and target ROI on posteromedial medulla. For the lateral VST, the seed ROI was placed on lateral vestibular nuclei of pons, and the target ROI on posterolateral medulla. Fractional anisotropy (FA), mean diffusivity (MD), and tract volume were measured. RESULT: Reconstructed lateral VST on both sides had significantly lower FA values in patients than controls (p<0.05). Tract volume of lateral VST in affected side was significantly lower than unaffected side and control group (p<0.05). However, no DTI parameters of the medial VST differed between patients and controls (p>0.05). CONCLUSION: Injury of the lateral VST was demonstrated in patients with lateral vestibular syndrome following dorsolateral medullary infarct. Analysis of the lateral VST using DTT would be helpful in evaluation of patients with lateral medullary syndrome.

Injury of the lateral vestibulospinal tract in a patient with the lateral medullary syndrome: Case report.

RATIONALE: Lateral medullary syndrome is a central vestibular disorder characterized by vertigo and ataxia. We report on a patient with injury of the lateral vestibulospinal tract (VST) following lateral medullary syndrome, detected on diffusion tensor tractography (DTT). PATIENT CONCERNS: A 56-year-old male patient was diagnosed with lateral medullary syndrome due to an infarction in the posterior inferior cerebellar artery area. DIAGNOSES: Two weeks following the infarction, he was transferred to the rehabilitation department of the same university hospital with severe vertigo, ataxia (Berg balance scale: 16 point), and dysphasia. In contrast, he maintained good motor power and cognitive function (Mini-mental state test: 26 points). INTERVENTIONS: N/A OUTCOMES:: Both the patient's medial VSTs and left lateral VST were well-reconstructed. In contrast, the right lateral VST was not reconstructed. On DTT parameters of the VST, the patient's medial VSTs and left lateral VST did not differ significantly from the control subjects. LESSONS: An injury of the right lateral VST was demonstrated in a patient with lateral medullary syndrome. We believe that the result will be helpful in clinical management and research for patients with lateral medullary syndrome.