Paramedian Thalamic Infarction Research Articles

Anatomical Variations in the Posterior Part of the Circle of Willis and Vascular Pathology in Bilateral Thalamic Infarction

Bilateral paramedian thalamic infarction is a rare subtype of stroke the etiology of which still remains undetermined in many patients. From a computed tomography (CT)/magnetic resonance imaging report database, we identified and analyzed 48 patients with bilateral paramedian thalamic infarction on diffusion-weighted imaging. Vascular pathologies were noted on CT angiography (CTA)/magnetic resonance angiography (MRA) and the P1 segments of the posterior cerebral artery (PCA) described as normal, hypoplastic, or absent. Vascular imaging revealed top of the basilar artery (BA) occlusion in 6 (12.5%), BA occlusion in 4 (8.3%), BA stenosis in 1 (2.1%), and BA hypoplasia in 3 (6.3%), PCA occlusion in 4 (8.3%), and PCA stenosis in 4 (8.3%) patients. In 18 (37.5%) patients, one or both P1 segments of the PCA were hypoplastic or absent. Patients with hypoplastic/absent P1 segments were more likely to have exclusively bilateral paramedian thalamic lesions (P < .001). An embolic source could be identified in 25 (55.6%) patients; there were no significant differences between both groups. Vascular imaging is useful to determine underlying vascular pathologies and may support the diagnosis of small vessel disease in those patients with isolated bilateral paramedian thalamic infarction, hypoplastic/absent P1 segment of the PCA, and lack of vascular pathology.

BILATERAL PARAMEDIAN THALAMIC AND MIDBRAIN INFARCTION: A Case Report

Background: Bilateral paramedian thalamic and midbrain infarct is rare and present with varying symptoms. The occlusion of a rare arterial variant called the artery of Percheron results in bilateral thalamic infarcts, with or without midbrain involvement. To this date, the diagnosis of ischemic infarction due to occlusion of the artery of Percheronhas was uncommon. Case: We reports a 50 year-old man with acute ischemic infarcts of both paramedian thalami and midbrain, presenting with complete ophthalmoplegia, arreactive mydriasis pupils, and altered mental status (somnolent and fluctuating hypersomnia). Conclusions: Based on clinical and neuroimaging findings, we concluded this case as acute ischemic infarctions due to occlusion of the artery of Percheron.

Bilateral thalamic infarct as a diagnosed conversion disorder

Bilateral thalamic infarcts are an uncommon type of cerebral infarct. Bilateral paramedian thalamic infarctions may lead to a severe impairment of consciousness. The sudden onset of a lethargy or comatose state, in the absence of motor deficits, easily evokes the idea of a subarachnoid hemorrhage. Other patients present with behavior changes, disorientation in space and time, memory loss, or thought disorders. We believe that bilateral thalamic infarction is often missed in emergency department (ED) in relatively young patients, especially when magnetic resonance imaging is not performed. In these cases, the patient can be discharged with various psychiatric diagnoses. We suggest that bilateral thalamic infarct should be considered in patients in the ED with new diagnoses of conversion disorder.

Bilateral Paramedian Thalamic Infarction Initially Presenting as a Convulsive Seizure

Bithalamic infarctions initially presenting as a convulsive seizure are rarely reported and, to our best knowledge, have never been reported in China. Here, we present a patient with convulsive seizure at the onset of bilateral paramedian thalamic infarction. The diffusion-weighted imaging revealed that the infarct area is supplied by Percheron artery. Associated with the relationship between seizure and centrencephalic system and reticular formation as previously reported, we suggest that seizure could be the onset symptom of paramedian thalamic infarction. Physicians should recognize this condition, because both seizure control and early ischemic stroke management are required.

Unusual Clinical Presentations and Mechanism of Bilateral Thalamic Infarcts: A Case Series (P06.250)

Objective: To highlight the breadth of clinical syndromes and mechanisms of artery of Percheron territory strokes. Background Simultaneous bilateral thalamic infarction represents a relatively rare stroke syndrome. The underlying vascular anatomy often suspected in these cases is a variant of the posterior circulation first described by Percheron in 1975, wherein the paramedian thalami as well as rostral midbrain structures are supplied by a single arterial branch of the proximal posterior cerebral artery. The artery of Percheron, though difficult to visualize even with conventional angiography, may be present in as many as one third of patients. Pathophysiologically, these strokes can be attributed to athero- or thromboembolic phenomena, or result from hypoperfusion due to poor cardiac output. The classical clinical presentation is described as a triad of hypersomnolence, amnesia, and vertical gaze paresis. However, in practice, presentations can be far more variable, with a myriad of cognitive and behavioral changes in addition to eye findings, representing a challenge to the clinician in terms of both lesion localization and determination of etiology. Design/Methods: Case series. Data collected from chart review, serial neurologic examinations. Results: We present a series of three cases of bilateral paramedian thalamic infarcts. In one, we report for the first time an association with WEBINO (wall-eyed bilateral internuclear ophthalmoplegia) syndrome, itself a rare phenomenon with fewer than 20 cases reported in the English literature.We describe another patient with unilateral oculomotor nerve palsy, an unusual stroke presentation. Finally, we present a patient with amnesia and behavioral changes whose stroke occurred in the setting of atrial myxoma. Conclusions: Patients with artery of Percheron territory strokes may present with unusual clinical findings that can confound the diagnosis and potentially delay treatment. The protean clinical presentation represents a challenge to the clinician with respect to lesion localization and etiology. Disclosure: Dr. Manchak has nothing to disclose. Dr. Odrzywolski has nothing to disclose. Dr. Kelly has nothing to disclose. Dr. Benesch has nothing to disclose.

意識障害で発症し, 顔面, 下肢の感覚障害と味覚障害を呈した両側性傍正中視床梗塞の1小児例

意識障害で発症し, 顔面, 下肢の感覚障害と味覚障害を呈した両側性傍正中視床梗塞の1小児例

Occlusion de l’artère de Percheron : difficultés du diagnostic clinique et place de l’IRM. À propos de six cas

Blood supply to the human thalami is complex and multiple variants exist. The artery of Percheron is one of those variants and is characterized by a solitary arterial trunk that branches from one of the proximal segments of either posterior cerebral artery and supplies blood to the paramedian thalami. Its occlusion results in bilateral paramedian thalamic infarction sometimes extending to the midbrain. We report six cases of bithalamic infarction secondary to occlusion of the artery of Percheron. We will illustrate the complex clinical symptomatology and underscore the role of imaging, especially MRI, for diagnosis.

Neuropsychological profile of bilateral paramedian infarctions: Three cases

Introduction: The thalamus is one of the strategic diencephalic structures of the human brain. The artery of Percheron, an asymmetrical common trunk arising from a P1 segment of the posterior cerebral artery, is a peculiar presentation of the three variants involved in the irrigation of the paramedian thalamic territory. Occlusion of this artery results in bilateral median thalamic infarction. The paramedian syndrome includes an acute loss or reduction of consciousness, often associated with oculomotor and neuropsychological disturbances. Patients and methods: We present three cases of bilateral paramedian thalamic infarction with onset of acute coma, followed by fluctuations in the level of consciousness, memory, and behavioural alterations. A neuroradiological study with MRI identified individual thalamic nuclei, and a complete neuropsychological study was performed one month after onset of ictus. Results: One of the patients showed severe memory and executive function impairments without improvement of vertical gaze palsy. The other two patients presented with mild executive dysfunction with complete resolution of neurological symptoms. Neuroimaging results showed a bilateral lesion of the dorsomedial nuclei in the three patients. Conclusions: Severe amnesia has been associated with an affection of the structures of the paramedian thalamic territory. Presently, the role of the dorsomedial nucleus remains controversial, with the suggestion that memory deficits observed in this type of lesion could be secondary to executive function deficits. In our case, the patient with the most severe dysexecutive deficit presented the most severe memory impairments.

A Case of Transient Hypersomnia with Increased Slow Wave Sleep after Unilateral Paramedian Thalamic Infarction

Received June 7, 2011 Revised June 10, 2011 Accepted June 20, 2011 Address for correspondence Jee Hyun Kim, MD, PhD Department of Neurology, Dankook University College of Medicine, 359 Manghyang-ro, Dongnam-gu, Cheonan 330-715, Korea Tel: +82-41-550-3292 Fax: +82-41-550-6245 E-mail: fever26@paran.com Paramedian thalamic stroke is known to be associated with hypersomnia, usually with bilateral lesions. We report a case of one patient who developed transient hypersomnia after unilateral paramedian thalamic infarction. A 79-year-old female patient with right paramedian thalamic infarction presented with left hemiparesis and hypersomnia. A night polysomnogram, 10 days after symptom onset, showed increased slow wave sleep and the presence of slow wave sleep throughout the entire night. Hypersomnia improved 7 weeks after the onset of symptom. J Korean Sleep Res Soc 2011;8:20-23

Improvement of sleep architecture in the follow up of a patient with bilateral paramedian thalamic stroke

Normal sleep architecture and arousal require an intact thalamus. Thalamic vascular lesions, particularly in the paramedian region may cause arousal disturbances and hypersomnolence. Although hypersomnolence is one of the main characteristics of acute bilateral paramedian thalamic infarcts, there are only scarce reports in literature concerning polysomnographic follow-up of these patients. The few reported cases in literature show that sleep stages do not significantly change from the acute to chronic phase. We present a case report of a patient with a bilateral paramedian thalamic infarct in which a polysomnographic evaluation of sleep was performed four days and five months after stroke. In the acute phase, polysomnography showed an impairment of phase 2 NREM and absence of phase 3 and 4 NREM with absent sleep spindles. After the acute stroke phase, hypersomnolence improved and sleep spindles reappeared as well as phase 3 and 4 of NREM sleep. Our patient clear clinical and polysomnographic improvement makes us suppose that in this case the initial impairment could have been essentially due to a functional transitory impairment of the thalamocortical and corticothalamic connections. This case report is peculiar because it discloses a marked improvement of sleep architecture which to the best of our knowledge has not been clearly described before.

Bilateral thalamic stroke transiently reduces arousals and NREM sleep instability

The vascularization of the human thalami is supplied by many perforating arteries, which exhibit complex distribution and many possible individual variations. One rare variant is the artery of Percheron that supplies the paramedian thalami bilaterally. Its ictal occlusion may result in a symmetric paramedian infarction, which generally leads to impairment of consciousness associated with hypersomnia. Our aim is to describe in detail sleep–wake schedules, sleep structure and microstructure in a 68-year-old patient with occlusion of Percheron's artery. EEG monitoring, performed 24 h after the onset of symptoms, showed severe disruption of the sleep–wake cycle, with episodes of sleep and wakefulness recurring irregularly during day and night. Thalamic nuclei are part of the human arousal system; medial thalamic nuclei play a pivotal role in sleep regulation at different levels. A diagnosis of paramedian thalamic infarction should be considered in patients who present with recurrent episodes of unresponsiveness.

Bilateral Paramedian Thalamic Artery Infarcts: Report of 10 Cases

The paramedian thalamic arteries can arise as a pair from each P1 of the posterior cerebral artery, but they may also arise equally from a common trunk off one P1, thus supplying thalamus bilaterally. Such a common trunk is called the artery of Percheron and supplies the mesial aspects of both thalami and the rostral midbrain. This is a retrospective review of 1,253 consecutive patients with ischemic stroke enrolled in a stroke registry within an 8-year period (January 2001-December 2008). All were evaluated with detailed clinical and neuropsychological evaluation, magnetic resonance imaging (MRI), blood studies, electrocardiogram, and transthoracic echocardiography. All standard risk factors were recorded in these patients. Ten patients (0.7%) in this series presented with a first-ever thalamic stroke demonstrating bilateral paramedian thalamic lesions on MRI. The main cause of bilateral paramedian thalamic infarctions was small artery disease (60%), followed by cardioembolism (40%). A well-defined clinical picture is shown in bilateral paramedian thalamic artery infarcts. These patients had disorder's consisting of consciousness, memory dysfunctions, various types of vertical gaze paresis, and psychological changes. Although neurologic deficits and hypersomnia recovered to large extent in patients with paramedian thalamic infarcts, cognitive deficits that were mainly linked with bilateral and left-sided lesions often persisted. Vertical gaze paresis tended to improve and never seriously disturbed the patient's activities. We believe that these kinds of strokes have been commonly overlooked, especially without widespread use of MRI.

Bilateral thalamic infarctions due to occlusion of artery of Percheron

The artery of Percheron is an uncommon anatomic variant in which a solitary trunk originates from either posterior cerebral artery and provides arterial supply to bilateral paramedian thalami and the rostral midbrain (Fig. 1). Recognition of this anatomical variant is essential in establishing the stroke mechanism in bilateral paramedian thalamic infarcts. We describe the clinical presentation and neuroimaging characteristics in a patient with bilateral thalamic infarctions due to occlusion of the artery of Percheron.

MR Imaging of Bilateral Paramedian Thalamic and Mesencephalic Infarcts

We describe MR imaging of bilateral infarction of the paramedian portion of the mesencephalus and thalamus due to an occlusion of the Percheron artery. This entity is due to one of the anatomic variants of the perforating arteries supplying the thalamus and mesenchephalus. Clinically this kind of infarction presents with neurologic impairment as a disorder of consciousness, memory dysfunctions, various types of vertical gaze palsy and psychic changes, which need to be differentiated from delirium and coma. At MRI evaluation infarction of the paramedian portion of thalami and midbrain, with a "butterfly wings" pattern, was demonstrated as high signal intensity areas on FLAIR and FSE-T2W images and with diffusion restriction on DWI images.

Ischemic Stroke of the Artery of Percheron with Normal Initial MRI: A Case Report

The artery of Percheron is a solitary trunk representing an uncommon anatomic variant that provides bilateral arterial supply to the paramedian thalami and the rostral midbrain. Occlusion of this artery results in bilateral thalamic and mesencephalic infarctions. The clinical diagnosis is difficult because the complex anatomy causes large clinical variability. We report a case of a comatose patient with normal early head-computed tomography and magnetic resonance imaging. A bilateral paramedian thalamic infarct due to an occlusion of the artery of Percheron was revealed two days later by a new head computed tomography. To our knowledge, this is the first report in the literature of a symptomatic patient presenting an acute Percheron stroke with normal early brain magnetic resonance imaging. Our case indicates that a normal initial magnetic resonance imaging cannot formally eliminate the diagnosis of acute stroke of the artery of Percheron. We discuss the causes of noncontributive brain magnetic resonance imaging at the onset of this acute Percheron stroke and the alternative diagnosis and therapy methods.

Persistent Akinetic Mutism After Bilateral Paramedian Thalamic Infarction

Back to table of contents Previous article Next article LETTERFull AccessPersistent Akinetic Mutism After Bilateral Paramedian Thalamic InfarctionAndrea Eugenio Cavanna M.D.,Luca BerteroStefano Cavanna,Serena Servo M.D.Gionata Strigaro M.D.Francesco Monaco M.D.,Andrea Eugenio Cavanna M.D.Search for more papers by this author,Luca BerteroSearch for more papers by this authorStefano CavannaSearch for more papers by this author,Serena Servo M.D.Search for more papers by this authorGionata Strigaro M.D.Search for more papers by this authorFrancesco Monaco M.D.Search for more papers by this author,Published Online:1 Jul 2009AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: Akinetic mutism is a pathological condition characterized by lack of spontaneous movements with little or no vocalization in subjects with intact corticospinal pathways. 1 This condition was first described in patients who suffered diencephalic damage, and current evidence indicates that it is a transient state resulting from lesions that interfere with reticular/cortical integration. 2 We present a rare case of persistent akinetic mutism after bilateral paramedian thalamic infarction. Case ReportS.I., an 81-year-old man without any significant previous medical history, was admitted to the Department of Neurology at Amedeo Avogadro University in Novara, Italy, after the acute onset of bilateral thalamic infarct. On admission he presented with a sleep-like state, respiratory failure, unresponsiveness, and double incontinence. While he was physically and emotionally active before stroke, he became apathetic, aspontaneous, indifferent, and seemed to have lost motor and affective drive, as well as the need itself for any psychic activity. A brain CT and MRI, performed on admission and during the following week, showed bilateral ring-shaped signal alterations in the paramedian thalamic regions with the right one being characterized by major dimension. The signal hyperintensity in long TR sequences and the hypointensity in T1 sequences were consistent with right paramedian artery territory infarction and contralateral territory involvement, which presumably led to ischemic lesions of paramedian and intralaminar nuclei. Electroencephalographic recordings demonstrated diffuse cortical slowing associated with epileptiform discharges. During hospitalization, the patient showed no sign of recovery, with the exception of normal sleep-waking cycle. At 6-month and 1-year follow-up visits he still met Cairns’ criteria for akinetic mutism.Discussion Bilateral thalamic infarcts are uncommon, as they represent about 0.6% of first ever acute stroke. 3 The most common clinical picture associated with bilateral paramedian thalamic artery infarction includes coma, loss of consciousness or somnolence at stroke onset, followed by transient concentration and orientation deficits, and memory dysfunctions (thalamic dementia). More rarely, small bilateral thalamic lesions can also lead to the clinical pictures of akinetic mutism (failure to respond to relevant stimuli) and athymhormia (“loss of psychic self-activation”). 2 – 4 Akinetic mutism is usually a transient condition, whereas with both thalamic dementia and athymhormia there is less of a chance of recovery. In our patient, the damage extended from the paramedian to intralaminar nuclei, possibly leading to permanent disruption of higher-level thalamocortical integration pathways controlling consciousness, without affecting the core of pontine tegmentum, whose damage is selectively associated with coma. 5 On the other hand, the circuitry from intralaminar thalamic nuclei to the prefrontal cortex and back to the nucleus reticularis has been suggested to serve as a gate control, selectively preparing the aroused organism for responses to meaningful stimuli. 6Department of Neurology, Amedeo Avogadro University, Novara, Italy; Institute of Neurology, UCL, LondonUniversity of Turin Medical School, Turin, ItalyDepartment of Neurology, Amedeo Avogadro University, Novara, Italy

Behavioral changes caused by diencephalic lesion

The core behavioral abnormalities of the paramedian thalamic infarct are a state of somnolence and abulia accompanied by amnesia and a ‘frontal brain’ syndrome. In addition to these findings, chronic amnesia, distractibility, hyperorality, affective dyscontrol, socially inappropriate behavior, and mood changes have been reported in some case studies. Sexual disinhibition and uncontrolled eating behavior are traditionally believed to be related to the lesion. We describe the case of the patient, who suffered a MR-documented ischemic lesion of left paramedian thalamus.

Persistent Akinetic Mutism After Bilateral Paramedian Thalamic Infarction

Persistent Akinetic Mutism After Bilateral Paramedian Thalamic Infarction

Bilateral paramedian thalamic and mesencephalic infarcts after basilar tip aneurysm coiling: role of the artery of Percheron

Bilateral paramedian thalamic and mesencephalic infarcts after basilar tip aneurysm coiling: role of the artery of Percheron

Acute bilateral thalamic infarction as a cause of acute dementia and hypophonia after occlusion of the artery of Percheron

The thalami of the human brain obtain their blood supply from many perforating arteries, which exhibit complex distribution and many variations. One rare variation is the artery of Percheron that supplies the paramedian thalami bilaterally. This artery arises from the first segment of the posterior cerebral artery and gives rise to bilateral medial thalamic perforants. Occlusion of the artery of Percheron none rarely results in bilateral thalamic and mesencephalic infarctions. We describe the case of a 38-year-old male patient with a presumed occlusion of this artery in which MR imaging revealed characteristic symmetrical bilateral paramedian thalamic infarctions. The unique characteristics of this case are based on the young age of the patient, the absence of any risk factors or other diseases and even more on the rare clinical manifestations consisted of hypophonia, memory dysfunction, time disorientation and apathy.