Artery of Percheron infarction as an unusual cause of coma: three cases and literature review

Wasp sting-induced bilateral thalamic and midbrain infarction

A male patient in his early 40s presented to the emergency department with an acute onset of respiratory distress and facial oedema, indicative of anaphylaxis. These symptoms emerged 2 hours subsequent to a wasp sting on the left side of his face. Despite initial stabilisation, the patient's state deteriorated into somnolence and disorientation. Notably, he denied any history of seizures, sensory or motor deficits, or bowel/bladder complications. Physical examination unveiled no focal neurological deficits. Routine laboratory tests and drug screening yielded no significant findings. Subsequent brain MRI with angiography exposed bilateral thalami diffusion restriction, strongly implying an acute infarction within the artery of Percheron territory, an atypical vascular variant. The sequence of events, alongside the absence of other conclusive aetiologies, indicated a wasp sting-induced thalamic infarction driven by vasogenic and thrombogenic effects of inflammatory substances.

Artery of Percheron Infarction: A Rare But Important Cause of Bilateral Thalamic Stroke

Artery of Percheron infarction is a serious but rare condition that can result in acute bilateral thalamic infarction and a wide range of neurological symptoms. It occurs due to occlusion of the single arterial branch that supplies the medial thalamus and rostral midbrain bilaterally. In this case report, we describe a 58-year-old female with a history of hypertension and hyperlipidemia who presented with sudden confusion, speech difficulties, and right-sided weakness. An initial CT scan showed ill-defined hypodensity in the left internal capsule, which, when combined with the clinical features, suggested acute ischemic stroke. The patient received an IV tissue plasminogen activator within the recommended time window. Several days later, repeated imaging showed bilateral thalamic hypodensity consistent with subacute infarction in the territory of the artery of Percheron. The patient was subsequently discharged to a rehabilitation facility for further recovery and rehabilitation with residual mild hemiparesis. It is important for healthcare providers to maintain a high index of suspicion for the artery of Percheron infarction and be aware of its potential to cause acute bilateral thalamic infarction and a variety of neurological symptoms.

Endovascular intervention for bilateral paramedian thalamic stroke due to occlusion of the unilateral P1 segment of the posterior cerebral artery: illustrative cases

BACKGROUND

Occlusion of the unilateral P1 segment can result in bilateral paramedian thalamic infarction in patients with anatomical variants of the bilateral paramedian thalamic artery arising from a single P1 segment. Despite the life-threatening presentation of bilateral paramedian thalamic stroke, timely diagnosis is often challenging.

OBSERVATIONS

The authors herein describe 3 patients treated with endovascular intervention for occlusion of the unilateral P1 segment wherein the bilateral paramedian thalamic arteries arose. All patients were admitted to the authors' emergency department with sudden-onset coma and respiratory distress; however, initial computed tomography was unremarkable. Despite suspicion of basilar artery occlusion, vertebral and carotid angiography revealed occlusion of the unilateral P1 segment. All patients were successfully treated with endovascular intervention. Overall, 2 patients had favorable outcomes (modified Rankin scale [mRS] scores of 0 and 1), whereas in 1 patient, the mRS score reached a baseline score of 3.

LESSONS

In patients with the variant of the bilateral paramedian thalamic artery arising from a single P1 segment, occlusion of the unilateral P1 segment can be life threatening; nevertheless, timely endovascular treatment is effective. Carotid and vertebral angiography, rather than magnetic resonance or computed tomography angiography, is useful for immediate and reliable diagnosis of the relatively small vascular lesions.

Artery of Percheron Occlusion in China: A Case Report and Chinese Literature Review

INTRODUCTION

The artery of Percheron (AOP) is a rare anatomical variant in which bilateral paramedian thalami are supplied by a single vascular branch arising from the P1 segment of the posterior cerebral artery. We present a case of AOP occlusion presenting as loss of consciousness and summarize the literature in Chinese to find the clinical characteristics.

CASE REPORT

An 83-year-old woman was found unconscious for 1 day at home and was sent to the hospital the next day. Cerebral magnetic resonance imaging on day 1 of the patient showed a recent bilateral paramedian thalamic infarction. Simultaneously, magnetic resonance angiography found evident artery stenosis of the right P1 segment of the posterior cerebral artery, suggesting that the patient was diagnosed with AOP occlusion. Since the patient has missed the best time for thrombolytic therapy, anticoagulant therapy was given immediately; as the patient was then found to have pulmonary infections, antibiotic therapy was also initiated. The neurological status of this patient improved very slow. In about 2 weeks, the patient becomes more conscious but still could not speak or move.

CONCLUSION

Our report suggests that unusual mood disorder and language disorder of aged patients might indicate the AOP occlusion, and cerebral imaging of magnetic resonance imaging (better with magnetic resonance angiography) should be performed to establish the diagnosis of AOP occlusion. The fast and accurate diagnosis of stroke because of AOP occlusion could best benefit the patients.

Intravenous thrombolytic therapy for cerebral infarction due to the Persheron artery occlusion. Case report

Occlusion of the artery of Percheron is the cause of bilateral thalamic infarctions, sometimes involving structures of the midbrain. A clinical case of intravenous thrombolytic therapy for ischemic stroke due to the occlusion of the Percheron artery in a 72-year-old female patient who developed depression of consciousness, oculomotor disorders, dysarthria, ataxia, pyramidal disorders, and cognitive disorders is presented. Magnetic resonance imaging, which detected bilateral thalamus paramedian infarction in the acute stage, made it possible to diagnose the occlusion of the Percheron artery. Intravenous thrombolysis led to a rapid regression of symptoms; at the end of the acute period of the disease, the patient was discharged from the hospital with a slight neurological deficit and with a good functional outcome. After a one year the dynamic observation revealed persistent mild cognitive disorders; magnetic resonance imaging showed small symmetric cystic-gliosis changes in the medial parts of the thalamus on both sides. Timely diagnosis and intravenous thrombolytic therapy contribute to a good outcome of cerebral infarction due to the Percheron's artery occlusion.

Frequency, clinical presentation and outcome of vigilance impairment in patients with uni- and bilateral ischemic infarction of the paramedian thalamus

Ischemic stroke of the paramedian thalamus is a rare differential diagnosis in sudden altered vigilance states. While efforts to describe clinical symptomatology exist, data on the frequency of paramedian thalamic stroke as a cause of sudden impaired vigilance and on accompanying clinical signs and outcome are scarce. We retrospectively analyzed consecutive patients admitted to a tertiary stroke center between 2010 and 2019 diagnosed with paramedian thalamic stroke. We evaluated frequency of vigilance impairment (VI) due to paramedian thalamic stroke, accompanying clinical signs and short-term outcome in uni- versus bilateral paramedian lesion location. Of 3896 ischemic stroke patients, 53 showed a paramedian thalamic stroke location (1.4%). VI was seen in 29/53 patients with paramedian thalamic stroke and in 414/3896 with any stroke (10.6%). Paramedian thalamic stroke was identified as causal to VI in 3.4% of all patients with initial VI in the emergency department and in 0.7% of all ischemic stroke patients treated in our center. Accompanying clinical signs were detected in 21 of these 29 patients (72.4%) and facilitated a timely diagnosis. VI was significantly more common after bilateral than unilateral lesions (92.0% vs. 21.4%; p < 0.001). Patients with bilateral paramedian lesions were more severely affected, had longer hospital stays and more frequently required in-patient rehabilitation. Paramedian thalamic lesions account for about 1 in 15 stroke patients presenting with impaired vigilance. Bilateral paramedian lesion location is associated with worse stroke severity and short-term outcome. Paying attention to accompanying clinical signs is of importance as they may facilitate a timely diagnosis.

Bilateral Thalamic Infarction Secondary to Thrombosis of Artery of Percheron

The artery of Percheron (AOP) is a rare anatomical variation emerging from the posterior circulation and supplies both thalami in the brain. As per the literature, the AOP infarction constitutes less than 2% of all stroke cases. AOP infarctions are usually caused by a combination of risk factors and a predisposing vascular territory. The areas most affected by AOP are the paramedian thalami with or without the involvement of the midbrain. AOP can be challenging as it is infrequent and mostly can be missed on the initial scans. We present a 58-year-old previously healthy male known to have hypertension with poor follow-up who presented with dysarthria and facial weakness, which he felt after waking up from sleep. After the initial physical examination and investigations, a preliminary diagnosis of stroke was made. As the patient was worked up for the stroke, his symptoms improved, and he was back to his baseline function within 48 hrs of presentation. What came to our surprise was that the stroke workup, including the initial CT scan with an angiogram, blood works (Hba1c and lipid panel), echocardiogram of the heart (ECHO), and Holter monitor was all unremarkable until an MRI head was done, which showed bilateral thalamic acute-sub acute infarct. This shows that AOP can be easily missed as it may not appear on the initial scans and workup and needs an adequate radiological study for diagnosis. Although some cases of AOP infarction are reported in the literature, the presentation with transient mild symptoms makes our case an interesting one.

A Case of Diagnostic Difficulty: Transient Loss of Consciousness in Artery of Percheron Infarct

The artery of Percheron (AOP) is a rare anatomical variant of the paramedian thalamic vessels in 7-10% of the general population. An AOP infarct can present with rare clinical manifestations like transient loss of consciousness (LOC) and lethargy, as was seen in the patient whose case is discussed in this report, due to the plethora of regulatory inputs and outputs by the thalamus, which cannot be compensated for because of the absence of anastomotic connections. The AOP supplies the reticular activating system (RAS), which regulates consciousness. Ischemia to this area from an AOP infarct can result in the transient LOC, which our patient experienced. The AOP is a small vessel that is often missed on a CT angiogram (CTA) alone due to low resolution. As a result, it is imperative that clinicians utilize MRI to diagnose AOP infarcts in patients who present with symptoms that raise concerns for decreased bilateral thalamic function and transient LOC.

Stroke masquerading as cardiac arrest: the artery of Percheron

The artery of Percheron (AOP) is a rare arterial variant of the thalamic blood supply. Due to the densely packed collection of nuclei it supplies, an infarction of the AOP can be devastating. Here we highlight a patient who had an AOP stroke in the community, which was initially managed as cardiac arrest. AOP strokes most often present with vague symptoms such as reduced conscious level, cognitive changes and confusion without obvious focal neurology, and therefore are often missed at the initial clinical assessment. This case highlights the importance of recognising an AOP stroke as a cause of otherwise unexplained altered consciousness level and the use of MRI early in the diagnostic work-up.

The time course of acute Percheron artery ischemic coma on imaging: A retrospective cohort study

We were to investigate the time course of lesions for awakening in acute Percheron artery ischemic coma (PAIC), which was previously unknown. Patients who had newly identified acute PAIC events in 2012-2015 and had not received thrombolytic therapy were enrolled retrospectively. The time course of lesions in PAIC was investigated by diffusion-weighted imaging (DWI). Ninety-three patients met the inclusion criteria, of whom 63 and 30 had transient PAIC and persistent PAIC, respectively. The time course of awakening events in persistent PAIC decreased over time, with large lesions in the bilateral paramedian thalamus/ rostral midbrain on DWI almost in all patients who was either plus or minus a "top of basilar artery" strokes. Whereas awakening events in transient PAIC increased over time, with small or lacunar lesions in the unilateral or bilateral thalamus/rostral midbrain about in 30.2 % cases, and the rest in naturally recanalization of infarcts or TIA. Lesion volumes were larger for persistent PAIC than for transient PAIC (median, 2.4 cm³ vs. 0.03 cm³, P < 0.0001). In Cox hazards ratio (HR) analysis, a lower GCS score was associated with mortality (HR, 5.5; 95 % confidence interval [CI],1.427-21.45). Multivaliate analysis shown that the predictors of higher risk of persistent PAIC were only increased NIHSS scores (HR,1.3; 95 % CI,1.109-1.640) and large lesions in bilateral thalamus/rostral midbrain (HR,15.0; 95 % CI,1.440-58.13). The time course of acute PAIC included transient and persistent. Most persistent PAIC was associated with large lesions in bilateral paramedian thalamus/ rostral midbrain, and with high mortality.

Thalamic strokes that severely impair arousal extend into the brainstem

In this study, we evaluate the role of the thalamus in the neural circuitry of arousal. Level of consciousness within the first 12 hours of a thalamic stroke is assessed with lesion symptom mapping. Impaired arousal correlates with lesions in the paramedian posterior thalamus near the centromedian and parafascicular nuclei, posterior hypothalamus, and midbrain tegmentum. All patients with severely impaired arousal (coma, stupor) had lesion extension into the midbrain and/or pontine tegmentum, whereas purely thalamic lesions did not severely impair arousal. These results are consistent with growing evidence that pathways most critical for human arousal lie outside the thalamus. Ann Neurol 2018;84:926-930.

Acute Onset of Hypersomnolence and Aphasia Secondary to an Artery of Percheron Infarct and a Proposed Emergency Room Evaluation

Artery of Percheron (AOP) is a rare anatomical variant, which supplies bilateral paramedian thalami and the rostral mesencephalon via a single dominant thalamic perforating artery arising from the P1 segment of a posterior cerebral artery. AOP infarcts can present with a plethora of neurological symptoms: altered mental status, memory impairment, hypersomnolence, coma, aphasia, and vertical gaze palsy. Given the lack of classic stroke signs, majority of AOP infarcts are not diagnosed in the emergency setting. Timely diagnosis of an acute bilateral thalamic infarct can be challenging, and this case report highlights the uncommon neurological presentation of AOP infarction. The therapeutic time window to administer IV tPA can be missed due to this delay in diagnosis, resulting in poor clinical outcomes. To initiate appropriate acute ischemic stroke management, we propose a comprehensive radiological evaluation in the emergency room for patients with a high suspicion of an AOP infarction.

Uncommon Association of Two Anatomical Variants of Cerebral Circulation: A Fetal-Type Posterior Cerebral Artery and Inferred Artery of Percheron, Complicated with Paramedian Thalamomesencephalic Stroke-Case Presentation and Literature Review

Background

The unilateral fetal variant of the posterior cerebral artery (FPCA) is characterized by the congenital absence of the P1 arterial segment. The artery of Percheron (AOP) is an uncommon vascular variant, in which a single dominant thalamoperforating arterial trunk arises from one P1 segment, bifurcates, and provides bilateral supply to the paramedian thalami and rostral midbrain.

Case Presentation

This is a retrospective case study of a 37-year-old man with multiple lifestyle risk factors (chronic marijuana and tobacco abuse), who suffered a thalamomesencephalic stroke, rapidly worsening to comatose state. After restoration of consciousness, he clinically manifested with left paramedian midbrain syndrome. Imaging demonstrated an asymmetric paramedian thalamic infarction with mesencephalon extension, patency of the basilar, vertebral arteries, and left PCA and right-sided FPCA, respectively. Left-sided thalamoperforating arterioles were not differentiated; AOP was inferred. Neither evident clinical source of embolus nor prothrombotic states were found. Mobile cardiac telemetry and transesophageal echocardiography were not available. The diagnosis was established too late for thrombolytic treatment. Anticoagulation was indicated during the acute and subacute stages, followed by low dose of antiplatelet.

Discussion

This uncommon cerebrovascular configuration (FPCA+AOP) might be the fourth case described in the literature. Sustained rehabilitation and abstinence from tobacco and cannabis led to favorable outcomes.

Artery of Percheron Infarct: An Acute Diagnostic Challenge with a Spectrum of Clinical Presentations

The artery of Percheron (AOP) is a variant of the paramedian thalamic vasculature that supplies blood to the medial aspect of the thalamus and the rostral midbrain. The presentation of an infarct in this territory varies widely and is often characterized by nonspecific neurological deficits, with altered mental status, decreased level of consciousness, and memory impairment being among the most common. AOP infarcts are often missed on initial computed tomography (CT) scan, and additional imaging is usually not done due to low suspicion for stroke in most cases. There have been an increasing number of reports of AOP infarction, illustrating the diversity of clinical presentations and the challenge this presents to clinicians in the acute setting. Lacking the classic signs of stroke, many of these patients experience a delay in recognition and treatment, with the majority of diagnoses occurring outside the tissue plasminogen activator (tPA) window. This case highlights the unusual presentation and diagnostic difficulty of a patient with an AOP infarct, and serves as a reminder to include thalamic pathology in patients presenting with vague neurological symptoms and no obvious signs of stroke.

Persistent anterograde amnesia due to the artery of Percheron occlusion: a case report

Bilateral thalamic infarction involving the artery of Percheron (AOP) can cause diagnostic difficulties due to the varying clinical presentations. AOP infarcts presented with isolated memory impairment are not common and the factors affecting the persistence of memory disorders are still unknown. A 41-year-old male patient was hospitalized with acute unconsciousness. MRI disclosed bilateral paramedian thalamic infarction The patient had isolated memory deficit and his anterograde amnesia continued without any change in the past decade. More cases might answer the questions concerning the intra- and extra-thalamic structures responsible for the amnesic syndrome and the factors affecting the persistence of the symptoms.

The Influence of Traumatic Axonal Injury in Thalamus and Brainstem on Level of Consciousness at Scene or Admission: A Clinical Magnetic Resonance Imaging Study

The aim of this study was to investigate how traumatic axonal injury (TAI) lesions in the thalamus, basal ganglia, and brainstem on clinical brain magnetic resonance imaging (MRI) are associated with level of consciousness in the acute phase in patients with moderate to severe traumatic brain injury (TBI). There were 158 patients with moderate to severe TBI (7-70 years) with early 1.5T MRI (median 7 days, range 0-35) without mass lesion included prospectively. Glasgow Coma Scale (GCS) scores were registered before intubation or at admission. The TAI lesions were identified in T2*gradient echo, fluid attenuated inversion recovery, and diffusion weighted imaging scans. In addition to registering TAI lesions in hemispheric white matter and the corpus callosum, TAI lesions in the thalamus, basal ganglia, and brainstem were classified as uni- or bilateral. Twenty percent of patients had TAI lesions in the thalamus (7% bilateral), 18% in basal ganglia (2% bilateral), and 29% in the brainstem (9% bilateral). One of 26 bilateral lesions in the thalamus or brainstem was found on computed tomography. The GCS scores were lower in patients with bilateral lesions in the thalamus (median four) and brainstem (median five) than in those with corresponding unilateral lesions (median six and eight, p = 0.002 and 0.022). The TAI locations most associated with low GCS scores in univariable ordinal regression analyses were bilateral TAI lesions in the thalamus (odds ratio [OR] 35.8; confidence interval [CI: 10.5-121.8], p < 0.001), followed by bilateral lesions in basal ganglia (OR 13.1 [CI: 2.0-88.2], p = 0.008) and bilateral lesions in the brainstem (OR 11.4 [CI: 4.0-32.2], p < 0.001). This Trondheim TBI study showed that patients with bilateral TAI lesions in the thalamus, basal ganglia, or brainstem had particularly low consciousness at admission. We suggest these bilateral lesions should be evaluated further as possible biomarkers in a new TAI-MRI classification as a worst grade, because they could explain low consciousness in patients without mass lesions.

A rare differential diagnosis of excessive daytime sleepiness - Artery of Percheron territory infarct

Stroke is an example of neurological diseases that can commonly drives Excessive Daytime Sleepiness (EDS). Extensive strokes with brain edema can leave a brain herniation and coma. Other causes of EDS after stroke are strategic lesions at Thalamus and brainstein. A 56-year-old man, right handed, with hypertension and hypercholesterolemia was admitted at Emergency Room due to 5 days onset of EDS, memory impairment, and left-sided weakness. A brain magnetic resonance imaging showed paramedian thalamic hyperintensity with rostral midbrain hyperintensity extending along the pial surface of the interpeduncular fossa. The artery of Percheron (AP) is an unusual anatomical variation that originates from the posterior cerebral artery and irrigates the paramedian regions of the thalamus and part of the midbrain. It is important the clinical suspicions with detailed drowsy patients history. Awareness of the clinical and neuroimaging features of this stroke syndrome is essential for timely diagnosis and appropriate management.

Assessment of Percheron infarction in images and clinical findings

OBJECTIVE

To assess the imaging and clinical features of patients with an artery of Percheron infarction comprehensively.

METHODS

Of 6539 patients with a first-ever stroke, 18 patients with a Percheron infarction were enrolled, and their images and clinical data were retrospectively investigated.

RESULTS

All patients underwent neurological intensive care unit (NICU) management. The initial symptom of a Percheron infarction included dizziness, transient blurred vision, double vision, barylalia, cerebellar ataxia, drowsiness, and a coma. Subsequent symptoms differed for the three subtypes of Percheron infarction, and the three subtypes are bilateral paramedian thalamic infarction with midbrain involvement, bilateral paramedian thalamic infarction without midbrain involvement, and bilateral paramedian and anterior thalamic infarction without midbrain involvement. Between favorable and unfavorable outcomes, there was no significant difference in the following patient characteristics including current smoking, hypertension, diabetes, hyperlipidemia, hyperhomocysteinemia, heart disease, time from stroke onset to medical care, and Glasgow Coma Scale score at admission (P>0.05), but there were significant differences in both the National Institute of Health stroke scale (NIHSS) and Acute Physiology and Chronic Health Evaluation II (APACHE II) score at admission (P<0.05). If the midbrain or larger infarct volume was involved or hemorrhagic transformation occurred, outcomes of a Percheron infarction were frequently unfavorable.

CONCLUSION

The clinical presentation of patients with a Percheron infarction is variable; early recognition, image performance, NICU management, NIHSS, and APACHE II score would help in diagnosis, evaluation, and treatment.

Degeneration of paramedian nuclei in the thalamus induces Holmes tremor in a case of artery of Percheron infarction

RATIONALE

Holmes' tremor is an uncommon neurologic disorder following brain insults, and its pathogenesis is undefined. The interruption of the dento-rubro-thalamic tract and secondary deterioration of the nigrostriatal pathway are both required to initiate Holmes' tremor. We used nuclear medicine imaging tools to analyze a patient with concurrent infarction in different zones of each side of the thalamus. Finding whether the paramedian nuclear groups of the thalamus were injured was a decisive element for developing Holmes' tremor.

PATIENT CONCERNS

A 36-year-old woman was admitted to our department due to a bilateral paramedian thalamic infarction. Seven months after the stroke, a unilaterally involuntary trembling with irregularly wavering motions occurring in both her left hand and forearm.

DIAGNOSIS

Based on the distinct features of the unilateral coarse tremor and the locations of the lesions on the magnetic resonance imaging (MRI), the patient was diagnosed with bilateral paramedian thalamic infarction complicated with a unilateral Holmes' tremor.

INTERVENTIONS

The patient refused our recommendation of pharmacological treatment with levodopa and other dopamine agonists based on personal reasons and was only willing to accept physical and occupational training programs at our outpatient clinic.

OUTCOMES

We utilized serial anatomic and functional neuroimaging of the brain to survey the neurologic deficit. A brain magnetic resonance imaging showed unequal recovery on each side of the thalamus. The residual lesion appeared larger in the right-side thalamus and had gathered in the paramedian area. A brain perfusion single-photon emission computed tomography (SPECT) revealed that the post-stroke hypometabolic changes were not only in the right-side thalamus but also in the right basal ganglion, which was anatomically intact. Furthermore, the brain Technetium-99m-labeled tropanes as a dopamine transporter imaging agents scan ( Tc-TRODAT-1) displayed a secondary reduction of dopamine transporters in the right nigrostriatal pathway which had resulted from the damage on the paramedian nuclear groups of the right-side thalamus.

LESSONS

Based on the functional images, we illustrated that a retrograde degeneration originating from the thalamic paramedian nuclear groups, and extending forward along the direct innervating fibers of the mesothalamic pathway, played an essential role towards initiating Holmes' tremor.

Stroke Chameleons and Stroke Mimics in the Emergency Department

PURPOSE OF REVIEW

We discuss the frequency of stroke misdiagnosis in the emergency department (ED), identify common diagnostic pitfalls, describe strategies to reduce diagnostic error, and detail ongoing research.

RECENT FINDINGS

The National Academy of Medicine has re-defined and highlighted the importance of diagnostic errors for patient safety. Recent rates of stroke under-diagnosis (false-negative cases, "stroke chameleons") range from 2-26% and 30-43% for stroke over-diagnosis (false-positive cases, "stroke mimics"). Failure to diagnosis stroke can preclude time-sensitive treatments and has been associated with poor outcomes. Strategies have been developed to improve detection of posterior circulation stroke syndromes, but ongoing work is needed to reduce under-diagnosis in other atypical stroke presentations. The published rates of harm associated with stroke over-diagnosis, particularly thrombolysis of stroke mimics, remain low. Additional strategies to improve the accuracy of stroke diagnosis should focus on rapid clinical reasoning in the time-sensitive setting of acute ischemic stroke and identifying imperfections in the healthcare system which may contribute to diagnostic error.

Artery of Percheron infarction: a case report

Background

The artery of Percheron is a rare anatomic variant of arterial supply to the paramedian thalamus and rostral midbrain, and occlusion of the artery of Percheron results in bilateral paramedian thalamic infarcts with or without midbrain involvement. Acute artery of Percheron infarcts represent 0.1 to 2% of total ischemic stroke. However, of thalamic strokes, occlusion of artery of Percheron is the cause in 4 to 35% of cases. Early diagnosis of artery of Percheron infarction can be challenging because it is infrequent and early computed tomography or magnetic resonance imaging may be negative. Thus, it can be confused with other neurological conditions such as tumors and infections.

Case presentation

This is a retrospective case study of a 56-year-old white man admitted to Umeå University Hospital and diagnosed with an artery of Percheron infarction. Medical records and the neuroradiological database were reviewed, and the diagnosis was made based on typical symptoms and radiological findings of artery of Percheron infarction.

We report the case of a 56-year-old man with a history of overconsumption of alcohol who was found in his home unconscious and hypothermic. He had a Reaction Level Scale-85 score of 4. He developed ventricular fibrillation on arrival at our emergency department, and cardiopulmonary resuscitation successfully restored sinus rhythm within an estimated 2 minutes of onset. He was then put on cardiopulmonary bypass for rewarming. The initial head computed tomography performed on admission was wrongly assessed as unremarkable. Bilateral ischemia in the paramedian thalamic nuclei and pons were first documented on a follow-up computed tomography on day 24 after hospitalization. He died on day 35 after hospitalization.

Conclusions

Artery of Percheron infarcts are rare. The radiological diagnosis can initially often be judged as normal and in combination with variability in the neurological symptoms it is a rather difficult condition to diagnose. For these reasons few clinicians have much experience with this type of infarct, which may delay diagnosis and initiation of appropriate treatment.

Paramedian Thalamic Ischemic Infarction: A Retrospective Clinical Observation

BACKGROUND

The study aimed to evaluate the clinical features in patients with bilateral and unilateral paramedian thalamic infarcts.

METHODS

Twenty-one patients with paramedian thalamic infarcts were included, and their case records were reviewed. We focused on the patients' neuroimaging and neurological symptoms including the duration of coma, vertical gaze palsy, and memory impairment. The causes of bilateral and unilateral paramedian thalamic infarcts were also investigated.

RESULT

Nine patients had bilateral paramedian thalamic infarcts and 12 patients had unilateral lesions. As an initial symptom, coma had occurred in 5 patients with bilateral lesions and 4 patients with unilateral lesions. Bilateral vertical gaze palsy and memory impairment were found in both groups. Most of them recovered well, except 1 patient who died due to bilateral thalamic paramedian infarction.

CONCLUSIONS

Our results show that both bilateral and unilateral paramedian thalamic infarcts can cause coma, vertical gaze palsy, and memory impairment. This may promote our understanding of paramedian thalamic infarction.

Lesson of the month 1: Artery of Percheron occlusion - an -uncommon cause of coma in a middle-aged man

Bilateral paramedian thalamic infarction resulting from artery of Percheron occlusion presents with a distinct clinical syndrome comprising impaired consciousness, often with vertical gaze palsy and memory impairment. This uncommon anatomical variant arises as a single artery supplying both paramedian thalami. Early recognition can be challenging in the obtunded patient, where the differential diagnosis is broad. The acute physician should consider this diagnosis in a patient presenting with unexplained coma so that emergent treatments such as thrombolysis can be employed. Early imaging with computerised tomography can often be normal; therefore the use of magnetic resonance imaging is essential in confirming the diagnosis.

Acute Occlusion of the Percheron Artery during Pregnancy: A Case Report and a Review of the Literature

OBJECTIVES

The Percheron artery (PA) is a rare variant vessel. Its acute occlusion can cause a bilateral symmetrical thalamic stroke, clinically manifested as a sudden alteration of consciousness that could vary from sleepiness to coma. In this paper, we illustrate a case of acute PA occlusion in a young, pregnant woman and present a review of the literature, focusing on the possible causes of the acute occlusion.

METHODS

A 35-year-old woman, at the fourth week of pregnancy, came to the emergency department of our hospital because of a sudden onset and persistent loss of consciousness. Brain magnetic resonance imaging (MRI) showed a symmetrical and bilateral thalamic infarction without evidence of other ischemic lesions, compatible with an acute PA occlusion.

RESULTS

The patient, who showed full clinical recovery within a few hours of symptom onset, received a short-term anticoagulant treatment followed by aspirin for long-term prevention.

CONCLUSIONS

We reviewed the literature about the possible causes of acute PA occlusion. This ischemic condition is usually associated with cardioembolic or small-vessel disease. However, in our patient, we did not find any element supportive for coagulative alteration or embolyzing conditions.

PRACTICE

The presence of this type of thalamic stroke should be considered in the management of persistent loss of consciousness. PA occlusion is rare, but it needs a brain MRI examination for a correct diagnosis, a narrow evaluation of all the possible causes, and a long-term anticoagulant therapy. Pregnancy itself should constitute a rare but possible cause of a PA occlusion.

Artery of Percheron Infarction as an Unusual Cause of Korsakoff's Syndrome

The Korsakoff syndrome is defined as "an abnormal mental state in which memory and learning are affected out of all proportion to other cognitive functions in an otherwise alert and responsive patient." Confabulation refers to false or erroneous memories arising, not deliberately, in the context of a neurological amnesia and is often thought of as pathognomonic of the Korsakoff syndrome. Although the exact pathophysiology is unknown, various studies have identified brain lesions in the thalami, mammillary bodies, and frontal cortex. We report a case of a 68-year-old male presenting with acute altered mental status on July 16, 2015. The neuropsychological dysfunctions included prominent Korsakoff's syndrome, which became apparent when the altered mental status resolved. Amnesia was accompanied by prominent confabulation, disorientation, and lack of insight into his own disability. Neuroradiological data indicated that the intralaminar and dorsomedial nuclei in bilateral thalami were infarcted by occlusion of the artery of Percheron. We believe that ours is one of few reported cases of Korsakoff syndrome in a patient with infarction involving the territory of the artery of Percheron. We conclude that bilateral thalamic lesions could cause Korsakoff's syndrome and the intralaminar and dorsomedial nuclei might be important structures in the pathogenesis of confabulation.