Etiologic Subtypes of Watershed Infarcts

Bilateral watershed infarcts due to hypoperfusion in the context of drug abuse: case report

BACKGROUND

Watershed infarcts (WIs) are a distinct type of stroke with a varying clinical presentation that affects the border areas between the territories of two cerebral arteries and are typically associated with hemodynamic impairment and internal carotid artery stenosis. However, there is a paucity of data concerning its association with the history of recreational substance and drug abuse.

METHODS/CASE REPORT

This case report presents a unique instance of bilateral internal watershed infarcts in a 23-year-old male with a history of polysubstance abuse, including methadone and cocaine. The patient's presentation included confusion, lower limb weakness, and systemic complications such as acute liver injury and myonecrosis, underlying the complexity of the clinical scenario.

RESULTS

The investigation revealed no evidence of arterial stenosis or thrombosis, leading to the conclusion that the infarctions were likely precipitated by a total loss of consciousness due to substance abuse-related cerebral hypoperfusion and vasoconstriction. Methadone and cocaine, both implicated in vasoconstriction, lowering the seizure threshold and contributing to QTc prolongation, thus leading to loss of consciousness, were identified as potential triggers for the episode.

CONCLUSIONS

In the young adult population, it is important to consider drug abuse as an etiological trigger for watershed infarcts, whereas the multi-system involvement and atypical presentation highlight the need for a comprehensive approach.

Etiopathology, Clinical and Imaging Characteristics of Border Zone Strokes

Introduction

A border zone infarct (BI) is defined as an infarction that is localized to watersheds or border zones in the brain. BI is further classified into cortical border zone infarct (CBZ) and internal border zone infarct (IBZ). This study was conducted to explore the clinical and radiological characteristics of BI.

Materials and Method

The study was conducted on eligible 400 acute ischemic stroke patients out of which 52 BI patients (diagnosed by the radiologist on DWI MRI images), patients >18 yrs of age were selected and divided into two groups of IBZ and CBZ infarct patients. The degree of intracranial and extracranial stenosis and characteristics on clinical presentation were assessed. The data were collected and analyzed using SPSS version 20.0 software at significance level p-value <0.05.

Results

25% and 75% of CBZ and IBZ patients, respectively, had history of presyncope or syncope before stroke. On vascular evaluation, 3.9% and 51.9% were in MCA and ICA stenosis group, respectively. Evidence of cardio embolism was found in 17.3% of patients. 53.3% of CBZ and 53.8% of IBZ patients were in ICA stenosis group, and 6.7% of CBZ and 7.7% of IBZ patients were in MCA stenosis group, with a statistically insignificant relation (p-value >0.05).

Conclusion

Association of BI with events causing hypotension or hypovolemia is well-established in our study, association of BI with large vessel atherosclerosis is common, and its contribution to CBZ and IBZ seems to be equal.

Intracranial Hemorrhage Presenting With ST-Segment Elevation and T-Wave Inversion Concerning for Acute Myocardial Infarction

Acute neurologic injury and increased intracranial pressure are associated with electrocardiographic (ECG) changes that include rhythm disturbances as well as ECG mimics of myocardial ischemia, such as focal or diffuse ST-segment or T-wave abnormalities. Both the mechanism and significance of these ECG changes are not clear. The authors report a case of a patient with a complex medical history who became hypotensive after he presented with acute intracranial hemorrhage. A subsequent ECG showing ST-segment elevation in the inferior and lateral leads was concerning for acute myocardial infarction. ST-segment elevation in the setting of acute intracranial hemorrhage can lead to diagnostic confusion and/or premature narrowing of the differential diagnosis. This case report starts with an example of this exact scenario, provides a concise overview of potential mechanisms, and concludes with several possible strategies that the emergency provider can use to identify this effect in an undifferentiated patient.

Case report: COVID-19-associated refractory thrombotic thrombocytopenic purpura complicated with Guillain-Barré syndrome

Thrombotic thrombocytopenic purpura (TTP), a rare and lethal thrombotic microangiopathy, is an autoimmune disease that can be triggered by viral infections such as COVID-19. This condition is characterized by hemolytic microangiopathy, thrombocytopenia, and neurologic alterations, possibly accompanied by fever and renal damage. Moreover, more than 220 patients with Guillain-Barré syndrome (GBS) have been reported in association with the COVID-19 infection. In this report, we present a case of a patient who developed refractory TTP complicated by GBS following a SARS-CoV-2 infection. We aimed to highlight the importance of accurately diagnosing neurological complications associated with a COVID-19 infection and to demonstrate our strategies for treating a patient with COVID-19 infection-related refractory TTP complicated by GBS.

A narrative review of the pathophysiology of ischemic stroke in carotid plaques: a distinction versus a compromise between hemodynamic and embolic mechanism

Atherosclerotic carotid artery stenosis causes about 10–20% of all ischemic strokes through two main mechanisms: hemodynamic impairment in case of significant stenosis and thromboembolism from an atherosclerotic plaque regardless of the degree of stenosis. The latter is the most frequent mechanism and appear to result from embolization from a vulnerable atherosclerotic plaque or acute occlusion of the carotid artery and propagation of thrombus distally. Downstream infarcts may occur in a territory of major cerebral artery or at the most distal areas between two territories of major cerebral arteries, the so-called watershed (WS), or border zone area. Although WS infarcts, especially deep WS infarct, were historically thought to be due to hemodynamic compromise, the role of microembolism has also been documented, both mechanisms may act synergistically to promote WS infarcts. Routine and more advanced imaging techniques may provide information on the underlying mechanism involved in ipsilateral ischemic stroke. A better understanding of ischemic stroke pathogenesis in carotid stenosis may limit the use of routine non-selective shunt, whose benefit-risk balance is debated, to patients with hemodynamic impairment.

After reviewing existing evidence underpinning the contribution of the two mechanisms in downstream ischemic stroke and the various imaging techniques available to investigate them, we will focus on the pathogenesis of WS infarcts that remains debated.

Borderzone Infarction and Small Vessel Disease in a Sample of Egyptian Stroke Patients: Differences and Similarities

Background

The anatomical location of white matter hyperintense lesions in small vessel disease are apparently similar to those of borderzone infarction. The objective of this study is to find clinical and radiological points of differentiation between the two vascular disorders in a sample of Egyptian patients which might have an impact on primary and secondary prevention.

Methods

Ischemic stroke patients with white matter lesions were categorized into two groups: small vessel disease and borderzone infarctions. NIHSS was done on admission. Risk factor profile was reported, and investigations done including: HbA1C, lipid profile, CRP, ECG, echocardiography, carotid duplex, brain MRI, MRA and MR perfusion study.

Results

46 patients completed the study, 29 with SVD and 17 with BZI. Smoking, hypertension and recurrent stroke were more common in borderzone infarctions, but only diabetes was significantly higher (p = 0.047). Limb shaking was more observed in borderzone infarctions (p = 0.049). Radiologically: lacunar pattern was observed more in small vessel disease, while rosary pattern was more in borderzone infarctions (p = 0.04). FLAIR symmetrical lesions and microbleeds were more significant in small vessel disease (p = <0.001; 0.048, respectively). Perfusion study time to peak denoted evidence of significant hypoperfusion in all regions of interest in borderzone infarctions.

Conclusion

Limb shaking, retinal claudication or syncope, with MRI showing rosary pattern of white matter hyperintensity, few microbleeds and markedly impaired perfusion favor the diagnosis of borderzone infarctions. On the other hand, presence of lacunae, FLAIR showing symmetrical WMH and microbleeds with minimal or no perfusion deficit suggests the diagnosis of small vessel disease.

Cortical and Internal Watershed Infarcts Might Be Key Signs for Predicting Neurological Deterioration in Patients with Internal Carotid Artery Occlusion with Mild Symptoms

Background

Treatment for acute ischemic stroke due to large vessel occlusion (LVO) with mild symptoms is under discussion. Although most patients have good outcomes, some patients deteriorate and have unfavorable results. Imaging findings that predict the prognosis of LVO with mild symptoms are needed to identify patients who require treatment. In this study, we focused on watershed infarctions (WSIs), because this clinical phenomenon quite sensitively reflects changes in cerebral blood flow. The purpose of this study was to assess positive rates of WSI on MRI findings in patients with internal carotid artery (ICA) occlusion, and compare WSI-positive rates between patients divided according to their clinical course.

Methods

We retrospectively collected data of 1,531 patients who presented with acute ischemic stroke between June 2006 and July 2019. Among them, we chose symptomatic ICA occlusion patients with a past history of atrial fibrillation who were treated conservatively. We divided these patients into two groups, those with maintenance or improvement in their NIHSS score after hospitalization, and those whose NIHSS score worsened. We compared WSI-positive rates between these two groups.

Results

Thirty-seven of the 1,531 patients were included in this study. Of them, total NIHSS score was maintained or improved in 8 patients (group A), 3 of whom (37.5%) had internal watershed infarctions (IWIs). In group B, consisting of patients whose NIHSS score worsened by >2 at 7 days from symptom onset, 24 (82.8%) had IWIs. Group A thus had statistically lower IWI positivity rates than group B (p = 0.02). Three patients (37.5%) in group A had cortical watershed infarctions (CWIs), while 27 patients in group B (93.1%) had CWIs. Group A thus had a significantly lower CWI positivity rate than group B (p = 0.002).

Conclusion

In patients with mildly symptomatic ICA occlusion, CWIs and IWIs might be key signs for predicting neurological deterioration after hospitalization.

Chronic Lymphocytic Leukemia Presenting as a Subcortical Watershed Infarct

Internal watershed infarcts (WI) involve white matter between deep and superficial arterial systems of middle cerebral artery. These infarcts are considered to be either from low blood flow or microembolism. Anemia is an extremely rare cause of watershed infarcts. Very few cases of hemolytic anemia causing watershed cerebral infarcts have been reported. Chronic lymphocytic leukemia (CLL) is frequently complicated with secondary autoimmune cytopenia such as autoimmune hemolytic anemia (AIHA), immune thrombocytopenia (ITP), and pure red cell aplasia. AIHA is present in about 7–10% of patients with CLL. AIHA from CLL presenting as WI is an extremely rare phenomenon with no previously published case reports to the best of our knowledge.

Cerebral border zone infarction: an etiological study

Background

Border zone infarcts (BZI) are ischemic lesions at the junction between two main arterial territories which may be either cortical or internal BZI.

Methods

This study was conducted on 76 cerebral BZI patients and 20 healthy control subjects. Patients were divided to group I included 26 internal BZI, group II included 19 cortical BZI and group III included 21 mixed internal/cortical BZI patients. Included subjects were submitted to neurological examination, laboratory investigations, ECG, echocardiogram, brain CT and/or MRI and extra and intracranial blood vessels imaging by duplex and CT angiography.

Results

Hypertension was significantly higher among groups I and III compared to group II while atrial fibrillation (AF) was significantly higher in groups II and III than group I (p < 0.05). Sonographic duplex assessment of extra and intracranial blood vessels revealed significant increase in mean flow velocities of CCA, ICC and MCA on both side in groups I and III compared to group II (p < 0.05). CT angiography revealed non-significant differences between BZI patients and control as well as in between the three BZI patient's groups regarding the existence of vertebral artery hypoplasia and/or circle of Willis anomalies.

Conclusions

Vascular stenosis is the main etiological factor in internal BZI while AF is the predominant etiological factor of cortical BZI. Congenital vascular anomalies play roles in the localization of BZI but cannot predispose to it except when comorbid with hemodynamic disturbances.

Clinical features and the degree of cerebrovascular stenosis in different types and subtypes of cerebral watershed infarction

Background

Whether there are differences in pathogenesis among different types and subtypes of cerebral watershed infarction (WSI) is controversial since they have been combined into a single group in most previous studies.

Methods

We prospectively identified 340 supratentorial WSI patients at Beijing Chao-Yang Hospital, Capital Medical University, China and classified them based on diffusion-weighted imaging(DWI) templates. Baseline characteristics, clinical courses and neuroradiological features were compared among patients with different types and subtypes of WSI.

Results

We identified 92 patients with cortical watershed infarction (CWI), 112 with internal watershed infarction (IWI) and 136 with mixed-type infarction. Compared with CWI patients, more IWI patients had critical stenosis of internal carotid artery (ICA) (P < 0.001). For the CWI group, patients with anterior watershed infarction (AWI) were more prone to critical ICA stenosis than those with posterior watershed infarction (PWI) (P = 0.011). For the IWI group, critical ICA stenosis was more prevalent in patients with partial IWI (P-IWI) than in those with confluent IWI (C-IWI) (P = 0.026). IWI patients were more frequently found to have clinical deterioration during the first 7 days of hospitalization and a poor prognosis at the 90th day than in CWI patients (P = 0.003 and P = 0.014, respectively).

Conclusions

IWI, especially the P-IWI subtype, is associated with hemodynamic impairment (HDI), whereas CWI has a weaker correlation with ICA steno-occlusion. Furthermore, IWI patients are more prone to poor prognosis.

Electronic supplementary material

The online version of this article doi: (10.1186/s12883-017-0947-6) contains supplementary material, which is available to authorized users.

The Pathophysiology of Watershed Infarction: A Three-Dimensional Time-of-Flight Magnetic Resonance Angiography Study

BACKGROUND

Most of the time, watershed infarcts (WIs) involve steno-occlusive carotid disease. The pathophysiological mechanism could be predicted by their pattern: internal WIs (IWIs) are thought to be due to hemodynamic impairment in contrast to cortical WIs (CWIs), which are more likely to be caused by microembolic phenomena. We used a 3D time-of-flight (TOF) magnetic resonance angiography (MRA) study to assess this hypothesis.

METHODS

In 45 consecutive patients with a recent WI and ipsilateral cervical carotid stenosis, clinical and radiological data were obtained retrospectively. 3D TOF MRA were analyzed both qualitatively and quantitatively (internal carotid and anterior, middle and posterior cerebral arteries). Then, 2 groups were determined depending on their radiological patterns: WIs with (IWI+) or without (IWI-) an internal watershed.

RESULTS

Thirty-two of the 45 patients (71%) had IWIs that were or were not associated with CWIs (IWI+), while 13 patients (29%) had only CWIs (IWI-). There was no significant relationship between the radiological pattern and the demographic data, the cardiovascular risk factors, or the degree of stenosis. However, IWI+ patients more frequently had motor weakness (P = .03) than CWI patients. An ipsilateral reduced middle cerebral artery intensity on 3D TOF MRA in both qualitative and quantitative analyses was significantly associated with IWI+. Instead within IWI-, no significantly reduced signal intensity was found.

CONCLUSION

These findings originally support the view that IWIs are mainly caused by a hemodynamic impairment related to carotid stenosis, whereas CWIs are mostly due to a microembolic mechanism. 3D TOF MRA, which gives pertinent information on pathophysiology on IWIs, can help in decision making.

Neurologic Complications in the Intensive Care Unit

Complications involving the central and peripheral nervous system are frequently encountered in critically ill patients. All components of the neuraxis can be involved including the brain, spinal cord, peripheral nerves, neuromuscular junction, and muscles. Neurologic complications adversely impact outcome and length of stay. These complications can be related to underlying critical illness, pre-existing comorbid conditions, and commonly used and life-saving procedures and medications. Familiarity with the myriad neurologic complications that occur in the intensive care unit can facilitate their timely recognition and treatment. Additionally, awareness of treatment-related neurologic complications may inform decision-making, mitigate risk, and improve outcomes.