Association between renal insufficiency and lesion characteristics of posterior reversible encephalopathy syndrome.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is characterized by cerebral blood flow dysregulation and the blood-brain barrier (BBB) disruption. While renal insufficiency has been considered a factor in BBB fragility, the relationship between renal insufficiency and the PRES lesions volume remains unclear. METHODS: This observational study was performed retrospectively. PRES patients were categorized into two groups with renal insufficiency, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73m2 on the day of symptom occurrence. Lesion volume was measured using fluid-attenuated inversion recovery (FLAIR) imaging, and the brain was divided into nine regions. The volume of the parietal-occipital-temporal lobe was considered typical, while the other six regions were labeled as atypical. RESULTS: The study included 200 patients, of whom 94 (47%) had renal insufficiency. Patients with renal insufficiency had a larger lesion volume (144.7 ± 125.2 cc) compared to those without renal insufficiency (110.5 ± 93.2 cc; p = 0.032); particularly in the atypical lesions volume (49.2 ± 65.0 vs. 29.2 ± 44.3 cc; p = 0.013). However, there was no difference in the reversibility of the lesions (35.2 ± 67.5 vs. 18.8 ± 33.4 cc; p = 0.129). Multiple regression analysis revealed that decreases in eGFR (ß = -0.34, 95% CI -0.62-0.05, p = 0.020) were positively associated with total lesion volume. CONCLUSION: Our findings suggest that PRES patients with renal insufficiency experience more severe lesion volumes, likely due to the atypical brain regions involvement. The lesions involving atypical regions may have a similar pathophysiology to typical lesions, as the PRES lesions reversibility was found to be similar between individuals with and without renal insufficiency.

Posterior reversible encephalopathy syndrome and acute ischemic stroke: an underreported association.

INTRODUCTION: Posterior reversible encephalopathy syndrome (PRES) is a rare and complex disorder with variable clinical presentation and a typical magnetic resonance imaging (MRI) pattern of vasogenic edema with typical and atypical locations. It is often triggered by other diseases and drugs and the most prototypical association is with persistently elevated arterial pressure values. Among the potential cerebrovascular complications, intracranial bleeding has been described, but ischemic stroke is uncommonly reported. METHODS: We are presenting a case of a male patient with prolonged and sustained arterial hypertension acutely presenting with lacunar ischemic stroke involving the right corona radiata and composite MRI findings with the association of chronic small vessel disease (SVD) markers, acute symptomatic lacunar stroke, and atypical, central variant, posterior fossa dominant PRES. In the MRI follow-up, the white matter hyperintensities in T2-fluid attenuated inversion recovery (FLAIR sequences) due to PRES. DISCUSSION: The pathophysiology of PRES is not yet fully known, but the association with markedly increased values of arterial pressure is typical. In this context, ischemic stroke has not been considered in the clinical and neuroradiological manifestations of PRES and it has been only occasionally reported in the literature. In this case, the main hypothesis is that sustained hypertension may have triggered both manifestations, PRES, and ischemic stroke and the last one allowed to diagnose the first one. CONCLUSIONS: Atypical variants of PRES are not so rare and it may also occur in typical triggering situations. The association with ischemic stroke is even rarer and it may add some clues to the pathomechanisms of PRES.

Posterior Reversible Encephalopathy Syndrome in Eclamptic Patients: The Relationship between Blood Pressure, Cranial Involvement, and Seizure Recurrence.

OBJECTIVES: Posterior reversible encephalopathy syndrome (PRES) is a clinic radiological disorder characterized by headache, epileptic seizure, encephalopathy, visual impairment, and focal neurological deficits. Gestational hypertension, which is a significant risk factor for PRES, may cause significant morbidity and mortality among pregnant women. DESIGN: Twenty-four patients with PRES caused by eclampsia who were admitted to our hospital in the last 5 years were included in this study. PARTICIPANTS/MATERIALS, SETTING, METHODS: Blood pressure at admission, the number of regions with vasogenic edema in the brain, and recurrent seizures were noted. Patients were divided into three groups: mild, moderate, and severe. RESULTS: Using Kruskal-Wallis and Pearson χ2 tests, there was no statistical significance between the groups in terms of cranial involvement (p = 0.471). However, binary logistic regression analysis showed that seizure recurrence increased in correlation with blood pressure (p = 0.04). LIMITATIONS: PRES is a rare syndrome associated with several etiologies. In our study, only patients with PRES due to eclampsia were included. Therefore, the number of included patients was limited (24 participants). CONCLUSION: PRES may occur in eclamptic patients with mild, moderate, or severe blood pressure values. Evaluation by magnetic resonance imaging is needed to confirm the diagnosis. Early and rapid treatment is essential for reducing morbidity and mortality among pregnant women.

COVID-19 and Cerebrovascular Disease.

COVID-19 has been associated with numerous neurological complications, with acute cerebrovascular disease being one of the most devastating complications. Ischemic stroke is the most common cerebrovascular complication of COVID-19, affecting between 1 and 6% of all patients. Underlying mechanisms for COVID-related ischemic strokes are thought to be due to vasculopathy, endotheliopathy, direct invasion of the arterial wall, and platelet activation. Other COVID-19-associated cerebrovascular complications include hemorrhagic stroke, cerebral microbleeds, posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome, cerebral venous sinus thrombosis, and subarachnoid hemorrhage. This article discusses the incidence of these cerebrovascular complications, risk factors, management strategies, prognosis and future research directions, as well as considerations in pregnancy-related cerebrovascular events in the setting of COVID-19.

Eclampsia with hypothyroidism complicated with posterior reversible encephalopathy syndrome-a case report.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disorder with complex physiopathological mechanisms that have not been fully understood. Early identification is of great prognostic significance, of which the symptoms and radiological abnormalities can be completely reversed. If the diagnosis and treatment are delayed, ischemia and massive infarction may be developed in some patients. Posterior reversible encephalopathy syndrome (PRES) has been reported mainly in association with postpartum eclampsia, which have been rarely reported, while the association with hypothyroidism has not been reported at home or abroad. CASE PRESENTATION: Here we report on a pregnant 29-year-old with multipara and a chief complication of hypothyroidism. She presented in the emergency department with frequent attacks of severe headache symptoms resulting from reversible cerebral vasoconstriction syndrome (RCVS), accompanied with prenatal eclampsia. PRES was determined by radiological examination. CONCLUSION: To the best of our knowledge, this is the first case of PRES complicated by hypothyroidism and prepartum eclampsia.Clinicians should be alert for the co-occurence of eclampsia, PRES, and RCVS when patients have convulsions after a typical throbbing headache. Moreover, regular monitoring of thyroid function during pregnancy should also occupy certain special attention.

Headache and systemic lupus erythematosus: A narrative review.

OBJECTIVE: To review the epidemiology, the differential diagnosis, and the clinical and laboratory factors associated with the care management of headaches in patients with systemic lupus erythematosus (SLE). BACKGROUND: SLE is a chronic autoimmune disease and in 12%-95% of patients, the nervous system is involved. Headache is a frequently reported, although nonspecific, symptom that may potentially represent serious underlying diagnoses. Primary headaches may also occur in these patients, thereby causing a negative and significant impact on their quality of life. METHODS: This is a narrative review. A literature review was conducted on the PubMed platform using the following terms: (1) headache and (2) lupus. All articles considered relevant were included. No limitations were imposed for the publication date. RESULTS: Headache is a frequent symptom in patients with SLE. Although its prevalence is similar to the general population, headaches nonetheless tend to have a greater negative impact on these patients. Patients with SLE are more likely to experience headache due to vascular diseases such as cerebral venous sinus thrombosis, stroke, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, and vasculitis. Aseptic meningitis, neuroinfections, intracranial neoplasms, and intracranial hypertension or hypotension may also be a cause of headache in these patients. Although used in disease activity scores, the concept of lupus headache is controversial. CONCLUSIONS: Headache is a frequent symptom in patients with SLE. An appropriate approach enables the potentially serious conditions, which are the causes of secondary headaches, to be recognized and treated, together with an appropriate diagnosis and treatment of primary headaches.

Dural and Leptomeningeal Diseases: Anatomy, Causes, and Neuroimaging Findings.

Meningeal lesions can be caused by various conditions and pose diagnostic challenges. The authors review the anatomy of the meninges in the brain and spinal cord to provide a better understanding of the localization and extension of these diseases and summarize the clinical and imaging features of various conditions that cause dural and/or leptomeningeal enhancing lesions. These conditions include infectious meningitis (bacterial, tuberculous, viral, and fungal), autoimmune diseases (vasculitis, connective tissue diseases, autoimmune meningoencephalitis, Vogt-Koyanagi-Harada disease, neuro-Behçet syndrome, Susac syndrome, and sarcoidosis), primary and secondary tumors (meningioma, diffuse leptomeningeal glioneuronal tumor, melanocytic tumors, and lymphoma), tumorlike diseases (histiocytosis and immunoglobulin G4-related diseases), medication-induced diseases (immune-related adverse effects and posterior reversible encephalopathy syndrome), and other conditions (spontaneous intracranial hypotension, amyloidosis, and moyamoya disease). Although meningeal lesions may manifest with nonspecific imaging findings, correct diagnosis is important because the treatment strategy varies among these diseases. ©RSNA, 2023 Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Brainstem and upper cervical cord involvement in a patient with posterior reversible encephalopathy syndrome: Neuro-images.

INTRODUCTION: Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological syndrome with acute heterogeneous neurological symptoms. It is usually preceded by hypertension or chemotherapy. Brain magnetic resonance imaging (MRI) shows vasogenic edema over the cortex and subcortex of parieto-occipital lobes. Involvement of the brainstem, basal ganglia, and spinal cord is rare. MATERIAL: Here we described an 18 years old woman with a history of systemic lupus erythematosus who was admitted due seizure and impaired consciousness. She had a mean arterial pressure of 160 and previously received cyclophosphamide. RESULTS: She had a unique involvement of diffuse bilateral asymmetric brain edema over the upper cervical cord, brainstem, cerebellum, thalami, basal ganglia, frontotemporal, and parieto-occipital lobes. She was diagnosed with PRES and after the treatment vasogenic edema vanished completely. CONCLUSION: When it is clinically applicable, physicians should consider PRES as the differential diagnosis of vasogenic edema over the upper cervical cord, cerebellum, and brainstem.

Diagnosis and management of endothelial disorders following haematopoietic stem cell transplantation.

Haematopoietic stem cell transplantation is a mainstay of therapy for numerous malignant and nonmalignant diseases. Endothelial activation and dysfunction occur after stem cell transplantation, driven by various patient- and transplant-specific factors. This can manifest as one of the relatively uncommon endothelial injury syndromes, such as sinusoidal obstruction syndrome, transplant-associated thrombotic microangiopathy, idiopathic pneumonia syndrome, capillary leak syndrome, engraftment syndrome or posterior reversible encephalopathy syndrome. This review focuses on the pathogenesis, classification and diagnosis of these disorders, as well as provides guidance on risk mitigation and treatment.

Acute headache in pregnant and post-partum patients: A clinical review.

BACKGROUND: Headaches during pregnancy and the post-partum period may be due to either an exacerbation of a pre-existing neurological presentation, a new pregnancy-related process, or a non-pregnancy related condition. Key physiologic changes during pregnancy and the post-partum period contribute to the vulnerability of this patient population and the increased risk of complications. OBJECTIVE OF THE REVIEW: Review causes of headaches in pregnant and post-partum patients as well as neuroimaging techniques performed. DISCUSSION: Headaches are a common complaint for pregnant and post-partum patients. For pregnant patients, a range of serious causes must be considered including cerebral venous thrombosis, posterior reversible encephalopathy syndrome and stroke. Primary headaches are responsible for most post-partum headaches, however other causes also include pre-clampsia, cerebral venous thrombosis and post-dural headache. Determining the optimal imaging technique in this vulnerable population remains a challenge given the scarce guidelines. CONCLUSION: The greatest difficulty while evaluating pregnant and post-partum patients presenting with an acute headache in an emergency setting is to determine whether the headache is due to a primary disorder such as migraines or is secondary to an underlying, sometimes serious pathology. The following review explores evidenced-based diagnosis of headache in this particular setting.

Recurrent exercise-induced acute kidney injury associated with hypouricemia: a case report and literature review.

BACKGROUND: Hereditary renal hypouricemia (RHUC) is a heterogenous disorder characterized by defective uric acid (UA) reabsorption resulting in hypouricemia and increased fractional excretion of UA. RHUC is an important cause of exercise-induced acute kidney injury (EIAKI), nephrolithiasis and posterior reversible encephalopathy syndrome (PRES). We present here an unusual case of a patient with RHUC who presented with recurrent EIAKI and had two heterozygous mutations in the SLC2A9 gene. CASE PRESENTATION: A 43-year old man was admitted to our clinic because of bilateral loin pain, nausea and sleeplessness for 3 days after strenuous exercise. The laboratory results revealed increased levels of blood urea nitrogen (BUN) (15 mmol/l) and serum creatinine (Scr) (450 µmol/l), while the UA level was extremely low at 0.54 mg/dl, and his fractional excretion of urate (FE-UA) was 108%. The patient had an episode of acute kidney injury after playing soccer approximately 20 years ago, and on routine physical examination, his UA was less than 0.50 mg/dl. In view of the marked hypouricemia and high FE-UA, a diagnosis of RHUC was suspected, which led us to perform mutational screening of the SLC22A12 and SLC2A9 genes. DNA sequencing revealed no mutation in SLC22A12 gene, but two heterozygous mutations in the SLC2A9 gene. CONCLUSIONS: This is a rare report of a patient with RHUC2 due to the mutation of SLC2A9. And this unique symptom of EIAKI and decreased or normal serum concentrations of UA warrant more attention as an early cue of RHUC.

Posterior reversible encephalopathy syndrome (PRES) associated with SARS-CoV-2 infection in a patient under maintenance haemodialysis: a case report.

BACKGROUND: Endothelial dysfunction is common in patients undergoing chronic haemodialysis, and is a major cause of posterior reversible encephalopathy syndrome (PRES). Recently, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to cause endothelial dysfunction by infecting vascular endothelial cells. Several cases of neurological complications in patients without kidney dysfunction, and only a few cases in patients with chronic kidney disease, have been reported in the literature. However, no previous report has yet described PRES associated with SARS-CoV-2 infection among patients undergoing maintenance dialysis. CASE PRESENTATION: A 54-year-old woman undergoing maintenance haemodialysis was admitted to our hospital for status epilepticus. She had developed end-stage kidney disease (ESKD) secondary to diabetic nephropathy. Seven days prior to admission, she had developed fever and was diagnosed with COVID-19. Subsequently her blood pressure increased from 160/90 mmHg to 190/100 mmHg. On admission, she presented with severe hypertension (> 220/150 mmHg), unconsciousness, and epilepticus. CT tomography revealed no signs of brain haemorrhage. Cranio-spinal fluid (CSF) examination revealed no signs of encephalitis, and CSF polymerase chain reaction (PCR) for SARS-CoV-2 was negative. MRI findings revealed focal T2/FLAIR hyperintensity in the bilateral parietooccipital regions, leading to the diagnosis of PRES. Deep sedation and strict blood pressure control resulted in a rapid improvement of her symptoms, and she was discharged without sequelae. CONCLUSIONS: We report the first case of PRES associated with SARS-CoV-2 infection in a patient undergoing maintenance haemodialysis. Patients undergoing maintenance haemodialysis are at high risk of PRES because of several risk factors. SARS-CoV-2 infection causes direct invasion of endothelial cells by binding to angiotensin-converting enzyme 2 (ACE2), initiating cytokine release, and hypercoagulation, leading to vascular endothelial cell injury and increased vascular leakage. In the present case, SARS-CoV-2 infection possibly be associated with the development of PRES.

Convexity subarachnoid haemorrhage: a practical guide.

Atraumatic convexity subarachnoid haemorrhage describes spontaneous bleeding into the convexities of the brain sulci without parenchymal involvement. Its many causes include reversible cerebral vasoconstriction syndrome, cerebral sinus venous thrombosis, posterior reversible encephalopathy syndrome and (in older people) cerebral amyloid angiopathy. We describe the clinical and radiological features of non-traumatic convexity subarachnoid haemorrhage with its various presentations, causes, treatments and prognoses, and use clinical vignettes to highlight important clinical points and pitfalls.

Risk of Stroke After Posterior Reversible Encephalopathy Syndrome.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) can cause short-term cerebrovascular complications, such as brain infarction and hemorrhage. We hypothesized that PRES is also associated with an increased long-term risk of stroke. METHODS: We performed a retrospective cohort study in the United States using statewide all-payer claims data from 2016 to 2018 on all admissions to nonfederal hospitals in 11 states. Adults with PRES were compared with adults with renal colic (negative control) and transient ischemic attack (TIA; positive control). Any stroke and the secondary outcomes of ischemic and hemorrhagic stroke were ascertained using International Classification of Diseases, Tenth Revision, Clinical Modification codes. We excluded prevalent stroke. We used time-to-event statistics to calculate incidence rates and Cox proportional hazards analyses to evaluate the association between PRES and stroke, adjusting for demographics and stroke risk factors. In a sensitivity analysis, outcomes within 2 weeks of index admission were excluded. RESULTS: We identified 1606 patients with PRES, 1192 with renal colic, and 38 216 with TIA. Patients with PRES had a mean age of 56±17 years; 72% were women. Over a median follow-up of 0.9 years, the stroke incidence per 100 person-years was 6.1 (95% CI, 5.0-7.4) after PRES, 1.0 (95% CI, 0.62-1.8) after renal colic, and 9.7 (95% CI, 9.4-10.0) after TIA. After statistical adjustment for patient characteristics and risk factors, patients with PRES had an elevated risk of stroke compared with renal colic (hazard ratio [HR], 2.3 [95% CI, 1.7-3.0]), but lower risk than patients with TIA (HR, 0.67 [95% CI, 0.54-0.82]). In secondary analyses, compared with TIA, PRES was associated with hemorrhagic stroke (HR, 2.0 [95% CI, 1.4-2.9]). PRES was associated with ischemic stroke when compared with renal colic (HR, 1.9 [95% CI, 1.4-2.7]) but not when compared with TIA (HR, 0.49 [95% CI, 0.38-0.63]). Results were similar with 2-week washout. CONCLUSIONS: Patients with PRES had an elevated risk of incident stroke.

Acute central nervous system toxicity during treatment of pediatric acute lymphoblastic leukemia: phenotypes, risk factors and genotypes.

Central nervous system (CNS) toxicity is common at diagnosis and during treatment of pediatric acute lymphoblastic leukemia (ALL). We studied CNS toxicity in 1,464 children aged 1.0-17.9 years, diagnosed with ALL and treated according to the Nordic Society of Pediatric Hematology and Oncology ALL2008 protocol. Genome-wide association studies, and a candidate single-nucleotide polymorphism (SNP; n=19) study were performed in 1,166 patients. Findings were validated in an independent Australian cohort of children with ALL (n=797) in whom two phenotypes were evaluated: diverse CNS toxicities (n=103) and methotrexate-related CNS toxicity (n=48). In total, 135/1,464 (9.2%) patients experienced CNS toxicity for a cumulative incidence of 8.7% (95% confidence interval: 7.31-10.20) at 12 months from diagnosis. Patients aged ≥10 years had a higher risk of CNS toxicity than had younger patients (16.3% vs. 7.4%; P<0.001). The most common CNS toxicities were posterior reversible encephalopathy syndrome (n=52, 43 with seizures), sinus venous thrombosis (n=28, 9 with seizures), and isolated seizures (n=16). The most significant SNP identified by the genome-wide association studies did not reach genomic significance (lowest P-value: 1.11x10-6), but several were annotated in genes regulating neuronal functions. In candidate SNP analysis, ATXN1 rs68082256, related to epilepsy, was associated with seizures in patients <10 years (P=0.01). ATXN1 rs68082256 was validated in the Australian cohort with diverse CNS toxicities (P=0.04). The role of ATXN1 as well as the novel SNP in neurotoxicity in pediatric ALL should be further explored.

Pathophysiology of reversible cerebral vasoconstriction syndrome.

Reversible cerebral vasoconstriction syndrome (RCVS) is a complex neurovascular disorder being recognized during the past two decades. It is characterized by multiple abrupt severe headaches and widespread cerebral vasoconstrictions, with potential complications such as ischemic stroke, convexity subarachnoid hemorrhage, intracerebral hemorrhage and posterior reversible encephalopathy syndrome. The clinical features, imaging findings, and dynamic disease course have been delineated. However, the pathophysiology of RCVS remains elusive. Recent studies have had substantial progress in elucidating its pathogenesis. It is now believed that dysfunction of cerebral vascular tone and impairment of blood-brain barrier may play key roles in the pathophysiology of RCVS, which explains some of the clinical and radiological manifestations of RCVS. Some other potentially important elements include genetic predisposition, sympathetic overactivity, endothelial dysfunction, and oxidative stress, although the detailed molecular mechanisms are yet to be identified. In this review, we will summarize what have been revealed in the literature and elaborate how these factors could contribute to the pathophysiology of RCVS.

Type of headache at onset and risk for complications in reversible cerebral vasoconstriction syndrome.

BACKGROUND: In a recent Italian study, 30% of patients with reversible cerebral vasoconstriction syndrome (RCVS) presented without thunderclap headache (TCH), and tended to present more severe forms of RCVS than patients with TCH. We aimed to analyze the risk for complications of RCVS in patients with and without TCH at onset. METHODS: In a pooled cohort of 345 French patients with RCVS, we compared patients with and without TCH at onset regarding rates of neurological complications, and the functional outcome at 3 months. RESULTS: As compared to the 281 patients with TCH at onset, the 64 patients without TCH had a higher risk for any neurological complication (61% vs. 24%, OR 4.9, 95% CI 2.8-8.7, p < 0.001). The association was strongest for cervical artery dissections (28% vs. 5%, OR 8.1, 95% CI 3.7-17.6, p < 0.001), followed by posterior reversible encephalopathy syndrome (17% vs. 3%, OR 7.1, 95% CI 2.7-18.4, p < 0.001), seizures (9% vs. 2.5%, OR 4.1, 95% CI 1.3-12.5, p = 0.019), and subarachnoid hemorrhage (41% vs. 16%, OR 3.5, 95% CI 1.9-6.3, p < 0.001). In multivariable analysis, the risk for any neurological complication remained significantly elevated in the absence of TCH (OR 3.5, 95% CI 1.8-6.8, p < 0.001). The functional outcome was equal in both groups, with a modified Rankin scale score of 0-1 in ≥90% of patients. CONCLUSIONS: Absence of TCH at onset might predict a higher risk of complications in RCVS. Our results warrant further multicentric studies to prove this finding.

The pathogenesis and treatment of posterior reversible encephalopathy syndrome after neuromyelitis optica spectrum disorder: a case report and literature review.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a rare disease characterized by reversible subcortical vasogenic brain edema. Neuromyelitis optica spectrum disorder (NMOSD) is a frequent neurological autoimmune disease that is rarely reported to complicate PRES. CASE PRESENTATION: Here, we report a case of neuromyelitis optica (NMO) concurrent with PRES. A 50-year-old woman presented with severe impairment of her health visual acuity, with significantly worsening of the motor weakness in both lower limbs during methylprednisolone therapy after her diagnosis of NMO. MRI showed new-onset brain edematous lesions of the bilateral frontal, occipital, and parietal lobes. PRES was considered. Her vision impairment and weakness of the extremities were alleviated after antihypertensive treatment and dehydration. The edema lesions detected by MRI also completely disappeared. CONCLUSIONS: We reviewed 14 cases of NMO with PRES and concluded that the etiology of NMOSD concurrent PRES may be multifactorial, involving pathogenic IgGs against aquaporin-4 (AQP-4) and immunotherapy treatment. Different underlying pathogeneses require different treatment approaches.

Cerebral amyloid angiopathy-related inflammation with posterior reversible encephalopathy syndrome-like presentation: a case report.

BACKGROUND: Cerebral amyloid angiopathy-related inflammation (CAA-RI), which presents with acute or subacute cognitive or functional decline, focal or multifocal neurologic deficits, new onset of seizures, or a combination of seizures and neurologic deficits, shares clinical and radiologic similarities with posterior reversible encephalopathy syndrome (PRES). Differential diagnosis is critical because the treatment principle for these 2 conditions differs greatly. Here, we present a case of PRES-like CAA-RI and the strategy used to discriminate between the 2 conditions. CASE PRESENTATION: A patient with probable CAA-RI was first thought to suffer from PRES. Initial high-dose methylprednisolone therapy caused rapid improvement of the neurologic symptoms but abrupt discontinuation of corticosteroids resulted in clinical relapse and deterioration. Subsequent reinitiation of high-dose methylprednisolone followed by tapering off of oral prednisone led to clinical and radiologic recovery at the 3-month follow-up. CONCLUSIONS: We suggest that in cases where it is difficult to distinguish between CAA-RI and PRES solely based on magnetic resonance imaging, a good response to corticosteroids and an apolipoprotein E (ApoE) ε4/ε4 genotype are critical for establishing a diagnosis of CAA-RI. If there is clinical deterioration, sudden withdrawal of high-dose corticosteroid during the active phase of CAA-RI should be avoided.

Neurological Complications of Dengue Fever.

PURPOSE OF REVIEW: To discuss the neurological complications of dengue virus (DENV) infection and their pathogenesis. RECENT FINDINGS: Include recognition of the four different serotypes of DENV and their epidemiology as well as recognition of the expanded dengue syndrome encompassing multisystem involvement in the severe form of the disease including involvement of the central nervous system (CNS). DENV is a neurotropic virus with the ability to infect the supporting cells of the CNS. Neural injury during the acute stage of the infection results from direct neuro-invasion and/or the phenomenon of antibody-dependent enhancement, resulting in plasma leakage and coagulopathy. Immune mechanisms have been implicated in the development of the delayed neurological sequelae through molecular mimicry. A myriad of neurological syndromes has been described as a result of the involvement of the CNS, the peripheral nervous system (PNS), or both. Neurological manifestations in DENV infection are increasingly being recognized, some of which are potentially fatal if not treated promptly. DENV encephalopathy and encephalitis should be considered in the differential diagnosis of other acute febrile encephalopathies, autoimmune encephalitides, and in cases of encephalopathy/encephalitis related to SARS-CoV2 infection, especially in dengue-endemic areas. Acute disseminated encephalomyelitis (ADEM) may be occasionally encountered. Clinicians should be knowledgeable of the expanded dengue syndrome characterized by the concurrent compromise of cardiac, neurological, gastrointestinal, renal, and hematopopoietic systems. Isolated cranial nerve palsies occur rather uncommonly and are often steroid responsive. These neuropathies may result from the direct involvement of cranial nerve nuclei or nerve involvement or may be immune-mediated. Even if the diagnosis of dengue is confirmed, it is absolutely imperative to exclude other well-known causes of isolated cranial nerve palsies. Ischemic and hemorrhagic strokes may occur following dengue fever. The pathogenesis may be beyond the commonly observed thrombocytopenia and include cerebral vasculitis. Involvement of ocular blood vessels may cause maculopathy or retinal hemorrhages. Posterior reversible encephalopathy syndrome (PRES) is uncommon and possibly related to dysregulated cytokine release phenomena. Lastly, any patient developing acute neuromuscular weakness during the course or within a fortnight of remission from dengue fever must be screened for acute inflammatory demyelinating polyneuropathy (AIDP), hypokalemic paralysis, or acute myositis. Rarely, a Miller-Fisher-like syndrome with negative anti-GQ1b antibody may develop.