Case report: Blood-transfusion induced posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome (PRES) is an increasingly recognized clinical entity associated with a variety of medical conditions. It is commonly considered in the presentation of uncontrolled, severe hypertension. However, more recently, it has been described in the setting of blood transfusion, particularly in those with chronic anemia, even in the absence of severe hypertension. We describe a patient who presented to the emergency department 12 days after large blood transfusion for severe, chronic anemia with headache, vision loss, expressive aphasia and a change in mental status, with only mild blood pressure elevation, who was ultimately diagnosed with PRES and refractory non-convulsive status epilepticus. Emergency physicians are often the first to initiate blood transfusion for those with a low hemoglobin. Therefore, it is prudent to proceed with caution in transfusing those with chronic anemia. It is also important for the emergency physician to keep PRES on the differential for those presenting with a neurologic complaint after correction of their chronic anemia, even in the absence of severe hypertension.

Neuropilin-1 is a novel host factor modulating the entry of hepatitis B virus.

BACKGROUND & AIMS: Sodium taurocholate cotransporting polypeptide (NTCP) has been identified as the cellular receptor for hepatitis B virus (HBV). However, hepatocytes expressing NTCP exhibit varying susceptibilities to HBV infection. This study aimed to investigate whether other host factors modulate the process of HBV infection. METHODS: Liver biopsy samples obtained from children with hepatitis B were used for single-cell sequencing and susceptibility analysis. Primary human hepatocytes, HepG2-NTCP cells, and human liver chimeric mice were used to analyze the effect of candidate host factors on HBV infection. RESULTS: Single-cell sequencing and susceptibility analysis revealed a positive correlation between neuropilin-1 (NRP1) expression and HBV infection. In the HBV-infected cell model, NRP1 overexpression before HBV inoculation significantly enhanced viral attachment and internalization, and promoted viral infection in the presence of NTCP. Mechanistic studies indicated that NRP1 formed a complex with LHBs and NTCP. The NRP1 b domain mediated its interaction with conserved arginine residues at positions 88 and 92 in the preS1 domain of the HBV envelope protein LHBs. This NRP1-preS1 interaction subsequently promoted the binding of preS1 to NTCP, facilitating viral infection. Moreover, disruption of the NRP1-preS1 interaction by the NRP1 antagonist EG00229 significantly attenuated the binding affinity between NTCP and preS1, thereby inhibiting HBV infection both in vitro and in vivo. CONCLUSIONS: Our findings indicate that NRP1 is a novel host factor for HBV infection, which interacts with preS1 and NTCP to modulate HBV entry into hepatocytes. IMPACT AND IMPLICATIONS: HBV infection is a global public health problem, but the understanding of the early infection process of HBV remains limited. Through single-cell sequencing, we identified a novel host factor, NRP1, which modulates HBV entry by interacting with HBV preS1 and NTCP. Moreover, antagonists targeting NRP1 can inhibit HBV infection both in vitro and in vivo. This study could further advance our comprehension of the early infection process of HBV.

A retrospective study to determine the correlation among HBV PreS1 antigen, HBV e antigen, alanine aminotransferase, and HBV DNA.

BACKGROUND AND AIM: Hepatitis B virus (HBV) infection presents with indicators of varying clinical significance. We aimed to evaluate the correlation among HBV Pre-S1 antigen (HBV PreS1-Ag), HBV e antigen (HBeAg), HBV DNA, and alanine aminotransferase (ALT) levels. METHODS: We retrospectively analyzed 6180 serum samples collected between 2020 and 2022 at the Shanghai General Hospital, China. Data regarding PreS1-Ag, HBeAg, ALT, and HBV DNA were compiled. Correlation analyses and cross-tabulations were employed to explore the diagnostic indicators. RESULTS: The detection rates of both antigen indicators showed a proportional increase with HBV DNA loads. The correlation between PreS1-Ag and HBV DNA (r = 0.616) was stronger than that between HBeAg and HBV DNA (r = 0.391). The specificity of PreS1-Ag (84.30 %) was lower than that of HBeAg (97.44 %), whereas the sensitivity of HBeAg (91.13 %) significantly surpassed that of PreS1-Ag (29.56 %). Among the HBV DNA positive patients, 92.04 % tested positive for at least one indicator, which exceeded the rate of PreS1+HBeAg- and PreS1-HBeAg+ (52. 28 % and 68. 56 %, respectively). Only 1.75 % of the patients exhibited double negativity, which was lower than the percentage of patients with single negativity (1.95 % and 12.00 % for PreS1-Ag and HBeAg, respectively). The PreS1 levels correlated with ALT levels (r = 0.317); patients with PreS1-positive status had higher ALT levels than patients with PreS1-negative status. CONCLUSION: PreS1-Ag is a more robust HBV replication indicator than HBeAg. PreS1-Ag displayed high sensitivity, whereas HBeAg demonstrated high specificity. Moreover, PreS1-Ag levels correlated with ALT levels. A combination of these indicators demonstrated dependable clinical value for detecting HBV infection and evaluating liver function.

Posterior Reversible Encephalopathy Syndrome in Children and Adolescents.

PURPOSE OF REVIEW: Posterior reversible encephalopathy syndrome, or PRES, is a constellation of severe, acute hypertension and specific brain imaging findings. This may be caused by failure of the cerebral autoregulatory system to manage acute or severe changes in blood pressure. The incidence in children is unknown but estimated to be more common in children with predisposing factors including renal disease, autoimmune disease, malignancy, solid organ transplantation, stem cell transplantation, hypertension, sepsis, and exposure to certain medications. RECENT FINDINGS: Management of PRES includes addressing hypertension, removing offending agents when possible, and anti-epileptic medications. Most children with PRES recover completely, but recurrence is possible. Lack of resolution of imaging findings likely portends a worse prognosis.

Clinical and Radiological Features of Unilateral Posterior Reversible Encephalopathy Syndrome (PRES): A Case Report.

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological entity characterized by reversible vasogenic edema predominantly affecting the posterior regions of the cerebral hemispheres. However, unilateral presentation of PRES is an exceptionally rare manifestation. We describe the case of a 34-year-old woman who presented with left-sided hemiparesis, hemisensory loss, headache, and focal motor seizures. Brain CT revealed right anterior and posterior hypodensities in the right frontal and parietal subcortical locations, brain MRI showed vasogenic edema in the subcortical right cerebral hemisphere, and cerebral angiogram revealed diffuse narrowing of the left internal carotid artery just distal to the carotid bifurcation with no flow of contrast beyond the ophthalmic segment. The patient's symptoms resolved during her admission, MRI findings improved on repeated imaging, and she was ultimately diagnosed with unilateral PRES. Unilateral PRES is a complex and challenging diagnosis, and this case sheds light on the atypical radiological features of unilateral PRES possibly intricately linked with contralateral steno-occlusive disease of the carotid artery. It is essential to maintain the atypical variants of PRES as part of the differential diagnosis when encountering acute neurological symptoms and vasogenic edema on imaging in the context of contralateral steno-occlusive disease of the carotid artery.

Genotyping Hepatitis B virus by Next-Generation Sequencing: Detection of Mixed Infections and Analysis of Sequence Conservation.

Our aim was to develop an accurate, highly sensitive method for HBV genotype determination and detection of genotype mixtures. We examined the preS and 5' end of the HBV X gene (5X) regions of the HBV genome using next-generation sequencing (NGS). The 1852 haplotypes obtained were subjected to genotyping via the Distance-Based discrimination method (DB Rule) using two sets of 95 reference sequences of genotypes A-H. In clinical samples from 125 patients, the main genotypes were A, D, F and H in Caucasian, B and C in Asian and A and E in Sub-Saharan patients. Genotype mixtures were identified in 28 (22.40%) cases, and potential intergenotypic recombination was observed in 29 (23.20%) cases. Furthermore, we evaluated sequence conservation among haplotypes classified into genotypes A, C, D, and E by computing the information content. The preS haplotypes exhibited limited shared conserved regions, whereas the 5X haplotypes revealed two groups of conserved regions across the genotypes assessed. In conclusion, we developed an NGS-based HBV genotyping method utilizing the DB Rule for genotype classification. We identified two regions conserved across different genotypes at 5X, offering promising targets for RNA interference-based antiviral therapies.

Hemolysis, Elevated Liver Enzymes and Low Platelet Count Syndrome Complicated by Disseminated Intravascular Coagulation and Posterior Reversible Encephalopathy Syndrome: A Case Report.

A 22-year-old pregnant woman was transferred from an external medical facility after experiencing an eclamptic seizure linked to hemolysis, elevated liver enzymes and low platelet count syndrome (HELLP) syndrome, and posterior reversible encephalopathy syndrome (PRES). Her situation was further complicated by intrauterine fetal demise and disseminated intravascular coagulation, necessitating a comprehensive multidisciplinary approach. This report details the diagnostic process and challenges in managing this complex patient with diverse medical requirements. Emphasis is placed on the observed hemostatic abnormalities, and we delineate the nuances in our approach compared to managing a similar condition in a nonpregnant patient. Heightened awareness among healthcare professionals is imperative for prompt diagnosis and effective intervention in such uncommon neurological complications during pregnancy.

Posterior reversible encephalopathy syndrome associated with antibiotic therapy: a case report and systematic review.

Posterior reversible encephalopathy syndrome (PRES) is an acute neurological condition associated with different etiologies, including antibiotic therapy. To date, most data regarding antibiotic-related PRES are limited to case reports and small case series. Here, we report a novel case description and provide a systematic review of the clinico-radiological characteristics and prognosis of available cases of PRES associated with antibiotic therapy. We performed a systematic literature search in PubMed and Scopus from inception to 10 January 2024, following PRISMA guidelines and a predefined protocol. The database search yielded 12 subjects (including our case). We described the case of a 55-year-old female patient with PRES occurring one day after administration of metronidazole and showing elevated serum neurofilament light chain protein levels and favorable outcome. In our systematic review, antibiotic-associated PRES was more frequent in female patients (83.3%). Metronidazole and fluoroquinolones were the most reported antibiotics (33.3% each). Clinical and radiological features were comparable to those of PRES due to other causes. Regarding the prognosis, about one third of the cases were admitted to the intensive care unit, but almost all subjects (90.0%) had a complete or almost complete clinical and radiological recovery after prompt cessation of the causative drug. Antibiotic-associated PRES appears to share most of the characteristics of classic PRES. Given the overall good prognosis of the disease, it is important to promptly diagnose antibiotic-associated PRES and discontinue the causative drug.

A Rare Case of Postpartum Paraplegia: A Case Report.

In this case report, a 27-year-old woman who had pre-eclampsia in the past and had a cesarean section as a result of the condition presents with an uncommon and difficult form of postpartum paraplegia. She experienced bilateral lower limb paralysis and urine incontinence soon after the surgery, which quickly led to unconsciousness and required mechanical ventilator support and intensive care treatment. Comprehensive diagnostic testing, which included magnetic resonance imaging scans of the brain and spinal cord, identified signs typical of "Posterior Reversible Encephalopathy Syndrome (PRES)" and spinal cord infarction affecting segments C3 to D2. "Antiphospholipid Antibody Syndrome (APLA)" was identified by laboratory testing, highlighting the significance of taking a thorough approach to comprehending this uncommon clinical condition. Treatment included anticoagulant therapy, high-dose steroid therapy, and antihypertensive drugs, emphasizing the crucial importance of inter-disciplinary care in handling such complex situations. Even if the patient's symptoms have partially improved, their condition is still being closely monitored in the intensive care unit. In the context of postpartum neurological problems and the complex interplay between pre-eclampsia, spinal cord infarction, and related clinical symptoms, this case emphasizes the need for increased awareness and prompt management.

Posterior Reversible Encephalopathy Syndrome With Hemorrhagic Transformation in the Postoperative Period of a Kidney Transplant.

Patients with end-stage renal disease (ESRD) who undergo kidney transplantation are at an increased risk of developing surgical and/or medical complications. Posterior reversible encephalopathy syndrome (PRES) is a rare complication that occurs in 0.34% of kidney transplant patients. It is characterized by a combination of neurological manifestations, risk factors, and characteristic radiological findings in neuroimaging studies. The development of PRES has been associated with various medical conditions and factors, including hypertension, the use of cytotoxic and immunosuppressive drugs, acute or chronic kidney disease, pre-eclampsia/eclampsia, autoimmune diseases, and solid organ and bone marrow transplantation. This report presents the case of a 19-year-old woman diagnosed with ESRD on hemodialysis due to lupus nephritis who experienced an episode of PRES with intraparenchymal hemorrhage during the postoperative period of kidney transplantation. The case emphasizes the importance of closely monitoring these patients during this period to enable early diagnosis and timely treatment of complications, ensuring a favorable prognosis.

Posterior Reversible Encephalopathy Syndrome in a Late Postpartum Patient With a Rare Complication of Subarachnoid Hemorrhage.

Posterior reversible encephalopathy syndrome (PRES) is considered a neuroclinical syndrome of headache, confusion, visual changes, and seizures associated with neuroimaging findings of posterior cerebral white matter edema. Although the incidence of the syndrome is largely unknown, this condition is becoming increasingly recognized. The prognosis is generally good with most symptoms resolving within one week and lesions on imaging resolving in two weeks. Death and significant neurological disability have been reported but are relatively rare. In this report, we present a 10-day postpartum patient with an atypical history of headache and seizure-like activity. Neuroimaging revealed findings consistent with PRES as well as a rare complication of subarachnoid hemorrhage. This case highlights the importance of clinicians considering preeclampsia/eclampsia-induced PRES when encountering a postpartum patient with headache and hypertension to further reduce morbidity and mortality in this patient population.

Preeclampsia With Posterior Reversible Encephalopathy Syndrome at 19 Weeks Gestation Resulting in Intrauterine Fetal Demise.

Posterior reversible encephalopathy syndrome (PRES) can be defined as a clinical syndrome of headache, seizures, visual disturbance, altered mental status, and characteristic magnetic resonance imaging (MRI) findings of vasogenic edema in the posterior subcortical parietal-occipital white matter. There are numerous potential inciting factors, including immunosuppression, renal disease, malignancy, cytotoxic medications, hypertension, preeclampsia, and eclampsia. In this paper, we present the case of a 21-year-old female at 19 weeks gestation presenting with symptoms consistent with preeclampsia with severe features and PRES. She was transferred to our facility after initial stabilization. She had an atypical course of preeclampsia prior to 20 weeks gestation, PRES lacking seizure activity, and ultimately her case resulted in intrauterine fetal demise (IUFD) at 20 weeks and six days gestation. As indicated by its name, PRES is considered a fully reversible syndrome, and the patient recovered after stabilization of her hypertensive disorder and delivery of the fetus. This case illustrates the importance of prompt recognition and treatment of hypertensive disorders in pregnant patients and the possibility of complications that can result in significant morbidity and mortality for both the mother and fetus.

Nephrotic Syndrome and Posterior Reversible Encephalopathy Syndrome as Clinical Presentations of Gemcitabine-Induced Thrombotic Micro-Angiopathy.

Gemcitabine-induced thrombotic micro-angiopathy (GiTMA) is a very rare pathology of micro-vascular occlusion with a poor prognosis. In this case report, we present a young male with pancreatic carcinoma who received gemcitabine as adjuvant chemotherapy and developed thrombotic micro-angiopathy (TMA) manifesting as nephrotic syndrome with renal dysfunction and posterior reversible encephalopathy syndrome (PRES). The case was successfully managed with discontinuation of the drug and conservative management. The pathogenesis of GiTMA might be direct endothelial dysfunction with consequent activation of the clotting system. The role of plasma exchanges and monoclonal antibodies is unclear in drug-induced TMA.

Posterior Reversible Encephalopathy Syndrome Presenting as Delirium With Psychosis and Agitation in the Postpartum Period.

Posterior reversible encephalopathy syndrome (PRES), which was first described in 1996, is a neurologic condition characterized by a combination of clinical and neuroimaging findings. PRES may arise in the context of preeclampsia, eclampsia, renal failure, and sepsis, among other conditions. Neuropsychiatric symptoms of PRES include altered mental status, agitation, and in some cases psychosis. PRES occurring in the postpartum period is understudied, especially with regard to its psychiatric manifestations. We aim to add to the literature a case of PRES associated with psychosis and agitation in a postpartum woman, highlighting clinical implications and offering suggestions for practice. A female in her late 20s, with no significant psychiatric or medical history, presented to the hospital at 29 weeks and one day of gestation following a witnessed seizure. She was found to be hypertensive and hyponatremic, was diagnosed with eclampsia, and underwent an emergent cesarean section due to fetal malpresentation. The next day, the patient developed paranoia with acute agitation, and the psychiatry team diagnosed her with delirium with psychosis/agitation secondary to her underlying medical condition. She required intramuscular medications for agitation, was placed in restraints, and was transferred to the ICU for sedation. Subsequently, CT and MRI scans of her head both indicated that she had developed PRES. The patient's delirium and psychotic behavior resolved after appropriate treatment of her eclampsia. To our knowledge, this case report is the second documented case in the literature, of a patient who presented with PRES characterized by agitation and psychotic features in the postpartum period. Due to the significant overlap in symptoms between delirium and postpartum psychosis, this case highlights the crucial importance of interdisciplinary collaboration for accurate diagnosis and prompt treatment of PRES in the postpartum period. The case also speaks to the importance of differentiating postpartum psychosis associated with a primary psychiatric disorder from delirium arising in postpartum patients with or without a previous psychiatric history.

Hemorrhagic Posterior Reversible Encephalopathy Syndrome in a Pediatric Patient With Acute Lymphoblastic Leukemia: A Case Report.

Posterior reversible encephalopathy syndrome (PRES) is an uncommon yet severe neurological disorder characterized by a combination of clinical and radiological features. Common clinical presentations of PRES include headaches, seizures, altered mental status ranging from lethargy to coma, visual disturbances, and behavior changes.  This case report outlines the occurrence of hemorrhagic PRES in an 11-year-old girl with B-cell acute lymphoblastic leukemia (ALL) relapse. Hospitalized for ALL relapse, the patient underwent reinduction chemotherapy. On the ninth day of admission, she had a generalized tonic-clonic seizure with a blood pressure peak of 170/120 mmHg. Magnetic resonance imaging (MRI) and a seizure episode suggested PRES. Initially, after the first tonic-clonic seizure, the neurological examination was normal, but after the second seizure, the meningeal symptoms were negative, and gaze palsy and right-sided homonymous hemianopsia were observed; muscle strength was symmetrically reduced in the upper and lower extremities and reflexes were symmetrical and diminished. A bilateral Babinski reflex was observed at the time of examination; the patient had mild motor aphasia, and she opened her eyes only in response to tactile stimulation. A follow-up MRI four days after the second seizure episode showed extensive PRES damage with hemorrhagic changes. Over two weeks, the patient's neurological status and blood pressure gradually improved, with persistent changes in the visual field. Subsequent MRI revealed a significant reduction in PRES lesions, but residual hemorrhage measuring 6x4 cm remained evident.

Tacrolimus-associated neurotoxicity isolated to the brainstem: two illustrative cases and a systematic review of the literature.

INTRODUCTION: Tacrolimus-associated neurotoxicity (TAN) manifests with wide clinical spectrum, ranging from mild tremors to severe encephalopathy. The isolated involvement of the brainstem is a rarely documented presentation of TAN, and its clinical and diagnostic characteristics are unclear. METHODS: We report two cases of brainstem-isolated TAN (bi-TAN). Moreover, we performed a systematic review of the literature on bi-TAN and extracted data concerning demographics, clinical characteristics, radiological features, and management. The systematic literature search followed PRISMA guidelines and a pre-defined protocol. RESULTS: Eleven patients, including our two, were identified (mean age: 41.3 years, ± 18.8; five males, 45%). Speech disturbance was the most common clinical presentation (45%). The mean latency from Tacrolimus initiation to bi-TAN onset was 26 days (± 30.8). Tacrolimus serum level tested above the reference range in three patients (mean: 26.83 ± 5.48). Brain MRI showed T2-FLAIR hyperintensities; three showed restricted diffusion on ADC maps. Neurological symptoms resolved completely in seven patients (63%) after Tacrolimus withdrawal or dose reduction. CONCLUSIONS: Our findings suggest that bi-TAN could represent a brainstem variant of posterior reversible encephalopathy syndrome. Recognition of bi-TAN as a potential cause of isolated brainstem lesions is crucial to disentangle the diagnostic work-up and ensure prompt withdrawal or reduction of the offending agent.

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.

Frequency of ischaemic stroke and intracranial haemorrhage in patients with reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES) - A systematic review.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) may cause ischaemic stroke and intracranial haemorrhage. The aim of our study was to assess the frequency of the afore-mentioned outcomes. METHODS: We performed a PROSPERO-registered (CRD42022355704) systematic review and meta-analysis accessing PubMed until 7 November 2022. The inclusion criteria were: (1) original publication, (2) adult patients (≥18 years), (3) enrolling patients with PRES and/or RCVS, (4) English language and (5) outcome information. Outcomes were frequency of (1) ischaemic stroke and (2) intracranial haemorrhage, divided into subarachnoid haemorrhage (SAH) and intraparenchymal haemorrhage (IPH). The Cochrane Risk of Bias tool was used. RESULTS: We identified 848 studies and included 48 relevant studies after reviewing titles, abstracts and full text. We found 11 studies on RCVS (unselected patients), reporting on 2746 patients. Among the patients analysed, 15.9% (95% CI 9.6%-23.4%) had ischaemic stroke and 22.1% (95% CI 10%-39.6%) had intracranial haemorrhage. A further 20.3% (95% CI 11.2%-31.2%) had SAH and 6.7% (95% CI 3.6%-10.7%) had IPH. Furthermore, we found 28 studies on PRES (unselected patients), reporting on 1385 patients. Among the patients analysed, 11.2% (95% CI 7.9%-15%) had ischaemic stroke and 16.1% (95% CI 12.3%-20.3%) had intracranial haemorrhage. Further, 7% (95% CI 4.7%-9.9%) had SAH and 9.7% (95% CI 5.4%-15%) had IPH. CONCLUSIONS: Intracranial haemorrhage and ischaemic stroke are common outcomes in PRES and RCVS. The frequency reported in the individual studies varied considerably.

Reversible cerebral vasoconstriction syndrome and posterior reversible encephalopathy syndrome following vaccination: analysis of the VAERS database and systematic review.

Objectives: This study aimed to analyze the Vaccine Adverse Event Reporting System (VAERS) database and systematically review the literature to provide a comprehensive analysis of reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES) secondary to vaccination. Methods: The authors analyzed the VAERS database and conducted a systematic review following PRISMA guidelines. The inclusion criteria for VAERS data were a score of ≥3 on the RCVS2 score and/or radiographic findings consistent with the diagnosis of RCVS or PRES. The systematic review was registered with PROSPERO. Results: Our combined data set included 29 cases (9 RCVS and 20 PRES). Most cases were women (72.4%) with a mean age of 50.7 years (SD 19.4 years). Most cases were associated with COVID-19 mRNA vaccines (58.6% Moderna, 20.7% Pfizer). Hypertension (37.9%), hyperlipidemia (13.7%), chronic kidney disease (CKD) (10.3%), and end-stage renal disease (6.8%) were common comorbidities. Furthermore, 20.6% (6/29) of cases were on immunosuppression therapy for various reasons. The mean time to symptom onset was 10.49 days after vaccination (SD 18.60), and the mean duration of hospitalization was 7.42 days (SD 5.94). The symptoms reported the most frequently were headache (41.3%), elevated blood pressure (31.0%), and emesis (17.2%). Typical radiographic findings included T2/FLAIR hyperintensities affecting the parieto-occipital lobes, indicative of vasogenic and/or cytotoxic edema. Conclusions: This study provides a comprehensive analysis of postvaccine RCVS and PRES. Both disease states were seen most often in those with pre-existing risk factors such as female sex, age over 50, hypertension, renal disease, and immunosuppression. Vaccines and their associated immune response may cause endothelial dysfunction leading to cerebral vasospasm and loss of cerebral autoregulation. However, further research is required to understand the underlying pathophysiological mechanisms. Despite the associations found, the absolute risk of these syndromes remains extremely low compared to the immense benefits of vaccination.