Susac Syndrome With Livedo Reticularis: Pathogenesis and Literature Review

Case report: Susac syndrome-two ends of the spectrum, single center case reports and review of the literature

Susac syndrome is a rare and enigmatic complex neurological disorder primarily affecting small blood vessels in the brain, retina, and inner ear. Diagnosing Susac syndrome may be extremely challenging not only due to its rarity, but also due to the variability of its clinical presentation. This paper describes two vastly different cases-one with mild symptoms and good response to therapy, the other with severe, complicated course, relapses and long-term sequelae despite multiple therapeutic interventions. Building upon the available guidelines, we highlight the utility of black blood MRI in this disease and provide a comprehensive review of available clinical experience in clinical presentation, diagnosis and therapy of this disease. Despite its rarity, the awareness of Susac syndrome may be of uttermost importance since it ultimately is a treatable condition. If diagnosed in a timely manner, early intervention can substantially improve the outcomes of our patients.

Sporadic Creutzfeldt-Jakob Disease With Status Epilepticus: Molecular Mechanisms and a Scoping Review of the Literature

Creutzfeldt-Jakob disease (CJD) is a rapidly progressing neurodegenerative disorder and is a spongiform encephalopathy. A 59-year-old male presented with subacute-onset worsening encephalopathy and was found to be in non-convulsive status epilepticus (NCSE) requiring intubation and a midazolam infusion for refractory seizures. Electroencephalogram (EEG) revealed triphasic repeats with focal epileptogenic originating from the left parietal region. The patient continued to have up to 25-40 non-convulsive seizures per day. Cerebrospinal fluid (CSF) analysis revealed elevated 14-3-3 and tau protein. A real-time quaking-induced conversion assay in CSF was positive. The patient was diagnosed with probable sporadic CJD based on criteria from the Centers for Disease Control. Supportive treatment was provided. Cellular prion protein (PrPC) plays an important role in myelination of the peripheral nervous system, regulation of the neuronal membrane, and circadian rhythm. The molecular mechanisms of CJD involve the catalyzation of the physiological PrPC into the pathological prion protein (PrPSc). This post-translational change in conformation leads to the generation of PrPSc and is involved in spongiform encephalopathies. Mechanisms of neurodegeneration include astrocytosis, neuronal apoptosis, and amyloid plaque formation. A scoping literature review was conducted in three databases on cases of CJD with SE. A total of 13 cases are identified that include the type of CJD and the morphology of the seizures. NCSE is the most prevalent form of SE in patients with CJD.

Plasma Microbial Cell-Free DNA (CF-DNA) Next-Generation Sequencing in Diagnosing Intracranial Abscesses: Pathophysiology and a Scoping Review of the Literature

Plasma microbial cell-free DNA (cf-DNA) from next-generation sequencing (NGS) provides improved sensitivity and specificity compared to standard microbial blood cultures. cf-DNA sequencing also has an improved turnaround time (TAT) and allows quicker commencement of antibiotics in life-threatening infections such as a brain abscess. Brain abscesses carry significant morbidity and mortality. Empiric treatment and management are critical in improving functional neurological outcomes. Reported here is the case of a severe central nervous system (CNS) infection with multiple ring-enhancing lesions seen throughout the cerebrum on magnetic resonance imaging (MRI). Standard microbial blood cultures were inconclusive and definitive identification of the pathogen was achieved through microbial cf-DNA NGS.  Brain abscesses develop in four distinct phases: early cerebritis, late cerebritis, early capsule formation, and late capsule formation. The pathogenesis of cerebral abscess involves direct parenchymal inflammation of the pathogen, the recruitment of inflammatory CNS cell types (microglia, inflammatory astrocytes, etc), and the chemotaxis of immune cells. cf-DNA is released into the bloodstream in response to pathogen opsonization and immune-mediated cell death. A scoping literature review includes cases of intracranial abscesses diagnosed via cf-DNA NGS.