Jennifer L. Lyons

Background and Purpose—: Human immunodeficiency virus (HIV) infection has been shown to increase both ischemic and hemorrhagic stroke risks, but there are limited data on the safety and outcomes of intravenous thrombolysis with tPA (tissue-type plasminogen activator) for acute ischemic stroke in HIV-infected patients. Methods—: A retrospective chart review of intravenous tPA-treated HIV patients who presented with acute stroke symptoms was performed in 7 large inner-city US academic centers (various search years between 2000 and 2017). We collected data on HIV, National Institutes of Health Stroke Scale score, ischemic stroke risk factors, opportunistic infections, intravenous drug abuse, neuroimaging findings, and modified Rankin Scale score at last follow-up. Results—: We identified 33 HIV-infected patients treated with intravenous tPA (mean age, 51 years; 24 men), 10 of whom were stroke mimics. Sixteen of 33 (48%) patients had an HIV viral load less than the limit of detection while 10 of 33 (30%) had a CD4 count 3 . The median National Institutes of Health Stroke Scale score at presentation was 9, and mean time from symptom onset to tPA was 144 minutes (median, 159). The median modified Rankin Scale score for the 33-patient cohort was 1 and for the 23-patient actual stroke cohort was 2, measured at a median of 90 days poststroke symptom onset. Two patients had nonfatal hemorrhagic transformation (6%; 95% confidence interval, 1%–20%), both in the actual stroke group. Two patients had varicella zoster virus vasculitis of the central nervous system, 1 had meningovascular syphilis, and 7 other patients were actively using intravenous drugs (3 cocaine, 1 heroin, and 3 unspecified), none of whom had hemorrhagic transformation. Conclusions—: Most HIV-infected patients treated with intravenous tPA for presumed and actual acute ischemic stroke had no complications, and we observed no fatalities. Stroke mimics were common, and thrombolysis seems safe in this group. We found no data to suggest an increased risk of intravenous tPA-related complications because of concomitant opportunistic infections or intravenous drug abuse.

Arboviruses are arthropod-borne viruses transmitted by the bite of mosquitoes, ticks, or other arthropods. Arboviruses are a common and an increasing cause of human illness in North America. Powassan virus, Chikungunya virus, and Zika virus are arboviruses that have all recently emerged as increasing causes of neurologic illness. Powassan virus almost exclusively causes encephalitis, but cases are rare, sporadic, and restricted to portions of North America and Russia. Chikungunya virus has spread widely across the world, causing millions of infections. Encephalitis is a rare manifestation of illness but is more common and severe in neonates and older adults. Zika virus has recently spread through much of the Americas and has been associated mostly with microcephaly and other congenital neurologic complications. Encephalitis occurring in infected adults has also been recently reported. This review will discuss the neuropathogenesis of these viruses, their transmission and geographic distribution, the spectrum of their neurologic manifestations, and the appropriate method of diagnosis.

Background. Powassan virus (POWV) is a rarely diagnosed cause of encephalitis in the United States. In the Northeast, it is transmitted by Ixodes scapularis, the same vector that transmits Lyme disease. The prevalence of POWV among animal hosts and vectors has been increasing. We present 8 cases of POWV encephalitis from Massachusetts and New Hampshire in 2013–2015. Methods. We abstracted clinical and epidemiological information for patients with POWV encephalitis diagnosed at 2 hospitals in Massachusetts from 2013 to 2015. We compared their brain imaging with those in published findings from Powassan and other viral encephalitides. Results. The patients ranged in age from 21 to 82 years, were, for the most part, previously healthy, and presented with syndromes of fever, headache, and altered consciousness. Infections occurred from May to September and were often associated with known tick exposures. In all patients, cerebrospinal fluid analyses showed pleocytosis with elevated protein. In 7 of 8 patients, brain magnetic resonance imaging demonstrated deep foci of increased T2/fluid-attenuation inversion recovery signal intensity. Conclusions. We describe 8 cases of POWV encephalitis in Massachusetts and New Hampshire in 2013–2015. Prior to this, there had been only 2 cases of POWV encephalitis identified in Massachusetts. These cases may represent emergence of this virus in a region where its vector, I. scapularis, is known to be prevalent or may represent the emerging diagnosis of an underappreciated pathogen. We recommend testing for POWV in patients who present with encephalitis in the spring to fall in New England.

Syphilis has reemerged as an important cause of neurological disease, affecting any part of the neuraxis at any stage of infection. What was once a dwindling diagnosis is now redoubling, particularly in the HIV-positive and in men who have sex with men populations. In the era of antibiotics and HIV coinfection, neurosyphilis presentations are protean, making diagnosis notoriously challenging. Advanced disease may be irreversible, and so early detection and treatment are ideal. Herein, we review recent advances in understanding neurosyphilis.

Fungal infections of the central nervous system have manifold presentations and courses that depend largely on both host and organism characteristics. Although subjects with impaired immunity are generally at higher risk for severe disease, several fungal organisms are considered primary pathogens and can also cause disease in otherwise immunocompetent individuals. Herein, we describe the epidemiology, presentation, diagnosis, and management of central nervous system complications of several fungal pathogens.