Recurrent Reversible Cerebral Vasoconstriction Syndrome: A Report of Two Cases.

Reversible cerebral vasoconstriction syndrome (RCVS) is a rare neurological condition that classically presents with recurrent, thunderclap headaches and radiographic findings of multifocal narrowing of cerebral vasculature. Complications of RCVS may include ischemic or hemorrhagic strokes. Sympathomimetic agents including cannabinoids have been associated as precipitants in many cases. RCVS is classically considered to be reversible, although cases of recurrent RCVS have been described in the literature. In this report, we describe two cases of recurrent RCVS, which were precipitated by recurrent exposures to inciting agents. The first patient was found to have a history of repeated exposure to tetrahydrocannabinol (THC) and suffered from recurrent multifocal ischemic strokes with evidence of persistent multifocal narrowing of cerebral vasculature by cerebral arteriography. The second case describes a patient with a history of use of ashwagandha, medical marijuana, and serotonin-norepinephrine reuptake inhibitors (SNRIs) who experienced multiple intracranial hemorrhages with radiographic evidence of multifocal narrowing of cerebral vessels as well.

Recurrent Embolic Strokes From Prosthetic Valve Endocarditis With Negative Initial Evaluation in a Non-Toxic-Appearing Patient: A Case Report.

Infective endocarditis (IE) is a common cause of embolic strokes. Early diagnosis and treatment are essential to decrease the risk of ischemic stroke and ensure appropriate treatment, particularly given the higher risk of hemorrhagic complications. Treatment is also essential to prevent other complications such as heart failure, perivalvular abscesses, or intracranial abscesses. Transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) may not show endocardial involvement in the early stages of IE and, rarely, some patients may lack systemic signs of infection, making the early detection of IE challenging. Multifocal ischemic strokes may be the initial manifestation of IE and warrant further workup directed at IE even if initial echocardiogram findings are negative. A high index of clinical suspicion and thorough history are of utmost importance.

Bilateral Acute Hippocampal Ischemia in Two Patients Abusing Cocaine: What is the Outcome?

Hippocampal ischemia is a rare complication of cocaine abuse that has been thought to arise from vasospasm, anoxic injury, and/or catecholaminergic excitotoxicity. We present two cases of patients abusing cocaine, who presented with an acute onset anterograde amnesia due to bilateral hippocampal ischemia, and had different outcomes. Case 1 is a 49-year-old male with a history of IV heroin abuse who presented after being found down for an unknown period of time. He awoke with no memory of events leading up to hospitalization and was unable to retain new information. Urine toxicology was positive for cocaine and opiates. Traditional vascular risk factors included obesity, hypertension, and hyperlipidemia. His recovery was complicated by continued drug use and one episode of cardiac arrest. Despite cognitive rehabilitation, only minimal improvements in his anterograde memory were observed during his annual follow-up. Case 2 is a 23-year-old male with a history of attention deficit disorder treated with dexmethylphenidate and a history of consistent marijuana and cocaine abuse, who presented with nausea, vomiting, chest pain, shortness of breath, and acute-onset short-term memory loss. Urine toxicology was negative for cocaine and opiates and positive for marijuana. He had no known vascular risk factors. With cognitive rehabilitation and discontinuation of illicit drug use, he demonstrated a significant improvement in his memory function over the course of six months. Brain MRI in both patients showed symmetric bilateral hippocampal diffusion restriction without post-contrast enhancement with corresponding hyperintensities on fluid-attenuated inversion recovery sequences. In both patients, cerebrospinal fluid (CSF) studies were unremarkable for inflammation or infection, and electroencephalograms were normal in awake and drowsy states. Bilateral hippocampal ischemia should be considered as a potential cause of acute onset anterograde amnesia in patients with a history of cocaine abuse. Other substances such as heroin and dexmethylphenidate may potentially increase susceptibility for hippocampal ischemia in patients using cocaine. Discontinuation of illicit drug abuse can influence the degree of recovery from acute bilateral hippocampal ischemia.

Evaluation of misting controls to reduce respirable silica exposure for brick cutting.

It is estimated that more than 1.7 million workers in the United States are potentially exposed to respirable crystalline silica, with a large percentage having been exposed to silica concentrations higher than the limits set by current standards and regulations. The purpose of this study is to characterize the use of water-misting engineering controls to reduce exposure to respirable crystalline silica for construction workers engaged in the task of brick cutting. Since data concerning the efficacy of engineering controls collected at worksites is often confounded by factors such as wind, worker skill level, the experiments were conducted in a laboratory environment. A completely enclosed testing chamber housed the brick-cutting saw. Respirable dust concentrations were measured using the Model 3321 Aerodynamic Particle Sizer. Specifically, the laboratory experiment was designed to compare dust suppression through water misting using conventional freely flowing water techniques. Brass atomizing nozzles with three flow rates were used for making this comparison: low (5.0 ml s(-1) or 4.8 gal h(-1)), medium (9.0 ml s(-1) or 8.6 gal h(-1)) and high (18 ml s(-1) or 17.3 gal h(-1)). The flow rate for freely flowing water, using manufacturer-supplied equipment, was 50 ml s(-1) (48 gal h(-1)). The experiment consisted of five replications of five samples each (low-misting, medium-misting, high-misting, freely flowing water and no control). The order of sampling within each replicate was randomized. Estimates of dust reduction showed that low-misting nozzles reduced the respirable mass fraction of dust by about 63%, medium-misting nozzles by about 67%, high-misting nozzles by about 79% and freely flowing water by about 93%. Based on these results, it may be feasible to use misting to control respirable silica dust instead of freely flowing water. This strategy is of practical interest to the construction industry which must frequently limit the amount of water used on construction sites.