Adherence to use of blood cultures according to current national guidelines and their impact in patients with community acquired pneumonia: A retrospective cohort.

BACKGROUND: Community acquired pneumonia (CAP) is the most frequent cause of mortality secondary to infectious etiologies. Recommendations about the use of blood cultures in the diagnosis and treatment of CAP has been a contentious topic of debate and ever-changing recommendations. METHODS: A cohort study was conducted in a community teaching hospital. All the patients that were admitted with a diagnosis of CAP, between January and December of 2019 were included. Sociodemographic and clinical characteristics were obtained. Blood cultures results were obtained, and it was evaluated if they were done in compliance with current recommendations by the Infectious Disease Society of America (IDSA). RESULTS: 721 patients were included in the study. Median age was 68 years and 50% of the patients were male (n = 293). Patients presented from home (84%) and the most common comorbidities were hypertension and diabetes (68% and 31%). 96 patients had positive blood culture and 34% (n = 247) of all the blood cultures were adequately ordered. 80 patients died or went to hospice and the median length of hospital stay in our cohort was 7 days. The multivariate model showed that mortality was associated with positive blood cultures (OR = 3.1 95%CI 1.63-5.87) and appropriateness of blood cultures (OR = 2.96 95% CI 1.2-5.7). CONCLUSION: Adequate use of blood cultures in patients with CAP might have some association with the outcomes of this disease. However, a prospective study evaluating the utility of this test following current IDSA recommendations is needed to understand their impact in mortality and morbidity.

Drug-induced Erythema Multiforme Major in an Elderly Female.

Erythema multiforme (EM) is an acute, immune-mediated condition which affects the skin and mucous membranes. EM is a type 4 hypersensitivity reaction typically mediated by cytotoxic T lymphocytes. It is usually a self limiting, transient, inflammatory disease that spontaneously resolves within weeks without major sequelae. However, occasionally patients might have frequent recurrences, persistent disease or serious complications like fluid and electrolyte abnormalities. The most common triggers are infection followed by medications. Here we present the case of an 81-year-old female who came in with worsening lip and tongue swelling associated with a rash and was diagnosed with EM major due to naproxen.

A Rare Case of Human Herpesvirus 6 Meningitis in an Immunocompetent Asian Male Presented With a Severe Intractable Headache.

Human herpesvirus 6 (HHV-6) manifesting as a central nervous system (CNS) infection (especially meningoencephalitis) is reported as a primary infection in children and from reactivation in immunocompromised patients; however, it has rarely been reported in immunocompetent adults. Latent infections of the CNS can cause a myriad of clinical presentations ranging from a benign, febrile, self-resolving illness to limbic encephalitis, temporal lobe seizures, and neuropsychiatric symptoms such as behavioral disturbances and psychosis. No standard diagnostic criteria or management guidelines exist for this condition. Possible neuroimaging findings include abnormalities in the medial temporal lobe involving the hippocampus and amygdala. We hereby present a case of HHV-6 meningitis in a 48-year-old immunocompetent male presenting without encephalopathic symptoms and normal neuroimaging findings.

An Unusual Association between Neurofibromatosis Type 1 and Diffuse B Cell Lymphoma.

Neurofibromatosis type 1 (NF-1) is known to be associated with increased risk of malignancy by at least fourfold. Malignant lymphomas are rare in adults with NF-1. Hereby, we present a 75-year-old male with NF-1 complaining of weakness, nausea, and vomiting associated with abdominal pain. Three months prior to presentation, he had suffered a motor vehicle accident (MVA) resulting in multiple rib fractures that was seen in chest X-ray. For the following three months, he had intermittent chest pain, but it was attributed to the recent rib fracture. During this admission, the severity of chest pain worsened and the associated vomiting inclined further investigation; including CT imaging and bone biopsy, it was revealed to be a rare case of diffuse B cell lymphoma in a patient with NF-1. However, we believe the recent MVA caused an anchoring bias in making a prompt diagnosis. In addition, the appearance of the neurofibroma, resulted in suboptimal physical examination, and hence, there was a delay in reaching the diagnosis. We will discuss here the presentation of this case, to highlight the rare association and to increase awareness of when encountering a challenging diagnosis.

αSynuclein control of mitochondrial homeostasis in human-derived neurons is disrupted by mutations associated with Parkinson's disease.

The etiology of Parkinson's disease (PD) converges on a common pathogenic pathway of mitochondrial defects in which α-Synuclein (αSyn) is thought to play a role. However, the mechanisms by which αSyn and its disease-associated allelic variants cause mitochondrial dysfunction remain unknown. Here, we analyzed mitochondrial axonal transport and morphology in human-derived neurons overexpressing wild-type (WT) αSyn or the mutated variants A30P or A53T, which are known to have differential lipid affinities. A53T αSyn was enriched in mitochondrial fractions, inducing significant mitochondrial transport defects and fragmentation, while milder defects were elicited by WT and A30P. We found that αSyn-mediated mitochondrial fragmentation was linked to expression levels in WT and A53T variants. Targeted delivery of WT and A53T αSyn to the outer mitochondrial membrane further increased fragmentation, whereas A30P did not. Genomic editing to disrupt the N-terminal domain of αSyn, which is important for membrane association, resulted in mitochondrial elongation without changes in fusion-fission protein levels, suggesting that αSyn plays a direct physiological role in mitochondrial size maintenance. Thus, we demonstrate that the association of αSyn with the mitochondria, which is modulated by protein mutation and dosage, influences mitochondrial transport and morphology, highlighting its relevance in a common pathway impaired in PD.

Differential inhibition onto developing and mature granule cells generates high-frequency filters with variable gain.

Adult hippocampal neurogenesis provides the dentate gyrus with heterogeneous populations of granule cells (GC) originated at different times. The contribution of these cells to information encoding is under current investigation. Here, we show that incoming spike trains activate different populations of GC determined by the stimulation frequency and GC age. Immature GC respond to a wider range of stimulus frequencies, whereas mature GC are less responsive at high frequencies. This difference is dictated by feedforward inhibition, which restricts mature GC activation. Yet, the stronger inhibition of mature GC results in a higher temporal fidelity compared to that of immature GC. Thus, hippocampal inputs activate two populations of neurons with variable frequency filters: immature cells, with wide-range responses, that are reliable transmitters of the incoming frequency, and mature neurons, with narrow frequency response, that are precise at informing the beginning of the stimulus, but with a sparse activity.