Hyperacute hyponatremia mimicking acute ischemic stroke.

We present a case of hyperacute hyponatremia with stroke like symptoms on presentation. Symptoms included confusion, left-sided facial droop, right-sided hemiparesis, dysarthria and aphasia, with an NIH stroke score of 5. Sodium level at the time of presentation was 119 mmol/L which dropped acutely from 138 mmol/L seven hours prior. Symptoms improved after treatment with 3% saline and no evidence of stroke, intracranial hemorrhage or space-occupying lesion was seen on imaging. The most likely cause of the hyponatremia was increased free water consumption and ADH surge. The patient remained symptom free after discharge with resolution of hyponatremia. Acute hyponatremia can cause focal neurological complaints and deficits, mimicking acute ischemic stroke. We advise clinicians to be aware of this entity when considering interventions for possible acute ischemic stroke and evaluating a patient with focal neurological deficits.

A unique presentation of Colovesical fistula.

A colovesical fistula (CVF) is a pathological connection between the colon and the urinary bladder. Although they are uncommon, consequences can severely affect quality of life and mortality. Diverticula are the most common cause of CVF. This case details a patient's CVF diagnosis in the emergency department with unremitting gastrointestinal and urinary symptoms. A 78-year-old male patient with recent hospitalization for stroke and left carotid endarterectomy complicated by urinary retention treated with a Foley catheter presented to the Emergency Department with a chief complaint of hematuria and unremitting diarrhea. Foley exchange resulted in improved urinary retention and diarrhea during hospitalization. One day following hospital discharge, the patient presented again with a blocked Foley catheter and diarrhea. Foley irrigations resulting in near immediate diarrhea and lack of bladder filling on bladder scan portended to a diagnosis of colovesical fistula despite no history diverticula or colon malignancy. An abdominal/pelvic computed tomography scan and cystogram confirmed a colovesical fistula. This case highlights the need for consideration of colovesical fistula in a seemingly simple ED complaint of urinary retention. It is prudent to closely follow bladder scan volumes when flushing a Foley catheter. Given the significant comorbidities such as urosepsis and health care impact of repeat ED visits and hospitalizations, CVF can and should be entertained and rapidly diagnosed in the emergency department. Our case highlights the need for consideration of a vesico-colic fistula despite the absence of initial relevant risk factors.

A proposed harmonized LPS molecular-subtyping scheme for Cronobacter species.

Cronobacter are opportunistic pathogens, which cause infections in all age groups. To aid the characterization of Cronobacter in foods and environments a harmonized LPS identification scheme for molecular serotyping is needed. To this end, we studied 409 Cronobacter isolates representing the seven Cronobacter species using two previously reported molecular serotyping schemes, described here as Mullane-Jarvis (M-J) and Sun schemes. PCR analysis revealed many overlapping results that were obtained when independently applying the two serotyping schemes. There were complete agreements between the two PCR schemes for Cronobacter sakazakii (Csak) O:1, Csak O:3, and Csak O:7 serotypes. However, only thirty-five of 41 Csak O:4 strains, identified using the M-J scheme, were PCR-positive with the Sun scheme primers. Also the Sun scheme Csak O:5 primers failed to identify this serotype in any of the C. sakazakii strains tested, but did recognize seven Cronobacter turicensis strains, which were identified as Ctur O:3 using the M-J scheme. Similarly, the Sun scheme Csak O:6 primers recognized 30 Cronobacter malonaticus O:2 strains identified with the M-J scheme, but failed to identify this serotype in any C. sakazakii strain investigated. In this report, these findings are summarized and a harmonized molecular-serotyping scheme is proposed which is predicated on the correct identification of Cronobacter species, prior to serotype determination. In summary, fourteen serotypes were identified using the combined protocol, which consists of Csak O:1-O:4, and Csak O:7; Cmal O:1-O:2; Cdub O:1-O:2, Cmuy O:1-O:2, Cuni O:1, as well as Ctur O:1 and Ctur O:3.

Identification and characterization of five new molecular serogroups of Cronobacter spp.

Cronobacter spp. (formerly Enterobacter sakazakii) is an emerging foodborne pathogen consisting of seven species including C. sakazakii, C. malonaticus, C. muytjensii, C. turicensis, C. dublinensis (with three subspecies, dublinensis, lausannensis, and lactaridi), C. universalis, and C. condimenti. To date, 12 Cronobacter serogroups have been identified. In this study, MboII restriction fragment length polymorphism patterns and DNA sequences of O-antigen gene clusters were used to identify novel serogroups of Cronobacter spp. Sequence analysis of the O-antigen regions, located between galF and gnd, of strains with distinct restriction fragment length polymorphism patterns revealed five unique gene clusters. These new O-antigen gene clusters were species specific and were termed C. turicensis O3, C. muytjensii O2, C. dublinensis O1, C. dublinensis O2, and C. universalis O1. Polymerase chain reaction assays were developed using primers specific to O-antigen processing genes and used to screen a collection of Cronobacter strains to determine the frequency of these newly identified serotypes.

Male-male competition, female mate choice and their interaction: determining total sexual selection.

Empirical studies of sexual selection typically focus on one of the two mechanisms of sexual selection without integrating these into a description of total sexual selection, or study total sexual selection without quantifying the contributions of all of the mechanisms of sexual selection. However, this can provide an incomplete or misleading view of how sexually selected traits evolve if the mechanisms of sexual selection are opposing or differ in form. Here, we take a two-fold approach to advocate a direction for future studies of sexual selection. We first show how a quantitative partitioning and examination of sexual selection mechanisms can inform by identifying illustrative studies that describe both male-male competition and female mate choice acting on the same trait. In our sample, the most common trait where this occurred was body size, and selection was typically linear. We found that male-male competition and female mate choice can be reinforcing or opposing, although the former is most common in the literature. The mechanisms of sexual selection can occur simultaneously or sequentially, and we found they were more likely to be opposing when the mechanisms operated sequentially. The degree and timing that these mechanisms interact have important implications for the operation of sexual selection and needs to be considered in designing studies. Our examples highlight where empirical data are needed. We especially lack standardized measures of the form and strength of selection imposed by each mechanism of sexual selection and how they combine to determine total sexual selection. Secondly, using quantitative genetic principles, we outline how the selection imposed by individual mechanisms can be measured and combined to estimate the total strength and form of sexual selection. We discuss the evolutionary consequences of combining the mechanisms of sexual selection and interpreting total sexual selection. We suggest how this approach may result in empirical progress in the field of sexual selection.