Headache that will not go away...Third ED visit is the charm?

Subdural hematoma is an uncommon complication of epidural analgesia or diagnostic lumbar puncture. Headache is a common complaint for patients with either a subdural hematoma or a post-dural puncture headache. Because post-dural puncture headaches are commonly seen in the Emergency Department, the potential to miss more serious pathology arises. We present the case of a young female who suffered bilateral subdural hematomas following epidural analgesia during childbirth. She presented twice to the Emergency Department and was treated for a post-dural puncture headache before computed tomography imaging revealed the diagnosis on the third Emergency Department encounter. This case highlights the importance of exploring all potential diagnoses when a patient presents with a headache after either epidural analgesia or a diagnostic lumbar puncture, especially if the patient returns after unsuccessful treatment for a presumptive post-dural puncture headache.

The high-dimensional space of human diseases built from diagnosis records and mapped to genetic loci.

Human diseases are traditionally studied as singular, independent entities, limiting researchers' capacity to view human illnesses as dependent states in a complex, homeostatic system. Here, using time-stamped clinical records of over 151 million unique Americans, we construct a disease representation as points in a continuous, high-dimensional space, where diseases with similar etiology and manifestations lie near one another. We use the UK Biobank cohort, with half a million participants, to perform a genome-wide association study of newly defined human quantitative traits reflecting individuals' health states, corresponding to patient positions in our disease space. We discover 116 genetic associations involving 108 genetic loci and then use ten disease constellations resulting from clustering analysis of diseases in the embedding space, as well as 30 common diseases, to demonstrate that these genetic associations can be used to robustly predict various morbidities.

Multiple regression analyses to determine the effect of sweating rate and tattoo characteristics on sweat outcome measures during exercise.

PURPOSE: To compare local sweating rate (LSR) and local sweat sodium ([Na+]), chloride ([Cl-]), and potassium ([K+]) concentrations of tattooed skin and contralateral non-tattooed skin during exercise. METHODS: Thirty-three recreational exercisers (17 men, 16 women) with ≥ 1 unilateral permanent tattoo on the torso/arms were tested during cycling, running, or fitness sessions (26 ± 4 °C and 54 ± 13% relative humidity). Forty-eight tattoos with a range of ink colors, ages (3 weeks to 20 years), and densities (10-100%) were included. Before exercise, the skin was cleaned with alcohol and patches (3 M Tegaderm + Pad) were placed on the tattooed and contralateral non-tattooed skin. LSR was calculated from sweat mass (0.80 ± 0.31 g), patch surface area (11.9 cm2), and duration (62 ± 14 min). Sweat [Na+], [Cl-], and [K+] were measured via ion chromatography. RESULTS: Based on the analysis of variance results, there were no differences between tattooed and non-tattooed skin for LSR (1.16 ± 0.52 vs. 1.12 ± 0.53 mg/cm2/min; p = 0.51), sweat [Na+] (60.2 ± 23.5 vs. 58.5 ± 22.7 mmol/L; p = 0.27), sweat [Cl-] (52.1 ± 22.4 vs. 50.6 ± 22.0 mmol/L; p = 0.31), or sweat [K+] (5.8 ± 1.6 vs. 5.9 ± 1.4 mmol/L; p = 0.31). Multiple regression analyses suggested that younger tattoos were associated with higher sweat [Na+] (p = 0.045) and colorful tattoos were associated with higher sweat [Cl-] (p = 0.04) compared with contralateral non-tattooed skin. Otherwise, there were no effects of LSR or tattoo characteristics on regression models for LSR or sweat electrolyte concentrations. CONCLUSION: There were no effects of tattoos on LSR and sweat [K+] during exercise-induced sweating, but tattoo age and color had small effects on sweat [Na+] and sweat [Cl-], respectively. CLINICAL TRIAL IDENTIFIERS: NCT04240951 was registered on January 27, 2020 and NCT04920266 was registered on June 9, 2021.

Sweating Rate and Sweat Chloride Concentration of Elite Male Basketball Players Measured With a Wearable Microfluidic Device Versus the Standard Absorbent Patch Method.

The purpose of this study was to compare a wearable microfluidic device and standard absorbent patch in measuring local sweating rate (LSR) and sweat chloride concentration ([Cl-]) in elite basketball players. Participants were 53 male basketball players (25 ± 3 years, 92.2 ± 10.4 kg) in the National Basketball Association's development league. Players were tested during a moderate-intensity, coach-led practice (98 ± 30 min, 21.0 ± 1.2 °C). From the right ventral forearm, sweat was collected using an absorbent patch (3M Tegaderm™ + Pad). Subsequently, LSR and local sweat [Cl-] were determined via gravimetry and ion chromatography. From the left ventral forearm, LSR and local sweat [Cl-] were measured using a wearable microfluidic device and associated smartphone application-based algorithms. Whole-body sweating rate (WBSR) was determined from pre- to postexercise change in body mass corrected for fluid/food intake (ad libitum), urine loss, and estimated respiratory water and metabolic mass loss. The WBSR values predicted by the algorithms in the smartphone application were also recorded. There were no differences between the absorbent patch and microfluidic patch for LSR (1.25 ± 0.91 mg·cm-2·min-1 vs. 1.14 ±0.78 mg·cm-2·min-1, p = .34) or local sweat [Cl-] (30.6 ± 17.3 mmol/L vs. 29.6 ± 19.4 mmol/L, p = .55). There was no difference between measured and predicted WBSR (0.97 ± 0.41 L/hr vs. 0.89 ± 0.35 L/hr, p = .22; 95% limits of agreement = 0.61 L/hr). The wearable microfluidic device provides similar LSR, local sweat [Cl-], and WBSR results compared with standard field-based methods in elite male basketball players during moderate-intensity practices.

Bilateral Pedicle Fractures at Contiguous Segments in a Low Trauma Setting: A Case Report.

CASE: A 74-year-old patient with a history of osteoporosis presented with a 2-month history of lower back pain after low-energy trauma. Imaging revealed bilateral subacute L4 and L5 pedicle fractures-the first reported case of this low-energy mechanism of bilateral contiguous-segment pedicle fractures. CONCLUSION: Bilateral pedicle fractures have infrequently been reported in the literature. There have been a few reports of bilateral pedicle fractures because of isolated osteoporosis, and these have all been single level. The current report presents an unusual fragility fracture pattern that can be conservatively managed.

Cervical Spine CT Can Miss Fractures in American Football Players When Protective Equipment is in Place: A Cadaver Study.

BACKGROUND: Iatrogenic worsening of spinal injury can result in significant harm to American football players and complicate management when equipment is removed in the acute setting by inexperienced personnel. Spine imaging before removal of protective equipment mitigates this risk. There is no consensus regarding the ideal timing of equipment removal or whether current diagnostic imaging modalities are effective to detect such injuries without equipment removal. Prior data suggest that CT is a diagnostic modality for this purpose; however, radiologists' accuracy in detecting fractures in the presence of protective equipment requires additional study. QUESTIONS/PURPOSES: (1) Does the introduction of American football equipment result in a significant reduction in sensitivity for cervical spine fracture detection? (2) Absent specific guidance as to parameters needed to establish diagnostic quality, can a radiologist determine whether such CTs are of diagnostic quality by subjectively relying on the ability to identify anatomic landmarks? METHODS: A pendulum device was engineered to deliver a measured axial load to the crown of cadavers to produce a variety of cervical spine fractures in 13 cadaver specimens. The cadavers were then imaged using a standardized CT protocol first without and then with protective football equipment. The images were presented to three board-certified, fellowship-trained radiologists to (1) identify all fractures from the occiput to T1 and (2) subjectively assess the diagnostic quality of the resulting CTs. A sensitivity analysis was performed against a reference standard of fractures produced by the consensus of all radiologists in this study to determine whether there was any reduction in radiologists' ability to detect fractures once football equipment was in place. RESULTS: We found that CT scans obtained with football protective equipment in place resulted in lower sensitivity in diagnosing cervical spine injuries than CT scans obtained without pads. A total of 42 fractures were identified in the reference standard, allowing for a combined 126 possible fracture identifications between the three interpreters. Without football equipment, a combined 98 fractures were identified, whereas a combined 65 fractures were identified once the equipment was introduced. Overall, the sensitivity was reduced by 26% (52% [65 of 126] versus 78% [98 of 126] [95% CI 14.8% to 37.5%]; p < 0.001). Of the 78 total CT series imaged with football equipment, 92% (72 of 78) were considered to be of diagnostic quality. However, the study radiologists failed to identify 50% (53 of 105) of fractures present in those CT images. CONCLUSION: The sensitivity of cervical spine fracture detection using CT is diminished in the setting of protective American football equipment. Future studies in live subjects with cervical spine fracture may be warranted to support these conclusions. CLINICAL RELEVANCE: These findings contradict previous studies that determined CT to be a diagnostic imaging modality to image the cervical spine through equipment. Although the interpreting radiologists consistently deemed CTs performed in the presence of helmets and shoulder pads to have subjectively diagnostic quality, numerous fractures that had been detected in the absence of equipment were missed in their presence. Furthermore, this study established that subjective approval of the appearance of an imaging study based on the ability to recognize anatomic landmarks is insufficient to reliably determine the diagnostic quality of a CT study.

Improving Arthroplasty Efficiency and Quality Through Concentrating Service Volume by Complexity: Surviving the Medicare Policy Changes.

We have an academic medical center (AMC), an associated community-based hospital (CBH) and several ambulatory care centers which are being prepared to provide same day discharge (SDD) total joint arthroplasty (TJA) and unicompartmental knee arthroplasty (UKA). The near-capacity AMC cared for medically and technically complicated TJA patients. The CBH wanted to increase volume, improve margins, and become a center of excellence with an efficient hospital outpatient department and SDD TJA experience. METHODS: We transitioned primary, uncomplicated TJA, UKA, and minimally invasive TJA to the CBH. Revision surgeries, patients with extensive comorbidities, and complex primaries were performed at the AMC. Protocols were developed to facilitate SDD UKA and total hip arthroplasty (THA) as well as rapid recovery protocols for total knee arthroplasty (TKA) at both hospitals. A protocol-based system was put in place to make both hospitals ready for the removal of TKA from the Inpatient-Only list to avoid Quality Improvement Organization and possible resultant Recovery Audit Contractor audits if referred after implementation. RESULTS: The CBH volume increased 36.7% (+239). AMC volume slightly decreased (-0.46%, -5) resulting in an increase in margin contribution for the system. CBH quality metrics (surgical site infections, length of stay, readmissions, and mortality) were improved. Surgeon satisfaction improved as their volume, efficiency, quality metrics, and finances were enhanced. Although CBH per case revenue was 80.3% and 74.4% of the AMC for THA and TKA, net margins were 3.6% and 18.8% higher for THA and TKA, respectively. Increased efficiency, lower hospital cost, and higher volume at the CBH allowed for an increase in revenue despite lower reimbursement per case. CONCLUSION: This strategy will help hospital systems improve net margins while improving patient care despite lower net revenue per TJA episode. These strategies will become increasingly important going forward with the transition of higher numbers of TJA patients to outpatient which will be subjected to further decreases in net revenue per patient.

Idiopathic fourth ventricular outlet obstruction misdiagnosed as normal pressure hydrocephalus: A cautionary case.

BACKGROUND: Fourth ventricular outlet obstruction is an infrequent but well-established cause of tetraventricular hydrocephalus characterized by marked dilatation of the ventricular system with ballooning of the foramina of Monro, Magendie, and Luschka. Multiple processes including inflammation, infection, hemorrhage, neoplasms, or congenital malformations are known to cause this pathological obstruction. However, true idiopathic fourth ventricular outlet obstruction is a rare phenomenon with only a limited number of cases reported in the literature. CASE DESCRIPTION: A 61-year-old female presented with several months of unsteady gait, intermittent headaches, confusion, and episodes of urinary incontinence. Conventional magnetic resonance imaging demonstrated tetraventricular hydrocephalus without transependymal flow, but with ventral displacement of the brainstem and dorsal displacement of the cerebellum without an obvious obstructive lesion on pre- or post-contrast imaging prompting a diagnosis of normal pressure hydrocephalus. However, constructive interference in steady state (CISS) and half-Fourier acquisition single-shot turbo spin echo (HASTE) sequences followed by fluoroscopic dynamic cisternography suggested encystment of the fourth ventricle with thin margins of arachnoid membrane extending through the foramina of Luschka bilaterally into the pontocerebellar cistern. Operative intervention was pursued with resection of an identified arachnoid web. Postoperative imaging demonstrated marked reduction in the size of ventricular system, especially of the fourth ventricle. The patient's symptomatology resolved a few days after the procedure. CONCLUSION: Here, we describe an idiopathic case initially misdiagnosed as normal pressure hydrocephalus. The present case emphasizes the necessity of CISS sequences and fluoroscopic dynamic cisternography for suspected cases of fourth ventricular outlet obstruction as these diagnostic tests may guide surgical management and lead to superior patient outcomes.

HLIBCov: Parallel hierarchical matrix approximation of large covariance matrices and likelihoods with applications in parameter identification.

We provide more technical details about the HLIBCov package, which is using parallel hierarchical (H-) matrices to: •Approximate large dense inhomogeneous covariance matrices with a log-linear computational cost and storage requirement.•Compute matrix-vector product, Cholesky factorization and inverse with a log-linear complexity.•Identify unknown parameters of the covariance function (variance, smoothness, and covariance length). These unknown parameters are estimated by maximizing the joint Gaussian log-likelihood function. To demonstrate the numerical performance, we identify three unknown parameters in an example with 2,000,000 locations on a PC-desktop.

An explicit marching-on-in-time scheme for solving the time domain Kirchhoff integral equation.

A fully explicit marching-on-in-time (MOT) scheme for solving the time domain Kirchhoff (surface) integral equation to analyze transient acoustic scattering from rigid objects is presented. A higher-order Nyström method and a PE(CE)m-type ordinary differential equation integrator are used for spatial discretization and time marching, respectively. The resulting MOT scheme uses the same time step size as its implicit counterpart (which also uses Nyström method in space) without sacrificing from the accuracy and stability of the solution. Numerical results demonstrate the accuracy, efficiency, and applicability of the proposed explicit MOT solver.

Pott's Disease in a Patient with Subtle Red Flags.

BACKGROUND: Tuberculosis (TB) is now rare in developed countries; however, it is an important diagnosis for the Emergency Physician to be able to make. Classically thought of as a respiratory disease, TB can present in other ways, making it more challenging to recognize. CASE REPORT: We report the case of a 41-year-old woman who presented to the Emergency Department with a 4-week history of back pain. A diagnosis of T12 osteomyelitis and right psoas muscle abscess was made after magnetic resonance imaging. The concurrent finding raised concern for TB as psoas muscle abscess is usually found along with spinal TB. A computed tomography-guided fine-needle aspiration confirmed the diagnosis. This patient's social history was negative for many of the classic predisposing factors associated with TB: immunosuppression, personal travel, crowded living conditions. Repeated investigation into the patient's history revealed a visit several months prior from a family member from Vietnam who had been treated for TB. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: It is important for Emergency Physicians to be aware of the relatively high incidence of TB as a cause for concurrent psoas abscess and vertebral osteomyelitis.

T1ρ magnetic resonance imaging for detection of early cartilage changes in knees of asymptomatic collegiate female impact and nonimpact athletes.

OBJECTIVE: To determine if T1ρ magnetic resonance imaging (T1ρ MRI) could assess early articular cartilage changes in knees of asymptomatic female collegiate athletes. It was hypothesized that impact cohort would demonstrate greater changes than nonimpact cohort. DESIGN: An institutional review board-approved prospective cohort study. Blinded MRI analyses. SETTING: Participants from collegiate athletic program. Imaging at university hospital, February 2008 to July 2009. PARTICIPANTS: Inclusion criteria were female collegiate athletes in athletic season and asymptomatic. Exclusion criteria were previous/current knee injuries/surgeries. Twenty-one female NCAA Division I athletes, 11 impact (basketball players) and 10 nonimpact (swimmers) participants were consented and imaged with 3.0-T MRI (Siemens) and T1ρ sequence (University of Pennsylvania). One patient was removed (injury diagnosis). Final roster was 10 impact and 10 nonimpact participants. No difference in cohort body mass index, height, or weight. MAIN OUTCOME MEASURES: Average T1ρ relaxation times (ART) for patellar and femoral cartilage to analyze defined regions and depth and modified International Cartilage Repair Society classification. RESULTS: Statistical analyses showed that ART of radial zone of central third weight-bearing region of cartilage in basketball players was significantly greater (P = 0.041) than swimmers and ART of the superficial zone in basketball players was significantly less (P = 0.003) than that of swimmers. For both groups, the ART of superficial zones were significantly greater than that of radial zones (P < 0.001). Four impact athletes showed macroscopic changes (none in nonimpact cohort). CONCLUSIONS: T1ρ MRI detected early changes in articular cartilage of asymptomatic collegiate female impact athletes, with significant differences between cohorts in radial zone of central third weight-bearing region and superficial zones ART. Both cohorts showed increased ART in superficial zone. Four impact athletes showed macroscopic changes. CLINICAL RELEVANCE: This study demonstrates a quantitative MRI sequence able to detect signal differences in articular cartilage in asymptomatic athletes.

A transnational approach to understanding indicators of mental health, alcohol use and reproductive health among indigenous mexican migrants.

The three studies presented in this Special Topics in Immigrant Health report findings from a novel transnational, mixed-methods study with indigenous Mayans in Yucatán, Mexico, and their satellite communities in Southern California. Indigenous migrants comprise the largest proportion of recent, first-time migrants from Mexico to the United States and are among the migrant populations most vulnerable to discrimination (e.g. work place) and health disparities. The studies presented focus on three topics: perceived discrimination and mental health among indigenous migrants and non-migrants, risky alcohol use behaviors associated with migration to the U.S. and within Mexico, and gendered power dynamics related to sexual health care access and utilization. This transnational research sheds new light on health issues and gender differences affecting indigenous Mexican migrant men, women and their families. Findings can serve to inform intervention research to improve migrant health in the U.S. and Mexico as well as transnational collaboration between countries.

Perceived discrimination and religiosity as potential mediating factors between migration and depressive symptoms: a transnational study of an indigenous Mayan population.

Evidence suggests that in the US perceived discrimination among migrants of Mexican origin is associated with depressive symptoms. Factors that confer resilience, such as religiosity, could serve as a mediating factor in the context of migration stressors. We hypothesized that migration is associated with higher depressive symptoms and that discrimination and religiosity would mediate this relationship in a binational (US and Mexican) sample of indigenous Mexican migrants. We applied path analysis modeling to test our hypotheses with a sample of 650 individuals (n = 583 in Mexico; n = 67 in US). Results indicated that migration experience and current US residence were associated with perceived discrimination, which in turn were associated with a higher risk for depressive symptoms. Among women not living in the US, religiosity was associated with lower perceived discrimination. Discrimination is pervasive among male and female transnational and domestic migrants and religiosity may serve as a protective factor against discrimination for some women.

Reconstructing parameters of the FitzHugh-Nagumo system from boundary potential measurements.

We consider distributed parameter identification problems for the FitzHugh-Nagumo model of electrocardiology. The model describes the evolution of electrical potentials in heart tissues. The mathematical problem is to reconstruct physical parameters of the system through partial knowledge of its solutions on the boundary of the domain. We present a parallel algorithm of Newton-Krylov type that combines Newton's method for numerical optimization with Krylov subspace solvers for the resulting Karush-Kuhn-Tucker system. We show by numerical simulations that parameter reconstruction can be performed from measurements taken on the boundary of the domain only. We discuss the effects of various model parameters on the quality of reconstructions.