			Home About us Contact

Posttest Probability (posttest + probability)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Can Computed Tomography Angiography of the Brain Replace Lumbar Puncture in the Evaluation of Acute-onset Headache After a Negative Noncontrast Cranial Computed Tomography Scan?

ACADEMIC EMERGENCY MEDICINE, Issue 4 2010
Robert F. McCormack MD
Abstract Objectives:, The primary goal of evaluation for acute-onset headache is to exclude aneurysmal subarachnoid hemorrhage (SAH). Noncontrast cranial computed tomography (CT), followed by lumbar puncture (LP) if the CT is negative, is the current standard of care. Computed tomography angiography (CTA) of the brain has become more available and more sensitive for the detection of cerebral aneurysms. This study addresses the role of CT/CTA versus CT/LP in the diagnostic workup of acute-onset headache. Methods:, This article reviews the recent literature for the prevalence of SAH in emergency department (ED) headache patients, the sensitivity of CT for diagnosing acute SAH, and the sensitivity and specificity of CTA for cerebral aneurysms. An equivalence study comparing CT/LP and CT/CTA would require 3,000 + subjects. As an alternative, the authors constructed a mathematical probability model to determine the posttest probability of excluding aneurysmal or arterial venous malformation (AVM) SAH with a CT/CTA strategy. Results:, SAH prevalence in ED headache patients was conservatively estimated at 15%. Representative studies reported CT sensitivity for SAH to be 91% (95% confidence interval [CI] = 82% to 97%) and sensitivity of CTA for aneurysm to be 97.9% (95% CI = 88.9% to 99.9%). Based on these data, the posttest probability of excluding aneurysmal SAH after a negative CT/CTA was 99.43% (95% CI = 98.86% to 99.81%). Conclusions:, CT followed by CTA can exclude SAH with a greater than 99% posttest probability. In ED patients complaining of acute-onset headache without significant SAH risk factors, CT/CTA may offer a less invasive and more specific diagnostic paradigm. If one chooses to offer LP after CT/CTA, informed consent for LP should put the pretest risk of a missed aneurysmal SAH at less than 1%. ACADEMIC EMERGENCY MEDICINE 2010; 17:444,451 © 2010 by the Society for Academic Emergency Medicine [source]

Who Should Be Screened for Asymptomatic Carotid Artery Stenosis?

JOURNAL OF NEUROIMAGING, Issue 2 2001
Experience From the Western New York Stroke Screening Program
ABSTRACT Objective. Identification of significant asymptomatic carotid artery stenosis (ACAS) is important because of the stroke-risk reduction observed with carotid endarterectomy. The authors developed and validated a simple scoring system based on routinely available information to identify persons at high risk for ACAS using data collected during a community health screening program at various sites in western New York. A total of 1331 unselected volunteers without previous stroke, transient ischemic attack, or carotid artery surgery were evaluated by personal interview and duplex ultrasound. The main outcome measure was carotid artery stenosis >60% by duplex ultrasound. In the derivation set (n= 887), 4 variables were significantly associated with ACAS >60%: age >65 years (odds ratio [OR] = 4.1, 95% confidence interval [CI] = 2.6,6.7), current smoking (OR = 2.0, 95% CI = 1.2,3.5), coronary artery disease (OR = 2.4, 95% CI = 1.5,3.9), and hypercholesterolemia (OR = 1.9, 95% CI = 1.2,2.9). Three risk groups (low, intermediate, and high) were defined on the basis of total risk score assigned on the basis of the strength of association. The scheme effectively stratified the validation set (n= 444); the likelihood ratio and posttest probability for ACAS in the high-risk group were 3.0 and 35%, respectively, and in the intermediate and low-risk groups were 1.4 and 20% and 0.4 and 7%, respectively. Routinely available information can be used to identify persons in the community at high risk for ACAS. Doppler ultrasound screening in this subgroup may prove to be cost-effective and have an effect on stroke-free survival. [source]

Clinical Features of Bacterial Conjunctivitis in Children

ACADEMIC EMERGENCY MEDICINE, Issue 1 2007
Parul B. Patel MD
Abstract Objectives Conjunctivitis is a common cause of primary care and emergency department (ED) visits. There is a paucity of data in recent literature on the prevalence of pediatric bacterial conjunctivitis, and there are no evidence-based clinical guidelines for empirical treatment. The study objective was to describe clinical features most predictive of bacterial conjunctivitis. Methods This was a prospective study in a children's hospital ED. Conjunctival swabs for bacterial culture were obtained from patients aged 1 month to 18 years presenting with red or pink eye and/or the diagnosis of conjunctivitis. Results A total of 111 patients were enrolled over one year. Patients had a mean (±SD) age of 33.2 (±37.5) months, and 55% were male. Eighty-seven patients (78%) had positive bacterial cultures. Nontypeable Haemophilus influenzae accounted for 82% (71/87), Streptococcus pneumoniae for 16% (14/87), and Staphylococcus aureus for 2.2% (2/87). Five clinical variables were significantly associated with a positive bacterial culture. Regression analysis revealed that the combination of a history of gluey or sticky eyelids and the physical finding of mucoid or purulent discharge had a posttest probability of 96% (95% confidence interval = 90% to 99%). Subjective scoring by physicians for a positive culture was 50.6%. Conclusions Conjunctivitis in children is predominantly bacterial, with nontypeable H. influenzae being the most common organism. A history of gluey or sticky eyelids and physical findings of mucoid or purulent discharge are highly predictive of bacterial infection. Based on the above data, empirical ophthalmic antibiotic therapy may be appropriate in children presenting with conjunctivitis. [source]