Items in AFP with MESH term: Predictive Value of Tests
Preoperative Cardiac Risk Assessment - Article
ABSTRACT: Heart disease is the leading cause of mortality in the United States. An important subset of heart disease is perioperative myocardial infarction, which affects approximately 50,000 persons each year. The American College of Cardiology (ACC) and American Heart Association (AHA) have coauthored a guideline on preoperative cardiac risk assessment, as has the American College of Physicians (ACP). The ACC/AHA guideline uses major, intermediate, and minor clinical predictors to stratify patients into different cardiac risk categories. Patients with poor functional status or those undergoing high-risk surgery require further risk stratification via cardiac stress testing. The ACP guideline also starts by screening patients for clinical variables that predict perioperative cardiac complications. However, the ACP did not feel there was enough evidence to support poor functional status as a significant predictor of increased risk. High-risk patients would sometimes merit preoperative cardiac catheterization by the ACC/AHA guideline, while the ACP version would reserve catheterization only for those who were candidates for cardiac revascularization independent of their noncardiac surgery. A recent development in prophylaxis of surgery-related cardiac complications is the use of beta blockers perioperatively for patients with cardiac risk factors.
Tympanometry - Article
ABSTRACT: Tympanometry provides useful quantitative information about the presence of fluid in the middle ear, mobility of the middle ear system, and ear canal volume. Its use has been recommended in conjunction with more qualitative information (e.g., history, appearance, and mobility of the tympanic membrane) in the evaluation of otitis media with effusion and to a lesser extent in acute otitis media. It also can provide useful information about the patency of tympanostomy tubes. Tympanometry is not reliable in infants younger than seven months because of the highly compliant ear canals of infants. Tympanogram tracings are classified as type A (normal), type B (flat, clearly abnormal), and type C (indicating a significantly negative pressure in the middle ear, possibly indicative of pathology). According to the Agency for Healthcare Research and Quality guidelines on otitis media with effusion, the positive predictive value of an abnormal (flat, type B) tympanogram is between 49 and 99 percent. A type C curve may be useful when correlated with other findings, but by itself it is an imprecise estimate of middle ear pressure and does not have high sensitivity or specificity for middle ear disorders.
ABSTRACT: Atypical organisms such as Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila are implicated in up to 40 percent of cases of community-acquired pneumonia. Antibiotic treatment is empiric and includes coverage for both typical and atypical organisms. Doxycycline, a fluoroquinolone with enhanced activity against Streptococcus pneumoniae, or a macrolide is appropriate for outpatient treatment of immunocompetent adult patients. Hospitalized adults should be treated with cefotaxime or ceftriaxone plus a macrolide, or with a fluoroquinolone alone. The same agents can be used in adult patients in intensive care units, although fluoroquinolone monotherapy is not recommended; ampicillin-sulbactam or piperacillin-tazobactam can be used instead of cefotaxime or ceftriaxone. Outpatient treatment of children two months to five years of age consists of high-dose amoxicillin given for seven to 10 days. A single dose of ceftriaxone can be used in infants when the first dose of antibiotic is likely to be delayed or not absorbed. Older children can be treated with a macrolide. Hospitalized children should be treated with a macrolide plus a beta-lactam inhibitor. In a bioterrorist attack, pulmonary illness may result from the organisms that cause anthrax, plague, or tularemia. Sudden acute respiratory syndrome begins with a flu-like illness, followed two to seven days later by cough, dyspnea and, in some instances, acute respiratory distress.
Diagnosis of Acute Coronary Syndrome - Article
ABSTRACT: The term 'acute coronary syndrome' encompasses a range of thrombotic coronary artery diseases, including unstable angina and both ST-segment elevation and non-ST-segment elevation myocardial infarction. Diagnosis requires an electrocardiogram and a careful review for signs and symptoms of cardiac ischemia. In acute coronary syndrome, common electrocardiographic abnormalities include T-wave tenting or inversion, ST-segment elevation or depression (including J-point elevation in multiple leads), and pathologic Q waves. Risk stratification allows appropriate referral of patients to a chest pain center or emergency department, where cardiac enzyme levels can be assessed. Most high-risk patients should be hospitalized. Intermediate-risk patients should undergo a structured evaluation, often in a chest pain unit. Many low-risk patients can be discharged with appropriate follow-up. Troponin T or I generally is the most sensitive determinant of acute coronary syndrome, although the MB isoenzyme of creatine kinase also is used. Early markers of acute ischemia include myoglobin and creatine kinase-MB subforms (or isoforms), when available. In the future, advanced diagnostic modalities, such as myocardial perfusion imaging, may have a role in reducing unnecessary hospitalizations.
Universal Newborn Hearing Screening - Article
ABSTRACT: Congenital hearing loss is estimated to affect one in every 1,000 newborns. Causes of hearing loss can be conductive, sensorineural, mixed, or central. Known risk factors for congenital hearing loss include cytomegalovirus infection and premature birth necessitating a stay in the neonatal intensive care unit. However, up to 42 percent of profoundly hearing-impaired children will be missed using only risk-based screening. Universal newborn hearing screening is a way to identify hearing-impaired newborns with or without risk factors. Newborns with positive screening tests should be referred for definitive testing and intervention services. Whether early intervention in hearing-impaired children identified with universal screening improves language and communication skills has not been established by good-quality studies. However, universal screening has been endorsed by most national children's health organizations because of the ease of administering the screening tests and the ability to identify children who may need early intervention.
ABSTRACT: Minor cytologic abnormalities of the cervix, such as atypical squamous cells of undetermined significance (ASCUS), are vastly more common than high-grade squamous intraepithelial lesions or invasive cancer. Current guidelines for the management of ASCUS include repeating the Papanicolaou (Pap) smear at specific intervals, referring all patients for colposcopy or using an adjunctive test such as hybrid capture human papillomavirus (HPV) testing or cervicography. The usefulness of the Pap smear is limited by its considerable false-negative rate and its dependence on clinician and laboratory performance. Colposcopy is a highly sensitive procedure, but many patients with ASCUS have normal colposcopic findings. The hybrid capture test not only measures quantitative HPV load but also detects both oncogenic and nononcogenic HPV types, thereby increasing the probability that serious cervical disease is not missed. Hybrid capture sampling is simple to perform, and positive results are strongly associated with cervical dysplasia. HPV testing in women with ASCUS can be used as an adjunctive test to identify those with HPV-associated disease; it can also serve as a quality assurance measure. Together, repeat Pap smears and HPV testing should identify most patients with underlying cervical dysplasia. Combined testing may also minimize the number of unnecessary colposcopic examinations in women who have no disease.
ABSTRACT: Lowering cholesterol can reduce the incidence of coronary heart disease. Treating hypertension reduces overall mortality and is most effective in reducing the risk of coronary heart disease in older patients. Smoking cessation reduces the level of risk to that of nonsmokers within about three years of cessation. Aspirin is likely to be an effective means of primary prevention, but a group in whom treatment is appropriate has yet to be defined. Evidence that supplementation with vitamin A or C reduces the risk of coronary heart disease is inadequate; the data for use of vitamin E are inconclusive. Epidemiologic evidence is sufficient to recommend that most persons increase their levels of physical activity. Lowering homocysteine levels through increased folate intake is a promising but unproven primary prevention strategy. Hormone replacement therapy was associated with reduced incidence of coronary heart disease in epidemiologic studies but was not effective in a secondary prevention trial.
ABSTRACT: The incidence of venous thromboembolic diseases is increasing as the U.S. population ages. At least one established risk factor is present in approximately 75 percent of patients who develop these diseases. Hospitalized patients and nursing home residents account for one half of all cases of deep venous thrombosis. A well-validated clinical prediction rule can be used for risk stratification of patients with suspected deep venous thrombosis. Used in combination with D-dimer or Doppler ultrasound tests, the prediction rule can reduce the need for contrast venography, as well as the likelihood of false-positive or false-negative test results. The inclusion of helical computed tomographic venography (i.e., a below-the-pelvis component) in pulmonary embolism protocols remains under evaluation. Specific combinations of a clinical prediction rule, ventilation-perfusion scanning, and D-dimer testing can rule out pulmonary embolism without an invasive or expensive investigation. A clinical prediction rule for pulmonary embolism is most helpful when it is used with subsequent evaluations such as ventilation-perfusion scanning, D-dimer testing, or computed tomography. Technologic advances are improving the resolution of helical computed tomography to allow detection of smaller emboli; however, further study is needed to provide definitive evidence supporting the role of this imaging technique in the diagnosis of pulmonary embolism. D-dimer testing is helpful clinically only when the result is negative. A negative D-dimer test can be used in combination with a clinical decision rule, ventilation-perfusion scanning, and/or helical computed tomography to lower the probability of pulmonary embolism to the point that aggressive treatment is not required. Evidence-based algorithms help guide the diagnosis of deep venous thrombosis and pulmonary embolism.
Evaluation of Macrocytosis - Article
ABSTRACT: Macrocytosis, generally defined as a mean corpuscular volume greater than 100 fL, is frequently encountered when a complete blood count is performed. The most common etiologies are alcoholism, vitamin B12 and folate deficiencies, and medications. History and physical examination, vitamin B12 level, reticulocyte count, and a peripheral smear are helpful in delineating the underlying cause of macrocytosis. When the peripheral smear indicates megaloblastic anemia (demonstrated by macro-ovalocytes and hyper-segmented neutrophils), vitamin B12 or folate deficiency is the most likely cause. When the peripheral smear is non-megaloblastic, the reticulocyte count helps differentiate between drug or alcohol toxicity and hemolysis or hemorrhage. Of other possible etiologies, hypothyroidism, liver disease, and primary bone marrow dysplasias (including myelodysplasia and myeloproliferative disorders) are some of the more common causes.
Predicting Benefit of Spinal Manipulation for Low Back Pain - Point-of-Care Guides