David A. Froehling

Benign Positional Vertigo: Incidence and Prognosis in a Population-Based Study in Olmsted County, Minnesota

A retrospective review of our population-based medical records linkage system for residents of Olmsted County, Minnesota, revealed 53 patients (34 women and 19 men; mean age, 51 years) with newly diagnosed benign positional vertigo in 1984. The age- and sex-adjusted incidence was 64 per 100,000 population per year (95% confidence interval, 46 to 81 per 100,000). The incidence of benign positional vertigo increased by 38% with each decade of life (95% confidence interval, 23 to 54%). One patient had an initial stroke during follow-up; thus, the relative risk for new stroke associated with benign positional vertigo was 1.62 (95% confidence interval, 0.04 to 8.98) in comparison with the expected occurrence based on incidence rates for an age- and sex-adjusted control population. The observed survival among the 53 Olmsted County residents with benign positional vertigo diagnosed in 1984 was not significantly different from that of an age- and sex-matched general population. Patients with benign positional vertigo seem to have a good prognosis.

The Canalith Repositioning Procedure for the Treatment of Benign Paroxysmal Positional Vertigo: A Randomized Controlled Trial

OBJECTIVE To compare the canalith repositioning procedure (CRP) with a sham maneuver for the treatment of benign paroxysmal positional vertigo. PATIENTS AND METHODS We recruited 50 patients with a history of positional vertigo and unilateral positional nystagmus on physical examination (Dix-Hallpike maneuver). Patients were randomized to either the CRP (n = 24) or a sham maneuver (n = 26). Measured outcomes included resolution of vertigo and positional nystagmus at follow-up examination. RESULTS The mean duration of follow-up was 10 days for both groups. Resolution of symptoms was reported by 12 (50%) of the 24 patients in the CRP group and by 5 (19%) of the 26 patients in the sham group (P = .02). The results of the Dix-Hallpike maneuver were negative for positional nystagmus in 16 (67%) of 24 patients in the CRP group and in 10 (38%) of 26 patients in the sham group (P = .046). CONCLUSION The CRP is effective treatment of benign paroxysmal positional vertigo, and this procedure can be performed by general internists on outpatients with this disorder.

Comparison of Natural Language Processing Biosurveillance Methods for Identifying Influenza From Encounter Notes

BACKGROUND An effective national biosurveillance system expedites outbreak recognition and facilitates response coordination at the federal, state, and local levels. The BioSense system, used at the Centers for Disease Control and Prevention, incorporates chief complaints but not data from the whole encounter note into its surveillance algorithms. OBJECTIVE To evaluate whether biosurveillance by using data from the whole encounter note is superior to that using data from the chief complaint field alone. DESIGN 6-year retrospective case-control cohort study. SETTING Mayo Clinic, Rochester, Minnesota. PARTICIPANTS 17,243 persons tested for influenza A or B virus between 1 January 2000 and 31 December 2006. MEASUREMENTS The accuracy of a model based on signs and symptoms to predict influenza virus infection in patients with upper respiratory tract symptoms, and the ability of a natural language processing technique to identify definitional clinical features from free-text encounter notes. RESULTS Surveillance based on the whole encounter note was superior to the chief complaint field alone. For the case definition used by surveillance of the whole encounter note, the normalized partial area under the receiver-operating characteristic curve (specificity, 0.1 to 0.4) for surveillance using the whole encounter note was 92.9% versus 70.3% for surveillance with the chief complaint field (difference, 22.6%; P < 0.001). Comparison of the 2 models at the fixed specificity of 0.4 resulted in sensitivities of 89.0% and 74.4%, respectively (P < 0.001). The relative risk for missing a true case of influenza was 2.3 by using the chief complaint field model. LIMITATIONS Participants were seen at 1 tertiary referral center. The cost of comprehensive biosurveillance monitoring was not studied. CONCLUSION A biosurveillance model for influenza using the whole encounter note is more accurate than a model that uses only the chief complaint field. Because case-defining signs and symptoms of influenza are commonly available in health records, the investigators believe that the national strategy for biosurveillance should be changed to incorporate data from the whole health record. PRIMARY FUNDING SOURCE Centers for Disease Control and Prevention.

The introduction of a diagnostic decision support system (DXplain™) into the workflow of a teaching hospital service can decrease the cost of service for diagnostically challenging Diagnostic Related Groups (DRGs)

BACKGROUND In an era of short inpatient stays, residents may overlook relevant elements of the differential diagnosis as they try to evaluate and treat patients. However, if a residents first principal diagnosis is wrong, the patients appropriate evaluation and treatment may take longer, cost more, and lead to worse outcomes. A diagnostic decision support system may lead to the generation of a broader differential diagnosis that more often includes the correct diagnosis, permitting a shorter, more effective, and less costly hospital stay. METHODS We provided residents on General Medicine services access to DXplain, an established computer-based diagnostic decision support system, for 6 months. We compared charges and cost of service for diagnostically challenging cases seen during the fourth through sixth month of access to DXplain (intervention period) to control cases seen in the 6 months before the system was made available. RESULTS 564 cases were identified as diagnostically challenging by our criteria during the intervention period along with 1173 cases during the control period. Total charges were

Sensitivity and Specificity of the Semiquantitative Latex Agglutination D-Dimer Assay for the Diagnosis of Acute Pulmonary Embolism as Defined by Computed Tomographic Angiography

1281 lower (p=.006), Medicare Part A charges

Evaluation of a Quantitative D-Dimer Latex Immunoassay for Acute Pulmonary Embolism Diagnosed by Computed Tomographic Angiography

1032 lower (p=0.006) and cost of service

Central venous catheter thrombosis complicated by paradoxical embolism in a patient with diabetic ketoacidosis and respiratory failure

990 lower (p=0.001) per admission in the intervention cases than in control cases. CONCLUSIONS Using DXplain on all diagnostically challenging cases might save our medical center over

The Health Archetype Language (HAL-42): Interface considerations

2,000,000 a year on the General Medicine Services alone. Using clinical diagnostic decision support systems may improve quality and decrease cost substantially at teaching hospitals.

Symptomatic Venous Thromboembolism is Associated with Inferior Survival among Patients Undergoing Nephrectomy with Inferior Vena Cava Tumor Thrombectomy for Renal Cell Carcinoma

OBJECTIVE To determine the sensitivity and specificity of the semiquantitative latex agglutination plasma fibrin D-dimer assay for the diagnosis of acute pulmonary embolism by using computed tomographic (CT) angiography as the diagnostic reference standard. PATIENTS AND METHODS From January 1, 1998, to June 26, 2000, patients who had both semiquantitative latex agglutination plasma fibrin D-dimer testing and CT angiography for suspected acute pulmonary embolism were selected for the study. A D-dimer value greater than 250 ng/mL was considered positive for thromboembolic disease. Diagnosis of acute pulmonary embolism was based solely on the interpretation of the CT angiogram. The D-dimer assay results were then compared with the CT angiographic diagnoses. RESULTS Of 946 CT studies, 172 (18%) were positive for acute pulmonary embolism. The D-dimer assay was positive for 612 (65%) of the 946 patients. For acute pulmonary embolism, the D-dimer assay had a sensitivity of 0.83 (95% confidence interval [CI], 0.76-0.88), a specificity of 039 (95% CI, 036-0.43), a negative likelihood ratio of 0.44 (95 % CI, 032-0.62), and a negative predictive value of 0.91 (95% CI, 0.87-0.94). CONCLUSIONS The semiquantitative latex agglutination plasma fibrin D-dimer assay had moderate sensitivity and low specificity for the diagnosis of acute pulmonary embolism. When used alone, the results of this test were insufficient to exclude this serious and potentially fatal disorder. Approximately two thirds of our patients had positive D-dimer assays and required further evaluation to exclude acute pulmonary embolism.

Poster 87 Boutonnière Deformity as a Presenting Feature of Multiple Myeloma: A Case Report

OBJECTIVE To determine the sensitivity and specificity of a quantitative plasma fibrin D-dimer latex immunoassay (LIA) for the diagnosis of acute pulmonary embolism. SUBJECTS AND METHODS Study subjects were Mayo Clinic Rochester inpatients and outpatients with suspected acute pulmonary embolism; all had undergone quantitative D-dimer LIA testing and multidetector-row computed tomographic (CT) angiography between August 3, 2001, and November 10, 2003. Multidetector-row CT angiography was the diagnostic reference standard. RESULTS Of 1355 CT studies, 208 (15%) were positive for acute pulmonary embolism. Median D-dimer levels were significantly higher for patients with acute pulmonary embolism (1425 ng/mL) than for patients without (500 ng/mL) (P<.001). The highest specificity that optimizes sensitivity for acute pulmonary embolism was achieved by using a discriminant value of 300 ng/mL, which yielded a sensitivity of 0.94 (95% confidence interval [CI], 0.89-0.97), a specificity of 0.27 (95% CI, 0.25-0.30), and a negative predictive value of 0.96 (95% CI, 0.93-0.98). CONCLUSION The quantitative D-dimer LIA with a discriminant value of 300 ng/mL had high sensitivity and high negative predictive value but low specificity for the diagnosis of acute pulmonary embolism. On the basis of these results, we believe that a negative quantitative D-dimer LIA result and a low pretest probability of thromboembolism together are sufficient to exclude acute pulmonary embolism.