The accuracy of physical examination to detect abdominal aortic aneurysm

BACKGROUND

Abdominal palpation during physical examination is an important means of detecting abdominal aortic aneurysm (AAA), but limited information is available on its accuracy.

METHODS

Two hundred subjects (aged 51-88 years), 99 with and 101 without AAA as determined by previous ultrasound, each underwent physical examination of the abdomen by 2 internists who were blinded to each other's findings and to the ultrasound diagnosis.

RESULTS

The overall accuracy of abdominal palpation for detecting AAA was as follows: sensitivity, 68% (95% confidence interval [CI], 60%-76%); specificity, 75% (95% CI, 68%-82%); positive likelihood ratio, 2.7 (95% CI, 2.0-3.6); negative likelihood ratio 0.43 (95% CI, 0.33-0.56). Interobserver pair agreement for AAA vs no AAA between the first and second examinations was 77% (kappa = 0.53). Sensitivity increased with AAA diameter, from 61% for AAAs of 3.0 to 3.9 cm, to 69% for AAAs of 4.0 to 4.9 cm, 72% for AAAs of 4.0 cm or larger, and 82% for AAAs of 5.0 cm or larger. Sensitivity in subjects with an abdominal girth less than 100 cm (40-in waistline) was 91% vs 53% for girth of 100 cm or greater (P<.001). When girth was 100 cm or greater and the aorta was palpable, sensitivity was 82%. When girth was less than 100 cm and the AAA was 5.0 cm or larger, sensitivity was 100% (12 examinations). Factors independently associated with correct examination findings included AAA diameter (odds ratio [OR], 1.95 per centimeter increase; 95% CI, 1.06-3.58); abdominal girth (OR, 0.90 per centimeter increase; 95% CI, 0.87-0.94); and the examiner's assessment that the abdomen was not tight (OR, 2.68; 95% CI, 1.17-6.13).

CONCLUSIONS

Abdominal palpation has only moderate overall sensitivity for detecting AAA, but appears to be highly sensitive for diagnosis of AAAs large enough to warrant elective intervention in patients who do not have a large girth. Abdominal palpation has good sensitivity even in patients with a large girth if the aorta is palpable.

A clinical prediction rule for the diagnosis of ureteral calculi in emergency departments

OBJECTIVE

To determine: 1) whether a simple clinical prediction rule could identify emergency department patients with ureteral calculi; 2) whether the kidney, ureter, and bladder (KUB) radiograph provides diagnostic information beyond that obtained from the history and physical examination; and 3) whether ureteral calculi can be diagnosed accurately in the emergency department without emergency excretory urography, commonly known as intravenous pyelography (IVP).

PATIENTS

Two hundred three patients who underwent emergency KUB and IVP studies for nontraumatic abdominal or flank pain (derivation group) were retrospectively identified from radiology department records; 72 patients were prospectively evaluated in the emergency department for suspected ureteral stones (validation group).

MEASUREMENTS

Clinical information included age, gender, characteristics of pain, associated symptoms, presence of fever, history of ureteral calculi, whether a stone was passed, and results of urinalysis and KUB and IVP studies. All KUB and IVP radiographs were independently reviewed by a radiologist blinded to the patient's clinical information and urinalysis results.

DESIGN

Stepwise linear discriminant analysis was used to derive a four-item prediction rule from the derivation group and the validation group; the areas under the receiver operating characteristic (ROC) curves and the misclassification rates were compared.

RESULTS

The four-item rule (acute onset, flank pain, hematuria, and positive KUB radiograph) correctly classified 83% of patients in the derivation group and 90% in the validation group. The four-item rule had an ROC area of 0.86 in the derivation group and 0.89 in the validation group. The KUB radiograph significantly improved the discriminant ability of the two history items and the urinalysis result. Thirty-three percent of patients were identified to be in a subset with a 96% probability of having a stone.

CONCLUSION

These findings, which should be confirmed in another emergency department, suggest that subsets of patients with suspected ureteral calculi may be managed without emergency IVP; this approach thereby reduces the time a patient spends in the emergency department, radiation exposure, expense, and morbidity.

Lipoprotein analysis in the evaluation of chest pain in the emergency department

Apolipoproteins were measured in a prospective blinded fashion in blood specimens from patients with chest pain in the emergency department. A definitive diagnosis for the chest pain (non-cardiac-related in 32% and angina or myocardial infarction in 68%) was available in 136 of the 162 patients originally enrolled in the study. Logistic regression and multivariate analysis failed to show any usefulness of apolipoprotein determinations in distinguishing patients with cardiac ischemia from those without it. The clinician's initial impression of the chest pain, the electrocardiogram, a history of previous angina, myocardial infarction, or peripheral atherosclerosis, and male sex were strongly associated with the final diagnosis. We conclude that, although apolipoprotein analysis has proved useful in epidemiologic studies, the most reliable indicators of ischemic pain remain the medical history, the electrocardiogram, and the clinician's overall initial impression.

Utility of the plain abdominal radiograph for diagnosing ureteral calculi

Our study was designed to measure sensitivity, specificity, predictive value, and accuracy of the plain abdominal radiograph (PAR) for diagnosing ureteral calculi (UC) in our emergency department (ED), and to determine if obtaining this test in the ED provides clinically useful diagnostic information. Records of 206 adult patients (147 men, 59 women) who underwent emergency excretory urography as part of an ED evaluation for possible ureteral stones were reviewed. A retrospective scoring index was devised to estimate the clinical probability of a ureteral stone for each patient. All patients had a PAR shortly before the excretory urogram (EXU) was performed. Each PAR was separated from the corresponding EXU, and both were independently reviewed for radiographic evidence of ureterolithiasis. The results of the PAR and EXU interpretations were compared. There were 92 true-positive PARs (45%), 19 false positives (9%), and 39 true negatives (19%), yielding a sensitivity of 62% and a specificity of 67%. In patients with a high estimated clinical probability of a ureteral calculus, the PAR had a positive predictive value of 86% and a negative predictive value of 22%. In the remaining patients, the positive and negative predictive values of the PAR were 69% and 72%, respectively. Each patient's clinical index score was compared to his or her EXU results. For detecting UC, the sensitivity of our scoring index was 82%, and the specificity was 51%; the positive predictive value of the scoring index was 82%, and the negative predictive value was 52%.(ABSTRACT TRUNCATED AT 250 WORDS)