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Biomedical subjects

S R McGee

Publications and source records attributed to S R McGee.

11 recordsLinked to original sources
PubMed1998

Physical examination and chronic lower-extremity ischemia: a critical review.

OBJECTIVE: To determine the clinical utility of physical examination in patients with suspected chronic ischemia of the lower extremities. DATA SOURCES: MEDLINE search (January 1966 to January 1997), personal files, and bibliographies of textbooks on physical diagnosis, surgery, and vascular surgery. STUDY SELECTION: Both authors independently graded the studies as level 1, 2, or 3, according to predetermined criteria. Criteria deemed essential for analysis of sensitivity, specificity, and likelihood ratios were (1) clear definition of study population, (2) clear definition of physical examination maneuver, and (3) use of an acceptable criterion standard test for comparison. RESULTS: The following positive findings help clinicians diagnose the presence of peripheral arterial disease: abnormal pedal pulses, a unilaterally cool extremity, a prolonged venous filling time, and a femoral bruit. Other physical signs help determine the extent and distribution of vascular disease, including an abnormal femoral pulse, lower-extremity bruits, warm knees, and the Buerger test. The capillary refill test and the findings of foot discoloration, atrophic skin, and hairless extremities are unhelpful in diagnostic decisions. Mathematical formulas, derived from 2 studies using multivariate analysis, allow clinicians to estimate the probability of peripheral arterial disease in their patients. CONCLUSION: Certain aspects of the physical examination help clinicians make accurate judgments about the presence of peripheral arterial disease and its distribution.

Aged↗
PubMed1998

Physical examination of venous pressure: a critical review.

OBJECTIVE: To explain why investigations of the measurement of central venous pressure (CVP) usually reveal a discrepancy between the clinician's estimate of CVP from physical diagnosis and supine measurement with a catheter. Data from MEDLINE search, personal files, and bibliographies of textbooks on physical diagnosis and cardiology were used. RESULTS: The most important reasons for this disagreement are the failure to standardize the external reference point used by the clinician to indicate "zero" venous pressure and the failure to recognize that venous pressure often depends on the position of the patient during examination. During physical examination clinicians tend to underestimate the CVP, as measured by a catheter in the same patient positioned supine, especially when the measured value is high. This occurs because the venous pressure of patients with heart failure, in contrast to that of healthy individuals, demonstrates an exaggerated postural fall when the patient is in the more upright positions that are necessary to visualize the elevated neck veins. The cause of this postural instability, increased venoconstriction from sympathetic tone, also helps explain two other physical findings of the jugular veins, the abdominojugular test, and Kussmaul's sign. CONCLUSIONS: Clinicians should avoid making decisions about degrees of CVP elevation that are imprecise and difficult to reproduce. Instead, they should determine during physical diagnosis merely whether the CVP is elevated. Until further research is done, the best definition of elevated CVP is that of Sir Thomas Lewis-when the top of the external or internal jugular veins is >3 cm of vertical distance above the sternal angle, the CVP is abnormally high.

Animals↗
PubMed1997

Diagnostic dilemmas in polymyalgia rheumatica.

Polymyalgia rheumatica is a clinical syndrome of proximal muscle pain in older patients that often presents a diagnostic challenge because of the large differential diagnosis, lack of definitive diagnostic criteria, and relatively frequent "atypical" clinical findings, such as peripheral synovitis, distal extremity pain, normal erythrocyte sedimentation rate, and mild weakness. Despite an extensive differential diagnosis that includes endocarditis and steroid-responsive malignant neoplasms, routine laboratory testing should be limited, and a low-dose corticosteroid trial is useful as the final step in the evaluation. The clinical overlap with seronegative rheumatoid arthritis is striking, suggesting that these diagnoses may represent different presentations of a similar disease process. While concurrent asymptomatic temporal arteritis is common, there are no data to support obtaining a temporal artery biopsy in patients with pure polymyalgia rheumatica symptoms.

Diagnosis, Differential↗
PubMed1995

Percussion and physical diagnosis: separating myth from science.

There are three percussion sounds, which are easily distinguishable by objective measures: tympany (heard with percussion over the intestines), resonance (heard over the normal lung), and dullness (heard over the liver or thigh). The percussion sound that is produced reflects the ease with which the body wall vibrates, which in turn is influenced by many variables, including the strength of the stroke, the condition and state of the body wall, and the underlying organs. Underlying organs or disease may cause dullness to occur at distant sites. There is good interobserver agreement among clinicians with regard to calling a particular percussion sound dull, resonant, or hyperresonant. In contrast, there is very poor interobserver agreement among clinicians using percussion to measure the span of a particular organ. The use of comparative percussion can detect most large pleural effusions, but this method is able to detect only a few pneumonias. Shifting dullness is a reliable and fairly accurate sign for the detection of ascites. Both of these techniques can still be recommended after a review of the literature. Topographic percussion (e.g., using percussion to locate the heart, liver, and spleen borders or dimensions) has poor reproducibility, is significantly inaccurate in many patients, and has little clinical utility; it should be abandoned. Its fundamental principle--that sound waves penetrate only several centimeters of tissue, resulting in a note reflecting abnormalities only in this layer of tissue--is incorrect. Auscultatory percussion offers no advantage over conventional percussion, with the possible exception of auscultatory percussion of the shoulder. Auscultatory percussion should be abandoned as a bedside diagnostic technique.

Auscultation↗
PubMed1995

Dizzy patients. Diagnosis and treatment.

This discussion was selected from the weekly Grand Rounds in the Department of Medicine, University of Washington School of Medicine, Seattle. Taken from a transcription, it has been edited by Jonathan Drachman, MD, Chief Medical Resident; Henry Rosen, MD, Professor and Associate Chair; and Paul Ramsey, MD, Professor and Chair of the Department of Medicine.

Cholinergic Antagonists↗
PubMed1990

Muscle cramps.

Painful involuntary skeletal muscle contractions, or cramps, are common patient complaints and may be classified as examples of true cramp, tetany, contracture, or dystonia. The pathophysiologic and clinical features of each of these diagnoses are described. The approach to the patient with cramps should emphasize the history, physical examination, and, if the diagnosis is unclear, minimal routine laboratory data. Although many therapies have been proposed for ordinary cramps, the best evidence supports stretching exercises and quinine. Areas for future study of this common symptom are proposed.

Contracture↗
PubMed1981

The influence of the onset of phonation on the frequency of disfluency among children who stutter.

This study was designed to assess the effects of on-off voice adjustments on the frequency of stuttering in children. Essentially, this is a replication of the experimental paradigm used by Adams and Reis (1971, 1974) with adult stutterers who were asked to read two passages: one contained a normal distribution of voiced and voiceless sounds; the other contained nearly all voiced sounds. The latter passage was associated with less stuttering and more rapid adaptation. In this study, 15 childhood stutterers in the third through the seventh grades were asked to read these same two passages. Contrary to the previous results with adults, however, the children did not stutter less nor adapt more rapidly with the all-voiced passage. These results are discussed with reference to previous literature and to the influence of pausing.

Child↗