Eye care: diabetic retinopathy.

Diabetic retinopathy is the leading cause of blindness in the United States for adults, ages 20 to 74 years. Yet, the strict control of blood glucose may help ameliorate the potentially catastrophic effects of diabetes on vision. Physicians need a working knowledge of diabetic retinopathy.

Cavernous hemangioma of the optic nerve.

BACKGROUND: Cavernous hemangioma of the retina and optic disc is a rare lesion that was first defined as a distinct entity by Gass in 1971. It is usually easily recognized by its characteristic appearance of saccular "grape-like" lesions. On fluorescein angiography, plasma-erythrocyte separation is seen. METHODS: Two patients with cavernous hemangioma of the optic nerve were examined over a period of 5 to 10 years. RESULTS: Although these tumors are usually considered to be static and not capable of growth, these two cases of cavernous hemangioma of the optic nerve showed documented growth. One case required vitrectomy for vitreous hemorrhage. CONCLUSION: Cavernous hemangioma of the optic disc can grow and can cause vitreous hemorrhage severe enough to require vitrectomy.

Accuracy and reproducibility of precordial percussion and palpation for detecting increased left ventricular end-diastolic volume and mass. A comparison of physical findings and ultrafast computed tomography of the heart.

OBJECTIVE: To assess the accuracy and reproducibility of indirect definitive precordial percussion in detecting increased left ventricular end-diastolic volume (LVEDV), left ventricular mass (LVM), and left ventricular end-diastolic wall thickness (LVEDWT), and to compare it with palpation of the apical impulse. DESIGN: Descriptive study. SETTING: Hospitals and clinics of a university medical center. PATIENTS: Convenience sample of 103 patients (62 men and 41 women) referred for ultrafast computed tomography (CT) of the heart. INTERVENTIONS: Percussion dullness distance from the midsternal line in the left fourth through sixth intercostal spaces, distance of the apical impulse from the midsternal line, and apical impulse diameter in the left lateral decubitus position were measured on all patients. Measurements of LVEDV, LVM, and LVEDWT were taken using ultrafast CT of the heart. Investigators performing the physical diagnostic maneuvers were blinded to the clinical history and CT results, and investigators performing the CT scans were blinded to physical findings. RESULTS: Percussion dullness distance in the left fifth intercostal space was the best discriminator of LVEDV (receiver operating characteristic [ROC] area, 0.680; 95% confidence interval [CI], 0.547 to 0.813), and dullness distance in the left sixth intercostal space was the best discriminator of LVM and LVEDWT (ROC areas, 0.831, 95% CI, 0.674 to 0.988; and 0.849, 95% CI, 0.651 to 0.999, respectively). A percussion dullness distance of greater than 10.5 cm in the left fifth intercostal space detected increased LVEDV or LVM with a sensitivity of 91.3% (95% CI, 70.5% to 98.5%) and a specificity of 30.3% (95% CI, 19.9% to 43.0%). There was moderate concordance between investigators for percussion dullness distance (kappa, 0.57; 95% CI, 0.18 to 0.96). In patients in whom an impulse was palpated, an apical impulse diameter of greater than 3.0 cm in the left lateral decubitus detected increased LVEDV or LVM with a sensitivity of 100% (95% CI, 77.1% to 100%) and a specificity of 40% (95% CI, 23.2% to 59.3%). However, an impulse was palpable in only 53% of cases and showed only slight interobserver reproducibility (kappa, 0.18; 95% CI, 0.0 to 0.58). CONCLUSION: Indirect definitive percussion of the precordium is a sensitive and moderately reproducible maneuver for excluding cardiomegaly due to increased LVEDV or LVM. Although measurement of apical impulse diameter was also sensitive in excluding cardiomegaly, lack of a palpable impulse in many patients and low precision between physicians may limit its utility in clinical practice.

Accuracy of precordial percussion in detecting cardiomegaly.

STUDY OBJECTIVE: To assess the value of precordial percussion in detecting cardiomegaly, and to compare it with palpation of the apical impulse. DESIGN: Descriptive study. SETTING: Hospitals and clinics of a university medical center. PATIENTS: Light indirect percussion of the precordium was performed on 72 inpatients and 28 outpatients. All patients had a posteroanterior radiograph of the chest. Percussors were unaware of the clinical history and of chest roentgenogram results. MEASUREMENTS AND MAIN RESULTS: Thirty-six patients (36%) had cardiomegaly, defined as a cardiothoracic ratio of greater than 0.5 on chest roentgenogram. The cardiothoracic ratio was significantly correlated with percussion distance from the midsternal line in the left fourth (r = 0.35, p less than 0.0006), fifth (r = 0.65, p less than 0.00001), and sixth (r = 0.40, p less than 0.0001) intercostal spaces. After adjustment for clinical symptoms and systolic and diastolic blood pressures, percussion distance in the left fifth intercostal space remained a significant independent predictor of the cardiothoracic ratio. Percussion distance in the left fifth interspace discriminated cardiomegaly with a receiver-operating characteristic (ROC) area of 0.95. Percussion dullness more than 10.5 cm from the midsternal line in the left fifth interspace had a sensitivity of 94.4% (95% confidence interval [CI], 79.9% to 99.0%) and a specificity of 67.2% (CI, 54.2% to 78.1%). Distance of the apical impulse from the midsternal line discriminated with an ROC area of 0.95, but an impulse was palpated in only 40% of cases. CONCLUSIONS: Percussion in the left fifth intercostal space accurately discriminates patients with and without cardiomegaly, and adds information beyond that obtainable from the history and other parts of the physical examination.

The effect of incomplete knowledge on the diagnoses of a computer consultant system.

The knowledge bases (KBs) of diagnostic decision support systems are often incomplete, and gaps in the KB could potentially lead systems to reach diagnoses that are implausible to physicians. To investigate this possibility we studied Iliad (Version 2.01), a computer consultant system that generates differential diagnosis across the domain of internal medicine. Data from the history, physical examination, and laboratory findings of 50 grand-rounds cases were entered into Iliad by a computer consultant aware of the diagnosis but blinded to its presence or absence in Iliad's KB. Two experienced internists were asked to diagnose these cases before and after seeing the results of the computer consultation, and to assess the plausibility of the computer's diagnoses. Twenty-eight of the 50 cases (56.0%) were diseases contained in Iliad's KB. After seeing Iliad's diagnoses for cases in the KB, physicians assigned to their correct diagnoses a higher mean ranked position (1.5 versus 2.0, p less than 0.008) and a higher mean probability (84.0% versus 77.6%, p less than 0.008) compared with their pre-Iliad values, whereas for cases not in the KB, mean position and probability for correct diagnoses did not change. Physician diagnostic accuracy did not change after consultation on cases included or not included in the KB. After adjusting for case difficulty, mean plausibility of Iliad's diagnoses was judged significantly higher (on a seven-point scale) for cases in the KB than for cases not in the KB (4.2 versus 3.2, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

The diagnostic usefulness of the history of the patient with dyspnea.

The diagnostic usefulness of the medical history may depend on the type of problem confronted. It has been suggested that dyspnea is an example of a condition the causes of which cannot be easily distinguished based on identification in the history of stereotypical disease patterns presented in standard texts. To evaluate this assertion, faculty members independently interviewed 146 consecutively admitted patients with dyspnea, and following the history of the present illness, made a diagnosis. After discharge of the patients, another faculty member, using preselected criteria, independently reviewed each record to make a final diagnosis. History-based diagnoses predicted final diagnoses 74% of the time. Therefore, the history appeared to be useful in identifying the primary diagnosis for most dyspneic patients admitted to the hospital. However, it is not known whether this identification provides sufficient rationale for therapy or leads to more efficient use of laboratory tests.