Fetal crown-rump length: reevaluation of relation to menstrual age (5-18 weeks) with high-resolution real-time US.

Because of recent challenges in the literature regarding the validity of the older crown-rump length (CRL) data developed with conventional static-image ultrasound scanners, the authors evaluated the relationship between CRL and menstrual age of fetuses in a population of 416 patients with good menstrual dates. By using a variety of commercially available transabdominal and transvaginal real-time ultrasound probes, the authors demonstrated that measurements can be made successfully for CRLs varying in size from 2 mm to 12 cm. Regression analysis of the data resulted in development of a new table for predicting menstrual age of fetuses on the basis of CRL measurements obtained between 5 and 18 weeks gestation. Although the magnitude of the raw residuals increased over time, the variability in predicting menstrual age was demonstrated to be relatively constant at +/- 8% (2 standard deviations) when expressed as a percentage of the predicted value. The accuracy in predicting menstrual age from CRL after 14 weeks was equivalent to but not better than conventional measurements such as biparietal diameter and femur length.

Sonographic fetal growth standards. Are current data applicable to a racially mixed population?

Currently available sonographic growth standards for fetal head size, abdominal size, and limb length are based primarily on studies from white populations. To determine whether these published standards are appropriate for a racially mixed, indigent population, we compared our published data from a middle-class white population with data generated from a black/Hispanic population seen at a county hospital in Houston, Texas. No statistically significant differences were found for any of the following fetal sonographic parameters (20 to 41 weeks): biparietal diameter, head circumference, abdominal circumference, femur length.

Estimating fetal age using multiple parameters: a prospective evaluation in a racially mixed population.

This study was designed to evaluate the accuracy of regression models for menstrual age prediction using single versus multiple fetal ultrasonographic measurements (biparietal diameter, head circumference, abdominal circumference, and femur length). The models tested had been previously developed from a study of middle-class white patients in a private hospital. The current study population consisted of 300 indigent black and Hispanic patients seen in a county hospital. This study demonstrated prospectively that the use of multiple parameters in estimating fetal age offers a significant advantage over any single parameter used alone and that the regression equations developed from a middle-class white population appear to be applicable to fetuses from a population with different socioeconomic and racial characteristics.

Ultrasound prediction of fetal lung maturity.

Amniocentesis for determination of fetal lung maturity and ultrasonographic (US) evaluation of the biparietal diameter (BPD) and placental grade were performed simultaneously in 261 nondiabetic pregnant women. A BPD of at least 9.3 cm and a grade 3 placenta were evaluated as predictors of fetal lung maturity using amniotic fluid phospholipids as indicators of a mature lung profile. The ability of the sonographic parameters to predict fetal lung maturity was closely related to menstrual age. Before 37 weeks, the false-positive prediction rate using a grade 3 placenta was 100%, and the false-positive prediction using the BPD was 85.6%. After 37 weeks, the false-positive rate using a grade 3 placenta was 5.9%, and the false-positive rate using the BPD was 9.5%. Thus menstrual age, and not these two US parameters, dictated fetal lung maturity. The authors conclude that the best use of US for predicting fetal lung maturity is in establishing menstrual age early in pregnancy.

Correlation of I-125 iothalamate and tc-99m DPTA measurements of GFR using the single injection method.

Simultaneous renal imaging and determination of GFR can be obtained using Tc-99m DTPA. In order to assess the accuracy of the GFR value, a comparison was made between commercial sources of Tc-99m DTPA and I-125 iothalamate. The calculation assumed monoexponential loss of each radiopharmaceutical from the renal compartment. Plasma measurements were made at two sampling intervals, 90 to 120 minutes and 180 to 240 minutes. An apparent volume of distribution calculated for plasma concentrations at 2 hours and 3 hours was examined as a single sample indication of GFR. GFR values appear to be higher with DPTA than with iothalamate at the earlier interval. Choice of the later sampling times may be desirable for patients with known renal disease. The apparent volume of distribution at 3 hours may be a convenient single sample for monitoring or surveying patients for renal disease.

Metabolic effects of chloride-deficient formula.

A seven-month-old infant presented with failure to thrive and hypochloremic alkalosis due to intake of chloride-deficiency formula. The metabolic changes were associated with hyperreninemia and hyperaldosteronism. Within one month of supplementation with a formula adequate in chloride content, the patient started to gain weight. Five months after adequate chloride intake, all metabolic parameters including plasma renin and plasma aldosterone were normal.

Malaria in children.

The incidence of malaria in the United States has tripled during the past decade. A high index of suspicion for this diagnosis is warranted in travelers, visitors and refugees who have persistent fever. The possibility of malaria in children among these groups should not be overlooked. A common cause of malaria in travelers returning to the United States from endemic areas is failure to complete the appropriate course of chemoprophylaxis. Except in Plasmodium falciparum infections, treatment should include both chloroquine and primaquine to curb relapse.