The role of color and power Doppler ultrasound in the prenatal diagnosis of sirenomelia.

Sirenomelia is a rare congenital abnormality characterized by a variety of anomalies involving the lower limbs, severe oligohydramnios, bilateral renal agenesis, anorectal atresia and aberrant fetal vasculature. The prenatal diagnosis and differentiation from isolated bilateral renal agenesis is severely limited by the accompanying oligohydramnios that hinders visualization of fetal anatomy. We present three prospectively assessed cases of sirenomelia, two of which had bilateral renal agenesis, and all of which had a single umbilical artery derived from the aberrant vasculature that accompanies the syndrome.

Ultrasonography of the fetal neck in the second and third trimesters. Part 3. Anomalies of the anterior and anterolateral nuchal region.

Current ultrasound instrumentation yields high-resolution scans that allow accurate assessment of the fetal neck. Most neck structures are normally small and barely visible, so anomalous development can be easily identified, for example, when the nuchal fold is measured in the second trimester. The author examined the anterior and anterolateral nuchal region in a total of 15,200 second- and third-trimester scans obtained over a 10-year period. The abnormalities identified were differentiated with respect to their position (at the central midline or anterolateral or lateral to the midline) and ultrasonographic characteristics (solid, cystic or mixed; calcified or vascular). This pictorial essay depicts the ultrasonographic appearance of masses that can be detected antenatally, including thyroid masses, teratoma, thyroglossal duct cyst, cystic hygroma, hemangioma, branchial cleft cyst and other developmental cystic lesions. In addition, the methods of elucidating these lesions is described.

Ultrasonography of the fetal neck in the first and second trimesters. Part 2. Anomalies of the posterior nuchal region.

Over a 5-year period, the author examined the posterior nuchal region of the fetus in 7200 first- and second-trimester sonograms. Nuchal fluid collections were analysed to differentiate physiologic collections, which resolve spontaneously, from pathologic ones, which necessitate invasive testing for chromosomal abnormalities. Recommendations for evaluating ultrasonographic findings, based on the results of the study, are presented algorithmically in this pictorial essay. A single echogenic line representing a skin reflection was usually visible in normal fetuses. Thin double echogenic lines, observed in eight cases in this series, were due to fetal rotation or the presence of an amniotic membrane adjacent to the normal dorsal pseudomembrane and were not indicative of abnormality. In three cases the spectral reflection of the fetal neck surface was relatively thick, leading to the appearance of thick double echogenic lines; of these, two cases involved Down's syndrome. Therefore, karyotyping is suggested in all cases of thick echogenic lines. Of the 11 nuchal fluid collections up to 5 mm in diameter observed in this series, 10 resolved spontaneously by 24 weeks gestational age. In the other case the collection enlarged, and karyotyping revealed Turner's syndrome. Of the 16 cases of nuchal fluid collections greater than 5 mm in diameter, 5 were associated with an abnormal karyotype (Down's syndrome in 4); karyotyping is recommended in all such cases. Nuchal edema occurred in 22 cases. It was associated with Down's syndrome in 8 cases and with trisomy 18 in 1 case. Among fetuses with nuchal edema, the frequency of aneuploidy was substantially greater if other abnormalities were also present.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonography of the fetal neck in the first and early second trimesters. Part 1. Normal appearance.

The soft tissues of the neck of 196 normal fetuses were examined with ultrasonography during the first and early second trimesters, and the criteria for normality are described here. The dorsal pseudomembrane is the most important feature of this area in a normal fetus. This feature appears as a single echogenic line lying parallel to the occiput and the upper cervical spine but separated from them by an anechoic area, which should be less than 2.8 mm deep before 18 weeks gestational age. The membrane is best observed when the fetus is in the "neck-up" position with the neck flexed. Although the superior-inferior extent of the membrane is variable, the occurrence of lateral extension, septations or hydrops or a bulbous appearance indicates abnormality. The membrane should move freely with the motion of the neck, which allows it to be differentiated from the normal amnion, amniotic bands or synechiae.

Schizencephaly: antenatal and postnatal assessment with colour-flow Doppler imaging.

Schizencephaly, a disorder of neuronal migration, is rarely discovered in utero. Three cases, detected in utero and followed through the early neonatal period, were assessed with colour-flow Doppler imaging in an attempt to determine whether the clefts were associated with any demonstrable vascular disturbance. The Doppler spectral wave-forms of the fetal and neonatal internal carotid and middle cerebral arteries were normal in two of the cases, whereas the right middle cerebral artery was persistently occluded in the third. Although Doppler imaging was not performed during the first trimester (when the defect occurs), these findings suggest that a vascular lesion, such as occlusion of the middle cerebral artery with or without complete recanalization, may result in the clefts seen in patients with schizencephaly. Two of the fetuses had been exposed to cocaine in the first trimester, and an association between cocaine-induced vasospasm and schizencephaly is suggested.

Colour-flow Doppler artifacts in anechoic soft-tissue masses of infants.

Colour-flow Doppler imaging is a noninvasive, readily accessible method of assessing the vascularity of soft-tissue masses. To produce acceptable images of flowing blood, various types of signal processing are needed to suppress the colour in moving but nonvascular masses. The author describes two infants with anechoic soft-tissue masses; both masses demonstrated colour flow. One patient had a vascular hemangioma, in which the colour was due to blood flow; the other had a nonvascular lymphangioma, in which the colour was caused by persistent movement between the transducer and the leg being scanned. Artifacts such as that observed in the lymphangioma may be misinterpreted as flow, unless Doppler spectral analysis is employed. Differentiation between vascular and nonvascular soft-tissue masses before surgical excision is important.

Fetal cystic hygromas: further insights into their natural history.

The authors report their experience with 17 cases of cystic hygroma diagnosed in utero over a period of 6 years and followed to early infancy. Attempts were made to determine which ultrasonographic features were significant in predicting the outcome of this condition. The intrauterine course of the 6 fetuses with a normal karyotype and the 11 fetuses with Turner's syndrome or another form of aneuploidy was analysed to determine whether the size of the hygroma or the presence of septation or nonimmune hydrops could be used to predict the eventual outcome of the pregnancy. An association between the presence of septation and outcome was not demonstrated, but there was a strong association between septation and aneuploidy. Septate lesions were present in 6 of the 10 fetuses with Turner's syndrome and only 2 of the 6 fetuses with a normal karyotype. In this series the most significant features indicating a favourable outcome were the size of the hygroma (no fetus in which the hygroma had a diameter greater than 6 cm survived) and the change in size from the time of diagnosis until 24 weeks' gestation. Of the three fetuses in which the hygroma did not regress by 24 weeks, two died in utero.

CT in tuberculous constrictive pericarditis.

Constrictive pericarditis (CP) and restrictive cardiomyopathy have the same pathophysiological disorder (impaired diastolic filling) and a similar presentation. To determine the value of a noninvasive technique, CT, in differentiating between the two, we reviewed the CT scans of 212 patients with clinical signs and symptoms of CP and/or restrictive cardiomyopathy, after 26 cases that did not proceed to surgery were excluded. Computed tomography showed pericardial thickening (greater than 3 mm) in 157 patients with proven tuberculous CP. In two children with proven constriction, the pericardium measured between 2 and 3 mm. We determined that pericardial thickening, in the correct clinical setting, is the only CT sign necessary to diagnose CP. Other CT signs, inferior vena cava dilatation (97%), and deviation of the interventricular septum (15%) were confirmatory. Computed tomography accurately differentiates between CP and restrictive myocardial disease, making more invasive modalities such as cardiac catheterization and endomyocardial biopsy, with few exceptions, unnecessary.

Paediatric Wegener's granulomatosis: two case histories and a review of the literature.

Wegener's granulomatosis is a rare disease in children, with only 37 previous cases described in the literature. We report two new cases, one in an 11-year-old child who presented with cavitating nodules in the right upper lung field as well as a maxillary sinusitis and nasal perforation, and the other in a 16-year-old female who initially presented with a purulent maxillary sinusitis and only later developed an orbital pseudotumour.

The predictive value of computed tomography and Haemophilus influenzae capsular antigen in subdural fluid collections.

A study was made of 52 patients with Haemophilus influenzae type B meningitis complicated by subdural collections of fluid to determine which of these collections were sterile (effusions) and which infected (empyema). This differentiation is important for the treatment which differs in the two conditions. Cranial computed tomography (CT) alone was not as reliable as the combination of CT associated with detection of Haemophilus influenzae capsular antigen, in accurately predicting if a subdural fluid collection was infected, or had a high probability of becoming infected.

Spinal cord schistosomiasis: a case report and review of the literature.

Spinal cord involvement by Schistosomiasis is considered to be rare. We report a case of acute transverse myelitis due to Schistosoma mansoni in which treatment with praziquantal and steroids was started three days after the onset of a paraparesis, with complete neurological recovery.

Population pharmacokinetics of phenytoin in South African black patients.

In the routine care of 37 patients at the epilepsy outpatient clinic of Baragwanath Hospital, Johannesburg, 100 steady-state serum phenytoin concentrations were measured. Total and free phenytoin as well as albumin serum concentrations were determined. Computer analysed data were fitted to the Michaelis-Menten model for steady-state serum concentrations. As a function of the Michaelis-Menten constant (P less than 0.1) total serum phenytoin concentration provided a significantly better fit than free phenytoin combined with albumin serum concentrations. The Vm and Km of 6.5 mg/kg/d and 13.6 mumol/l respectively, determined by using total serum concentration, could be to estimate phenytoin dosage requirements in a hospital population.

Therapeutic drug level monitoring in the management of epilepsy.

A selected group of poorly controlled epileptic patients had their drug plasma concentrations measured. Of those on a single drug, 33% were noncompliant, 33% had drug concentrations in the subtherapeutic or toxic ranges and 34% had levels in the therapeutic range, 86% of which were in the low therapeutic range. In only 9% of the group on multiple drugs were both drug levels in the therapeutic range. Twenty-two per cent of patients were non-compliant for both drugs. Patients were followed up over 12 months with drug level monitoring and dosage adjustments; 49% were seizure-free and 36% had a reduction in seizure frequency of at least 50% over an 8-month period. All but 3.9% were put on a single-drug regimen, and 15.6%, which matched well with the number of non-compliant patients, had no change in seizure frequency. Therapeutic drug level monitoring is a most useful aid in rationalising drug therapy and improving seizure control.