Second trimester choroid plexus cysts and trisomy 18

Transitory and Vestigial Structures of the Developing Human Nervous System

As with many body organs, the human central nervous system contains many structures and cavities that may have had functions in embryonic and fetal life but are vestigial or atrophic at maturity. Examples are the septum pellucidum, remnants of the lamina terminalis, Cajal-Retzius neurons, induseum griseum, habenula, and accessory olfactory bulb. Other structures are transitory in fetal or early postnatal life, disappearing from the mature brain. Examples are the neural crest, subpial granular glial layer of Brun over cerebral cortex, radial glial cells, and subplate zone of cerebral cortex. At times persistent fetal structures that do not regress may cause neurological problems or indicate a pathologic condition, such as Blake pouch cyst. Transitory structures thus can become vestigial. Examples are an excessively wide cavum septi pellucidi, suprapineal recess of the third ventricle, trigeminal artery of the posterior fossa circulation, and hyaloid ocular artery. Arrested maturation might be considered another aspect of vestigial structure. An example is the persistent microcolumnar cortical architecture in focal cortical dysplasia type Ia, in cortical zones of chronic fetal ischemia, and in some metabolic/genetic congenital encephalopathies. Some transitory structures in human brain are normal adult structures in lower vertebrates. Recognition of transitory and vestigial structures by fetal or postnatal neuroimaging and neuropathologically enables better understanding of cerebral ontogenesis and avoids misinterpretations.

A Bayesian risk analysis for Trisomy 21 in isolated choroid plexus cyst: combining a prenatal database with a meta-analysis

OBJECTIVE

The purpose of this study was to quantify the possible additional risk of a fetus with an isolated choroid plexus cyst (ICPC) for Trisomy 21 by combining a large controlled cohort study with data from existent studies.

METHODS

We searched our prenatal database between 2000 and 2014 for all singleton pregnancies between 18 + 0 and 26 + 6 gestational weeks with either an isolated choroid plexus cyst (study group) or no abnormality found in the detailed ultrasound scan (control group). We assessed all prenatal karyotyping results if invasive testing was performed and attempted to collect the postnatal outcome reports of all patients. The prevalence of Down syndrome was calculated. By using previous studies that met our inclusion criteria, a meta-analysis following the Bayesian Independent Model was created. From this meta-analysis, we computed the posterior predictive distribution of the probability (Trisomy 21 | ICPC) = P1 including posterior means, standard deviations, quantiles (2.5, 50, and 97.5%). By calculating the posterior of the difference (Δ) between the probability (Trisomy 21 | ICPC) and the probability (Trisomy 21 | Normal Ultrasound) = P2, we investigated the additional risk of an ICPC (ΔB = P1-P2).

RESULTS

Overall, we detected 1220 fetuses with an isolated plexus cyst at 19-27 weeks of gestational age (GA). In our study group, the prevalence of Trisomy 21 was 2/1220 (0.16, 95% CI: 0.1-0.6%). The median of the pooled probability of Trisomy 21 given isolated PC across the studies included in the meta-analysis was 0.2% (CI: 0.1-0.4%). In the given periods (GA and time), 66,606 (74.8%) out of 89,056 investigated fetuses met the inclusion criteria and had a normal ultrasound result without any abnormality. The Δ between our study group and the control group was 0.08% (CIΔA: 0-0.5%). Including the meta-analysis, the median of the posterior distribution of Δ between P1 and P2 was 0.08% (CIΔB: 0-0.4%) (ΔB = P1-P2).

CONCLUSION

The posterior distribution of Δ between P1 and P2 including the meta-analysis corresponds to showing no difference between the cases and controls (95% CIΔB: 0-0.4%). The additional risk of a fetus with an ICPC for Trisomy 21 is 97.5% likely to be lower than 0.4% (about 1/250). However, in our collective, the positive predictive value of ICPC for Down syndrome was 0.16% (about 1/625). In prenatal counseling, the additional risk should be added to the individual risk (based on maternal age, earlier screening test results, and sonographic markers) and the diagnostic options including fetal DNA and diagnostic procedures should be discussed according to the posterior individual risk.

A Retrospective Study of Cytogenetic Results From Amniotic Fluid in 5328 Fetuses With Abnormal Obstetric Sonographic Findings

OBJECTIVES

The purpose of this study was to evaluate the diagnostic utility of karyotype analysis of amniotic fluid for fetuses with abnormal sonographic findings and to determine the detection rates of abnormal karyotypes.

METHODS

We conducted a retrospective study of 5328 fetuses with abnormal sonographic findings in the first or second trimester enrolled from October 1998 and September 2015. Cytogenetic results from amniotic fluid were obtained in all of these pregnancies. Sonographic abnormalities were stratified according to anatomic system involvement.

RESULTS

A total of 238 abnormal karyotypes were encountered in the 5328 fetuses (4.5%). The highest rate of chromosomal anomalies was in fetuses with structural abnormalities in multiple organ systems (25.7%), followed by an abnormal amniotic fluid volume (7.9%), structural abnormalities in a single system (7.3%), multiple nonstructural anomalies (7.2%), isolated placental abnormalities (7.1%), and isolated soft markers for aneuploidy (2.4%; P < .01). Among abnormalities in a single system, gastrointestinal and neck/body fluids had particularly high detection rates (26.1% and 26.2%, respectively). A detailed analysis suggested that the probability of an abnormal karyotype among every anatomic system was statistically significant (P < .01). This study identified several common indications with extremely high abnormal rates: duodenal atresia (53.1%), holoprosencephaly (48.8%), fetal hydrops (39.5%), cerebellar hypoplasia (32.0%), cystic hygroma (31.5%), absent/short nasal bone (11.0%), and bilateral choroid plexus cysts (8.5%).

CONCLUSIONS

Cytogenetic analysis has important clinical utility in a wide range of settings, such as prenatal diagnosis. For fetuses with indications of a highly abnormal detection rate, karyotype analysis should be suggested.

Multi-level partnerships to promote health services among internally displaced in eastern Burma

Ethnic populations in eastern Burma are the target of military policies that result in forced labour, destruction of food supplies, and massive forced displacement. Despite international assistance to Burmese refugees along the Thai-Burma border, traditional humanitarian models have failed to reach these internally displaced persons (IDPs) within Burma. Nevertheless, through the cultivation of a model (cross border local-global partnerships) 300,000 IDPs in eastern Burma now receive critical health services where, otherwise, there would be none. We describe key elements of the partnership model's genesis in eastern Burma. The role of the local partner, Backpack Health Worker Team (BPHWT), is highlighted for its indigenous access to the IDP populations and its maintenance of programmatic autonomy. These local elements are potentiated by international support for technical assistance, training, resources, and advocacy. International policy and investment should prioritize support of locally-driven health initiatives that utilize local-global partnerships to reach not only IDPs but also other war-torn or traditionally inaccessible populations worldwide.

Discovery of soft markers on fetal ultrasound: maternal implications

OBJECTIVE

to explore women's experiences of referral to tertiary care on the basis of uncertain ultrasound findings.

DESIGN

a qualitative method using Rice and Ezzy's thematic analysis approach. Data were gathered through two in-depth interviews over a six to eight-month period.

PARTICIPANTS

a total of 20 interviews were conducted among pregnant women, purposively recruited at a tertiary facility. Inclusion criteria were based on detection of an isolated soft marker in an otherwise normal pregnancy.

DATA ANALYSIS

interview data were transcribed and data were subjected to thematic analysis.

FINDINGS

mothers journeyed through a temporal sequence of adjustment following referral to specialist services. Four distinct phases were identified: realisation; making sense of events; anxious waiting; and having no clear resolution.

CONCLUSION

trends of increasing prenatal surveillance together with advancing technology make this study timely and of global interest. Findings suggest that women identified as 'at risk' before being discharged uneventfully may be prone to attachment issues and a host of other difficulties. The complexities inherent in this experience should be of interest to a broad range of health professionals. An appreciation of this experience may assist midwives and other health professionals to provide more meaningful maternal support to women identified as 'at risk'.

Trisomy 18: Fetal ultrasound findings at different gestational ages

The aim of this article is evaluate the sonograhic findings in fetuses with trisomy 18 at different gestational ages. The cases were recruited from pregnant women, who underwent to prenatal diagnosis in the period from October 1995 to September 2006. Seventy-one fetuses with trisomy 18 were diagnosed. On review of the sonograms the majority of these cases had ultrasound anomalies (sensitivity of 91.5%). The most frequent anomalies were abnormalities of extremities (40.8%) and fetal growth restriction (35.2%). More frequently (54.9%) two or more anomalies were present. Nearly all fetuses with trisomy 18 had sonographic abnormalities. Likely improved high-resolution equipment and attention to details by skilled operators led to the detection of most anomalies to trisomy 18. Knowledge of types of specific ultrasound findings can improve prenatal diagnosis in order to provide invasive procedures only when indicated, and to avoid amniocentesis when ultrasound signs are not observed in women at high risk from positive biochemical testing.

Women's response to fetal choroid plexus cysts detected by prenatal ultrasound

OBJECTIVES

To determine maternal responses to detection of a minor structural variant, the choroid plexus cyst (CPC), in their fetus on prenatal ultrasound.

STUDY DESIGN

We interviewed 34 pregnant women with an isolated CPC detected on mid-pregnancy ultrasound about their objective experience at diagnosis, emotional response and subsequent reactions. Audiotaped, transcribed responses were evaluated by two independent raters and analyzed qualitatively and quantitatively.

RESULTS

All women reported negative emotional responses including shock, distress, fear and decreased attachment, despite counseling by 82% of providers that the CPC was probably benign. Three women underwent amniocentesis purely for reassurance after CPC detection. Most (79%) sought information beyond what their physician provided, frequently on the internet. One half of women reported that intense negative responses were temporary. However, weeks after diagnosis, 62% continued to believe that the CPC presented some danger to their baby.

CONCLUSIONS

Detection of CPC prenatally can evoke profound, negative maternal emotional responses despite accurate provider counseling. Practitioners should consider these responses when counseling parents about these and other structural variants of unclear functional significance.

Clinical characteristics and survival of trisomy 18 in a medical center in Taipei, 1988–2004

Trisomy 18 is the second most common autosomal trisomy in newborns. The birth prevalence of this disorder is approximately 1 in 3,000 to 1 in 8,000, and the life span of the majority of patients is less than 1 year. As information regarding outcome in trisomy 18 is rather fragmentary in the literature, this study is aimed at investigating the survival and natural history of trisomy 18. We also evaluated the survival age and management of trisomy 18 in two different periods, before and after the implementation of National Health Insurance (NHI) program. Thirty-nine cases of trisomy 18 were collected in Mackay Memorial Hospital in a 17-year period, from 1988 to 2004. Delivery data, survival age, management before and after the implementation of NHI program, structural defects, image findings and cytogenetic results were analyzed by medical and nurse's records. The diagnosis of trisomy 18 was based on the prenatal amniocentesis or postnatal chromosome analysis. Three patients had trisomy 18 mosaicism. Since cardiovascular and central nervous systems are the most common organ systems involved in this disorder, 31 patients received brain ultrasonography and heart ultrasonography for evaluation of their multiple anomalies after admission. All patients except one died in their first year due to severe malformations of the cardiovascular or central nervous systems. The median survival age was 6 days. We found a longer survival with female patients than with male patients (P < 0.05). Implementation of NHI program in the more recent decade of this study period was associated with longer survival of trisomy 18 (P < 0.05). The three most common structural defects were clenched hands (95%), rocker bottom feet (90%), and low set or malformed ears (90%). Low birth weight was present in 90%. By cardiac ultrasonography, the top four heart defects were ventricular septal defect (94%), patent ductus arteriosus (77%) and atrial septal defect (68%). However, ten cases (32%) had complex congenital heart defects. By brain ultrasonography, the most common brain lesion was cerebellar hypoplasia (32%), followed by brain edema (29%), enlarged cisterna magna (26%) and choroid plexus cysts (19%). Although most patients with trisomy 18 die within the first few weeks after birth, it is important to recognize that a small but notable percentage of these patients will survive the first year. When prenatal or postnatal decisions need to be made, the possibility of long-term survival should be included in any discussion to enable families to make the most appropriate decision.

Ultrasound Imaging of Fetal Brain Abnormalities

Prenatal ultrasound evaluation of the fetal brain requires documentation of specific structures according to guidelines set by the American College of Radiology and the American Institute of Ultrasound in Medicine. Among these required structures are: cerebellum, cisterna magna, lateral cerebral ventricles, choroid plexus, midline falx, and cavum septum pellucidum. All these structures can be visualized in three crucial planes of imaging that include cisterna magna/cerebellum, cavum septum pellucidum, and ventricular atria. A systematic approach can be achieved by instituting a protocol that includes these three basic levels of imaging of the fetal head. These anatomical levels should be incorporated in daily routine for complete obstetric ultrasound evaluation.