Fetal acrania: five new cases and review of the literature

The far-reaching impact of abortion bans: reproductive care and beyond

On 24 June 2022, the US Supreme Court overturned Roe v. Wade, a 49-year-old precedent that provided federal constitutional protection for abortions up to the point of foetal viability, returning jurisdiction to the individual states. Restrictions that came into effect automatically in several states, and are anticipated in others, will severely limit access to abortions in approximately half of the US. Even though every state allows for exceptions to the abortion bans, in some instances these exceptions can be used to preserve the health of a pregnant patient, while in other instances, only to preserve their life. The vague and confusing nature of the abortion ban exceptions threatens to compromise the standard of care for patients with pregnancy complications that are distinct from abortions, such as nonviable pregnancies, miscarriages, and ectopic pregnancies. Additionally, we envision challenges for the treatment of women with certain autoimmune conditions, pregnant cancer patients, and patients contemplating preimplantation genetic diagnosis as part of assisted reproductive technologies. The abortion ban exceptions will impact and interfere with the medical care of pregnant and non-pregnant patient populations alike and are poised to create a medical and public health crisis unlike any other one from the recent past.

Imaging in the presence of meroanencephaly

Meroanencephaly occurs when there is an incomplete open median calvarial defect. This condition, which is in the spectrum of anencephaly, results in ectopic brain without skin covering and a normal foramen magnum. We present a rare case of a female fetus with meroanencephaly referred to our institution at 24 weeks and imaged with both prenatal ultrasound and MRI, demonstrating an open neural tube defect in the high parietal area and lack of visualization of the supratentorial ventricular system. Postnatal the child survived and went on to require antibiotic therapy and closure of the defect without cerebral spinal fluid diversion but demonstrates severe permanent neurologic deficits.

The role of the "beret" sign and other markers in ultrasound diagnostic of the acrania-exencephaly-anencephaly sequence stages

INTRODUCTION

Neural tube defects (NTDs) are a group of heterogeneous congenital anomalies of the central nervous system (CNS). Acrania is a non-NTD congenital disorder related to the CNS. It can transform into anencephaly through the acrania-exencephaly-anencephaly sequence (AEAS). In AEAS, the cerebral tissue is not protected and is gradually destroyed due to exposure to the harmful effect of amniotic fluid and mechanical injuries. These lead to exencephaly and then into anencephaly. In contrast to primary anencephaly (NTDs), this type of anencephaly authors suggests calling secondary anencephaly.

OBJECTIVE

Analysis of the known prenatal ultrasonography (US) signs associated with AEAS. Simultaneously, the authors propose a new sign in the differentiation of acrania from exencephaly and anencephaly, called the "beret" sign.

METHODS

It is a two-centre retrospective observational study. As part of the study, 4060 US scans were analyzed.

RESULTS

In 10 cases, the absence of calvarium was diagnosed, allowing recognition of either AEAS stages or primary anencephaly. In 5 cases, cerebral structures were enclosed by an inertial rippled thin membrane, with a smooth outer contour. Between the described membrane and the brain structures, a thin anechoic space corresponding to cerebrospinal fluid was observed. This sign was defined as the "beret" sign. In these cases, acrania was diagnosed. In three cases calvarium was missing. The brain structures had an irregular appearance, did not wave and remained motionless. The outer contour was unequal as if divided into lobes. Amniotic fluid was anechoic. Exencephaly was diagnosed in these cases. In two cases calvarium, brain structures, and meninges were missing. The "frog eyes" sign and slightly echogenic amniotic fluid were visible. In this case, anencephaly was diagnosed.

CONCLUSIONS

The "beret" sign seems to be a promising tool in the diagnosis of acrania. Furthermore, echogenicity of amniotic fluid could be useful during differentiation between primary and secondary anencephaly.

Characteristics of fetuses evaluated due to suspected anencephaly: a population-based cohort study in southern Brazil

CONTEXT AND OBJECTIVE

Anencephaly is considered to be the most common type of neural tube defect. Our aim was to assess the clinical and gestational features of a cohort of fetuses with suspected anencephaly.

DESIGN AND SETTING

Population-based retrospective cohort study in a referral hospital in southern Brazil.

METHODS

The sample consisted of fetuses referred due to suspected anencephaly, to the Fetal Medicine Service of Hospital Materno Infantil Presidente Vargas, between January 2005 and September 2013. Clinical, radiological, pathological and survival data were gathered.

RESULTS

Our sample was composed of 29 fetuses. The diagnosis of suspected anencephaly was made on average at 21.3 weeks of gestation. Seven fetuses had malformations that affected other organs, and these included oral clefts (n = 4) and congenital heart defects (n = 2). In 16 cases, there was termination of pregnancy (n = 12) or intrauterine death (n = 4). Regarding those who were born alive (n = 13), all of them died in the first week of life. After postnatal evaluation, the diagnosis of anencephaly was confirmed in 22 cases (75.9%). Other conditions included amniotic band disruption complex (6.9%), microhydranencephaly (6.9%), merocrania (3.4%) and holoprosencephaly (3.4%).

CONCLUSIONS

Different conditions involving the cranial vault may be confused with anencephaly, as seen in our sample. However, these conditions also seem to have a poor prognosis. It seems that folic acid supplementation is not being properly performed.

Length of life and treatment intensity in infants diagnosed prenatally or postnatally with congenital anomalies considered to be lethal

OBJECTIVES

The objectives of this study were (1) to compare age at death and the intensity and cost of medical treatment for infants diagnosed prenatally or postnatally with congenital anomalies considered to be lethal. (2) To determine whether greater treatment intensity is associated with longer life.

STUDY DESIGN

This is a retrospective cohort study of all fetuses and neonates with congenital anomalies classified as lethal who were diagnosed or treated at the University of North Carolina Hospitals from January 1998 to December 2003.

RESULT

The cohort consisted of 192 fetuses and infants: 160 were diagnosed prenatally, 2 were diagnosed perinatally, and 30 were diagnosed postnatally. In all, 115 (72%) pregnancies were terminated. Of the liveborn infants, 75% died before 10 days of age and 90% before 4 months of age. Compared with postnatally diagnosed infants, prenatally diagnosed infants received less intense treatment (median average daily Neonatal Therapeutic Intervention Scoring System score 8.3 versus 14.0; P=0.02), at less cost (median direct cost of hospitalization $1550 versus $8474; P=0.03) and died sooner (median age at death <1 day versus 4 days; P=0.01). Greater treatment intensity did not correlate with longer survival (r=-0.04; P=0.66).

CONCLUSION

Although some kinds of medical therapy may be appropriate for newborns with lethal congenital anomalies, highly aggressive interventions did not prolong survival and should not be offered. Even when pregnancy termination is not elected, infants diagnosed prenatally receive less intense care.

"Hugging sisters": thoracoomphalopagus with anencephaly confirmed by three-dimensional ultrasonography at 9 weeks of gestation

We describe a rare conjoined twinning at 9 weeks of gestation. We compared the results of two- and three-dimensional sonography with autopsy findings after the termination of pregnancy. These results showed a thoracoomphalopagus with a shared heart and visceral organs. Three-dimensional sonography showed anencephaly in one of the embryos. Early and accurate prenatal diagnosis of this type of conjoined twins using three-dimensional sonography is critical for both parental counseling and minimizing maternal morbidity.

Anencephaly

Anencephaly is easily diagnosed by sonography. This article presents images and a discussion of embryology, maternal serum testing, and management.

Prenatal diagnosis of fetal acrania using three-dimensional ultrasound

Fetal acrania is uniformly lethal and termination is suggested whenever the diagnosis is made. Traditionally, the diagnostic tool was 2-D ultrasound (US). In this series, we report our work of detecting acrania using 3-D US. We reviewed our medical records of prenatal diagnosis on fetal acrania in National Cheng Kung University Hospital from May 1997 to December 2002. All the cases were scanned by a 3-D US scanner. In total, 29 cases of fetal acrania were diagnosed. The range of gestational age at prenatal diagnosis by US was between 11 and 21 weeks and 44% were depicted in the first trimester. Among them, 93.1% were isolated findings, and one was associated with trisomy 18. Comparing with previous literature, 3-D US can detect fetal acrania as early as 2-D US, and it also can provide additional vivid illustration after various modes of reconstruction, which 2-D US cannot. In conclusion, 3-D US may contribute to early detection of fetal acrania and provide a novel visual depiction of this defect after reconstruction; thus, assists substantially in diagnosis as well as consultation.

Anencephaly: MRI findings and pathogenetic theories

We describe the MRI appearances of an anencephalic newborn who survived for 13 h; particularities of this case are male gender and the absence of other associated malformations. Moreover, we discuss the pathogenetic theories of anencephaly, correlating MRI findings with embryological data. An exencephaly-anencephaly sequence due to amnion rupture is hypothesized.

Subclassification of anencephalic human fetuses according to morphology of the posterior cranial fossa

Anencephaly is a designation for congenital absence of the cranial vault with cerebral hemispheres completely missing or decreased to small masses attached to the base of the skull. The etiology is unknown. Whether the bony tissue or soft brain tissue is a primary factor is also unknown. The present study has focused on the posterior cranial fossa in anencephaly. The goal is to determine whether differences in the posterior cranial fossa could provide a basis for subclassification of anencephalic fetal skeletons. Twenty-three human anencephalic fetuses, at gestational ages 13 to 22 weeks, were studied. Radiologic and cephalometric analyses, including measurements of bone sizes and different angles, were performed. Permission for autopsy of the central nervous system was not available. For comparison of anencephalic findings with normal conditions, standards from a recent publication were used. Foot length served as a parameter for age comparison. The study showed 2 morphologic types of the posterior cranial fossa. One type had a fossa cranial morphology close to normal morphology, whereas the other had a malformed and much smaller posterior cranial fossa. The latter condition was presumed to be due to a primary error in chondral and cranial development. The current skeletal subgrouping might be essential for clinicians' or pathologists' future assessment of the autopsy results. The skeletal subgrouping should, if possible, be associated with karyotyping and analysis of the central nervous system. The goal is to distinguish between congenital conditions resulting in anencephaly and acquired conditions resulting in anencephaly.

A case study of amnion rupture sequence with acalvaria, blindness, and clefting: clinical and psychological profiles

The purpose of this article is to report the case of a 10-year-old girl born with anophthalmia, bilateral oblique facial clefts, and missing scalp and bones over the temporal and parietal areas of the cranial vault bilaterally. Early amnion rupture seems to be the most probable cause of this rare combination of anomalies. Because no similar case has been reported in the literature so far, we describe here the clinical and psychosocial history of this unusual patient, who has been able to live the intellectually and socially normal life of a blind child in spite of the major craniofacial deformities. The already completed and possible future therapeutic strategies are discussed.

Diagnosis of fetal acrania during the first trimester nuchal translucency screening for Down syndrome

OBJECTIVES

Prenatal screening during the first-trimester using fetal nuchal translucency (NT) measurement and maternal serum levels of free beta-human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein-A (PAPP-A) has become an established method for the detection of fetal Down syndrome. Increasing evidence has shown that some of the fetal structural abnormalities could be identified during NT scanning. Second trimester maternal serum alpha-fetoprotein (MSAFP) measurements and ultrasound scans have been widely used in clinical practice to identify fetal neural tube defects (NTDs). In this study, we evaluated the effectiveness of early diagnosis of fetal acrania during NT scanning.

METHODS

We reviewed the medical records of 5890 pregnancies that were delivered in our hospital between January 1, 1999 and January 31, 2001. Among them, 3600 pregnant women received NT-based Down syndrome screening at 10-13 weeks' gestation. Pregnancies with fetal NTDs were evaluated and their maternal serum levels of free beta-hCG and PAPP-A were compared with those of the normal control pregnancies.

RESULTS

Seven of the 3600 pregnancies were identified with fetal acrania and all of them were detected during first-trimester NT scanning. Among the seven cases, five had measurements of maternal serum concentration free beta-hCG and PAPP-A concentration, yet there were not significant difference between the pregnancies with fetal acrania and those of the control pregnancies (PAPP-A, 1.13 vs. 0.96; free beta-hCG, 1.10 vs. 1.06; P>0.05). Two of the seven affected patients did not have maternal serum biochemical measurements due to the immediate termination of pregnancies.

CONCLUSIONS

We demonstrated that pregnancies with fetal acrania could be easily identified at the time of NT scanning. Careful ultrasound inspection of fetal structure during NT measurements at 10-13 weeks of gestation provides an encouraging advantage for early diagnosis of fetal acrania.

Screening for neural tube defects

Neural tube defects are separated into two main categories: (1) abnormalities of the skull and brain (anencephaly, acrania, and encephalocele) and (2) malformations of the spine (meningomyelocele or spina bifida). The cause of neural tube defects is not always clear, and include chromosomal abnormalities, single gene mutations, maternal disease, or maternal exposure to teratogens. Mostly the disorder emerges as a multifactorial trait. Routine screening for neural tube defects was introduced in the United Kingdom in the mid-1970s and the United States in the mid-1980s. The use of screening has resulted in a marked decline in the frequency of neural tube defects diagnosed at birth.

Fetal acalvaria with amniotic band syndrome

A case of amniotic band syndrome (ABS) presenting with acalvaria is reported. ABS includes a spectrum of non-genetic anomalies, varying from simple digital band constriction to major craniofacial and visceral defects, and even fetal death. Acalvaria is a rare congenital malformation characterised by the absence of the dome-like superior portion of the cranium comprising the frontal, parietal, and occipital bones and dura mater, in the presence of a normal skull base and facial bones with complete cranial contents. No two cases are the same. Acrania or absence of the flat skull bones with disorganised cerebral hemispheres have been reported in the presence of amniotic bands. ABS is an aetiological factor in acalvaria. Appropriate counselling for affected families needs to be given after prenatal diagnosis.