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Publicly Available Published by De Gruyter April 11, 2017

Iniencephaly: a rare congenital anomaly reaching the term

Hale Göksever Çelik, Seda Yilmaz Semerci, Gökhan Yildirim and Merih Çetinkaya

Abstract

Introduction

Iniencephaly is characterized by a defect in the occipital bone in the inion, occipital encephalocele, spinal dysraphism and fixed hyperextension of the fetal head. The associated anomalies are observed in many systems including the central nervous system and the gastrointestinal system. Prenatal diagnosis is rare because early and careful ultrasonographic evaluation is necessary. Fetuses with iniencephaly are almost always stillborn. We aimed to present a fetus with iniencephaly reaching term in utero.

Case

A 25-year-old healthy primigravida Syrian woman consulted with labor pain at 39 weeks of gestation. She had no laboratory tests or ultrasonographic examination during the pregnancy. Ultrasound evaluation demonstrated a single live intrauterine fetus with a retroflexed fetal head and excess amniotic fluid. A girl was delivered by cesarean section weighing 3350 g with a length of 48 cm. The fetal head was retroflexed with an occipital bone defect. Associated anomalies such as club foot were also observed (Figures 1 and 2).

Discussion

Iniencephaly is an extremely rare neural tube defect first described by Saint-Hilare in 1836. Its incidence varies from 0.1 to 10 : 10,000. The incidence is higher in families with a history of neural tube defect. Maternal drug use, smoking, alcohol use, low parity and low socioeconomic status are risk factors. Prenatal diagnosis is possible by careful and early ultrasonographic examination. Termination of pregnancy is the generally accepted approach in these pregnancies because of poor prognosis and severe mortality. The most important precaution is to prevent obstructed labor and maternal trauma due to corporal distortion of the fetus.

Introduction

Iniencephaly is characterized by defects in the occipital bone in the inion, occipital encephalocele, spinal dysraphism and fixed hyperextension of the fetal head. Most associated anomalies are observed in the central nervous system including anencephaly, encephalocele, hydrocephalus, holoprosencephaly and Dandy-Walker malformations. Cyclopia, absence of a mandible, cleft lip/palate, single umblical artery, polycystic kidneys, congenital heart diseases and club foot can also be seen in these fetuses [1].

Prenatal diagnosis is rare because early and careful ultrasonographic evaluation is necessary. Fetuses with iniencephaly are almost stillborn. Because the disease itself and the associated anomalies are incompatible with life [2]. We aimed to present a fetus with iniencephaly reaching term in utero.

Case

A 25-year-old healthy multigravida Syrian woman consulted with labor pain at 39 weeks of gestation. She had no laboratory tests or ultrasonographic examination during the pregnancy. The pregnancy was uncomplicated regarding maternal health problems, vaginal bleeding or exposure to teratogens. She had not used folic acid supplementation during the pregnancy. She had an unremarkable family history. The fetal movements were normal and its growth parameters were appropriate for the gestational age for except the head measurement. Ultrasound evaluation demonstrated a single live intrauterine fetus with a retroflexed fetal head and excess amniotic fluid. A girl was delivered by cesarean section weighing 3350 g with a length of 48 cm. The fetal head was retroflexed with an occipital bone defect. Associated anomalies such as club foot were also observed (Figure 1and Figure 2). The baby was transferred to the prematurity intensive care unit. However, the baby died 10 min after delivery despite all the interventions. The family did not allow advanced examinations of the baby such as cranial and abdominal ultrasonography after death or the autopsy of the baby because of religious reasons.

Figure 1: 
The fetus had associated anomalies such as club foot.

Figure 1:

The fetus had associated anomalies such as club foot.

Figure 2: 
The retroflexed fetal head with the occipital bone defect.

Figure 2:

The retroflexed fetal head with the occipital bone defect.

Discussion

Iniencephaly is an extremely rare neural tube defect first described by Saint-Hilare in 1836 [3]. Its incidence varies from 0.1 to 10 : 10,000. Females are most frequently affected. Etiopathogenesis of the iniencephaly is not well understood. However, the incidence is higher in families with a history of neural tube defect [4]. Iniencephaly is diagnosed with a triad consisting of the absence of the occipital bone, exaggerated cervicothoracic retroflexion and cervical dysraphism. Many other malformations including the central nervous system, the gastrointestinal system and the cardiovascular system may be associated [5, 6]. Maternal drug use (antibiotics, antihistamines, etc.), cigarette smoking, alcohol use, low parity and low socioeconomic status are risk factors. Also, genetic predisposition may have a role although it has not yet been clearly elucidated [7].

Prenatal diagnosis is possible by careful and early ultrasonographic examination. Magnetic resonance imaging could be offered to evaluate equivocal fetal ultrasonographic findings [8].

Termination of pregnancy is the generally accepted approach in these pregnancies because of poor prognosis and severe mortality. If the woman does not accept an elective abortion, the most important precaution is to prevent obstructed labor and maternal trauma due to corporal distortion of the fetus during delivery [9]. Termination or birth at in the preterm period could be achieved via the vaginal route because the risk of cephalopelvic disproportion is small in early pregnancies [10]. The baby of our patient was delivered by cesarean section because the mother had a previous cesarean section. But even if the pregnant woman has had no previous cesarean section, the preferred route for birth should be by cesarean section for these babies at term to prevent poor outcomes for both the mother and the fetus. It is difficult to give examples about the birth route of term pregnancies with iniencephaly from the literature because it is encountered very rarely at term.

The recurrence incidence of iniencephaly is less than 1%. Although the underlying pathophysiologic mechanism is not well understood, the important point is the recommendation of folic acid supplementation to these women for future pregnancies because of higher incidence in families with a history of neural tube defect [4].


Corresponding author: Dr. Hale Göksever Çelik, MD, Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Training and Research Hospital, Astera Park Houses, A blok, kat 11, daire 47, Küçükçekmece-Istanbul, Turkey, Tel.: + 905326673150

Author’s Statement

  1. Conflict of interest: Authors state no conflict of interest.

Material and Methods

  1. Informed consent: Informed consent has been obtained from all individuals included in this study.

  2. Ethical approval: The research related to human subject use has complied with all the relevant national regulations, and institutional policies, and is in accordance with the tenets of the Helsinki Declaration, and has been approved by the authors’ institutional review board or equivalent committee.

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Received: 2016-10-01
Accepted: 2017-02-15
Published Online: 2017-04-11

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