Citation, DOI, disclosures and article data
Citation:
Weerakkody Y, Jarvis M, Elfeky M, et al. Iniencephaly. Reference article, Radiopaedia.org (Accessed on 29 Mar 2024) https://doi.org/10.53347/rID-10294
Iniencephaly is a rare neural tube defect resulting in the following features 1,2:
- occipital bone defect
- partial or total absence (rachischisis) of cervicothoracic vertebrae
- fixed fetal head retroflexion
The estimated incidence is at ~0.1-10 per 10,000 live births 5. There is a recognized female predilection 5.
The exact etiology is unknown.
Subtypes
Markers
Associations
Antenatal ultrasound
The fetus is described to have a fixed "stargazer" type extended posture. Other features include:
- exaggerated cervicothoracic lordosis
- deficient (short) or fused cervical vertebrae
- variable deficit in the occipital bone
- due to the head position, the fetal crown-rump length may be lower than expected for gestational age
- may have concurrent polyhydramnios
Treatment and prognosis
Iniencephaly is almost always lethal. However, usually there is no increased risk of recurrence in a future pregnancy.
History and etymology
Derived from the Greek words inion = back of head and encephalos = brain.
For an extended head position on antenatal ultrasound consider:
- physiological cervical hyperextension: transient, no occipital body defects and/or vertebral anomalies
- Klippel Feil syndrome
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1. Tugrul S, Uludoğan M, Pekin O et-al. Iniencephaly: Prenatal diagnosis with postmortem findings. J. Obstet. Gynaecol. Res. 2007;33 (4): 566-9. doi:10.1111/j.1447-0756.2007.00558.x - Pubmed citation
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2. Sahid S, Sepulveda W, Dezerega V et-al. Iniencephaly: prenatal diagnosis and management. Prenat. Diagn. 2000;20 (3): 202-5. Prenat. Diagn. (link) - Pubmed citation
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3. Balci S, Aypar E, Altinok G et-al. Prenatal diagnosis in three cases of iniencephaly with unusual postmortem findings. Prenat. Diagn. 2001;21 (7): 558-62. doi:10.1002/pd.97 - Pubmed citation
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4. Loo CK, Freeman B, Stanford D. CNS findings in iniencephaly: case report and literature review. Pathology. 2001;33 (1): 112-5. - Pubmed citation
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5. Pungavkar SA, Sainani NI, Karnik AS et-al. Antenatal diagnosis of iniencephaly: sonographic and MR correlation: a case report. Korean J Radiol. 8 (4): 351-5. Korean J Radiol (link) - Free text at pubmed - Pubmed citation
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6. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon
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7. Merz E, Bahlmann F. Ultrasound in obstetrics and gynecology. Thieme Medical Publishers. (2005) ISBN:1588901475. Read it at Google Books - Find it at Amazon
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8. Foderaro AE, Abu-yousef MM, Benda JA et-al. Antenatal ultrasound diagnosis of iniencephaly. J Clin Ultrasound. 1987;15 (8): 550-4. - Pubmed citation
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9. Chen CP. Prenatal diagnosis of iniencephaly. Taiwan J Obstet Gynecol. 2007;46 (3): 199-208. doi:10.1016/S1028-4559(08)60021-2 - Pubmed citation
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10. Gadodia A, Gupta P, Sharma R et-al. Antenatal Sonography and MRI of Iniencephaly apertus and clausus. Fetal. Diagn. Ther. 2010;27 (3): 178-80. doi:10.1159/000291472 - Pubmed citation
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