Hydrocephaly – communicating

Hydrocephaly – communicating


Hydrocephalus is defined as an excessive amount of cerebrospinal fluid (CSF) in the cranial cavities. CSF is mainly produced in the choroid plexuses situated in the lateral ventricles, flowing from either side into the third ventricle via the foramen of Monro and then through the Sylvian aqueduct to reach the fourth ventricle, located within the brainstem. CSF then exits the ventricular system through the foramina of Luschka and Magendie into the cisterna magna and subarachnoid space to be reabsorbed by the granulations of Pacchioni located along the superior sagittal sinus. Although the above definition can be satisfied in situations where there is an apparent increase in ventricular size due to destruction or maldevelopment of adjacent cerebral tissue (secondary to porencephaly or agenesis of the corpus callosum respectively), known as hydrocephaly ex vacuo, it is typically and more practically applied where any of the following criteria coexist: º,overproduction of CSF (as in the rare choroid plexus papilloma) º,obstruction of CSF flow (due to stenosis of the Sylvian aqueduct) º,impairment of CSF resorption by the arachnoid granules The cause is unknown in over one third of cases. Obstructive hydrocephalus is by the far the most common type and is usually associated with spina bifida, the Arnold Chiari type II malformation, aqueduct stenosis, and the Dandy-Walker malformation. Other obstructive causes include intracranial tumors, intracranial haemorrhage or cysts blocking the foramina of Monro, Luschka or Magendie.


Ventriculomegaly is the most typical feature. The enlargement is often so obvious that measurements are unnecessary, but an abnormal increase in the size of the lateral ventricles measured at the atrium in the transverse plane (the lateral atrial diameter) is the most useful objective ultrasonographic diagnostic aid. Any measurement over 10mm is abnormal, the normal range lying between 7 to 10 mm from fifteen to thirty five weeks gestation. Examination of the choroid within the lateral ventricles may also be helpful. The choroid plexus always lies in the gravitationally dependent position until it rests against the lateral ventricular wall. If the choroid plexus is seen to fill the lateral ventricular body in its transverse dimension ventriculomegaly is not present. In true ventriculomegaly the choroid plexus will be seen dangling downwards and will be angulated from the mid-line. Occasionally the poor echogenicity of the brain parenchyma in this region may be mistaken for cerebrospinal fluid surrounding the atrial choroid and a misdiagnosis of hydrocephaly may be made. This mistake will not be made if close attention is paid to the position of the choroid plexus. As the diagnosis may be difficult to make in some cases, especially between eighteen and twenty four weeks gestation, serial scans become important particularly with progressively obstructive lesions. It should be emphasised that a normal head size does not exclude hydrocephaly. If lateral ventriculomegaly is found, then a careful assessment of spinal and intracranial anatomy should be undertaken to ascertain the extent of the condition and its underlying cause.

Differential Diagnosis

Once a diagnosis of hydrocephalus has been made a search should be carried out for the cause. This may include intrauterine viral infection (TORCH), trisomies 13 or 18, the Dandy Walker malformation, arachnoid cyst, agenesis of the corpus callosum, holoprosencephaly, intraventricular haemorrhage, vein of Galen aneurysm, Meckel-Gruber syndrome, choroid plexus papillomas or cysts, lissencephaly, hydranencephaly, porencephaly, schizencephaly, spina bifida and encephalocele (with Arnold Chiari malformation causing obstruction). It is therefore important to have a plan of action once ventriculomegaly has been found. Even in expert hands however it is not always possible to differentiate obstructive from non-obstructive (communicating) hydrocephalus. If ventriculomegaly is found first check the choroid plexus to rule out a large cyst or echogenic mass. If no mass is seen choroid plexus papilloma is ruled out. Next evaluate the posterior fossa in the transcerebellar plane. The cisterna magna, lying posterior to the cerebellum, is readily seen. The normal depth is 5 mm, and any measurement over 10 mm is abnormal; the differential includes Dandy-Walker malformation or subarachnoid cyst. If the posterior fossa is normal but the third and lateral ventricles are enlarged aqueduct stenosis is likely. Attention is now paid to the cranium. If the head circumference is decreased in the presence of ventriculomegaly the possibility of cytomegalovirus infection as a cause should be considered. A bony defect will be seen if a cephalocele exists; the ‘lemon’ sign of the Arnold-Chiari malformation will be seen with spina bifida. The spine itself should be evaluated to rule out defects before proceeding with a careful morphologic scan of the other fetal systems. Fetal karyotype and echocardiography are essential in cases where ventriculomegaly is found particularly where additional malformations coexist. The outcome of fetal ventriculomegaly will depend on the presence of associated malformations. Review of the literature suggests that there is an 80% chance of survival and a 50% chance of normal development with isolated ventriculomegaly.

Sonographic Features

Transverse atrial diameter greater than 10 mm.

Choroid plexus not filling atrium.

Dangling choroid plexus (due to increased CSF in ventricle).

Cisterna magna greater than 10 mm in transcerebellar plane, and visualisation of other prominent subarachnoid fluid collections, prompts the diagnosis of communicating hydrocephalus.

Enlargement of third and fourth ventricles (normal fourth ventricle may be seen in aqueductal stenosis).

Associated Syndromes

  • Aminopterin
  • Aminopterin-like
  • Amniocentesis
  • Aniridia-renal anomalies
  • Anophthalmia-abnormal nares
  • Anophthalmia-cleft lip/palate
  • Aqueduct stenosis-basilar impression
  • Basal cell nevus
  • Beemer: dense bones
  • Bijlsma: aqueduct stenosis
  • Bone fragility-proptosis
  • Campomelia-aankyloglossia
  • Cataract-ossified pinnae
  • Centromere instability-immunodeficiency
  • Cerebroarthrodigital
  • CHARGE association
  • Chromosome
  • Ciliary akinesia/dyskinesia
  • Clefting-corneal opacity
  • Crouzon
  • Daish: tall stature-joint hypermobility
  • De Hauwere: iris dysplasia
  • Epidermal nevus syndrome
  • Fine: ocular anomalies-cleft palate-asymmetry
  • Fraser: cryptophthalmos
  • Goldenhar
  • Habel: microstomia-hydrocephalus
  • Hajdu-Cheney
  • Hanhart: hypoglossia-hypodactyly
  • Heptacarpo-octatarso-dactyly
  • Hydrocephalus-endocardial fibroelastosis-cataracts
  • Hydrocephalus-proliferative vasculopathy
  • Hydrolethalus
  • Jeune thoracic dysplasia
  • MASA
  • MULIBREY nanism
  • Neurocutaneous melanosis
  • Neurofibromatosis
  • Ochoa: urofacial syndrome
  • Osteogenesis imperfecta, lethal type
  • Osteoglophonic dwarfism
  • Oto-palato-digital II
  • Palmer-Pagon: hydrocephalus-low umbilicus
  • Petersí-plus
  • Pfeiffer: synostosis-deafness
  • Pseudomarfanism
  • Renal cysts
  • Rhizomelic chondrodysplasia-thrombocytopenia
  • Rogers: anophthalmia
  • Schinzel-Giedion: dwarfism
  • Sengers: obesity-hypogenitalism
  • Thakker-Donnai
  • Tibial aplasia-ectrodactyly
  • Trigonocephaly
  • Van Biervliet: thoracic dystrophy
  • Waaler: costovertebral dysplasia
  • Walker-Warburg
  • Weaver: craniosynostosis
  • Winter: thoracic dysplasia
  • Winter-Wigglesworth: cerebro-renal
  • X linked-unusual facies-callosal agenesis


Levitsky DB, Mack LA, Nyberg DA, Shurtleff DB, Shields LA, Nghiem HV, Cyr DR Fetal aqueductal stenosis diagnosed sonographically: how grave is the prognosis? AJR 164: 715-730
mmÁlÁ P, Salonen R First-trimester diagnosis of hydrolethalus syndrome Ultrasound Obstet Gynecol 5: 60-62
GiuffrË R, Pastore FS, De Santis S Connatal (fetal) hydrocephalus: an acquired pathology? Childís Nerv Syst 11: 97-101
Mondkar J, Kalgutkar A, Nalavade Y, Fernandez A Congenital primary cerebral neuroblastoma Indian Pediatr 31: 698-702
Paidas MJ, Cohen A Disorders of the central nervous system Semin Perinatol 18: 266-282
Twining P, Jaspan T, Zuccollo J The outcome of fetal ventriculomegaly Br J Radiol 67: 26-31
Farrell SA Down syndrome and fetal ventriculomegaly Prenat Diagn 14: 647-652
Farrell TA, Hertzberg BS, Kliewer MA, Harris L, Paine SS Fetal lateral ventricles: reassessment of normal values for atrial diameter at US Radiology 193: 409-411
Alagappan R, Browning PD, Laorr A, McGahan JP Distal lateral ventricular atrium: reevaluation of normal range Radiology 193: 405-408
Montemagno R, Soothill PW, Scarcelli M, OíBrien P, Rodeck CH Detection of alloimmune thrombocytopenia as cause of isolated hydrocephalus by fetal blood sampling Lancet 343: 1300-1301
Hertzberg BS, Lile R, Foosaner DE, Kliewer MA, Paine S, Paulson EK, Carroll BA, Bowie JD Choroid plexus-ventricular wall separation in fetuses with normal-sized cerebral ventricles at sonography: postnatal outcome AJR 163: 405-410
Patel MD, Filly AL, Hersh DR, Goldstein RB Isolated mild fetal cerebral ventriculomegaly: clinical course and outcome Radiology 192: 759-764
Hogge WA, Blank C, Roochvarg LB, Hogge JS, Wulfsberg EA, Raffel LJ Gorlin syndrome (naevoid basal cell carcinoma syndrome): prenatal detection in a fetus with macrocephaly and ventriculomegaly Prenat Diagn 14: 725-727
Achiron R, Pinhas-Hamiel O, Lipitz S, Heiman Z, Reichman B, Mashiach S Prenatal ultrasonographic diagnosis of fetal cerebral ventriculitis asociated with asymptomatic maternal cytomegalovirus infection Prenat Diagn 14: 523-526
Ko T-M, Hwa H-L, Tseng L-H, Hsieh F-J, Huang S-F, Lee T-Y Prenatal diagnosis of X-linked hydrocephalus in a Chinese family with four successive affected pregnancies Prenat Diagn 14: 57-60
Gupta JK, Bryce FC, Lilford RJ Management of apparently isolated fetal ventriculomegaly Obstet Gynecol Surv 49: 716-721
Hill LM, Grzybek PC Sonographic findings with Pfeiffer syndrome Prenat Diagn 14: 47-49
Holzgreve W, Feil R, Louwen F, Miny P Prenatal diagnosis and management of fetal hydrocephaly and lissencephaly Childís Nerv Syst 9: 408-412
Schwanitz G, Schžler H, Gembruch U, Zerres K Chromosomal findings in fetuses with ultrasonographically diagnosed ventriculomegaly Ann GÌnÌt 36: 150-153
Brocard O, Ragage C, Vibert M, Cassier T, Kowalski S, Ragage J-P Prenatal diagnosis of X-linked hydrocephalus J Clin Ultrasound 21: 211-214
Chari R, Bhargava R, Hammond I, Ventureyra ECG, Lalonde AB Antenatal unilateral hydrocephalus Canad Assoc Radiol J 44: 57-59
Patten RM, Mack LA, Finberg HJ Unilateral hydrocephalus: prenatal sonographic diagnosis AJR 156: 359-363
Bromley B, Frigoletto FD, Benacerraf BR Mild fetal lateral cerebral ventriculomegaly: clinical course and outcome Am J Obstet Gynecol 164: 863-867
Bronshtein M, Ben-Shlomo I Choroid plexus dysmorphism detected by transvaginal sonography: the earliest sign of fetal hydrocephalus J Clin Ultrasound 19: 547-553
Amato M, Hžppi P, Durig P, Kaiser G, Schneider H Fetal ventriculomegaly due to isolated brain malformations Neuropediatrics 21: 130-132
Spirt BA, Oliphant M, Gordon LP Fetal central nervous system abnormalities Radiol Clin North Am 28: 59-73
Nicolaides KH, Berry S, Snijders RJM, Thope-Beeston JG, Gosden C Fetal lateral cerebral ventriculomegaly: associated malformations and chromosomal defects Fetal Diagn Ther 5: 5-14
Roume J, Larroche JC, Razavi-Encha F, Gonzales M, Migne G, Mulliez N Fetal hydrocephalus; clinical significance of associated anomalies and genetic counselling: a pathological approach Genet Couns 1: 185-196
Gaston BM, Jones BE Perinatal unilateral hydrocephalus: atresia of the foramen of Monro Pediatr Radiol 19: 328-329
Drugan A, Krause B, Canady A, Zador IE, Sacks AJ, Evans MI The natural history of prenatally diagnosed cerebral ventriculomegaly JAMA 261: 1785-1788
Mahony BS, Nyberg DA, Hirsch JH, Petty CN, Hendricks SK, Mack LA Mild idiopathic lateral cerebral ventricular dilatation in utero: sonographic evaluation Radiology 169: 715-721
Cardoza JD, Goldstein RB, Filly RA Exclusion of fetal ventriculomegaly with a single measurement: the width of the lateral ventricular atrium Radiology 169: 711-714
Cardoza JD, Filly RA, Podrasky AE The dangling choroid plexus: a sonographic observation of value in excluding ventriculomegaly AJR 151: 767-770
Pretorius DH, Drose JA, Manco-Johnson ML Fetal lateral ventricular ratio determination during the second trimester J Ultrasound Med 5: 121-124
Pilu G, DePalma L, Romero R, Bovicelli L, Hobbins JC The fetal subarachnoid cisterns: an ultrasound study with report of a case of congenital communicating hydrocephalus J Ultrasound Med 5: 365-372
Chervenak FA, Berkowitz RL, Romero R, Tortora M, Mayden K, Duncan C, Mahoney MJ, Hobbins JC The diagnosis of fetal hydrocephalus Am J Obstet Gynecol 147: 703-716
Watt-Morse ML, Laifer SA, Hill LM The natural history of fetal cytomegalovirus infection as assessed by serial ultrasound and fetal blood sampling: a case report Prenat Diagn 15: 567-570
Mai R, Rempen A, Kristen P Color flow mapping of the middle cerebral artery in 23 hydrocephalic fetuses Arch of Gynecol Obstet 256: 155-158
Peters MT, Lowe TW, Carpenter A, Kole S Prenatal diagnosis of congenital cytomegalovirus infection with abnormal triple-screen results and hyperechoic fetal bowel Am J Obstet Gynecol 173: 953-954