Hydrocephalus



Hydrocephalus


Roya Sohaey, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Chiari II Malformation


  • Aqueductal Stenosis, Late


  • Dandy-Walker Continuum: Classic


Less Common



  • Intracranial Hemorrhage


  • Encephalomalacia


Rare but Important



  • Obstructing Mass


  • Choroid Plexus Papilloma


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Routine lateral ventricle measurement



    • Measure atria of lateral ventricle



      • At level of choroid plexus glomus


      • Measure inner to inner wall


    • Normal atrial measurements



      • < 10 mm between 14-40 wks


    • Ventriculomegaly



      • Mild: 10-12 mm


      • Moderate: 12-15 mm


      • Severe: > 15 mm


  • Use transvaginal ultrasound



    • Cephalic presentation



      • Frontal fontanelle as acoustic window


    • Best for corpus callosum visualization



      • Color Doppler to show pericallosal artery


Helpful Clues for Common Diagnoses



  • Chiari II Malformation



    • Hindbrain herniation



      • Causes obstructive hydrocephalus


    • Variable ventriculomegaly



      • 55% at time of diagnosis


      • 33% progress during pregnancy


    • Variable calvarial measurements



      • Normal or small in 2nd trimester


      • Macrocephaly if ↑ ventriculomegaly


    • Posterior fossa compression



      • Small or obliterated cisterna magna


      • Variable cerebellar compression


      • “Banana sign” if cerebellum wraps around midbrain


    • “Lemon-shaped” calvarium



      • Frontal bone narrowing and “tenting”


    • Almost always with spina bifida



      • 90% lumbosacral


      • 80% with overlying sac


  • Aqueductal Stenosis, Late



    • Aqueduct of Sylvius narrowing/obstruction



      • ↑ 3rd and lateral ventricles


      • Normal 4th ventricle/posterior fossa


    • Progressive hydrocephalus



      • Initial normal or mild ventriculomegaly


      • Macrocephaly common near term


    • X-linked form



      • Bickers-Adams syndrome


      • < 5% of all cases


      • 50% recurrence risk in male fetuses


      • Adducted thumbs is additional finding


    • 90% with mental retardation



      • More severe retardation if X-linked


  • Dandy-Walker Continuum: Classic



    • Most severe cystic posterior fossa malformation



      • Absent cerebellar vermis


      • Cystic dilatation of 4th ventricle


      • Variable ventriculomegaly


    • Ultrasound findings



      • Splayed cerebellar hemispheres


      • Small/absent cerebellum if severe


      • Posterior fossa cyst


    • Associated findings



      • Dysgenesis of corpus callosum


      • Encephalocele, neural tube defect


      • Cleft lip/palate


      • Cardiac defects


      • Polycystic kidneys


Helpful Clues for Less Common Diagnoses



  • Intracranial Hemorrhage



    • Most common locations include: Subependymal, germinal matrix, intraventricular, intraparenchymal, subdural


    • Ventriculomegaly from 2 causes



      • Brain destruction image ventricular expansion


      • Intraventricular bleed image obstructive hydrocephalus


    • Ventricle findings



      • Hyperechoic intraventricular clot


      • Echogenic cerebrospinal fluid


      • Bulky irregular choroid plexus


      • Echogenic irregular ependyma


    • Causes



      • Maternal/fetal ↑ or ↓ blood pressure


      • Trauma


      • Thrombocytopenia/coagulation disorders



      • Infection


      • Fetal arteriovenous malformation


  • Encephalomalacia



    • Brain parenchyma destruction


    • Ultrasound findings



      • Early: Periventricular heterogeneity


      • Late: Cystic change


    • Causes



      • Hypoperfusion from any cause


      • Infection


      • Teratogen exposure


Helpful Clues for Rare Diagnoses



  • Obstructing Mass



    • Mass or mass-like lesions obstruct cerebrospinal flow


    • Cystic mass



      • Arachnoid cyst


      • Glioependymal cyst


      • Cystic teratoma


    • Solid mass



      • Solid teratoma


      • Astrocytoma or other rare tumor


      • Choroid plexus papilloma


    • Mass-like lesion



      • Vein of Galen malformation


      • Arteriovenous fistula


      • Intracranial hemorrhage


  • Choroid Plexus Papilloma



    • Hydrocephalus from over production of cerebral spinal fluid (CSF)



      • Often rapid onset


    • Well-defined, lobular, hyperechoic mass


    • Occurs anywhere in ventricular system



      • Lateral ventricle most common


    • Mass may also obstruct ventricle causing asymmetric enlargement

Only gold members can continue reading. Log In or Register to continue

Related posts:

  1. Intracranial Cysts: Lateral
  2. Hepatomegaly
  3. Abnormal Placental Location
  4. Abnormal Umbilical Cord

Stay updated, free articles. Join our Telegram channel
Tags:
Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Hydrocephalus

Full access? Get Clinical Tree
Get Clinical Tree app for offline access