Handbook of Genetic Counseling/Choroid Plexus Cysts on Ultrasound

Choroid Plexus Cysts on Ultrasound

Introduction and Contracting edit

  • Ask how the pregnancy is going
  • Ask about dates
  • Explain the session
    • Getting family hx/pregnancy hx
    • Talking about what a chorioid plexus cyst is and what it means for the pregnancy, testing that may be offered
    • What questions do you have?

Pregnancy hx edit

  • Any illnesses?
  • Any infections/exposures?
  • Any medications?
  • Verify dates
  • Screening tests up to now…ultrasounds? Triple screen test?

Family hx (probably at end of session) edit

  • Get two generation pedigree
  • Determine any risks to pregnancy
  • Specify any particular ethnic concerns as well

Choriod Plexus Cysts (probably at beginning of session) edit

  • What have you heard about them?
  • The Choroid plexus
    • A spongy layer of cells and blood vessels along the edge of the ventricles (pockets or spaces in the brain
    • Produces the cerebrospinal fluid that fills the ventricles and provides a cushion to the brain and spinal cord.
    • Development starts at 6th week
    • By 9th weeks the choroids plexus fills ~75% of lateralventricles
    • Starts to slowly decrease in size and by 20th week the chorioid plexus has assumed its adult form
  • Choriod Plexus Cysts
    • Description
      • Caused by folding of the spongy layer = trapping fluid in the area
      • BENIGN!!! They do not cause any problems for the fetus
      • Usually <1cm in size
      • Can be unilateral or bilateral
      • Usually can be detected by 11th week of pregnancy
      • usually resolve by the 24-28th week of pregnancy
    • Incidence
      • Found in 1% of pregnancies scanned between the 16th - 20 week.
      • Found in 50% of autopsies (fetuses, adults, elderly)
  • Association with chromosomal abnormalities
    • HIGHLY controversial
    • Trisomy 18
      • ~45% of fetuses with Trisomy 18 had chorioid plexus cysts
        • does not depend on gestational age, unilateral or bilateral or size
      • 1-2% risk of a chromosomal abnormality when CPC are found. Most likely Trisomy 18 if anything
      • TRISOMY 18 the syndrome
        • Describe genes and chromosomes
        • 1/3000-1/7000 live births
        • most do not survive to term
        • if live birth, usually die in days,weeks following birth
        • 90% die within the first year of live
        • severe congenital anomalies
    • 90% heart defects
        • severe mental retardation
      • 70-77% babies with Trisomy 18 will have other findings on ultrasound (some studies say ~100% after 24 weeks)
        • clenched fists
        • heart defects
        • rocker-bottom feet
        • omphalocele
        • hydrocephalus
    • VERY CONTROVERSIAL- relation to Down syndrome (thought to be coincidental by most authors)
      • Very rarely seen to be related to CPC cysts
      • 1/660 live births
      • DS - the syndrome
        • Mild-moderate MR
        • Heart problems in 40%
        • Characteristic facial features
      • Ultrasound findings
        • Echogenic bowel
        • Femur length
        • Nuchal fold thickness

Discussion of triple screen results (if they are present) edit

  • SCREENING test - NOT diagnostic
  • Measuring three values of proteins in the mother'sblood
  • They are produced by the baby in its liver
  • MoM values of 1.0 are the standard
  • Maternal age and gestational age are considered
  • For risks associated with Trisomy 18 = expect all three values to be low
  • Your results show (no/an) increased risk over the general pop of mothers who are your gestational age.

Risk of having a baby with Trisomy 18 edit

  • Consider maternal age
  • Consider CPC
  • Consider triple screen results
  • Consider presence of other markers on ultrasound
  • USE CHART (see attached or ask Kris for a copy of hers)

Testing Offered edit

  • Detailed ultrasound to look for other markers (previously discussed)
  • Amniocentesis
    • Risk 1/200
    • Determines presence or absence of aneuploidy
    • Does not guarantee a healthy baby
    • Some centers debate about offering based solely on CPC

Important Points edit

  • 18% of unaffected fetuses will have more than just CPC on ultrasound!!!!!

Notes edit

The information in this outline was last updated in 2001.