Handbook of Genetic Counseling/Choroid Plexus Cysts on Ultrasound

Choroid Plexus Cysts on Ultrasound

Introduction and Contracting

 * 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

 * 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)

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

Choriod Plexus Cysts (probably at beginning of session)

 * 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)

 * 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

 * 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

 * 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

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