fetal disorders and prenatal diagnosis Flashcards
what are the three classifications of fetal disoreders?
chromosomal
structural
immune
what are the numerical chromosomal disorders?
fetus has an extra chromosome
or
the fetus has a missing chromosome
what are the chromosomal fetal disorders which have a nextra chromosome ?
down syndrome ( trisomy 21) Edwards syndrome ( trisomy 18) patau syndrome ( trisomy 13) klinfelter syndrome ( 47 XXY)
what are the fetal disorders in which there is a missing chromosome ?
turner syndrome (45 X)
what is the most common chromosomal disorder with living outcomes ?
down syndrome ( trisomy 21)
what are the risk factors of birthing a baby with down syndrome ?
maternal age above 35
previous children with down syndrome
parent with a translocated gene
what are the physical features of a child with down syndrome ?
excess skin at the nape of the neck separated joints small ears small mouth white spots on the coloured part of the eye : Brush-field spots
what are the more specific features of babies with down syndrome ?
eyes that slant up at the outer corner small ears flat noses short neck most patients have cardiac anomalies
how can we make a diagnosis of Down Syndrome ?
- first an ultrasound needs to be made , looking for the thickness of the nuchal translucency , give that it is more than 3 mm there is a higher susceptibility of down syndrome
- double and triple marker test can be performed
- NIPT ( non invasive prenatal testing) can also be used for screening
but to make a final diagnosis of down syndrome , genetic testing must be performed
what are the risk factors for neural tube defects ?
low serum folate concentration specific drugs such as antiepileptic drugs positive family history diabetic mothers high body temperature obesity
what can NTD be classified into ?
open and closed
what is hydrocephalus ?
excessive accumulation of CSF in the brain
what is the harmful effect of hydrocephalus ?
excessive fluid causes an abnormal widening of spaces in the brain called ventriculomegalia creating a harmful pressure on the brain
what is the most common cause of hydrocephalus ?
gene mutation
what are the symptoms of hydrocephalus ?
large head with a transparent scalp bulging forehead seizures visual problems abnormal reflexes
what is the treatment for hydrocephalus ?
shunt operation to release excess CSF
what is anencephaly ?
when the skull, scalp and the brain dont form properly in the womb
what is the prognosis of a baby with anencephaly ?
baby will only live for a few hours after birth
where are the most commonn spinal defects found ?
lumbar ans sacral bifida
what are the types of spinal defects ?
spina bifida occulta
meningocele
myelomeningocele
at what time during pregnancies fo fetal anomalies happen ?
during the first trimester when organogenesis happens