Sept11 M1-Perinatal Pathology Flashcards
fetus and mother relationship
- uterine wall (implant high up to avoid rupture on delivery)
- placenta with maternal surface and fetal surface
- fetal surface (linked to placenta with amniotic cord)
appropriate size of placenta for gestational age def
each age has an ideal size to weight ratio and this ratio changes with age
(imp) 4 components of placenta
- fetal membranes (amnion and chorion)
- umb cord
- trophoblastic villi
- retro-placental decidua and vessels
fetal membrane def
wraps around fetus and extends on placental surface
trophoblastic villi def
where O2 and nutrients transfer occurs. the maternal vessels supply these villi
retro-placental decidua and vessels def
the retroplacental surface has decidua and vessels
fetal surface of placenta blood supply
- umb cord on top (fetal surface)
- ramifications into cotyledons (stems of trees)
- stem villus (main branch of cotyledon)
- villous tree, trophoblastic villi (other branches of cotyledon)
- intervillous spaces filled with RBCs of the mom
- decidua in bottom (maternal vessels, side)
- so RBCs will swim in branches then cotyledons then cord*
fetal surface of placenta 2 surfaces on top
- amnion
- chorion below it
* are where this blood exchange is happening
how many cotyledons for how many villous trees
each cotyledon gives one villous tree
cells in trophoblastic villi
- cytotrophoblasts (gives rise to syncytiotrophoblasts)
- syncytiotrophoblasts
- syncytio = final differentiation for exchange through capillaries
fetal capillaries are considered to be where in the placenta
are the trophoblastic villi (bc will receive RBCs from mother that are outside)
villi cells behavior and why
group together so thinner BM so more exchange
decidua component
maternal vessels and intermediate trophoblasts
1st step of delivery
rupture of membrane surrounding fetus and spreading around placenta
extra-placental fetal membranes def
limit between rupture site (of membrane) and edge of placenta
relevance of rupture site clinically
infection often there if rupture too early. first there and then spreads up to placental cells
how membranes prepared for path
make a roll with it starting at the rupture site (most internal) so external part of roll is most external
inflammation more in center of membrane roll meaning
early infection
inflammation in whole membrane roll def
infection from >24 hours
normal nbr of vessels in umb cord
3
what if cord has 2 vessels
possible malformations
how to see if blood flow obstruction in placenta
check if change in color
variations in placental shape (normal = oval)
- bilobed (because of a true knot in cord)
- accessory lobe (lobe that goes away from main chorionic plate. prob = goes near internal os and membrane fragile, can rupture vessels)
- circumvallate (vessels don’t go to the edge of the placenta, membrane goes around and forms a ring around it. prob = possible hemorrhage at wall of membrane, margin at time of delivery)
green placenta reason
passed meconium. either
- premature baby that passed meconium which stained the membrane
- sign of fetal stress (hypoxia, less O2, less sphincter control)
anomalus insertions of the umb cord
- marginal, at edge of chorionic plate
- velamentous, outside chorionic plate
velamentous insertion charact
out in extra placental membrane away from placenta, vesses have to travel, can be precarious (unsafe, dangerous)
condition for bacteria to infect placenta and exception
membrane has to rupture
-except beta hemolytic strep, can get through if intact
most common way of infection (bacteria)
- trans cervical amniotic region has a ruptured membrane
- infection comes from vagina
common bacteria for placental infection
- e coli (gram - enteric bacteriae)
- anaerobes
- beta strep if non ruptured
what infection can do once in placenta
can reach the fetus
2 ways of infections of the placenta and fetus + name of the infection
- hematogenous (from mother blood, for ex CMV). called VILLITIS
- ascending infection (most common, ruptured memb near cervix, inf ascends form vagina) called CHORIONITIS OR CHORIO-AMNIONITIS
how to suspect infection at delivery
cloudy fetal surface, not clear fetal surface of placenta
thing for biggest suspicion of infection other than cloud surface
premature ruptured membranes (2 days before delivery)
chorionitis or chorioamnionitis on histo
inflam infiltrate through chorion or both chorion and amnion (those are on fetal side)
funisits def
- infection of chorion and amnion extends into Wharton’S jelly (mesenchymal substance arround tree vessels giving them bouncy stability) of the cord
- vasculitis of cord vessels
how to detect funisits on histo
inflammatory infitlrate extends from amnion and chorion to Wharton’s Jelly
order of infection in a funisitis
- infection spreads from amnion and chorion to a vein and get vasculitis in a VEIN
- funisitis
- infection spreads from Wharton’s jelly to artery = get vasculitis in an ARTERY
signs of vasculitis in cord infection
inflammation + polymorphs (polymorphonuclear neutrophils)
what fetus does during infection
keeps swallowing and urinating and passing feces as usual so infection can end up in the lung
first sign of intra-fetal infection
pneumonitis = infection in the lung (peribronchiolar inflammatory infiltrates)
causes of hematogenous infections of placenta and fetus
- TORCH group (toxoplasma, rubella, CMV, herpes simplex)
- parvovirus
sign of parvovirus infection in the fetus
fetal hydrops
- edema in the fetus
- cause = virus attacks hemopoietic system of fetus so gets anemic and heart works harder)
how to see parvovirus infection of placenta and fetus on histo
- intervillositis (inflam in intervillous spaces)
- maternal polymorphs in intervillous space
- villitis eventually if extends in villi
how to see CMV infection of placenta and fetus on histo
- big inclusions of CMV
- lymphocytes in villi (NOT polymorphs, meaning no neutrophils)
order of arteries to reach decidua (or top of endometrium, normally, in non pregnant woman)
- uterine a (vertical)
- arcuate a (horizontal)
- radial a (vertical))
- spiral aa (continuation of radial a, vertical)
- basal aa (branches of spiral aa)
spiral aa normal reaction to pregnancy
dilate to accomodate blood to placenta
pre-eclampsia prob
spiral aa don’t dilate and remain thick walled and narrow
-placenta poorly perfused
signs of pre-eclampsia, thickened maternal vessels on histo (and progression with severity)
- hypertrophic vessels in the decidua of placenta
- subintimal degenerative changes (accum of fat laden macrophages under the intima)
AND perivascular lymphocytes - vasculopathy (fibrinoid replacement of intima)
thickened vessels on macroscopy how to see
see an amount of marginal blood clots and blood in the placenta that is abnormal (ruptured vessels and clots (in excess). marginal blood clots is normal but too blood in placenta is abnormal.
abruptio placentae def
- retro-placental bleed
- bleed covering whole maternal surface now and not just margins
- elevation of a bed of clots over whole maternal surface
- still related to thickened vessels*
possible consequence of placental decidua vessels rupture or thrombosis
- villi are infarcted (collapse and undergo changes bc of vascular obstruction)
- villi eventually necrotic
how to recognize villous infarctions on placenta
- very dark, not red
- placenta firm not spongy
other name of villous infarctions
infarction of maternal vessels
when can villous infarction cause fetal damage
if extended over more than 30% of thickness of placenta
histo of hematomas (blood clots) on side of villous infarction during maternal vessel infarction shows what
crevisses
etiologies of fetal asphyxia
- placental pathology (e.g. abruptio placentae)
- cord accidents (a problematic true knot (not always prob), anomalous insertion with rupture, thrombosis
- sepsis (GBS with endotoxic shock)
cause of asphyxia in sepsis and endotoxic shock
endothelial damage
non problematic true knot
all same color and red
true knot with thrombosis, causing fetal demise
change in color. red to pale
main way of detecting asphyxia in the fetus
- petechiae hemorrhages on serosal surfaces (chest organs, etc.)
- more severe asphyxia = periventricular hemorrhage in the brain (can cause cerebral palsy)
intra-uterine growth restriction def
perinatal pathology where the baby is small for gestational age, also called small baby
small baby determined how
by checking size to weight ratio after delivery and check if is right for gestational age
causes of small baby
- constitutional (small placenta) (asymmetric)
- placental insufficiency (deficient maternal blood flow. will see mature villi (38 weeks) at week 34 for ex bc tried to accomodate and mature) (asymmetric)
- malformation syndromes (trisomies, etc.) (asymmetric)
- social habits (SMOKING is the main one. drugs, etc.) (asymmetric)
- congenital infections of TORCH group during T1. called symmetric smallness bc caused early and stay small throughout pregnancy.
cocaine used assoc with what perinatal pathology
abruptio placentae
causes of intrauterine fetal deaths (stillbirths)
-placental insufficiency
-asphyxia
-infection
malformation syndromes (can be assoc with maternal disease like pre-eclampsia so don’t rule out placental causes important**)
-others
