Placental inflammation, acute
Etiology, pathogenesis
- the infection ascends from the vagina and the cervix
- inflammation of the fetal membranes (amnion, chorion),
infectious agent penetrates the amniotic cavity
- common flora of the urogenital tract is implicated:
- Streptoccocus agalactiae (the most virulent agent)
- Escherichia coli
- anaerobic microorganisms: Fusobacterium,
Bacteroides, Peptostreptococcus species
Clinical signs
- inflammation causes loss of membrane integrity, which is often
the cause of premature rupture of fetal membranes (with effluence of
the amniotic fluid) and premature delivery
- is one of the most important causes of spontaneous abortion
in 2nd trimester and premature birth before the
30th week of gravidity
- mother is usually without other symptoms, sometimes there
are subfebrilias and/or tenderness of the uterus
Macroscopic appearance
- fetal membranes and fetal surface of the placenta are
are dim, yellowish or greenish, eventually fetid
in severe inflammation
- in twin gestation the infection attacks
the presenting twin first (twin A)
Histology
- The inflammation begins in fetal membranes in the region
of cervical os and spreads into the chorionic plate
- fetal membranes are infiltrated with neutrophils
- if the inflammation lasts longer acute funisitis develops:
inflammation in the umbilical cord, neutrophils are first
found in the walls of umbilical vessels, later in the
Whartons jelly
- at even longer persistence of the inflammation the fetus is also infected:
it swallows the infected amniotic fluid, that gets
into the lungs — adnate pneumonia, early sepsis of the newborn
Pictures
Chorionamniitis:
Chorionamniitis, HE 40x (72673)
Chorionamniitis:
Chorioamniitis, HE 40x (73028)
Adnate pneumonia, 20-week:
Fetus, 20th week, lung, pneumonia, HE 40x (72613)
Fetus, 20th week, lung, pneumonia, HE 40x (72614)
Long lasting adnate pneumonia:
Pneumonia adnata, HE 40x (72111)
