Chorioamnionitis

Chorioamnionitis
Classification and external resources
Micrograph showing chorioamnionitis. The clusters of blue dots are inflammatory cells (neutrophils, eosinophils and lymphocytes). H&E stain.
ICD-10	O41.1, P02.7
ICD-9	658.4, 762.7
eMedicine	ped/89
MeSH	D002821

Chorioamnionitis is an inflammation of the fetal membranes (amnion and chorion) due to a bacterial infection. It typically results from bacteria ascending into the uterus from the vagina and is most often associated with prolonged labour. Risk of developing chorioamnionitis increases with each vaginal exam during final month of pregnancy and during labor.^[3]

Background

The fetal membranes consist of two parts:

• The outer membrane is the chorion. It is closest to the mother and physically supports the much thinner amnion.
• The inner membrane is the amnion. It is in direct contact with the amniotic fluid, which surrounds the fetus.

Diagnosis

Intermediate magnification micrograph of moderate chorioamnionitis. H&E stain.

Clinical

Chorioamnionitis is diagnosed clinically in the setting of:^[1]

• maternal fever.
• uterine tenderness in the presence of confirmed premature rupture of membranes (PROM).

Exclusions:

• maternal upper respiratory infection.
• maternal urinary tract infection.

Pathologic

Chorioamnionitis can be diagnosed from a histologic examination of the fetal membranes.

Infiltration of the chorionic plate by neutrophils is diagnostic of (mild) chorioamnionitis. More severe chorioamnionitis involves subamniotic tissue and may have fetal membrane necrosis and/or abscess formation.

Severe chorioamnionitis may be accompanied by vasculitis of the umbilical vessels (due to the fetus' inflammatory cells) and, if very severe, funisitis (inflammation of the umbilical cord's connective tissue).

Treatment

Treatment consists of:

• antibiotics (amoxicillin + gentamicin + metronidazole) for the mother, and
• quickly delivering the baby.

Associations

Chorioamnionitis is a risk factor for periventricular leukomalacia and cerebral palsy.^[2]

See also

• Cerebral palsy
• Wharton's jelly
• Chronic deciduitis

References

1. ^ Elmar Peter Sakala, MD, MA, MPH, FACOG. Professor of GYNOB, Loma Linda University of medicine, California. Codirector of Student Clerkship. Dept of GYNOB
2. ^ Wu YW, Colford JM (2000). "Chorioamnionitis as a risk factor for cerebral palsy: A meta-analysis". JAMA 284 (11): 1417–24. doi:10.1001/jama.284.11.1417. PMID 10989405. 

3. Excess Digital Exams Raise Risk of Chorioamnionitis, Ob.Gyn. News, August 15, 1997

External links

• Overview at Cleveland Clinic.
• Cerebral palsy inflammation link (29 November 2003) at BBC.