Intraamniotic infection: Clinical sciences

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Introduction0:00–1:09

Intraamniotic infection, commonly called chorioamnionitis, is an infection that causes inflammation of the amniotic fluid, placenta, decidua, fetus, fetal membranes, or any combination of these.
It is usually caused by an ascending infection of polymicrobial bacteria, including both aerobic and anaerobic species, that are present in the vaginal flora.
While both preterm and term pregnancies can be affected, it most commonly affects full term pregnancies and usually presents while patients are in labor.
Intraamniotic infection is associated with an increased risk of both maternal and neonatal complications. Maternal complications include dysfunctional labor, postpartum uterine atony leading to hemorrhage, endometritis, peritonitis, sepsis, acute respiratory distress syndrome and, in some instances, death.
In neonates, acute complications include pneumonia, meningitis, sepsis, and possibly death; as well as long-term complications such as bronchopulmonary dysplasia and cerebral palsy.When assessing a patient who presents with a chief concern suggesting an intraamniotic infection, start with a focused history and physical exam.

Patient presentation1:09–3:28

Patients may have one or more risk factors, including low parity, exposure to multiple digital examinations, use of internal monitors like an intrauterine pressure catheter or fetal scalp electrode, meconium-stained amniotic fluid, genital tract pathogens such as group B Streptococcus or a sexually transmitted infection, prolonged rupture of membranes, defined as greater than 18 hours, and prolonged labor.
Next, evaluate your patient for intraamniotic infection. This is done by checking your patient's temperature, reviewing the fetal heart tracing, obtaining or reviewing a CBC, and performing a sterile speculum exam.
A suspected intraamniotic infection is diagnosed clinically when a patient has either a one-time fever, with a temperature of at least 39.0 degrees Celsius; or an elevated temperature between 38.0 and 38.9 degrees Celsius, along with at least one of the following clinical findings: fetal tachycardia, defined as a fetal heart rate above 160 beats per minute; maternal leukocytosis, with a white blood cell count above 15,000; or the presence of purulent fluid from the cervical os.
Fundal tenderness may also be present. Okay, here is a clinical pearl!
The diagnosis of a suspected intraamniotic infection can be confirmed objectively either by amniocentesis and analysis of amniotic fluid or by placental pathology.
Amniotic fluid analysis will reveal a positive Gram stain, low glucose, or a positive amniotic fluid culture; whereas placenta pathology will show histologic evidence of infection and placental inflammation.
In practice, however, all patients with clinical suspicion of an intraamniotic infection need prompt intervention, so the distinction between a suspected and a confirmed intraamniotic infection is meaningful only in research settings.

Isolated Maternal Fever Management3:28–4:55

First let's look at management of isolated maternal fever. Now, if your patient has an elevated temperature between 38.0 and 38.9 degrees Celsius, with or without a persistent temperature elevation 30 minutes later and with no other clinical findings indicating intraamniotic infection, you can diagnose an isolated maternal fever.
Treatment involves first ruling out other potential benign causes of a transient maternal temperature elevation such as epidural anesthesia, prostaglandin use, dehydration, hyperthyroidism, or excess ambient heat.
Next, consider administering IV antibiotics, unless an obvious source other than intraamniotic infection is identified and documented.
At the same time, keep in mind that regardless of whether the fever is due to an infection or some other cause, maternal intrapartum fever is associated with poor long- and short-term neonatal outcomes.
This seems to be related to how fetal hyperthermia influences the fetal metabolic rate, which can increase the negative effects of tissue hypoxia.
Finally, monitor your patient for additional signs and symptoms of infection, and be sure to notify the neonatal care team so they can appropriately assess and manage the infant post-delivery.
Now that we’ve covered the management of isolated maternal fever, let’s go back and talk about the management of intraamniotic infection.

Intraamniotic Infection Management4:55–7:35

As a reminder, you can diagnose an intraamniotic infection if a patient has either a temperature of 39.0 degrees Celsius, or more, or a temperature between 38.0 to 38.9 degrees Celsius with at least one of the following; fetal tachycardia, maternal leukocytosis, or purulent fluid from the cervical os.Here is another clinical pearl!
While on rounds, you may hear intraamniotic infection or chorioamnionitis called intraamniotic infection and inflammation or “triple I”.
This name change has been suggested to more accurately reflect the spectrum of disease.Okay, let’s get back to management.
Intrapartum Management begins with IV broad-spectrum antibiotics like ampicillin and gentamicin. Additionally, administer antipyretics, like acetaminophen, to help decrease your patient’s temperature.
Next, notify the neonatal care team, as the fetus may require additional assessments and management, including monitoring for sepsis and antibiotic administration.
Also be sure to monitor labor progression and begin augmentation if indicated, due to the increased risk of labor dystocia in patients with an intraamniotic infection.
Here’s another clinical pearl! In terms of delivery, vaginal delivery is safe and recommended, as long as the patient and fetus are stable and labor is progressing.
While a c-section may be performed for the usual indications, an intraamniotic infection alone is rarely, if ever, an indication.
Now, back to our patient. For postpartum management, continuation of antibiotics is guided by patient risk factors and mode of delivery, specifically taking into account whether a patient is at risk of postpartum endometritis.
In general, no additional antibiotics are indicated after a spontaneous vaginal delivery, whereas one additional dose of ampicillin, gentamicin, and either clindamycin or metronidazole is recommended after c-section.
This is because patients who undergo a c-section are at a higher risk of postpartum endometritis than those who deliver vaginally.Here is a final clinical pearl!
Postpartum endometritis develops when an infection persists after childbirth and affects the endometrium. Risk factors are similar to those for intraamniotic infection, like prolonged rupture of membranes, prolonged labor, intraamniotic infection, c-section, and manual removal of the placenta.
Alright, as a quick recap… Intraamniotic infection, or chorioamnionitis, is characterized by inflammation in various parts of the amniotic sac, fetus, and surrounding tissue.

Review7:35–8:15

A focused history and physical exam is used to make the clinical diagnosis. Isolated maternal fever management involves consideration of IV antibiotics unless an alternative cause of fever is evident.
For those with intraamniotic infection, IV antibiotics and antipyretics are recommended. Once postpartum, antibiotics are generally discontinued unless a patient has risk factors for postpartum endometritis,