Villitis of unknown etiology

Villitis of unknown etiology - very high mag

Villitis of unknown etiology (VUE) is a pathological condition affecting the placenta, specifically the chorionic villi, which are essential for nutrient and gas exchange between the mother and fetus. VUE is characterized by inflammation of the villi, and as the name suggests, its cause remains largely unknown. This condition can have significant implications for both maternal and fetal health, potentially leading to poor pregnancy outcomes such as fetal growth restriction, preterm birth, and stillbirth.

Etiology

The exact cause of VUE is not well understood, which is why it is termed "of unknown etiology." However, it is thought to be an immune-mediated process. Some researchers suggest that it may be related to maternal immune response to fetal antigens, possibly involving maternal-fetal HLA incompatibility. There is also speculation that undiagnosed or subclinical infections could play a role in its development.

Pathophysiology

In VUE, there is a chronic inflammatory infiltrate within the chorionic villi. This infiltrate is primarily composed of T lymphocytes, macrophages, and occasionally plasma cells. The inflammation can lead to villous damage and fibrosis, impairing the placenta's ability to support the growing fetus adequately. The exact mechanism by which this inflammation leads to adverse pregnancy outcomes is not fully understood but is believed to involve compromised placental function due to the inflammatory damage.

Clinical Presentation

VUE is typically asymptomatic and is most often diagnosed postpartum through histopathological examination of the placenta. In some cases, it may be associated with intrauterine growth restriction (IUGR), small for gestational age (SGA) infants, preterm birth, and increased risk of stillbirth. It is also associated with a higher incidence of preeclampsia and maternal vascular malperfusion.

Diagnosis

The diagnosis of VUE is made histologically by examining placental tissue, usually after delivery. The presence of inflammatory cells within the chorionic villi, along with associated villous damage and fibrosis, is indicative of the condition. There are no specific antenatal diagnostic tests available due to its asymptomatic nature in most cases.

Treatment and Management

There is no specific treatment for VUE. Management strategies are generally focused on monitoring and addressing any complications that may arise during the pregnancy. This includes close surveillance for fetal growth restriction and other signs of fetal distress. In some cases, early delivery may be considered to prevent adverse outcomes.

Prognosis

The prognosis for pregnancies affected by VUE varies. While some pregnancies may proceed without significant complications, others may be at increased risk for adverse outcomes such as fetal growth restriction, preterm birth, and stillbirth. The severity of the inflammation and the extent of placental involvement appear to be key factors influencing the prognosis.

Prevention

Given the unknown etiology of VUE, specific preventive measures are not well established. However, general good prenatal care and early detection of potential complications through routine antenatal visits may help in managing the risks associated with this condition.