Molar pregnancy (mechanism of disease)

Summary

This video provides a comprehensive overview of molar pregnancy, focusing on the pathophysiology, etiology, and clinical manifestations of complete and partial moles. It explores the differences between these types, highlighting the fertilization processes leading to each. The video explains the trophoblastic tissue proliferation, beta HCG increases, and common symptoms, such as vaginal bleeding and nausea. Additionally, it touches on complications like preeclampsia, hyperthyroidism, invasive mole, and choriocarcinoma. Ultrasound findings and the appearance of molar pregnancy are also discussed, providing essential insights for medical understanding and diagnosis.

Takeaways

• 😀 Molar pregnancy can be classified into two types: complete moles (without fetal or embryonic parts) and partial moles (with fetal or embryonic parts).
• 😀 A complete mole occurs when an empty egg is fertilized by a single sperm, which duplicates its chromosomes (uniparental disomy), or by two sperm fertilizing an empty egg.
• 😀 A partial mole occurs when a normal egg is fertilized by two sperm, resulting in 69 chromosomes (triploid), and contains fetal parts.
• 😀 Molar pregnancies often lead to trophoblastic tissue overgrowth and hydropic degeneration of the chorionic villi, causing destruction of the placenta.
• 😀 Common symptoms of molar pregnancy include vaginal bleeding, pelvic tenderness, and nausea, with symptoms typically more severe in complete moles.
• 😀 High levels of beta-HCG are a hallmark of molar pregnancy, with complete moles often showing more significantly elevated levels, leading to symptoms like hyperemesis gravidarum.
• 😀 Elevated beta-HCG levels can cause complications like ovarian theca lutein cysts, hyperthyroidism, preeclampsia, and symptoms of hyperthyroidism (e.g., tachycardia, nervousness, weight loss).
• 😀 On ultrasound, a complete mole often appears as a 'bunch of grapes,' a snowstorm, or Swiss cheese-like structure, while a partial mole may show fetal parts or increased placental thickness.
• 😀 Complications of molar pregnancy include invasive mole (when trophoblasts invade the uterine muscle) and malignant transformation into choriocarcinoma (a form of trophoblastic neoplasia).
• 😀 Choriocarcinoma can spread to distant organs, such as the lungs (causing dyspnea or hemoptysis) or the brain (causing seizures), and can lead to postpartum bleeding and inadequate uterine regression.
• 😀 Most women recover normally after a molar pregnancy and can have successful future pregnancies, but the potential complications require careful monitoring.

Q & A

What is the difference between a complete mole and a partial mole in molar pregnancy?

A complete mole involves trophoblastic tissue without fetal or embryonic parts, while a partial mole contains trophoblastic tissue along with fetal or embryonic parts.

What causes a complete mole in molar pregnancy?

A complete mole typically results from the fertilization of an empty egg by a single haploid sperm, which then duplicates its chromosomes, leading to a diploid set with no contribution from the egg.

What is the significance of uni-parental disomy in the pathophysiology of a complete mole?

Uni-parental disomy occurs when a single sperm contributes both sets of chromosomes, resulting in a diploid cell with both sets of chromosomes coming from one parent, causing a complete mole.

How does a partial mole develop?

A partial mole develops when a normal egg is fertilized by two sperm, leading to a triploid set of chromosomes (69 chromosomes in total). This can result in the presence of fetal parts.

What are some predisposing factors for a molar pregnancy?

Factors that increase the risk of molar pregnancy include a history of a prior molar pregnancy, miscarriage, and extreme maternal ages (under 15 or over 35 years old).

How does trophoblastic tissue proliferation affect molar pregnancies?

The proliferation of trophoblastic tissue in molar pregnancies leads to an overgrowth of cytotrophoblasts and syncytiotrophoblasts, causing hydropic degeneration and excessive swelling of the placental tissue, which ultimately leads to the death of the embryo.

Why is beta-hCG elevated in molar pregnancies, and what symptoms can this cause?

Beta-hCG levels are elevated in molar pregnancies due to the excessive trophoblastic tissue. This can cause symptoms like hyperemesis gravidarum (severe nausea), preeclampsia, and in some cases, thyroid dysfunction (hyperthyroid symptoms).

What is the ultrasound appearance of a complete mole?

On ultrasound, a complete mole typically appears as a 'bunch of grapes,' or a snowstorm-like pattern, characterized by cystic spaces within the trophoblastic tissue.

What are some possible complications of a molar pregnancy?

Complications can include invasive mole (trophoblastic tissue invading the uterine muscle), choriocarcinoma (malignant transformation of trophoblastic tissue), and metastasis to organs like the lungs or brain.

How can a molar pregnancy be diagnosed and managed?

Diagnosis is typically made through ultrasound and elevated beta-hCG levels. Management may involve surgical removal of the molar tissue, and monitoring for complications such as invasive mole or choriocarcinoma after the procedure.