Mediastinitis is inflammation of the tissues in the mid-chest, or mediastinum. It can be either acute or chronic. It is thought to be due to four different etiologies:direct contamination
hematogenous or lymphatic spread
extension of infection from the neck or retroperitoneum
extension from the lung or pleuraAcute mediastinitis is usually caused by bacteria and is most often due to perforation of the esophagus. As the infection can progress rapidly, this is considered a serious condition. Chronic sclerosing (or fibrosing) mediastinitis, while potentially serious, is caused by a long-standing inflammation of the mediastinum, leading to growth of acellular collagen and fibrous tissue within the chest and around the central vessels and airways. It has a different cause, treatment, and prognosis than acute infectious mediastinitis. Space infections: Pretracheal space – lies anterior to trachea. Pretracheal space infection leads to mediastinitis. Here, the fascia fuses with the pericardium and the parietal pleura, which explains the occurrence of empyema and pericardial effusion in mediastinitis. However, infectious of other spaces can also lead to mediastinitis. Symptoms
Acute
Acute mediastinitis is an infectious process and can cause fever, chills, tachycardia. Pain can occur with mediastinitis but the location of the pain depends on which part of the mediastinum is involved. When the upper mediastinum is involved, the pain is typically retro-sternal pain. When the lower mediastinum is involved, pain can be located between in the scapulae and radiate around to the chest. Chronic
Symptoms depend on what organs of the mediastinum the disease is affecting.
The high vascular resistance outside of the placenta leads to higher maternal blood pressure throughout the body.The fetal cells that implant into the uterine wall are known as the trophoblast. The hemochorial placenta bathes the fetal trophoblast in maternal blood by forming lacunae, or lakes, of the mothers blood that surround fetal tissue. The lacunae are filled by the spiral arteries, which means that the mothers blood pressure is the driving force behind the introduction of new blood, which contains both oxygen and food for the fetus, to the system. It is thought that humans need the increased diffusion provided by the hemochorial placenta in order to grow the large brains compared to their body size that distinguish them from other primates. Incorrect placental implantation
It is thought that "failings" in normal hemochorial placental structure lead to pre-eclampsia and gestational hypertension. The human placenta implants "earlier, deeper, and more extensively" into the uterine wall, which can potentially lead to many problems that are found in human pregnancies, but not as much in other animals. Miscarriage and pre-eclampsia are both very rare in other species, but are two of the most common pregnancy-related diseases in humans. The genetic roots of gestational hypertension and pre-eclampsia are certain, as women with a family history of the condition are three times more likely to develop it when they are pregnant.One of the potential causes of gestational hypertension and pre-eclampsia is when the trophoblast does not invade far enough into the uterine lining.