USMLE GIT 2: Developmental Pathology (Tracheoesophageal Fistula and more) скачать в хорошем качестве

USMLE GIT 2: Developmental Pathology (Tracheoesophageal Fistula and more)

Want to support the channel? Be a patron at:   / lymed   Welcome to LY Med, where I go over everything you need to know for the USMLE STEP 1, with new videos every day. Follow along with First Aid, or with my notes which can be found here: https://www.dropbox.com/sh/m55dzy5jju... In this video we will discuss developmental pathology of the gastrointestinal tract! We start from the top down, with a talk about the development of the esophagus. The esophagus and the trachea share a common embryological origin, and when you're an embryo it can develop in different ways. The most common malformation is called tracheoesophageal fistula with esophageal atresia. This allows air to enter the stomach, but nothing else. The baby will not be able to feed and nasogastric tubes will lie coiled into the blind pouch. Signs can even appear during pregnancy as polyhydramnios. Moving on down, we discuss congenital pyloric stenosis of the stomach. This is the hypertrophy of the pylorus, causing projectile non-billous vomiting at around 4 weeks after birth. It is nonbillous because it never reaches the bile rich duodenum. On physical exam you can feel a palpable mass. Labs include hypokalemic hypochloremic metabolic alkalosis. Next, onto the development and path of the pancreas! The pancreas comes from the duodenum and starts as two buds, the ventral and dorsal bud. These two buds will swing around the duodenum and form your pancreas. If it doesn't swing around right, it can lead to pathology. For example, if it swings around inappropriately, it can form a ring of pancreatic tissue around the duodenum and cause obstruction. We call this annular pancreas and can lead to billous vomiting. Another problem in forming is when the two buds don't swing around at all! They stay separated and we call this pancreas divisum. Lastly, we talk about midgut pathologies. Recall your midgut protrudes out and returns later in the 10th week. If your midgut never returns back, you can have things like omphalocele and gastroschisis. Omphalocele occurs when the midgut leaks out through the umbilical cord/ring. It leaks out centrally and is covered in peritoneum. If it doesn't go through the umbilical ring, it's not covered by peritoneum. We call this gastroschisis and is often lateral to the umbilicus. But just because your midgut returns to your stomach, doesn't mean you're in the clear! You can have intestinal atresia, in which it doesn't develop properly. For example, your duodenum can not develop and we call this duodenal atresia. Know that this is associated with Down syndrome and shows up on the "double bubble" sign. Other parts of your intestine can also undergo atresia, especially if the blood supply is limited. This leads to "apple peel" atresia. That does it for this video!