USMLE GIT 6: Stomach Pathology (H. Pylori, Ulcers and more)

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Follow along with First Aid, or with my notes which can be found here: https://www.dropbox.com/sh/m55dzy5jjuahmav/AABZGpqvdSytIuEmxIjyt5V0a?dl=0

After our discussion on the physiology of the stomach, we can now move on to pathology. Path of the stomach heavily revolves around acid. Increases in acid, or decrease in mucosal protection can lead to inflammation of the stomach, or gastritis. Acute gastritis can occur from NSAID use, or H. pylori infection. Other outside influences include brain injury, which can lead to increase vagal stimulation, as well as hypovolemia, which may lead to ischemia and lead to loss of the mucosa.

Causes of CHRONIC gastritis include:
Pernicious anemia: autoimmune destruction of parietal cells
ZE syndrome: uncontrolled gastrin production
H.pylori: this is a gram negative flagellated rod that can infect the antrum of the stomach. This bug is triple positive, meaning it is catalase positive, oxidase positive, and urease positive. Why is this important? We can use the urease positive characteristic of H. pylori to our advantage, by using the urea breath test. We can also test for it in fecal matter. Treatment includes triple therapy. If this fails, then you move on to quadruple therapy!

Complications of ulcers is another big topic. It can ulcerate through your stomach and lead to air under the diaphragm, leading to phrenic nerve pain. This also leads to hemorrhage, which can be severe! Know the arteries and vessels that are affected.
Another commonly tested topic is the difference between duodenal ulcers and gastric ulcers. For example, duodenal ulcers are more likely caused by h. pylori, the pain improves with meals, and are less likely to be malignant. Know these facts!

One stomach disease that doesn't fit well anywhere else is Menetrier disease. This disease leads to hypertrophy of the rugae, as well as excessive mucus production. It leads to atrophy of the parietal cells and is precancerous. This leads us unto our last topic - gastric cancer. There are three types of gastric cancer, two associated with H. pylori and one that isn't. The three types are:
Intestinal-type gastric cancer: looks like an ulcer. Also related to nitrosamines of smoked foods and affects the Japanese to a higher proportion.
MALT lymphoma: cancer of the collection of lymphoid tissue in the stomach.
Diffuse-type gastric cancer: affects the entire stomach. Causes signet ring cells.
A highly tested subject includes recognizing signs of stomach cancer metastasis. These include: Krukenberg tumor (tumor of the ovaries that show signet ring cells), acanthosis nigricans, Leser Trelat sign (eruption of seborrheic keratosis), Virchow's node (spread to the left supraclavicular lymph node), and Sister Mary Joseph nodule (umbilicus mets).

Видео USMLE GIT 6: Stomach Pathology (H. Pylori, Ulcers and more) канала LY Med