Digestive System
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-MRCP does not usually require contrast.  The technique enhances any fluid  (the normal fluid which is present in the biliary and pancreatic ducts) as an intrinsic contrast medium by using heavily T2-weighted sequences. T2 potentiate water , therefore this structures will appear hyperintense against the surrounding non-fluid-containing tissues. We can see structures like stomach or duodenum being also bright due to the fluid content.

-Gadolinum is the typical MRI contrast causing brigher T1-weighted images , helping detection of focal lesions (e.g. tumor, abscess, metastasis) venography or calculating MR perfusion parameters.

-Omnipaque® is a low-osmolar iodinated contrast media is indicated for intravenous, intra-arterial or  oral use. Iodine-based contrast are often used in CT scan.

-SonoVue ® is a constrast based on sulphur hexafluoride microbubbles , which used is mainly on contrast-enhanced ultrasound imaging. Bubbles are extremely small—smaller than a red blood cell—and have a high degree of "echogenicity", reflecting ultrasound waves. Structures with higher echogenicity will be brighter on ultrasound.  The microbubbles dissolve, usually within 10 to 15 minutes, and the gas within them is cleared from the body through exhalation.

Should be endoscopic ablation (Radiofrequency or similar).  We cannot resect endoscopically a lesion that we cannot see.  Check the guidelines

Even though only 10% of hep B infections will become chronic and we have an effective vaccination that can virtually prevent infection, the reality is that hepatitis B incidence and prevalence is very high.  WHO estimates that 254 million people were living with chronic hepatitis B infection in 2022, with 1.2 million new infections each year. Maternal-to-newborn perinatal transmission of the virus can be high (70 to 90% in HBeAg-positive-indicating high viral replication-, or 10% to 30% if the mother is HBeAg-negative )

Hepatitis C , despite easy to become chronic (80% of infections) and no effective vaccine, is less common, (Estimated 50 million worldwide) partly because the vertical transmission is low and also because the new  direct-acting antiviral (DAA) tablets are highly effective at clearing the infection in more than 90% , reducing transmission.

Mucosal xantoma - benign lesion composed of foamy macrophages within the lamina propria. fibrovascular. They presents as discrete single to multiple yellowish-white patches, most commonly in the antrum or pyloric region of the stomach . Endoscopically it sometimes can resemble candidiasis, polyp, lymphangiectasia, Russell body gastritis, and Pseudoxanthoma elastic or gastric malignancy.

Lymphangiectasia would have showed prominent dilated lymphatics in the lamina propria region of the villous structure, often with extension into submucosa . These are more commonly seen in duodenum or terminal ileum

Delirium tremens is a form of severe withdrawal syndrome in which, long term alcohol has chronically bound to GABA receptors and modified its expression( GABA is the inhibitory neurotransmitter which normally reduces neuronal excitability) . This leads to  GABA downregulation of α1- and α3-containing GABA-A receptors (Liang and Olsen, 2014). GABAA receptor downregulation may contribute to anxiety and shakes of withdrawal once alcohol is not present in the nervous system. Also, chronic hyperestimulation of the GABA system by alcohol leads to brain mechanism of up-regulation of the postsynaptic N-methyl-D-aspartate (NMDA) type of glutamate receptor, which mediates the postsynaptic excitatory effects of glutamate to counteract this inhibitory effect of GABA, and once alcohol is suppressed this excitatory system takes over causing autonomic hyperactivity, tachicardia, cardiovascular collapse, seizures or even comma and death.

According to the US Hpylori Guidelines, BQT  is the first option for both standard and penicillin allergic patients.  This is a PPI (standard dose)  b.i.d.   Bismuth subcitrate (120–300 mg) or subsalicylate (300 mg) q.i.d. Tetracycline (500 mg)e q.i.d. and Metronidazole (500 mg) t.i.d. or q.i.d

In treatment-experienced patients with persistent H. pylori infection  , they recommend O+L+  either Amoxicillin or Metronidazole

Based on this  article of the NEJM

Whenever an HCC (Hepatocelullar carcinoma) is resected in an early starge, 5-year recurrence occurs in up to 60-70% of the cases,  either as a result of intrahepatic metastases (true recurrent disease) or de novo cancer in the remaining cirrhotic liver .  However, similar rates of reccurence occurs if we use ablation instead of surgical resection (  between 60% and 85% recurrence with ablation) via the same mechanisms (either incomplete tumor erradication, or new tumor formation)

5-year recurrence after liver transplant is way lower (8-20%) and of course varies depending on the tumoral burden --> potential microvascular invasion at the time of the transplant.

See BSG guidelines

GERD is a well known risk factor for adenocarcinoma of esophagus, but not for squamous cell carcinoma.

Risk factors for SCC are low socioeconomic status, consumption of tobacco, alcohol, hot beverages, and nitrosamines (e.g cured or smoked) . Additionally, micronutrient deficiencies have also been linked to the development of esophageal squamous cell cancer. These include vitamin C, vitamin E, and folate

Plummer-Vinson syndrome (PVS) is a rare condition characterized by the classic triad of dysphagia, iron-deficiency anemia, and esophageal webbing.  Approximately 10% of patient can develop SCC.

Remember Achalasia as other importart pathology in which there is an increased risk of esophageal cancer, particularly SCC

 Low amplitude propagated contractions (LAPC) Haustral contractions, triggered by chyme, facilitate the slow movement and mixing of food to enhance water absorption. Those are slow, segmenting movements that further mix chyme, most comoon in proximal colon.  (5 to 40 mm Hg) and last about 3  seconds.They happen  about every 30 minutes.