29 ABSITE Quick Hits 2_Edited
[00:00:00] All right, folks and jokes, we are back with some more ab site review. I'm joined by Nina Clark and Dan Sheese, our lovely surgical education fellows. And we're going to start off with Nina today, looking at hematology. All right, Nina, what's the most common congenital hypercoagulable disorder? That is factor five Leiden.
Yeah, this is a resistance to activated protein C. Okay we have a question stem in which a patient develops hit. How do we treat it? How do you treat it? Well, you first have to recognize it and this is where your four t's come in So thrombocytopenia usually over 50 and it stays above 20 000 The timing of the platelet drop is your second t And this usually is on days five to ten or less than one day after getting heparin with a recent exposure.
Your third T is thrombosis or other sequelae of HIT. And then the fourth T is kind of dumb, it's the T in other, which means that you don't have other causes for thrombocytopenia that are present. When you suspect somebody has HIT, you're going to stop [00:01:00] giving them heparin or heparin products and you're going to start an alternative anticoagulant, usually Fondoparinux or bivalirudin.
Yeah. How do STDs decrease DVT? So they primarily work by decreasing venous stasis, but they also increase AD3, TPA, and fibrinolysis, which I actually didn't know before studying for this. And if I have a patient with a provoked DVT, how long am I going to treat with anticoagulation? Yeah, this is probably the most common context that you're going to be treating somebody for a DVT, both clinically and on abcite, and you'll give them typically about three months anticoagulation.
All right, we covered this in our last episodes, but what are the vaccines we need for folks who are getting splenectomy? Yeah, you want to prevent overwhelming post splenectomy infections, or OPSI by giving them vaccinations against encapsulated organisms. So those are your shin bugs. So H. flu, strep pneumo, and Esseria meningitis are all going to get your vaccines.
Okay, I'm going to give you a medication. I want you to tell me how to reverse it when it comes to these blood thinners. Let's start with aspirin. All right. [00:02:00] For aspirin, it is a cox inhibitor and it results in permanent platelet dysfunction. So you're going to get platelets or decimopressin. Okay, clavix.
Clopidogrel is an ADP receptor inhibitor, but it also affects platelets just like aspirin, so you're also going to get platelets or desmopressin. Heparin or noxaparin. Antithrombin 3 activators, and you're going to get protamine sulfate. Okay, how about argatibin, bivalirudin, or dabigatrine? So these are your direct thrombin inhibitors.
And Dabigatran is the only one that has a direct reversal agent. It's Idiz, and I think about it as like the DA in Dabigatran and the IDA that starts, idiz go together. Who names these things? It's horrible. Awful. All right. Very common. Rivaroxaban and or apixaban. Yes. These both have an X in them for factor 10 inhibitors, and you reverse them with another thing that has an X in it.
AdNet alpha. Right. And, or PCC if present. How about warfarin? Warfarin is the old school vitamin K dependent inhibitor. So it inhibits the [00:03:00] production of factor 2, 7, 9, and 10, and then prothrombin. And for warfarin reversal, you're going to give PCC, which is probably the fastest option that we have. Or you can get vitamin K and FFP, which work a little slower.
All right, let's round this off with tag. This is definitely some topic you'll see on the app site as well. Let's think about how you interpret a tag. So starting with the R time. Yeah. So this is, I'm going to shamelessly cite my friend, Paul from my residency, who sent me the most deranged text, but it helped me literally nail this question on app site like last year.
So our time is rally time. How long does it take to get things out the door? And to fix a prolonged R time, you're finding friends to party, so you're going to do FFP. All right, I like it. R time, rally time. Fix it with FFP, finding your friends to party, okay. Next what about the angle, the alpha angle?
Yeah, so the alpha angle is basically like how steep that little, the, the tag angle gets going, and [00:04:00] the K time is also the duration of how long it takes to become steep. So these go together in my mind. So they're K and alpha. They're both just looking at how fast things get going. And my friend Paul remembers to get cryo precipitate, which he spells with a K in this case.
I love it. Max amplitude. What does that indicate? This is where it truly gets ridiculous. So maximum amplitude is pretty self explanatory. It's. It's like the highest distance between your, your X axis on your chart and your curve from your tag, and this is looking at, this is looking at thickness. So in this text, I got platelets are thick little boys compared to factors or fibrins that you give your thick platelets to make your graph thicker.
Thick T H I C C for all those who are listening. Thick. All right. We have then one more factor and that's fibrinolysis. So that's, that's the last one. This one doesn't have a funny one from Paul, but LY30 is basically the measure of fibrinolysis, and it's impacted by giving TXA. Alright, so along our time, we're [00:05:00] thinking FFP, a shallow alpha angle, we're thinking cryoprecipitate, a low max amplitude, we are thinking about platelets, and for a high fibrinolysis, we are thinking about TXA.
Fantastic. Let's move on. Dan, we're talking small intestine. What is absorbed in the duodenum? In the duodenum main thing primarily absorbed is iron. Okay. And the jejunum? Jejunum is pretty much all other nutrients that the ileum does not absorb, which is primarily B12, bile, and folate. And you can think of that with the patients with Crohn's who need who need their terminal ileum removed.
They can have B12 deficiency. Okay, which fatty acid chains are released directly into the portal circulation? Short and medium chains go directly into the portal circulation, which is why we talk about using medium chain fatty acids for patients with chi leaks. What's the mnemonic for fistulas and why they fail to close?
Yeah, [00:06:00] so F being foreign body, R being radiation, I being inflammation or infection, E being epithelialization, N being neoplasm, D being distal obstruction, or S being steroids. Alright, tell me about the Meckel's diverticulum. So, Meckle's diverticulum, it's a true diverticulum on the anti mesenteric side of the bowel.
Forms from incomplete obliteration of the vitiline duct. We think of the rule of twos for Meckle's, which is two feet from the IC valve, two percent of the population, two inches long, presents before the age of two. It has two types of ectopic tissue. The ectopic tissue we see is gastric, which is most common and detected with the Meckle scan or pancreatic tissue.
And presentation for Meckles, usually a child with painless GI bleed. We can also see either a child or adult with intussusception with this being the, the cause of the intussusception. We can see patients present with appendicitis like symptoms that when you go in for operation, the appendix looks [00:07:00] normal.
You want to make sure you check to see if they have a Meckles. All right, carcinoid syndrome that's another highly testable topic for the ab site, so tell me a little bit about that. Yeah, so carcinoid tumor, most commonly found in the appendix and the rest of the small bowel, it's becoming more commonly found in the rectum due to our increased use of endoscopic techniques.
This tumor produces serotonin and bradykinin. If it metastasized to the liver, you can see flushing and diarrhea. If it remains local in the appendix or rectum, the 5 HT that's produced from the tumor is inactivated by the liver, so you don't see the flushing and diarrhea. We can localize this with an octreotide scan, which is also known as a somatostatin receptor scintigraphy, to visualize a tumor that may not be seen on CT scan.
Also, if a patient has mets and is symptomatic, we can use octreotide to treat that as well in regards to resection of this tumor. Tumors that require right hemi colectomy include those greater than two [00:08:00] centimeters, as well as those with SQL involvement. Lymphatic invasion. lymph node involvement, meso appendix infiltration, positive margins, goblet cell malignancy, or cellular pleomorphism with a high mitotic index.
Okay, so carcinoid, most commonly appendix, produces serotonin, which causes flushing and diarrhea. You can find it if you can't see on a CT with an actreatide scan. You can also treat it with actreatide if you have symptoms. And if greater than two centimeters when it comes to the appendix you're going to want to perform that formal right hemicolectomy.
There are some other indications for that as well. All right, let's move on to vascular. So for a patient who has carotid artery stenosis and they're symptomatic versus asymptomatic, what are those put offs in terms of intervention? Yeah, so for a symptomatic patient with carotid disease, you're going to intervene on anybody with stenosis of greater than 50%.
And then if they're asymptomatic, your threshold is a [00:09:00] little bit higher. This is 60 or 70%, depending on the imaging modality that you've used. Yeah. So typically that's 50 percent cutoff, 70 percent cutoff, and that 70 percent cutoff is an important one. You can also use flow rates on Doppler through that narrowed vessel to think about the percent stenosis as well.
So if I have an internal carotid artery, a peak systolic velocity of greater than 230 centimeters per second, that correlates to a greater than 70. percent stenosis. Nina, there are a couple other measures we can use as well. What are those? So your ICA to common carotid artery ratio of greater than four also indicates 70 percent stenosis or more.
And then your ICA end diastolic velocity of greater than 100 centimeters per second is probably the most commonly used and also is that indicative of greater than 70 percent stenosis. Okay, so internal carotid artery and diastolic velocity greater than 100 centimeters per second that is correlated with greater than 70 percent stenosis.
What's the most common nerve injury following carotid endarterectomy and what are the [00:10:00] signs of that injury? Yeah, this is typically a clamp or traction related injury to the vagus nerve and can result in hoarseness, but usually that's transient. Okay, when is stenting indicated over carotid endarterectomy?
I think of stenting as the option for a sick patient or a patient where you really don't want to go back into their neck and operate again. So those are patients who have a high lesion, prior radiation, prior neck dissections, or patients who are reoperative. So re stenosis after getting a CEA. Similarly, if they have an ipsilateral recurrent nerve palsy, you really don't want to go messing around in their neck again.
And so those are generally other patients who would get a stent. Okay. What's the most common cause of ascending aortic aneurysm? This is going to be your cystic medial necrosis secondary to Marfan's disease, which is a fibrillin defect or Ehlers Danlos, which is a collagen defect. Okay. What are the cutoffs for large vessel aneurysm repair?
Let's start with the ascending aorta. Yep. That's going to be a five centimeter cutoff. Okay. Descending [00:11:00] thoracic aorta. Little bit bigger. Six centimeters. Okay. Abdominal aortic aneurysm. Shrinks back down to five to 5. 5 centimeters. Iliac? Three centimeters. How about popliteal? Great question. Nice try.
You repair all of these. Check for aneurysms in other places, too, because these patients are forming aneurysms in weird places. Right. Right. And in general, if you find an aneurysm, you want to check other, other large vessels as well. And how about the splenctic vessels? Yeah, in general, you're going to repair all of these except for splenic artery aneurysms, where you would only repair a splenic artery aneurysm if the patient's symptomatic, or if they're pregnant, or if they're likely to become pregnant, so females of childbearing age.
Okay, what is the DeBakey classification for aortic dissection? Yep, so class one is an ascending plus descending dissection, class two is ascending only, and then class three is descending only. Okay, number one risk factor for AAA. Something nobody should ever do, ever, smoking cigarettes. Alright, types of endoleaks.
[00:12:00] You've had your public service announcement for today. Yes, I'll get out my soapbox to talk about endoleaks. So type 1 endoleak is an issue with the proximal or distal attachments. So proximal is at type 1a and distal is type 1b. Type 2 endoleak is backflow from perforators. Type 3 endoleak is a component problem, so this is usually like a tear or an issue between multiple pieces of graphs and how they fit together.
A type 4 endoleak is actually pretty rarely seen nowadays because we've changed what we make our graphs out of, but this is a leak related to graph porosity or porous graph materials. And then a type 5 endoleak is when you've tried to figure it out and you can't figure out why, so it's a no identifiable cause.
A wise, a wise vascular surgeon went through these with me and explained a way to remember them easily too, is for one, being that the, it's leaking out of one side. So whether that's proximal or distal. Two, being perforators, usually it's coming from lumbar, which are either coming from the left or the right.
So there's two lumbar perforators [00:13:00] there. Three, being that the endograph is actually made of, it's three different components. So you think of the components coming apart. Four, being poor. And that's, that's just quickly how I always remember it for the exam. And then five is, darn it, we don't know why. I like it.
You know, what are the surgical indications for peripheral arterial disease? Yeah, this would be like critical limb ischemia is what I think about. So rest pain, alterations or gangrene to the limb or any lifestyle limiting claudication. Okay. What the characteristics of renal vascular stenosis?
Atherosclerosis in the renal vasculature tends to turn up on the left side. side and be more proximal in the vessel and be more common in men, whereas fibromuscular dysplasia is more commonly found on the right side is more distal in the vessel and more commonly seen among women. This is where you're going to get either an image or a description of that classic string of beads.
So when you see string of beads in the renal artery, think fibromuscular dysplasia. The treatment for most renal [00:14:00] artery stenosis at this point in time is angioplasty and stenting. All right, can you ligate the right renal vein? No, Patrick. And can I ligate the left renal vein? You can't ligate the left.
Okay, why? I think about this, yeah, I think about this as like the left vein has like a meandering course to go across midline to get to the cava. And so as it takes more time along the way, there's collaterals. So there's collaterals via the adrenals and the gonadal veins that you can leave in place. If even if you take the left renal whereas the right renal vein has like a direct shot from the cava to the kidney.
So there's really no collaterals necessary and there's no backup plan if you ligate that one. All right. And last, what causes the vast majority of venous ulcers? That would be incompetent valves resulting in venous stasis. So I think stasis ulcer and. Blood's pooling because there's no valve to keep it propelled forward.
All right, Dan, let's talk big stinky colon. What are colorectal, current colorectal cancer screening recs? Yeah, so this is usually always one or two questions on Abcite about colorectal, sorry, colon cancer screening. So for [00:15:00] somebody at average risk, a recommendation is colonoscopy every 10 years starting at age 45.
If you have a first degree relative with cancer, screening begins at 40 or 10 years prior to the earliest diagnosis. And if you have a history of FAP, then sigmoidoscopy or colonoscopy every one to two years starting at the age of 10. Alright, I performed a right hemicolectomy for cancer on a patient, they're back in clinic, and I'm describing their surveillance schedule, specifically colonoscopies, how often do they need them?
Yeah, so you're going to start with a one year interval then move to three years, and then move to five years. Okay. There are multiple watershed areas in the colon. What are those and where are they? So the first is a Griffith's point and this is at the splenic flexure. This is where the SMA and the IMA meet.
And then the other one is Sudex point, which is at the rectum the rectosigmoid area. This is where the superior rectal and middle rectal arteries meet. Alright, what is the main energy source for colonocytes? Yeah, so this is butyrate, [00:16:00] or think of it, butyrate, and then it's a short chain fatty acid, or a short chain fatty acid.
Alright, what extra intestinal manifestations have you seen improve when the patient gets colectomy? Yeah, so with the colectomy the things that get better are anemia, arthritis, and ocular issues. Things, the manifestations that do not get better are the primary sclerosing, cholangitis, and the ankylosing spondylitis.
And then about half of pyoderma gangrenosum patients get better with colectomy. All right, describe the four degrees of internal hemorrhoids. So first degree is you have no prolapse. Second degree is that you have a spontaneously reducing prolapse. Third degree is prolapse that requires manual reduction and fourth degree is prolapse that cannot be reduced.
Okay, and what's the treatment for ectal prolapse? So good operative candidates. Here you can do laparotomy with rect, opexy with or without sigmoid resection depending on if the patient has constipation. For others that may not be great operative [00:17:00] candidates, you can think of an alt, an altmeyer procedure, which is a rectal sigmoid via perennial approach, or a alarms procedure, which is a perennial approach with resection of the mucosa and submucosa of the prolapse segment only.
Okay, what's the nigro protocol and when is it used? Yeah, so this is preoperative chemo with 5 FU and mitomycin with medical radiation. And we use this for squamous cell carcinoma of the anal canal. And patients should undergo a salvage APR if the cancer remains following the protocol. Excellent.
Absolutely crushing it. I love it, guys. That's more great. High yield review. We'll be back with another episode shortly. In the meantime, dominate the day, dominate your studying, dominate life.