General Surgery in the GI Tract Flashcards
LO:
- Abdominal pain: Relate the symptoms and signs of abdominal pain to the diagnosis and treatment of common intra-abdominal pathology
- Intestinal disorders: Summarise the pathology and pathophysiology of small and large intestine disorders
- Intestinal disorders: Describe the clinical features and treatment options of small and large intestine disorders
- Gastrooesophageal disorders: Describe the clinical features and treatment options of gastrooesophageal disorders
- Hepatobiliary and pancreatic disorders: Describe the clinical features and treatment options of hepatobiliary and pancreatic disorders
Session plan
Acute abdomen - General Approach
P C stands for presenting complaint. So, as we’ve discussed before, pain assessment using Socrates, we should got on the right here. Socrates standing for site, onset, character of the pain, radiation of the pain, Is the pain associated with anything else, It’s time cause of onset, Any exacerbating or relieving factors, And some description of the severity of the pain.
So as we discussed in that tutorial on abdominal pain, a good, thorough history can usually give you an answer before you even examined the patients. And certainly you often have a good idea before getting specific investigations.
PMHx is past medical history. DHx is drug history and SHx is social history.
Each particular acute general surgical problem requires an investigation to be performed. Depending on your suspicion of what’s going on. So the range of investigations include bloods, VBG is venous blood gases, FBC is full blood count, CRP is C reactive protein, U and Es is essentially urea and electrolytes, your renal profile, LFTs=liver function tests.
Always do urine analysis, because a lot of acute abdominal problems actually come from urinary tract infection. So a urinary microscopy, culture and sensitivity is essential and certainly a dipstick to see if there’s any blood there, or proteins.
Imaging of any acute abdomen, it consists of an erect chest x ray and an abdominal x ray, CTAP stands for C.T. abdomen and pelvis and a C.T. angiogram is when you suspect bleeding or infarction of a large intraabdominal blood vessel. The specific thing there is they get in contrast, which is showing an arterial phase, you can see the arteries very clearly. Another part of your armoury of investigation is an ultrasound scan, also, endoscopy.
Management should be your ABCDE approach. So any emergency- airways, breathing, circulation, D stands for disability, so you’re looking at pupils and looking at drug charts to see if anything’s happened, conscious level, blood glucose, etc. The management will be discussing all of this. Is there a conservative approach that can be taken, or has it got to be a surgical management?
Differential Diagnosis
Differential Diagnosis-RUQ
Lists are not exhaustive!
Kidney stones=nephrolithiasis
Differential Diagnosis-RLQ
Differential Diagnosis-Epigastrium
Differential Diagnosis-suprapubic/central
Differential Diagnosis-LUQ
LLL=left lower lobe pneumonia
Differential Diagnosis-LLQ
PID=pelvic inflammatory disease
Bowel Ischaemia - Presentation
The greater the length and the greater the thickness of the colon affected, the greater the severity of pain expected.
Risk factors-cardiac arrhythmias, specifically atrial fibrillation.
Patients undergoing cardiac surgery often have quite a profound shock/hypotension during the operation, and they are often referred with query bowel ischaemia.
In an attempt to distinguish between two different types of ischaemia, we can divide it into acute mesenteric ischaemia, and ischaemic colitis.
So the first acute mesenteric ischaemia tends to be in small bowel. It’s usually occlusive and usually secondary to a thromboemboli, so if someone has got atrial fibrillation, called a cardiac arrhythmia, small little clots can come and get blocked in a blood vessel, and usually that’s the superior mesenteric artery. Now, if that happens, of course, if that’s a complete obstruction that’s devastating as you lose all the bowel from the DJ flexure to the splenic flexure, so all the small bowel goes, three quarters of the large bowel round to the splenic lecture goes. If it’s catastrophic like that, it’s a sudden onset. But presentation and severity does vary.
Abdominal pain is often out of proportion of clinical signs. You often see no clinical signs at all. They’ve got a soft abdomen, there’s nothing to feel. Conversely, something catastrophic can be going on, but actually the patient feels quite well. I remember one particular case of a patient who had infarcted slowly everything from the D.J. flexure to the splenic Flexure, he was thought to have a simple thing like I think was acute cholecystitis, and he was actually having a shower that morning. So it’s very difficult to exclude bowel ischaemia, it is very variable.
Ischaemic Colitis is slightly different. It usually affects large bowel, and it’s usually due to non-occlusive low flow states or atherosclerosis. Unlike in theory, acute mesenteric ischaemia, where we get sudden onset, this is milder, more gradual onset in about 80 to 85 percent of the cases and the pain is less severe.
Bowel Ischaemia - Investigations
So we start with FBC-full blood count, you look for a neutrophilic leukocytosis. Now that’s essentially an abnormally high number of neutrophils in the blood.
VBG again, venous blood gases. You’re looking for a lactic acidosis, and that’s essentially a build-up of lactic in the blood, forming an excessively low P.H. in the bloodstream. It’s a form of metabolic acidosis and it’s associated with late stage mesenteric ischaemia and extensive transmural intestinal infarction. And an important thing to remember there, is that if a patient has got lactic acidosis. That means it’s late stage, the bowel is dead already. The difficulty is trying to find patients whose bowel is not dead. And you can intervene before it dies.
Imaging: the only real way to work out what’s going on is to do a C.T. or a C.T. angiogram. What that does is it detects any sternosis within the vasculature. If you look at this diagram on the right, this is with arterial contrast, white arrow is pointing to the superior mesenteric vein, you can see blood, which is the white contrast coming to a sudden stop within the superior mesenteric artery. Look to direct right of white bit, this is very this is healthy bowel here, but if look below can see this greyish bit, this part of the bowel is not enhancing at all, showing it’s not getting any blood supply.
So as well as vascular stenosis, you sometimes see a not completely occluding obstruction. You see disrupted flow. You can also see something called pneumatosis intestinalis, which is essentially transmural ischaemia or infarction.
Ischaemic colitis can be seen as what looks like thumbprints, so it has little defects. That’s a non specific sign of colitis.
Endoscopy is always a possibility, but not for anything severe. This is for patients who you think might have Ischaemic colitis, which is mild or moderate. And what you see when you do a endoscopy there, is you see oedema, you see cyanosis of the mucosa itself, you see lots of little tiny bits of ulceration of the mucosa.
Bowel Ischaemia – Conservative Management
So is it possible to manage these things conservatively? Yes, it is, because you’re trying to work out if there is something catastrophic going on inside. If all the signs point that this is mild to moderate ischaemic colitis you can consider conservative management, but certainly conservative management is not suitable for small bowel ischaemia or acute mesenteric ischaemia.
What does that consist of? That consists of intravenous fluid resuscitation, bowel rest ie nil by mouth, broad spectrum antibiotics, because, remember, colonic ischaemia can result in bacterial translocation and subsequent sepsis. Always put a Nasogastric tube in for decompression, because often, even though it’s not an obstruction, they get a concurrent ileus. Now, ileus just means the bowel is not peristalsing, it’s not moving. Always give anticoagulation and try and treat stroke, manage the underlying cause. If you go down the line of conservative management, you have to do repeat regular abdominal examinations, examine the abdomen to check there are no changes. Repeat imaging to see if there’s any sign of something changing and any signs of peritonitis etc inside the abdomen should push you away from continuing conservative management.
Bowel Ischaemia – Surgical management
Ultimately, surgical management is a necessity in most patients. And in fact, surgeons often ask, would you kindly exclude bowel ischaemia? Well, actually, the only way to exclude it, because the signs are very different in different people, sometimes they have lactic acidosis and you are too late. The only real way of doing it is to actually look inside to see what the bowel looks like. That’s the only way you can 100 percent exclude it.
So what are the indications for surgical management?
Well, if you look and think clinically and with all your investigations think that that patient has got bowel ischaemia, then no hesitation, it’s one of the true emergencies in surgery, they have to go straight to theatre. Any signs of peritonitis or sepsis, any haemodynamic instability, if there’s any massive bleeding you’d think may be associated with that ischaemua, and fulminant colitis with patients who have toxic mega colon.
So what do you do at your exploratory laparotomy?
Well, first of all, you’re hoping you don’t find anything. In this diagram here, here (bottom left of diagram) you can see this is healthy, large bowel. Here (right of diagram), you can see relatively healthy small bowel. But here (arrow), this is dead small bowel, and when one does an operation, from things like this, you know, straightaway what’s going on, because there’s this ghastly smell of dead bowel. So obviously, you examine everything down from DJ flexure, all the way down to the rectum, to identify any bits that were ischaemic. Sometimes you get skip lesions and it can get very complicated and anything that’s dead has to be resected.
Sometimes if it looks catastrophic, you can consider an on table surgical embolectomy. That essentially means accessing the superior mesenteric artery and putting a balloon catheter down to pull out the thrombus. It’s very rare that someone would consider doing a mesenteric arterial bypass.
Other things to consider without surgery, prior to getting that, is endovascular revascularisation. Balloon angioplasty prior to going to theatre. This is for patients with more chronic ischaemia.
Acute Appendicitis – Presentation
A very good question to ask someone you think has got appendicitis is do you want a meal? Would they feel like eating it? If they got appendicitis pretty much 99% say absolutely not.
And why does that change in bowel habbit happen?
Well if you have an appendix that is inflamed and it’s, let’s say, within the pelvis and it’s adjacent to the rectum that can irritate the rectum and that can alter the bowel habit with any bit of large bowel it comes into contact with.
McBurney’s point is most important as that’s where most appendices lie.
Very good sign for an acute appendicitis is if someone has a soft abdomen but then if you press down and suddenly release, they get rebound tenderness.
Rovsing sign-press in left iliac fossa and they report pain in the right iliac fossa, because your moving peritoneum causing irratation on the other side. That’s a very strong sign for an acute appendicitis.
Psoas sign-right iliac fossa or right lower quadrant pain which you can produce by flexion of the right hip against resistance
These signs aren’t really used by anyone because everyone just immediately jumps to get a an ultrasound scan or C.T. scan. Not so long ago, they were very difficult investigations to get hold off, especially in the middle of the night. So in some ways, these become slightly obsolete.
Basically all signs have right lower quadrant pain from whatever they do!
Acute Appendicitis – Investigations
Urinalysis-sometimes you get a small bit of blood or some white cells (remember from before change in bowel habits is from inflammed appendix adjacent to colon. The same thing can happen to bladder, you get inflammation and that gets transferred to urine.)
He said clinical tests are most important. If clincally it seems they have an appendictis even if all tests are negative they still have one.
Main reason to get a CT is to check if there is anything else going on, because with anything going on in the abdomen there is large cross over. And CT scans are very easily available now so there is no reason not to make use of it.
Ultrasound scans are done especially in women where you can have gynaecological problems, ovarian cysts etc.
If clinically you think something is going on, you can then perform a diagnostic laparscopically. Difficult as if appendix looks normal, do you take it out?
Note: pretty much all appendicectomies are done laparascopically now.
Alvarado’s score-isn’t commonly used, but is used as clinical score for appendicities. There are 6 clinical items.
Left shift describes when immature neutrophils are released from the bone marrow due to an outpouring of cells, typically due to infection.
Acute Appendicitis – Conservative Management
Can be managed conservatively.
Usually intravenous antibiotics, certainly to start with, and then converting to oral antibiotics as patient gets better.
If there is a collection, as well as antibiotics, consider a percutaneous drainage of that collection.
Now the indications which go back to this, this management plan can either do it if you’ve imaged and you think you’ve got an uncomplicated appendicitis, but it’s not obvious. So you can try a trial of conservative management. But this is used more frequently with someone that’s presenting late. So they’ll report a history of about a week’s worth of abdominal pains. And when you clinically examine them, they have a mass in their right iliac fossa, and a big inflammatory mass going on. And you then image and it then becomes apparent that to take their appendix out is actually a major undertaking. So it’s far better to try and treat conservatively with I.V. antibiotics, drain what you can with CT percutaenous drainage, and then revisit later to do what we call an interval appendicectomy. Pretty much everyone will advise that to the patients because the rate of recurrence after this conservative management of an abscess or seals perforation is up to 25 percent. So the plan is if they presented late instead of taking it out there and then which would be a major surgery rather than a quick appendicectomy where the patient goes home the next day, instead you treat them, they get better, go home, then they come back electively to have their appendix out, befor it causes a further problem
Acute Appendicitis – Surgical Management
Most times one can take out an appendix lapascopically.
Can be done through 3 portal sites.
endoloops are like a lasso, so imagine you have your appendix mobilised, you then lasso it around the base and tighten them, rather than doing stitches which you have to do at an open operation.
Appendix is always retrieved in a plastic bag as you want to avoid infection, so you don’t want to be pulling out an infected appendix through a port site.
Always very important in any operation where there is pus around, is lots and lots and lots of levage ie irrigation.
Bowel Obstruction - Classification
2 main groups:
- Paralytic ileus, so say someone has an abdomen full of pus, that irritates the bowel, the bowel stops peristalsis, so that’s an ileus, it stops working, and it doesn’t get better until the infection is gone. So that is not a mechanical obstruction, it’s from an irritation of the outside of the bowel.
- Mechanical ie blockage
In simple obstruction, bowel is still perfusing and bowel is still healthy.
Stragulating-can be caused by a volvulus-ie twisting of the bowel to give a closed loop. Or intussusception is seen on diagram on left. Intussusception is a serious condition in which part of the intestine slides into an adjacent part of the intestine. This telescoping action often blocks food or fluid from passing through. Intussusception also cuts off the blood supply to the part of the intestine that’s affected.
Causes
- Gallstone ‘ileus’ is where a gallstone erodes through the gall bladder into the bowel and starts passing through bowel and gets wedged in that bowel, so that’s a mechanical luminal obstruction.
- Crohn’s-get thickening and hypertrophy of the wall of the small bowel
Bowel Obstruction – Aetiology
Small bowel- Adhesions are most common!
Large bowel-colorectal cancer often occuldes left side, has to be very big tumour to block right side as there the bowel can expand and compensate.
Bowel Obstruction – Presentation
Vomiting-late onset in large bowel obstruction as backfilling takes longer, compared to small bowel obstruction which is closer to mouth.
Other signs-if someone is vomiting, they will be dehydrated. Clinical auscultation of bowel sounds, they have very high picthed sounds, no bowel sounds-indicate no peristalsis so worried we have ischaemic bowel.
Diffuse abdominal tenderness is worrying sign and suggests need to intervene quickly.
Bowel Obstruction – diagnosis
It is not uncommon for people to be taken for laparotomies and then actually finding they’ve got an obstructed inguinal hernia.
If they have got an obstruction-is it simple or strangulating? Simple-bowel is still viable, strangulating bowel is not viable, you have to intervene quickly to rescue that.
Hernias
In the groin you get inguinal and femoral hernias which are essentially defects in the abdominal wall.
Anyone that has had a previous surgery can get an incision hernia, and that’s essentially where the skin may have healed, but the muscle underneath it has a defect, so bowel can come through that. Umbilical hernias occur around the umbilicus, epigastric in the epigastrium.
3 diagrams show 3 important things. What is important is how big is that hernia. So if it’s a large defect, then actually bowel can go in and out without any problem. The smaller the hole the greater the chance it is of the hernia obstructing and strangulating. So in second pic we can see we have a tight neck so a loop of bowel has gone in and the tighter it is you start compromising the blood flow, venous return is the first to go, then the bowel becomes odematous and the blood stops coming out and that compresses arterial blood coming in, and then you have a strangulated hernia with ischaemic bowel.
One thing to remember is that not all hernias are associated with obstruction. Richter’s hernia is where just a knuckle of bowel can get caught, but actually there is still continuity of small bowel or large bowel. So you can still have dead bowel, without proper obstruction.
Bowel Obstruction - Investigations
May have an electrolyte balance if patient has been vomiting.
They might be hypokalaemic or hypochloraemic, they may have metabolic alkalosis.
With venous blood gases if strangulated bowel, they may have a lactic acidosis as well.
Always give contrast either orally or intravenously to work out where the bowel is enhancing.
