 In this lecture, we're going to discuss the diagnosis of acute appendicitis. Now clinical evaluation remains the mainstay of the diagnosis. Once the decision has been made that a patient has acute appendicitis, there's very little use for continuing the investigation to prove your clinical diagnosis. Clinical diagnosis is extremely accurate and there are very few tests that can really compete with it. It's only for cases that you are unsure that you can continue the investigations to help you make the diagnosis. So once the clinical diagnosis has been made, the only role really for further investigations are investigating your patient for anesthetic risks, looking at comorbid disease investigation. Patient might be a diabetic, patient might have lung or heart conditions and you need to evaluate these before you decide on treatment. And lastly, just the extent of the disease. A patient can present with early appendicitis, but the patient may also present with late appendicitis with complicated appendicitis, the formation of abscesses, and these might be treated differently. In these cases, you want to continue your investigation. So here's a non-exhaustive list of all these special investigations that you can consider. If we just look at the laboratory side, we have our full blood count, we have a CRPC reactive protein, we have pro-calcitonin, urea creatinine and electrolytes and glucose, we have liver function tests, lipase, urinalysis, MCNS, that's microscopy, culture and sensitivity of urine and blood, and pregnancy tests, either urine or blood based. On the imaging side, we have chestache and abdominal x-ray, we have ultrasound, computer tomography, magnetic resonance imaging and even a contrast enema. Let's discuss some of these. Now if we look at the laboratory investigations, remember that these are all markers of infection, but that's not specific to the appendix. You can have infection in the colon, in any parts of the abdominal cavity or even elsewhere, and they will all have these markers that we're going to discuss now, abnormal or raised. Let's look at the white cell count. So a patient with appendicitis and a patient with diverticulitis will both have a raised white cell count. You must remember that these are not specific just to the appendix. They cannot make the diagnosis of acute appendicitis. Of course, remember, I said it's a clinical diagnosis and you're going to use these tests to support the work up as far as the comorbid disease and the extent, etc., is concerned. So yes, you will have a white cell count. In the majority of cases, very early appendicitis or patients that might be immunocompromised might not always have a raised white cell count, but definitely this would be the norm. A raised white cell count, most specifically neutrophils because this is a bacterial infection. Or if you have access to these kind of reports, they might mention a left shift in the white cell count. The seriative protein might be raised. Again, there are cases in which it's normal. A normal white cell count and normal CRP does not exclude the diagnosis of acute appendicitis. Also to mention in the CRP is it's best to have serial CRP values. A rise, a trend of rising of the CRP might be more important just than an absolute count. If we look at pro-calcitonins, also a marker of infection. But really, the reports do not suggest that it should be used in acute early appendicitis even as much as it only starts rising when we have complicated appendicitis. Once there is a rupture in a bit of peritoneal soiling and advanced cases of acute appendicitis that the PCT starts to rise. So not really useful in early settings. You have to look for raised glucose counts, specifically in diabetics. Glucose levels that become difficult to control is usually a sign of sepsis in the diabetics. Right Aliexpressin, with the symptoms and signs that we've discussed and problems for the patient to manage their glucose levels is an indication of infection. Once again, I want to reiterate, none of these are specific for appendicitis but they do aid you in that diagnosis of a bacterial infection being present. Now in very severe cases, now we're talking septicemia, septic shock. Other laboratory investigations that would help you is the lowering of HP. If you have a vert sepsis, your HP will drop and your platelet count will drop but now we're really talking advanced cases of sepsis. So not of real use in early appendicitis. Now it's important just to look at your renal function if there's one of the areas for an aesthetic help for the anesthetist and for investigation of comorbid disease, usually the kidneys. You want to know where your patient is dehydrated and has electrolyte abnormalities. Remember these patients present with a bit vomiting and they will lose electrolytes. Your ears up might be an indication just of dehydration. Once the creatinine starts going up, of course we're talking acute kidney injury and this is usually in more advanced cases. Now we have to consider alternate diagnosis. So if your clinical investigations were not specific your clinical impression was not specific for acute appendicitis. You did not confirm the diagnosis. You might want to look for an alternate diagnosis. So you're an MCNS and just your analysis with the dipsticks is very important. Females with cystitis or more severe kidney infections, pylonephritis might present exactly the same way as an acute appendicitis scan. So what do you want to see on the dipsticks? Well, you at least want to see nitrates. Remember that white cells, proteins in the urine are indications of other diseases. Urinary tract infections, simple and complicated urinary tract infections should have nitrates. Make sure that your dipsticks actually test for that. Many a time have I seen a report that says, dipsticks normal. But when you go pick up the dipstick you see well, it's one of the cheap variety and it doesn't actually have nitrates on it. So remember to have a look at what dipsticks was used before you just interpret a normal urine dipsticks report in the nursing notes for instance. MCNS, microscopy culture and sensitivity, if you're really concerned it can be spun down, various investigations are possible that can give you very reference on these if you really do suspect urinary tract infections. Pregnancy tests, either urine-based or much better serum-based patients with ectopic pregnancies, right-hand side can really look like an acute appendicitis and you want to rule this out. You might also want to know this, even in a case of acute appendicitis if a patient is pregnant because it might alter your management. Pancreatitis, every now and again can be misdiagnosed. We like a lipase levels, it's much more specific to pancreatitis as opposed to the amylase levels and it also rises a bit sooner and stays positive a bit longer. That would be as opposed to the amylase levels. Pancreatitis is also important, we do want to know whether the colis is right or not, acute appendicitis are going to have raised or abnormal liver function tests, but any abnormality they might be due towards looking towards the biliary tree and the liver for an alternate diagnosis. Imaging, let's start with plain forms and chest x-ray. You really should consider chest x-ray if a patient has overt symptoms and signs of peritoneal irritation. An erect chest x-ray looking for air under the diaphragm. Now appendices do rupture, but it usually does not go with massive amount of free air. Now with entertaining alternate diagnosis, is there a perforated ulcer? Is there a perforated or a particular disease? If we look at the abdominal x-ray, usually not sensitive or specific for acute appendicitis in very rare instances, perhaps less than 5% of cases you might see a fecalith, but what you will often see though is just a bit of localised alias. A bit of air fluid levels in the right alia fossa as you have a paralytic alias in that area of inflammation. That might help you a bit. Ultrasound, of course it's very safe to do, but we have a problem in it as much as we're dealing with an area where there's a lot of gas, which might make it very difficult for the sonographer. And also it only has a sensitivity of about 80%, which really is not any better than clinical evaluation. Now remember what sensitivity is? That is your true positive rate in all cases with appendicitis. So if you took 100 patients who really do have acute appendicitis, it will only pick up 80% of them. So that's just as good as clinical evaluation and it doesn't add much. What does help you with really is female patients, one on the pregnancy side, but two just on the tubovarion side, can really have a good look at the tubovarion area. CT scan has become very prevalent. It really has very good sensitivity. It's going to show you any complicated disease which really might change your mind in management. If it shows an inflammatory mass, we're going to continue just with antibiotics. If it shows abscess formation, it might be drainable percutaneously, which saves the patient, the general anesthetic, and surgery. Very sensitive to pick up. It's going to pick up most cases of acute appendicitis. Also very good for alternative noses. Really investigates the whole abdomen and can give a lot of information. The problem is it is a form of radiation. And it is something that we really want to curtail. Obviously, cost and availability is also a problem. So what are they going to see on ultrasound and on the CT scan? Well, you see a thick walled structure which you really shouldn't see on the ultrasound and on the CT scan. It should be really less than a millimetres without any surrounding signs of inflammation. And on the CT scan, that would be some fat straining, as well as the ileus localised bowel wall thickening. On the ultrasound, this is a non-compressible little worm of more than six millimetres in diameter. And with compression over that area, with the probe of the ultrasound, they can elicit the pain very specific to acute appendicitis. MRI, very expensive, not universally available. And really probably only has a role in the investigation of a pregnant patient. Inasmuch as sensitive, you can probably approach that of CT scan, but there is no ionising radiation. Contrast enema really has gone on the back burner, full the colon with contrast, and if the appendix doesn't fall, that used to be seen as the diagnosis of acute appendicitis due to the blockage by fecalith. But really in a modern setting, should not have to be entertained. Now a variety of scoring systems, I just want to finish off with, the Alvarado score, modified Alvarado score, perhaps the two most important, I do not want to go into specifics of these because what they really do, is just summarise all your findings. Because it scores certain points for what you found during history and examination, and some basic blood investigations. Now there is a variety out on these, there is a lot of reports in the literature, some that show benefit, some that don't show benefit, and these can be looked up, and they can be pasted on the wall in an acute care setting, and you can read off of those. It really has not become a universally accepted way of diagnosing a patient. It really is just a summary of what you found, and you can make a logical clinic decision on what does, what the...