 Okay, when the right lower quadrant ultrasound fails to show findings of appendicitis, you need to look elsewhere. So look at the pelvis, particularly in female adolescents, as gynecologic conditions can mimic appendicitis, and we'll look at that in the next talk. And also, look at the upper abdomen. Instead of appendicitis accounted for 22 to 25% of diseases, there are other causes of acute pain, gynecologic, bowel, 10% pylonephritis, pneumonia, constipation, gastrointestinal disease, 10% of alternative diagnoses when appendicitis is suspected, and the diagnoses include bowel disease, Crohn's disease, infection, hematocinal and purpore, mechal diverticulum, mesenteric adenitis, and endosusception, and we do not see the diseases that we see in adults. So Crohn's disease, even infection, simply thick walled bowel, one layer of the bowel measures greater than three millimeters, which is the normal cutoff, typically between four and six millimeter thickness. Both sides are effective, but when we do measurements, we're talking about measuring one wall. It's slightly compressible, it doesn't have a blind ending, and it's hypervascular. Looking for the blind ending is key, and you may see nodes. This is Crohn. Infectious enteritis is another cause of right lower quadrant pain. It can be viral or bacterial. All for some, usually normal and viral infection, and bacterial infection, you may see wall thickening in nodes. You cannot exclude it from Crohn's disease, there are many cultures. So how about this, 15 year old girl with diarrhea and pain? This is bowel. You can see the walls are thick, some air and aluminum, lots of color. This turned out to be infection, E. coli enteritis, but it certainly could be Crohn's as well. We're going to identify bowel wall thickening, not necessarily the same with the causes. This is another one. Hinaxialum purpura affects young children in the first decade. It's a small vessel vasculitis. It affects the skin, the inner rash, small bowel, kidney, joints, and it can cause extreme abdominal pain due to a hematoma or inter-susception, or just the fact there's a vasculitis and it's involved the bowel wall. So once again, you get thickened bowel, it looks like the other cases I showed you, and it involves the duodenum, the genome, the ilium, any place, and it's very vascular. Now the clue here is that it's a younger patient, so you might think about Hinaxialum purpura and look for the rash, but certainly infection could look like this in a rare case of Crohn. Mechal dive reticulum to mimic appendicitis, it's the most common anomaly of the GI tract affecting 2-3% of the population. 60% of patients, 60% with mechal dive reticulum, present in the first decade, and they present with pain due to inflammation, gets inflamed, or maybe inter-susception. And the dive reticulum is a remnant of the amphilomessenteric duct, and the duct in utero connects the bowel to the umbilicus, and normally it disappears, but if the proximal end stays open, you've got a mechal dive reticulum. It arises from the terminal ilium, not the cecum, within 10 centimeters of the ilial cecal valve. It is blind ending, this is it, you know, do a target sign on the short axis, and it likes the right lower quadrant, or it may be midline. So this should be, it's not 72, 12-year-old girl with right lower quadrant pain and vomiting. And we saw this too, it's blind ending, but when you traced it back, it came from the ilium, and we did a CT to prove it, here is the cecum. This is the dive reticulum coming from the ilium, and here's another one, target sign, this is laying it out, this is a blind ending tube coming from the ilium. So when you see a blind ending tube, even the appendix, trace it back, make sure it does come from the cecum. Mesenteric adenitis mimics appendicitis, it's self-limited, normally they're given something for pain, it will disappear in a couple of days, it's a benign inflammation of lymph nodes within the mesenteric, it likes young children and young adults, sort of like the same age, ages of appendicitis, often viral, but occasionally bacterial. And it's nothing more than a collection of lymph nodes. The strict diagnosis requires seeing more than three lymph nodes, and the right lower quadrant on the mesenteric root, and they have to be greater than five millimeters in short axis, and if the normal appendix and bowel are seen, one lymph node that's enlarged does not allow the diagnosis of mesenteric adenitis. And if you turn color on, you see the characteristic flow in the central highland, just like any other lymph node. And finally, interceception is a cause of acute pain. It's prolapse of one segment of the bowel, the interceceptum, into another, and it causes acute pain in early childhood, okay? Early childhood, under three years, 90% are iliocolic. The remainder may be iliocolic, coliocolic or iliolio, but this is what you're commonly going to see. 90% are iliopathic and have no leap point, and they're just due to hypertrophy of prior patches, small nodes. So typically three months to three years, 10% older children, they have abdominal pain, may have vomiting and bloody stool, and this is an interceception. Ilium going into colon, and the total length is usually 8.5 centimeters. And on ultrasound, you're going, and typically we see it because it's ilium going into the colon and the right abdomen. You're going to see multiple layers. The target sign, the bull's eye sign, and if you lay it out, you've got the pseudo kidney sign, okay? Oh boy, it's sort of like a kidney, at least that's what they call it. Here's another one. The target sign, the right abdomen, and you'll lay it out, you've got the pseudo kidney sign. That is interceception. Turn color on. If the bowel is viable, you're going to see lots of color. And it's sort of helpful if you're going to go ahead and try to reduce this because it tells you that you have a viable bowel, and this is usually reducible. Here's another one. There's no flow. We made an attempt, a reduction, it didn't work, and that was the schemic bowel surgery. Lead points, 10 percent of patients were common at older children. The lead points include mechal diverticulum, polyp, hematoma, duplication, cysts, and lymphoma. And ultrasound, you're just going to see a mass and the interceception. Here is the interceception, a multi-layered mass, right abdomen, right upper quadrant, not right lower quadrant. This echogenic part is the mesentery that goes along with the bowel. This is a mass. That was a hematoma. This is an interceception target sign, multiple layers. The echogenic part is the mesentery oementum. And this was a polyp. Here's another interceception, multiple layers. There's an anechoic mass in this interceception that's a duplication system. The ultrasound factors that predict that you're going to have difficulty reducing this, if you see absent blood flow, I showed you that. If you have a large amount of fluid in the central interceception, it's a bad sign. If you see a lot of trapped lymph nodes in the interceception and if there's a lead mass. Sensitivity, 94 to 100%, specificity up to 100%, occasionally fecal contents, inflammatory bowel disease, hematoma will mimic interceception. This patient had acute pain. We thought maybe that was interceception. Did an enema? This turned out to be a colitis. And the differential is the other interceception, transient interceception. It occurs in the left upper quadrant, a right subgenum. It's very short compared to the standard interceception, which is much larger. It resolves spontaneously. And it's only the one lesion. Don't touch it. It's going to go away. So these patients had pain. We do look at the right lower quadrant, but we also look, as I mentioned, in the entire abdomen. If we don't find something in the right lower quadrant, this was in the left upper quadrant. It's a target appearance. It's an interceception. It's small. Another one, it's small. Those are transient interceceptions. We feel comfortable with that. We leave it alone. As I mentioned, there are a few other diseases you occasionally may see, pylonephritis, pneumonia, constipation. We're not going to see this well in ultrasound, but we do scan the entire abdomen. We look at both kidneys. We look at the liver, the gallbladder, pancreas. And we trace the bowel. This is a patient with acute right-sided pain. And the reason is pylonephritis. Here's an echogenic area in the kidney and no flow. On Doppler, that's acute pylonephritis. So to sum it up, we discussed some of the common causes of acute right lower quadrant pain. Appendicitis, 20%, 25% of the diagnosis, blind immune to both lots of color. Once it becomes ischemic, you see secondary findings and you may lose flow. We talked about other causes, mimics, bowel disease, and mesenteric anitis, a cluster of lymph nodes, bowel disease, we did mention. We talked about Crohn's disease. This is Crohn's disease. But we said infection could look the same. We talked about the diverticulum, the mechal diverticulum, and the fact that it arises from the ilium and not the cecum. And finally, we brought in into this inception the world target appearance, a classically right upper quadrant because it's ilium going into colon. So to finish this talk, appendicitis is always a diagnosis that's requested for us in the examination. But you'll see that up to 25% of the time. You'll see other diagnosis related to bowel or GYN. We're going to look at GYN shortly. And then most cases, many cases, you're not going to make a diagnosis, probably viral. Well done ultrasound. It's a great tool. And it does allow a correct diagnosis in the majority of patients. It's just a matter of looking for the clues.