scan demonstrating acute appendicitis (note the appendix has a diameter of 17.1 mm and there is surrounding fat stranding) a fecalith marked by the arrow that has resulted in acute appendicitis. where it is readily available, computed tomography (ct) has become frequently used, especially in people whose diagnosis is not obvious on history and physical examination. although some concerns about interpretation are identified, a 2019 cochrane review found that sensitivity and specificity of ct for the diagnosis of acute appendicitis in adults was high. concerns about radiation tend to limit use of ct in pregnant women and children, especially with the increasingly widespread usage of mri. the accurate diagnosis of appendicitis is multi-tiered, with the size of the appendix having the strongest positive predictive value, while indirect features can either increase or decrease sensitivity and specificity. a size of over 6 mm is both 95% sensitive and specific for appendicitis. however, because the appendix can be filled with fecal material, causing intraluminal distention, this criterion has shown limited utility in more recent meta-analyses. this is as opposed to ultrasound, in which the wall of the appendix can be more easily distinguished from intraluminal feces. in such scenarios, ancillary features such as increased wall enhancement as compared to adjacent bowel and inflammation of the surrounding fat, or fat stranding, can be supportive of the diagnosis. however, their absence does not preclude it. in severe cases with perforation, an adjacent phlegmon or abscess can be seen. dense fluid layering in the pelvis can also result, related to either pus or enteric spillage. when patients are thin or younger, the relative absence of fat can make the appendix and surrounding fat stranding difficult to see. magnetic resonance imaging magnetic resonance imaging (mri) use has become increasingly common for diagnosis of appendicitis in children and pregnant patients due to the radiation dosage that, while of nearly negligible risk in healthy adults, can be harmful to children or the developing baby. in pregnancy, it is more useful during the second and third trimester, particularly as the enlargening uterus displaces the appendix, making it difficult to find by ultrasound. the periappendiceal stranding that is reflected on ct by fat stranding on mri appears as an increased fluid signal on t2 weighted sequences. first trimester pregnancies are usually not candidates for mri, as the fetus is still undergoing organogenesis, and there are no long-term studies to date regarding its potential risks or side effects. x-ray appendicolith as seen on plain x-ray in general, plain abdominal radiography (par) is not useful in making the diagnosis of appendicitis and should not be routinely obtained from a person being evaluated for appendicitis. plain abdominal films may be useful for the detection of ureteral calculi, small bowel obstruction, or perforated ulcer, but these conditions are rarely confused with appendicitis. an opaque fecalith can be identified in the right lower quadrant in fewer than 5% of people being evaluated for appendicitis. a barium enema has proven to be a poor diagnostic tool for appendicitis. while failure of the appendix to fill during a barium enema has been associated with appendicitis, up to 20% of normal appendices do not fill. scoring systems several scoring systems have been developed to try to identify people who are likely to have appendicitis. the performance of scores such as the alvarado score and the pediatric appendicitis score, however, are variable. the alvarado score is the most known scoring system. a score below 5 suggests against a diagnosis of appendicitis, whereas a score of 7 or more is predictive of acute appendicitis. in a person with an equivocal score of 5 or 6, a ct scan or ultrasound exam may be used to reduce the rate of negative appendectomy. alvarado score migratory right iliac fossa pain 1 point anorexia 1 point nausea and vomiting 1 point right iliac fossa tenderness 2 points rebound abdominal tenderness 1 point fever 1 point high white blood cell count (leukocytosis) 2 points shift to left (segmented neutrophils) 1 point total score 10 points pathology even for clinically certain appendicitis, routine histopathology examination of appendectomy specimens is of value for identifying unsuspected pathologies requiring further postoperative management. notably, appendix cancer is found incidentally in about 1% of appendectomy specimens. pathology diagnosis of appendicitis can be made by detecting a neutrophilic infiltrate of the muscularis propria. periappendicitis (inflammation of tissues around the appendix) is often found in conjunction with other abdominal pathology. micrograph of appendicitis and periappendicitis. h&e stain micrograph of appendicitis showing neutrophils in the muscularis propria. h&e stain acute suppurative appendicitis with perforation (at right). h&e stain classification of acute appendicitis based on gross pathology and light microscopy characteristics patterngross pathologylight microscopyimageclinical significance acute intraluminal inflammation none visible only neutrophils in lumen no ulceration or transmural inflammation probably none acuta mucosal inflammation none visible neutrophils within mucosa, and possibly in submucosa mucosal ulceration may be secondary to enteritis. suppurative acute appendicitis may be inapparent. dull mucosa congested surface vessels fibropurulent serosal exudate in late cases dilated appendix neutrophils in mucosa, submucosa and muscularis propria, potentially transmural. extensive inflammation commonly intramural abscesses possibly vascular thrombosis can be presumed to be primary cause of symptoms gangrenous/necrotizing appendicitis friable wall purple, green or black color transmural inflammation, obliterating normal histological structures necrotic areas extensive mucosal ulceration will perforate if untreated periappendicitis may be inapparent. serosa may be congested, dull and exudative serosal and subserosal inflammation, no further than outer muscularis propria to be called isolated if isolated, probably secondary to other disease eosinophilic appendicitis none visible >10 eosinophils/mm2 in muscularis propria. no changes conforming to other types of appendicitis possibly parasitic, or eosinophilic enteritis. differential diagnosis coronal ct scan of a person initially suspected of having appendicitis because of right-sided pain. the ct shows in fact an enlarged inflamed gallbladder that reaches the right lower part of the abdomen. children: gastroenteritis, mesenteric adenitis, meckel's diverticulitis, intussusception, henoch–schönlein purpura, lobar pneumonia, urinary tract infection (abdominal pain in the absence of other symptoms can occur in children with uti), new-onset crohn's disease or ulcerative colitis, pancreatitis, and abdominal trauma from child abuse; distal intestinal obstruction syndrome in children with cystic fibrosis; typhlitis in children with leukemia. women: a pregnancy test is important for all women of childbearing age since an ectopic pregnancy can have signs and symptoms similar to those of appendicitis. other obstetrical/ gynecological causes of similar abdominal pain in women include pelvic inflammatory disease, ovarian torsion, menarche, dysmenorrhea, endometriosis, and mittelschmerz (the passing of an egg in the ovaries approximately two weeks before menstruation). men: testicular torsion adults: new-onset crohn disease, ulcerative colitis, regional enteritis, cholecystitis, renal colic, perforated peptic ulcer, pancreatitis, rectus sheath hematoma and epiploic appendagitis. elderly: diverticulitis, intestinal obstruction, colonic carcinoma, mesenteric ischemia, leaking aortic aneurysm. the term "pseudoappendicitis" is used to describe a condition mimicking appendicitis. it can be associated with yersinia enterocolitica. management acute appendicitis is typically managed by surgery. while antibiotics are safe and effective for treating uncomplicated appendicitis, 26% of people had a recurrence within a year and required an eventual appendectomy. antibiotics are less effective if an appendicolith is present. surgery is the standard management approach for acute appendicitis; however, the 2011 cochrane review comparing appendectomy with antibiotics treatments has been withdrawn due to inclusion of a retracted article and not updated since. the cost effectiveness of surgery versus antibiotics is unclear. using antibiotics to prevent potential postoperative complications in emergency appendectomy procedures is recommended, and the antibiotics are effective when given to a person before, during, or after surgery. pain pain medications (such as morphine) do not appear to affect the accuracy of the clinical diagnosis of appendicitis and therefore should be given early in the patient's care. historically there were concerns among some general surgeons that analgesics would affect the clinical exam in children, and some recommended that they not be given until the surgeon was able to examine the person. surgery