E. coliQ (77%).Clinical Features:Diagnosis can be made primarily on the basis of the history and physical examination in most casesQ.Typical presentation: Periumbilical pain followed by anorexia and nausea.The pain then localizes to the right lower quadrant as the inflammatory process progresses to involve the parietal peritoneum overlying the appendix.This classic pattern of migratory pain is the most reliable symptom of acute appendicitisQ.A bout of vomiting may occur. Fever ensues, followed by the development of leukocytosis.Occasional patients have urinary symptoms or microscopic hematuriaTenderness is directly over the appendix, at McBurney's pointQ.Rectal and pelvic examinations are most likely to be negative (Tenderness on P/R examination in pelvic appendix)QDunphy's signQ* Pain on coughingQRovsing's signQ* Pain in the right lower quadrant during palpation of the left lower quadrantQObturator signQ* Pain on internal rotation of the hipQ* Suggestive of pelvic appendixQIliopsoas signQ* Pain on extension of the right hipQ* Suggestive of retrocecal appendixQDiagnosis:Laboratory StudiesWBC count is elevated, with more than 75% neutrophils in most patientsQ.Normal WBC count and differential is found in 10% of patients with acute appendicitisQ.High WBC count (>20,00d/mL) suggests complicated appendicitis with gangrene or perforationQ.Microscopic hematuria is common in appendicitis (gross hematuria may indicate the presence of a kidney stone)QUltrasound:USG has a sensitivity of 85% and a specificity >90% for the diagnosis of acute appendicitis in patients of abdominal pain.Characteristic findings: Appendix >7 mm diameter, a thick-walled, non-compressible luminal structure seen in cross section (target lesion), or the presence of an appendicolithQ.Commonly used in children & pregnant patients0 with equivocal clinical findings suggestive of acute appendicitis.Plain X-ray:A calcified appendicolith is visible in only 10-15% of patients with acute appendicitis.Failure of the appendix to fill during a barium enema has been associated with appendicitisQ (this finding lacks sensitivity and specificity because up to 20% of normal appendices do not fill).CT ScanCT scan: Sensitivity of 90% and a specificity of 80-90% for the diagnosis of acute appendicitis in patients with abdominal painQ.Classic findings on CT: Distended appendix >7 mm in diameter and circumferential wall thickening and enhancement (appearance of a halo or target)QCT detects appendicoliths in 50% of patients with appendicitis.Most valuable for older patients and in patients with atypical symptoms.Treatment:Most patients are managed by prompt appendectomyQ.">