A common presentation of appendiceal inflammation. Inflammation can result in infection, thrombosis, necrosis, and perforation or rupture of the intestine. Peritonitis (inflammation of the peritoneal cavity) may follow, as the contents of the lower gastrointestinal tract enter the abdominal cavity. Classic presentations, which occur about 60% of the time, include abdominal pain (initially diffuse, gradually localizing to the right lower quadrant), loss of appetite, nausea, fever, and an elevated white blood cell count. The disease is more common in males and generally occurs in the young, usually between the ages of 10 and 20, but rarely before age 2 and less often after age 50. It is nevertheless important in the differential diagnosis of abdominal pain in older adults.

DIAGNOSIS
Diagnosis is simple when pain eventually localizes to the right lower quadrant, with rebound tenderness and rigidity over the right rectus muscle or McBurney's point. Walking bent over or lying with the right knee flexed are maneuvers the patient may use instinctively to reduce discomfort. If the abdominal pain suddenly stops, perforation or infarction may have occurred. Diagnostic difficulties may arise because the anatomical location of the appendix can vary; as a result, pain may be present in the pelvis, in the right upper quadrant, or in other locations. Tachycardia and moderate to severe discomfort are common. The differential diagnosis of acute appendicitis includes flares of inflammatory bowel disease, mesenteric adenitis, pelvic inflammation, and many other illnesses. When this diagnosis is considered in a woman, it must be differentiated from pain associated with ovulation (mittelschmerz), ruptured ectopic pregnancy, torsion of the ovary, and pelvic inflammatory disease. To aid preoperative diagnosis, imaging studies, such as ultrasound or computed tomography, are often performed.

Some Severe Illnesses That May Mimic Appendicitis

Disease	Clinical Findings That May Suggest the Diagnosis
Abdominal aortic aneurysm, rupture	Pulsatile abdominal mass; abdominal bruits; mature patient; imaging studies
Colic caused by kidney stone	Blood present in the urine; visualization of stone by pyelography or computed tomography
Crohn's disease, flare	History of inflammatory bowel disease; pus or blood in stools
Diverticulitis, right-sided	May be difficult to distinguish without imaging studies, laparotomy, or laparoscopy
Ectopic pregnancy	Positive pregnancy test; abdominal ultrasound
Gastroenteritis	Others at home also ill; recent travel abroad; vomiting and diarrhea present
Ischemia of the GI tract	Pain more notable than physical findings; metabolic acidosis; blood in stools; mature patient; smoker
Perforation of an internal organ	Abdominal rigidity; free air under the diaphragm on abdominal x-ray studies
Pyelonephritis	Leukocytes and bacteria in catheterized urine specimen
Salpingitis	Sexually active woman; cervical purulence; tenderness of pelvic organs on examination
Typhlitis	History of leukemia

The greater the delay in diagnosis, the higher the incidence of complications, such as abscess formation, appendiceal rupture, sepsis, and death.

PATIENT CARE
Preoperative: The patient is assessed for signs and symptoms of appendicitis, such as elevated temperature; nausea or vomiting; onset, location, quality, and intensity of pain; rebound tenderness; constipation or diarrhea; and a moderately elevated white blood cell count (12,000 to 15,000/ul) with an increase in immature white blood cells. Abdominal ultrasound or CT scan may be used to confirm the diagnosis. The patient is positioned for comfort, kept NPO, intravenous fluids are started for hydration, and he/she is prepared physically and emotionally for surgery.

To prevent possible rupture of an inflamed appendix, cathartics or enemas should not be used.
Postoperative: Vital signs, the status of bowel sounds, abdominal flatus, lung sounds, and intake and output, including prescribed intravenous fluids, are monitored and documented. The patient is positioned comfortably (Fowler's position in the case of a ruptured appendix or peritonitis). Prescribed analgesics and noninvasive comfort measures are provided. Position changes, incentive spirometry for deep breathing and coughing, and early ambulation are encouraged. The patient's ability to urinate is ascertained and documented. If required, antibiotics are administered as prescribed. The dressing is inspected for any bleeding or drainage and the findings documented. Possible surgical complications include abscess formation (evidenced by continued pain and fever postoperatively) and wound dehiscence (reopening of the surgical incision after it has been closed). Nasogastric drainage may be required for decompression of the gastrointestinal tract, and prevention of nausea and vomiting if peritonitis occurs as a complication. The patient is prepared for return to home, work, and other activities.

Main entry:
appendicitis