Acute Appendicitis

ACUTE APPENDICITIS YIN Detao MD Department of General Surgery, the First Affiliated Hospital of ZhengZhou University

一， Essentials of Diagnosis • • • • •

Abdominal pain; Anorexia, nausea and vomiting; Localized abdominal tenderness; low-grade fever; Leukocytosis.

二， General considerations • In approximately 70% of acutely inflamed appendices, obstruction of the proximal lumen by fibrous bands, tumors, parasites, or foreign bodies can be demonstrated.

• Introaluminal obstruction is not found in one-third of specimens, however, and external compression by bands has been postulated to explain these cases. • It has also been suggested that acute appendicitis may begin with mucosal ulceration, perhaps viral, followed by secondary bacterial invasion.

• As appendicitis progresses, the blood supply is impaired by bacterial infection in the wall and distention of the lumen by pus; gangrene and perforation occur at about 24 hours, although the timing is highly variable. • Gangrene implies microscopic perforation and bacterial peritonitis.

三， Clinical findings • Acute appendicitis has protean manifestations. • It may simulate almost any other acute abdominal illness and in turn may be mimicked by a variety of conditions. • Progression of symptoms and signs is the rule-in contrast to the fluctuating course of some other diseases.

1, symptoms and signs: • Typically, the illness begins with vague abdominal discomfort followed by slight nausea, anorexia, and indigestion. • The pain is persistent and continuous but not severe, with occasional mild epigastric cramps.

• There may be an episode of vomiting, and within several hours the pain shifts to the right lower quadrant, becoming localized and causing discomfort on moving, walking, or coughing. • The patient has a sense of being constipated and may feel the need for a cathartic or an enema.

• Examination at this time will show cough tenderness localized to the right lower quadrant. • There will be well-localized tenderness to one finger palpation and possibly very slight muscular rigidity. • Rebound tenderness is classically referred to the same area. • Rectal and pelvic examinations are likely to be negative. • The temperature is only slightly elevated (37.8℃) in the absence of perforation.

2, Laboratory finding: • The average leukocyte count is 15,000/μl, and 90% of patients have counts over 10, 000/μl. In three-fourths of patients, the differential white count shows more than 75% neutrophils.

• The urine is usually normal, but a few leukocytes and erythrocytes and occasionally even gross hematuria may be noted, particularly in retrocecal or pelvic appendicitis.

3, X-ray finding: • Abdominal X-rays may be of value in detecting other causes of abdominal pain, since plain films seldom contribute to the diagnosis of acute appendicitis.

• Localized air-fluid levels, localized ileus, or increased soft tissue density in the right lower quadrant is present in 50% of patients with early acute appendicitis. • Positive radiologic signs become more frequent as appendicitis progresses.

四， Differential diagnosis • The diagnosis of acute appendicitis is particularly difficult in the very young and in the elderly. These are the groups where diagnosis is most often delayed and perforation most common.

• Infants manifest only lethargy, irritability, and anorexia in the early stages, but vomiting, fever, and pain are apparent as the disease progresses. • Classic symptoms may not be elicited in aged patients, and the diagnosis is often not considered by the examining physician. • The course of appendicitis is more virulent in the elderly, and suppurative complications occur earlier.

五， Complications • The complications of acute appendicitis include perforation, peritonitis, abscess, and pylephlebitis.

1, Perforation: • Perforation is accompanied by more severe pain and higher fever than in slight appendicitis.

• It is unusual for the acutely inflamed appendix to perforate within the first 12 hours. • The appendicitis has progressed to perforation by the time of appendectomy in about 50% of patients under age 10 or over age 50. • Nearly all deaths occur in the latter group.

2, Peritonitis: • Localized peritonitis results from microscopic perforation of a gangrenous appendix, while spreading or generalized peritonitis usually implies gross perforation into the free peritoneal cavity.

• Increasing tenderness and rigidity, abdominal distention, and adynamic ileus are obvious in patients with peritonitis. • High fever and severe toxicity mark progression of this catatrophic illness in untreated patients.

3, Appendiceal abscess: • Localized perforation of appendix leads to formation of an appendiceal abscess that is protected from the free peritoneal cavity by omentum or loops of small bowel.

4, Pylephlebitis: • Pylephlebitis is suppurative thrombophlebitis of the portal venous system.

• Chills, high fever, low-grade jaundice, and, later, hepatic abscesses are the hallmarks of this grave condition. • The appearance of shaking chills in a patient with acute appendicitis demands vigorous antibiotic therapy to prevent the development of pylephlebitis.

六， Treatment • With few exceptions, the treatment of appendicitis is surgical. • The use of prophylactic antibiotics decreases the incidence of septic complications in both perforated and nonperforated appendicitis.

七， Prognosis • Although a death rate of zero is theoretically attainable in acute appendicitis, deaths still occur, some of which are avoidable. • The death rate in simple acute appendicitis is approximately 0.1% and has not changed significantly since 1930.