Patients most commonly present with appendicitis between the ages of 10 and 40 years. Approximately 75% of patients will present with pain of less than 24 hours duration. Classically, the pain is described as starting at the umbilicus and then migrating over several hours’ time to the RLQ as the stimulus changes from the visceral to somatic nerves. However, this classic migration is not always present, and nearly 40% of patients will have atypical pain, with only vague abdominal pain or even flank pain.

Atypical pain can frequently be caused by subtle variation in the appendix location with right upper quadrant pain being caused by an anteriorly located appendix on a high-riding cecum, tenesmus triggered by an inflamed appendix tip in the pelvis, and flank pain triggered by a retrocecal appendix.

Nausea, vomiting, and anorexia are classically associated with appendicitis but are variably present. Of these, the sequence of having anorexia and/or abdominal pain preceding vomiting is more consistent with appendicitis. When vomiting is the first symptom elicited, the diagnosis of appendicitis is questionable. Diarrhea is fairly nonspecific.

Physical exam findings consistent with appendicitis are dependent on the location of the appendix. Because the appendix may be located anywhere on the cecum, signs are extremely variable. Classic RLQ point tenderness at McBurney point is present in the normal anterior location of the appendix. Rovsing’s sign (RLQ pain when left lower quadrant is pressed) may also be present.

When the appendix is located in a retrocecal position, a positive psoas sign (pain with extension of the right thigh with the patient lying on the left side) can be elicited. When the inflamed appendix is in the pelvis, the classic obturator sign (pain with internal rotation of the flexed thigh in the supine position) may be positive.

Additional tests for subtle peritoneal irritation, including gently shaking the hospital stretcher or having the patient walk, cough, or jump to determine if this exacerbates pain, are nonspecific for appendicitis and simply indicate peritoneal irritation.

Diffuse peritonitis is consistent with ruptured appendicitis and intraabdominal sepsis. These patients usually present with temperature greater than 39°C and tachycardia.

Laboratory studies and radiologic studies can be complementary to history and physical exam in establishing the diagnosis. A mild leukocytosis is generally present. Occasionally, a “left shift” with normal leukocyte count is seen. Fewer than 5% of patients presenting with acute appendicitis will have both a normal white blood cell (WBC) count and no shift.

Urinary analysis may show a few white or red cells but should not reflect bacteriuria.

Serum chemistry testing for amylase and lipase and liver function tests are useful in cases where the history of presentation and physical exam findings are not classic and there is an atypical presentation.

Imaging studies have come to the forefront of appendicitis diagnosis in recent years. Computed tomography (CT) enhanced with intravenous (IV) and enteral contrast is the gold standard for evaluation of appendicitis. Case series differ slightly in their reports, but a reasonable estimation is that CT is 90% sensitive and 95% specific for detection of appendicitis.

Widespread use of CT has been shown to reduce the incidence of negative appendectomy.¹ Furthermore, findings of phlegmon or abscess on CT may prompt the surgeon to undertake an alternate approach in treating complex cases of appendicitis with percutaneous drainage and IV antibiotic therapy as the first step of therapy in order to minimize morbidity to the patient.

Ultrasound remains an imaging modality that is operator dependent. In skilled centers, it can be especially helpful in pediatric patients and in early pregnancy.

Plain abdominal radiographs should not be considered routine or mandatory in the specific evaluation of appendicitis but can be used as an initial test in patients presenting with diffuse peritonitis and signs of intraabdominal sepsis.

The bulk of surgical treatment should be discussed in the “Techniques” section. Here, consider indications and other more general concerns, such as discussed in the following sections.