Appendicitis: Risk Factors, Management Strategies and Clinical Implications.

Acute abdominal pain can be a potentially life-threatening status requiring urgent surgery. Appendicitis is worldwide the most common cause of acute abdomen in children as well as in adults. The typical medical history (positive findings of appendicitis in the physical examination e.g. tenderness at McBurney´s point, fever and elevated inflammatory markers such as C-reactive protein and white blood cell count in the lab tests) can lead to the correct diagnosis.
Still, preoperative imaging can be decisive for confirming the diagnosis of acute appendicitis. Five imaging techniques are applicable: plain radiography, barium enema, ultrasound (US), multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI).
Plain radiography and barium enema are not routinely used in cases of suspected appendicitis, but are helpful in detecting nonappendiceal causes of acute abdominal pain. US is a non-invasive, cost-effective and reproducible tool and therefore, considered to be the first line imaging modality, especially in children. Nevertheless, the findings of a transabdominal US are highly dependent on the physician’s experience and can be limited by factors such as overlying intestinal gas, abdominal guarding and obesity.
MDCT is superior to US and shows higher sensitivity and specificity. Furthermore, MDCT scanners are readily available today in many countries and can be seen as a major diagnostic tool in patients with suspected appendicitis. However, standard-dose contrast-enhanced MDCT does not seem to be superior to low-dose unenhanced MDCT when it comes to detecting the following five imaging signs of acute appendicitis: cross-sectional appendiceal diameter greater than six mm (most important parameter), thickened appendiceal wall greater than two mm, periappendiceal edema, abscess in the right lower quadrant, and an appendicolith. The first three mentioned criteria (primary findings) together are pathognomonic for the diagnosis. An abscess is usually associated with appendiceal perforation and the detection of an appendicolith (secondary finding) without the primary findings is not an indicator for acute appendicitis.
In patients with higher radiation sensitivity than the normal population (pregnant women, young adults and children) or in patients with other contra-indications for MDCT, MRI is the diagnostic tool of choice when US was inconclusive in the diagnosis of appendicitis, because of its equal sensitivity and specificity as MDCT.
This article provides a comparative overview of the state-of-the-art imaging techniques and their clinical relevance as well as positive and negative aspects in patients with suspected appendicitis.