The appendix is a blind ended tube like structure connected to the cecum near the ileocecal valve. The most common location of the appendix is approximated by McBurney’s point, a point over the lower right quadrant of the abdomen located one-third of the distance of a straight line from the anterior superior iliac spine (ASIS) to the umbilicus, as seen in this Daily Doodle. The appendix is variable in length, ranging from 2-20cm and although McBurney’s point approximates the most common location, the tip of the appendix may migrate to the retrocecal, subcecal, preileal, postileal, and pelvic positions (1). To find the appendix during surgery, follow the taenia coli. They will eventually converge to form the base of the appendix, unless you are going in the wrong direction. If you run into the rectum, turn around!

The appendix contains all three layers of the colonic wall (mucosa, submucosa, muscularis) and the serosal covering. It is histologicically different from cecal mucosa because it contains B and T lymphoid cells.

Inflammation of the appendix is known as appendicitis. It is one of the most common causes of acute abdomen and one of the most frequent indications for emergency abdominal surgery worldwide (1). The proposed primary cause of appendicitis is obstruction, which can occur from a fecalith or calculi becoming lodged into the hollow viscus (dotted circular line in the Daily Doodle) or by infectious processes, lymphoid hyperplasia, and benign or malignant tumors.

The classic presentation of acute appendicitis is often described as “Pain first, vomiting next and fever last”. Pain associated with appendicitis often follows a pattern starting as a vague visceral periumbilical pain to a well-localized parietal pain around McBurney’s point. If pain is associated with appendicitis, it will not improve with time, it will only get worse, which is why there is a clock in the lower right corner of the Daily Doodle. The pain maybe followed by anorexia, nausea and vomiting.

Clinical signs/features:

1. McBurney’s Sign: Tenderness over McBurney’s point
2. Rovsing’s sign: Right lower quadrant pain upon palpation of the left lower quadrant.
3. Obturator sign: Right lower quadrant pain upon flexion of right hip and knee followed by internal rotation of the right hip. Associated with pelvic appendix.
4. Psoas sign: Right lower quadrant pain with passive right hip extension. Associated with a retrocecal appendix.

The diagnosis of acute appendicitis is usually a clinical diagnosis based on history and physical examination. Uptodate, an online clinical resource which offers detailed information on the management of acute appendicitis states that “the goal of therapy of acute appendicitis is early diagnosis and prompt operative intervention”. For acute appendicitis, appendectomy is the gold standard. Pre-operative management includes adequate IV hydration, correction of electrolyte abnormalities, and perioperative antibiotics. Appendectomy can be performed by both open and laporoscopic approach. If the appendix appears normal, an appendectomy should still be performed and the area should be explored for the cause of the right lower quadrant pain. Other possible causes include: terminal ileitis, cecal or sigmoid diverticulitis, Meckel’s diverticulitis, mesenteric adenitis or perforating colon carcinoma. In females, other causes may include uterine, fallopian, or ovarian pathology.

References:

1. R. Martin.  “Acute Appendicitis”. November. 6, 2013. www.uptodate.com
2. D. Smink and D. Soybel. “Acute appendicitis in adults: Management”. September 16, 2013. http://www.uptodate.com/contents/acute-appendicitis-in-adults-management?source=see_link

01/13/13 – Appendicitis Daily Doodle by Michiko Maruyama