Sarah E. Greer
Samuel R.G. Finlayson
Presentation
A 24-year-old woman presents to the emergency department with abdominal pain, nausea, vomiting, and anorexia that began the previous evening. She describes her abdominal pain as initially periumbilical, but now localized to the right lower quadrant (RLQ). Her temperature is 37.9. Her vital signs are otherwise normal. On abdominal exam, her abdomen is soft and nondistended, but tender to palpation over McBurney’s point. She has no signs of peritonitis.
Differential Diagnosis
In the United States, acute appendicitis is the most common time-sensitive surgical problem. The signs and symptoms of acute appendicitis are believed to develop as a result of obstruction of the appendiceal lumen. This obstruction leads to bacterial proliferation, which can result in appendiceal necrosis and perforation.
While the classic symptoms of abdominal pain migrating to the RLQ, nausea, and anorexia occur in a majority of patients with acute appendicitis, symptoms may be less specific, requiring clinicians to consider a broad differential diagnosis, including gastrointestinal, urologic, and gynecologic pathology. Alternative gastrointestinal diagnoses that must be considered include gastroenteritis, colitis, ileitis, diverticulitis, and inflammatory bowel disease. Infectious causes, such as mesenteric adenitis, urinary tract infection, and pyelonephritis, should also be considered. In women, it is important to include Mittleschmirz, salpingitis, tuboovarian abscess, ovarian torsion, and ruptured ovarian cyst in the differential diagnosis.
Workup
A full history and physical exam must be performed to help establish the diagnosis. In addition to eliciting a history of symptoms and their temporal evolution, the surgeon should ask the patient about any family history of inflammatory bowel disease and a complete menstrual and pregnancy history in women.
On physical exam, pain over McBurney’s point (one-third the distance from the anterior superior iliac spine to the umbilicus) is a classic presenting sign of acute appendicitis. Additional physical exam findings may suggest appendicitis as a diagnosis. Rovsing’s sign is pain in the RLQ when pressure is applied in the left lower quadrant (LLQ); an obturator sign is pain with passive rotation of the flexed right hip; and a psoas sign describes pain on extension of the right hip, the latter commonly present in patients with a retrocecal appendix that lies in contact with the iliopsoas muscle. A pelvic exam in women of childbearing age must not be omitted, as it may reveal gynecologic conditions to which the patient’s symptoms can be attributed.
Laboratory tests that should be obtained include a complete blood count, which will typically reveal a low-grade leukocytosis. Other laboratory tests that should be ordered include a coagulation profile, type and screen (if an operation is anticipated), and a urinalysis to exclude urinary pathology. A pregnancy test should also be performed in women of childbearing age.
In the patient above, pelvic exam reveals no adnexal mass or cervical motion tenderness. Laboratory evaluation reveals a leukocytosis of 16,000. The patient is otherwise healthy, with no history of previous abdominal surgery and no pertinent family history.
Diagnostic Imaging
In young males with symptoms and signs consistent with acute appendicitis, imaging studies to confirm the diagnosis are generally unnecessary prior to proceeding to surgery. In many cases, however, when the diagnosis is not clear after thorough history taking and physical examination, imaging may be helpful in making the decision whether or not to proceed with surgery. Many clinicians are more liberal in the use of imaging in young female patients, both because of the presence of gynecologic conditions in the differential diagnosis and because of the risk of infertility associated with ruptured appendicitis that might result from a delay in diagnosis.
The two most common imaging modalities used in the diagnosis of appendicitis are ultrasound and computed tomography (CT). CT has demonstrated significantly higher sensitivity for the diagnosis of appendicitis, 94% versus 83% to 88%. However, because CT scans expose patients to ionizing radiation, this modality should be used judiciously, especially in children.
Although CT scans are an expensive technology, a focused contrast CT scan limited to the appendix may actually be cost saving. A study by Rao et al. found that routine appendix-focused CT in patients with suspected appendicitis prevented unnecessary appendectomies as well as unnecessary hospitalization for observation, with a net reduction in use of hospital resources and cost per patient.
In the patient in this case, a CT scan was performed that demonstrates a dilated, thickened appendix with surrounding inflammatory changes, consistent with acute appendicitis (Figure 1).
FIGURE 1 • CT radiograph showing appendiceal dilation, wall thickening, and periappendiceal fat stranding consistent with acute appendicitis.
Diagnosis and Treatment
Although a few studies in the surgical literature support nonoperative management of nonperforated acute appendicitis, surgical appendectomy represents the standard of care in the United States. Management of the 15% to 30% of patients who present with perforated appendicitis is controversial. Perforated appendicitis with abscess can be treated initially with antibiotics and image-guided percutaneous drainage, with interval appendectomy 6 to 12 weeks later to prevent recurrence. This approach has been advocated to decrease complication and reoperation rates associated with immediate appendectomy for perforated appendicitis. However, others have argued that an immediate operative approach to perforated appendicitis may improve long-term outcomes and consume fewer healthcare resources.
Surgical Approach
The technique for open appendectomy was described by McBurney in 1894 and has been used with little modification throughout the 20th century. In 1983, Semm introduced the option of laparoscopic appendectomy. Since then, there has been much debate regarding the superiority of one approach versus the other. Advantages of laparoscopic appendectomy include the ability to perform diagnostic laparoscopy if the appendix is found to be normal. Laparoscopic appendectomy is also associated with less postoperative pain, faster recovery, and lower wound infection rates. In contrast, open appendectomy has been found to be less costly and less time-consuming.
Open Appendectomy
Following administration of preoperative antibiotics and induction of general anesthesia, with the patient in a supine position, an incision is made in an oblique or transverse direction overlying McBurney’s point. The subcutaneous fat and Scarpa’s fascia are divided to expose the external oblique aponeurosis. The aponeurosis is sharply opened along the direction of its fibers. The fibers of the internal oblique muscle and transverses abdominus are then bluntly separated. The underlying peritoneum is then elevated into the wound and sharply opened along the length of the incision (Table 1).
TABLE 1. Key Steps of Open Appendectomy
Upon entering the abdominal cavity, presence of purulent fluid or foul smell should be noted. If the appendix is not immediately visualized, exploration with the index finger may reveal an inflammatory mass. Alternately, the teniae coli of the right colon can be followed proximally to the base of the appendix, which is then delivered into the wound with gentle traction, taking care not to avulse the appendix.
The mesoappendix including the appendiceal artery is divided between clamps and ligated. The base of the appendix once free of the mesentery is doubly ligated close to the cecum and sharply divided. The stump mucosa is often cauterized to prevent the development of a mucocele, and then the stump is invaginated into the cecum with a purse-string suture or Z-stitch.
After copious irrigation and ensuring hemostasis, the wound is closed in layers with absorbable suture. The skin may be closed primarily with a subcuticular suture, or may be left open for a delayed primary closure in the setting of significant contamination.
Laparoscopic Appendectomy
Similar to an open approach, the patient receives preoperative antibiotics and general anesthesia and is positioned supine on the operating table. Gastric decompression should be accomplished with an orogastric tube, and a urinary catheter should be placed to decompress the bladder. Once the abdomen has been sterilely prepped and draped, a three-port-site approach is used: one at the umbilicus and the other two according to surgeon preference. The abdomen is systematically explored to confirm the diagnosis and rule out other pathology (Table 2).
TABLE 2. Key Steps of Laparoscopic Appendectomy
The appendix is then mobilized to expose its base. A window in the mesoappendix is created near the base of the appendix using blunt dissection, and then an endoscopic stapler may be used to divide the appendix. If the tissue at the base of the appendix is not deemed viable, a small portion of the cecum may be removed with the appendix to ensure that the staple line traverses tissue that will heal well. The mesoappendix and appendiceal artery are then divided with cautery and clips, or with a stapler using a vascular load. A specimen bag is typically used to remove the appendix through the largest port site.
The RLQ is then copiously irrigated and hemostasis assured. Provided no other pathology is noted, the ports are removed under direct vision to ensure the absence of abdominal wall bleeding. The fascia is reapproximated with absorbable suture at port sites larger than 5 mm. The skin is then closed with a subcuticular suture.
Special Intraoperative Considerations
When the appendix is found to be normal, the abdominal cavity must be searched diligently for an alternative explanation for the patient’s symptoms. In female patients, the ovaries and uterus should be inspected carefully for pathologic findings, such as tubo-ovarian abscess, ovarian torsion, tumor, or cyst. The small bowel should be systematically inspected for sources of inflammation, such as Crohn’s disease or Meckel’s diverticulitis. The gallbladder should also be inspected for signs of cholecystitis.
Traditionally, a normal appendix is removed when it is discovered during open appendectomy, mainly to prevent future surgeons from assuming that the appendix is absent on the basis of a RLQ scar. This traditional approach has been called into question since the advent of laparoscopic appendectomy.
Appropriate management of the normal appendix requires judgment when Crohn’s disease is found as the cause of the patient’s illness. If the base of the appendix and cecum appear to be uninvolved in the inflammatory process, appendectomy is likely safe. The major benefit of appendectomy in the setting of Crohn’s disease is that subsequent episodes of RLQ pain will not be confused with appendicitis.
Appendiceal tumors are rare, but given the prevalence of appendectomy, most surgeons will occasionally encounter them. Carcinoid tumors comprise the majority of appendiceal tumors. If a carcinoid tumor is suspected at the time of surgery, the appendix should be sent to the pathology laboratory for a frozen section histologic diagnosis. For carcinoids <2 cm, simple appendectomy is sufficient. For larger carcinoids, right hemicolectomy with ileocolic lymphadenectomy is recommended. If the histology shows adenocarcinoma of the appendix, a right hemicolectomy is also warranted.
Postoperative Management
For patients with acute appendicitis in the absence of perforation, abscess, or gangrene, a single dose of prophylactic antibiotics is sufficient. Antimicrobial therapy for established intra-abdominal infection should be continued until after the resolution of all clinical signs of infection, including resolution of leukocytosis and fever.
SUGGESTED READINGS
Addiss DG, Shaffer N, Fowler BS, et al. The epidemiology of appendicitis and appendectomy in the United States. Am J Epidemiol. 1990;132:910–925.
Chung RS, Rowland DY, Li P, et al. A meta-analysis of randomized controlled trials of laparosopic versus conventional appendectomy. Am J Surg. 1999;177:250–256.
Rao PM, Rhea JT, Novelline RA, et al. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Engl J Med. 1998;338:141–146.
Silen W, ed. Cope’s Early Diagnosis of the Acute Abdomen. 19th ed. New York, NY: Oxford University Press, 1996.
Simillis C, Symeonides P, Shorthouse AJ, et al. A metaanalysis comparing conservative treatment versus acute appendectomy for complicated appendicitis. Surgery. 2010;147:818–829.