You are in: eMedicine Specialties > General Surgery > Abdomen Vermiform AppendixArticle Last Updated: Mar 10, 2006AUTHOR AND EDITOR INFORMATIONAuthor: Steven L Lee, MD, Regional Pediatric Surgeon, Department of Surgery, Kaiser-Permanente, Los Angeles Medical Center Steven L Lee is a member of the following medical societies: Alpha Omega Alpha, American College of Surgeons, American Pediatric Surgical Association, and Society of American Gastrointestinal and Endoscopic Surgeons Coauthor(s): Jeffrey J DuBois, MD, Consulting Staff, Division of Pediatric Surgery, Kaiser Permanente, North Sacramento Medical Center; Devin P Puapong, MD, Staff Physician, Department of General Surgery, Kaiser Permanente Los Angeles Medical Center Editors: Brian James Daley, MD, MBA, FACS, Associate Program Director, Professor, Department of Surgery, Division of Trauma and Critical Care, University of Tennessee School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; David Chelmow, MD, Professor of Obstetrics and Gynecology, Tufts University School of Medicine; Program Director, Tufts University Affiliated Hospitals OB/GYN Residency Program; Chair, Tufts University Health Sciences Campus Institutional Review Board; Frederick B Gaupp, MD, Consulting Staff, Department of Family Practice, Assumption Community Hospital; Lee P Shulman, MD, Professor of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University; Chief, Division of Reproductive Genetics, Department of Obstetrics and Gynecology, Prentice Women's Hospital, Northwestern Memorial Hospital Author and Editor Disclosure Synonyms and related keywords: acute appendicitis, suppurative appendicitis, gangrenous appendicitis, perforated appendicitis, lymphoid hyperplasia, fecaliths, fecal stasis INTRODUCTIONIn 1886, Reginald H. Fitz, a Harvard pathologist, first described the clinical condition of acute appendicitis (Condon, 1991). He correctly pointed out the importance of its early diagnosis and timely treatment, based on his analysis of 257 cases of perforating inflammation of the appendix and 209 cases of typhlitis or perityphlitis (Fitz, 1886). A few years later, Charles McBurney described the clinical findings prior to rupture and advocated early surgical intervention. Despite aggressive intervention, mortality and morbidity rates remained high through the rest of the 19th century and the first half of the 20th century. The mortality rate associated with appendicitis declined with the introduction of antibiotics and with the development of anesthesia and better perioperative care. Currently, the diagnosis of acute appendicitis remains a challenge. Only slightly more than half of patients present with classic signs and symptoms of acute appendicitis. Atypical presentations often lead to a delay in diagnosis, perforation, prolonged hospitalization, and increased morbidity (Lee, 2001). Thus, all clinicians must be knowledgeable about diagnosing and managing this disease process. For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education articles, Appendicitis and Abdominal Pain in Adults. History of the ProcedureThe appendix was probably first noted as early as the Egyptian civilization (3000 BC). During the mummification process, abdominal parts were removed and placed in Coptic jars with inscriptions describing the contents. When these jars were uncovered, inscriptions referring to the "worm of the intestine" were discovered (Herrinton, 1991). Aristotle and Galen did not identify the appendix because they both dissected lower animals, which do not have appendices. Celsus, however, probably discovered the appendix because he was allowed to dissect criminals executed by Caesar (Herrinton, 1991). Leonardo da Vinci first depicted the appendix in anatomic drawings in 1492 (Ho, 1999). In 1521, Jacopo Beregari da Capri, a professor of anatomy in Bologna, identified the appendix as an anatomic structure. In the 1500s, Vesalius (1543) and Pare (1582) referred to the appendix as the caecum. Laurentine compared the appendix to a twisted worm in 1600, and Phillipe Verheyen coined the term appendix vermiformis in 1710 (Herrinton, 1991). ProblemAcute appendicitis remains one of the most common surgical diseases encountered by physicians. When appendicitis manifests in its classic form, it is easily diagnosed and treated. Unfortunately, these classic symptoms occur in just over half of patients with acute appendicitis. Accurate and timely diagnosis of atypical appendicitis therefore remains clinically challenging and one of the most commonly missed problems in the emergency department. Furthermore, the consequence of missing appendicitis, thus leading to perforation, significantly increases morbidity and prolongs hospitalization (Lewis, 1975). FrequencyIn Western countries, approximately 7% of individuals develop appendicitis at some time during their lives. Approximately 200,000 appendectomies are performed annually in the United States (Condon, 1991). The peak incidence of acute appendicitis has gradually declined to about half of its peak incidence in the early 20th century, with the current annual incidence of 1 per 1000 population in the United States and 86 cases for every 100,000 persons worldwide (Carr, 2000; Korner, 1997). Acute appendicitis is less common in Africa and parts of Asia because of the high-residue diets of the inhabitants. EtiologyAppendicitis results from obstruction of the lumen of the appendix. Obstruction may be from lymphoid hyperplasia (60%), fecalith or fecal stasis (35%), foreign body (4%), and tumors (1%) (Liu, 1997). PathophysiologyThe basic pathophysiology of appendicitis is obstruction of the lumen of the appendix followed by infection. In 60% of patients, obstruction is caused by hyperplasia of the submucosal follicles. This form of obstruction is mostly observed in children and is known as catarrhal appendicitis. A fecalith or fecal stasis causes luminal obstruction 35% of the time and is usually observed in adults. Obstruction may also be caused by foreign bodies (4%) and tumors (1%). Following obstruction, an increase in mucus production occurs, and this leads to increased pressure. With increased pressure and stasis from obstruction, bacterial overgrowth ensues. The mucus then turns into pus that causes a further increase in luminal pressure. This leads to distention of the appendix and visceral pain, which is typically located in the epigastric or periumbilical region. As the luminal pressure continues to increase, lymphatic obstruction occurs, leading to an edematous appendix. This stage is known as acute or focal appendicitis. The overlying parietal peritoneum becomes irritated, and the pain now localizes to the right lower quadrant (RLQ). This series of events results in the classic migrating abdominal pain described in patients with appendicitis. Further increase in pressure leads to venous obstruction, causing edema and ischemia of the appendix. At this stage, bacterial invasion of the wall of the appendix occurs and is known as acute suppurative appendicitis. Finally, with continued pressure increases, venous thrombosis and arterial compromise occur, leading to gangrene and perforation (Liu, 1997). If the body successfully walls off the perforation, the pain may actually improve. However, symptoms do not completely resolve. Patients may still have underlying right lower quadrant pain, decreased appetite, change in bowel habits (eg, diarrhea, constipation), or intermittent low-grade fever. If the perforation is not successfully walled off, then diffuse peritonitis will develop. ClinicalThe classic presentation of a patient with appendicitis includes a history of initial periumbilical or epigastric abdominal pain migrating to the RLQ. The pain is gradual in onset and progressively worsens. Anorexia, nausea, and vomiting are typically associated with the disease. In early appendicitis, the patient is initially afebrile or has a low-grade fever. Higher fevers are associated with a perforated appendix (Lee, 2001). On physical examination, the patient is usually lying still, as movement worsens the pain. Having the patient cough elicits localized pain in the RLQ. Local tenderness to palpation is usually observed. Percussion tenderness is also noted in this area. Tenderness on the right side during rectal examination may occur, whereas pelvic and testicular examination findings are normal. Other signs (eg, Rovsing, psoas, obturator) are unreliable and typically occur late in the disease process (Lee, 2001). Unfortunately, only 55% of patients with appendicitis present with classic history and physical findings. This is because the early signs and symptoms are primarily dependent upon the location of the tip of the appendix, which is highly variable (Liu, 1997). INDICATIONSIndications for surgical consultation A surgeon should evaluate any patient with classic migrating abdominal pain and RLQ tenderness. Because only a little more than half of patients with appendicitis present with a classic history and physical findings, acute appendicitis should be on the list of possible diagnoses for any patient with abdominal pain. Thus, a surgeon should also evaluate patients with focal RLQ tenderness or progressively worsening abdominal pain. To minimize the time between presentation and appendectomy, obtain surgical consultation prior to performing additional diagnostic studies such as CT scan, ultrasound, and technetium (Tc)-labeled WBC scan (Lee, 2001). Indications for operation Any patient with suspected appendicitis who has (1) persistent pain and becomes febrile, (2) an increasing WBC count, or (3) worsening clinical examination findings should undergo appendectomy or at least diagnostic laparoscopy. In patients with an atypical presentation, the most important determination for appendectomy is serial physical examinations. The WBC count often does not increase after the patient is admitted and hydrated; therefore, any patient sent home from the emergency department should undergo a follow-up evaluation the next day (Lee, 2001). RELEVANT ANATOMYEmbryologically, the appendix is a continuation of the cecum and is first delineated during the fifth month of gestation. The appendix does not elongate as rapidly as the rest of the colon, thus forming a wormlike structure (Condon, 1991). The appendix averages 10 cm in length but can range from 2-20 cm. The wall of the appendix consists of 2 layers of muscle, an inner circular and outer longitudinal. The longitudinal layer is a continuation of the taeniae coli. The appendix is lined by colonic epithelium (Condon, 1991). Few submucosal lymphoid follicles are noted at birth. These follicles enlarge, peak from 12-20 years, and then decrease. This correlates with the incidence of appendicitis. Blood supply to the appendix is mainly from the appendicular artery, a branch of the ileocolic artery. This artery courses through the mesoappendix posterior to the terminal ileum. An accessory appendicular artery can branch from the posterior cecal artery. This artery can lead to significant intraoperative and postoperative hemorrhage and should be searched for carefully and ligated once the main appendicular artery is controlled (Liu, 1997). The base of the appendix is fairly constant and is located at the posteromedial wall of the cecum about 2.5 cm below the ileocecal valve. This is also where the taeniae converge (Liu, 1997). The base is at a constant location, whereas the position of the tip of the appendix varies. In 65% of patients, the tip is located in a retrocecal position; in 30%, it is located at the brim or in the true pelvis; and, in 5%, it is extraperitoneal, situated behind the cecum, ascending colon, or distal ileum. The location of the tip of the appendix determines early signs and symptoms. CONTRAINDICATIONSNo contraindications to performing an appendectomy in patients with suspected appendicitis exist; however, patients with a well-developed abscess (detected on CT scan) following perforated appendicitis may be initially treated with percutaneous drainage and intravenous antibiotics. Once bowel function resumes, the patient may be discharged on oral antibiotics (total IV + PO antibiotics for 7-10 d) with consideration for interval appendectomy in 6 weeks (Kaminsky, 2005). WORKUPLab Studies
Imaging Studies
Diagnostic Procedures
Histologic FindingsA small percentage of normal-appearing appendices have focal appendicitis on microscopic examination. In addition, early appendicitis may be encountered in the form of increased interleukin (IL)-2 and tumor necrosis factor (TNF)-alpha secretion, which may not be detected on gross examination. Approximately 1% of patients have appendicitis from carcinoid or adenocarcinoma (Lee, 2001). StagingAppendicitis progresses through the following stages: acute or focal appendicitis, suppurative appendicitis, gangrenous appendicitis, and perforated appendicitis (Liu, 1997). TREATMENTMedical therapyNo medical treatment exists for acute appendicitis. Surgical therapyA total of 17 prospective randomized trials have compared laparoscopic versus open appendectomy. The two techniques are similar with respect to the negative appendectomy rate (lap = 14.4% vs open = 14.5%), length of hospital stay (lap = 3.0 d vs open = 3.7 d), and intra-abdominal abscess (lap = 1.9% vs open = 0.8%). Laparoscopic appendectomy appears to have a slightly lower wound infection rate (2.9%) compared to open appendectomy (7.4%) (Ho, 1999). Preoperative detailsAll patients diagnosed with appendicitis should be adequately hydrated with isotonic intravenous fluids. In addition, broad-spectrum intravenous antibiotics (ampicillin, gentamicin, and metronidazole or a third-generation cephalosporin and metronidazole) should be started prior to the operation. Newer single agent, broad-spectrum antibiotics may also be used. Antibiotics, analgesics, or antipyretics should not be administered to patients admitted for serial examination because these medications may mask the underlying disease process. To minimize the time from presentation to the time of appendectomy, surgical consultation should be obtained prior to obtaining additional diagnostic studies, as these tests are often unnecessary (Lee, 2001). Intraoperative detailsThe basic technique for open and laparoscopic appendectomy is described below and is individualized to the authors' preference (Ho, 1997). Other approaches, suture materials, or techniques may be employed with equal success. Open appendectomy Incision: Most surgeons perform appendectomy through a RLQ incision over the McBurney point (two thirds of the distance between the umbilicus and the anterior superior iliac spine). The subcutaneous tissue and Scarpa fascia are dissected until the external oblique aponeurosis is identified. This aponeurosis is divided sharply along the direction of its fibers. A muscle-splitting technique is then used to gain access to the peritoneum. Once the peritoneum is entered, any purulent fluid should be cultured. Delivering the appendix: Small Richardson retractors are placed into the peritoneum, and the cecum is identified and partially exteriorized using a moist gauze pad or Babcock clamp. The taenia coli is followed to the point where it converges with the other taenia, leading to the base of the appendix. The rest of the appendix is then brought into the field of vision. Gentle manipulation may be required to bluntly dissect any inflammatory adhesions. Division of the mesoappendix and ligation of the appendix: Once the appendix is exteriorized, the mesoappendix is divided between clamps, divided, and ligated. The base of the appendix is clamped after milking potential fecaliths into the lumen of the appendix. The appendix is then tied off with a 0-polyglycolic (PG) acid suture. The appendix is amputated and passed off the field as a specimen. The mucosa of the appendiceal stump may be cauterized to avoid future mucus production. Inverting the appendiceal stump is not necessary. The cecum and appendiceal stump are then placed back into the abdomen. The pelvis and the right pericolic gutter are suctioned to remove any fluid. If no evidence of free perforation exists, further peritoneal lavage is not necessary and may potentially be harmful; however, if free perforation is encountered, the authors prefer to thoroughly irrigate the abdomen with warm saline solution. A drain is not required unless an obvious cavity is present following drainage of a well-developed abscess. Closure of the incision: The peritoneum is identified, and hemostats are placed on the cut ends at both apices and the midpoint of the superior and inferior sides. The peritoneum is closed with a continuous 3-0 PG suture. The inferior oblique muscles are reapproximated with a figure-of-eight 3-0 PG suture, and the external oblique fascia is closed with a continuous 2-0 PG suture. The skin may be closed with staples or subcutaneous sutures. Use of staples is recommended if the appendix was perforated and skin closure is to be performed. Some authors believe that the skin should be left open in cases of perforated appendicitis, with delayed primary closure performed on postoperative day 4 or 5. Laparoscopic appendectomy A urinary bladder catheter is placed, and the surgeon typically stands on the left side of the patient. Video monitors are placed at the patient's feet. A 6-mm infraumbilical incision is made, followed by placement of the Veress needle. After confirmation of intraperitoneal placement, a pneumoperitoneum (14 mm Hg) is established and maintained using a carbon dioxide insufflator. The Veress needle is replaced with a 5-mm trocar, and a 5-mm, 30-degree laparoscope is used. Alternatively, the 5-mm trocar can be placed directly into the abdominal cavity using an open cutdown approach. Under direct visualization, a 12-mm trocar is inserted into the left lower quadrant (LLQ) and another 5-mm trocar in the right periumbilical region. Through the right periumbilical trocar, a grasper is used to gain control of the appendix. A small hole in the mesoappendix is made using a dissector placed through the LLQ port at the base of the appendix. An endo-gastrointestinal assistant stapler is then used to staple the base of the appendix, and a vascular reload is used to staple across the mesoappendix. Once the appendix is free, it is removed through the LLQ port. Appropriate peritoneal irrigation is then performed. The fascia of the LLQ and infraumbilical port sites are closed with 0-PG suture, and the skin incisions are closed with subcuticular sutures. Treatment of perforated appendicitis with abscess Patients with perforated appendicitis and abscess formation or phlegmon may be treated with initial nonoperative management. Patients may be initially treated with broad-spectrum, intravenous antibiotics alone or in combination with percutaneous aspiration of the abscess and/or drain placement (Oliak, 2001). Intravenous antibiotics are continued until the patient is afebrile for 24 hours, has a return of normal gastrointestinal function, and has a normal WBC count with a normal differential. At this time, patients are switched to oral antibiotics for a total antibiotic course of 10-14 days. Traditionally, interval appendectomy is performed 6-8 weeks later. The need for routine interval appendectomy has recently been challenged given the low incidence of recurrent appendicitis (Kaminsky, 2005). Postoperative detailsIf acute appendicitis is encountered, perioperative antibiotics covering skin flora should be continued for 24 hours. If suppurative appendicitis is encountered, intravenous antibiotics covering enteric flora should be continued for 48-72 hours and can be safely discontinued once the patient remains afebrile for 24 hours. In both instances, clear liquids can be started once the patient is stable from anesthesia, and diet can be advanced as tolerated. If gangrenous or perforated appendicitis is encountered, continue intravenous antibiotics until the patient is afebrile and has return of bowel function and a normal WBC count with a normal differential. Once bowel function returns, clear liquids can be started and the diet advanced as tolerated. In most patients, a nasogastric tube is not needed (Hoelzer, 1999). Follow-upThe patient should return to the clinic 1-2 weeks following discharge for wound evaluation and discussion of the pathology. Full activity may resume in 2 weeks following appendectomy if performed through an RLQ incision. If a midline incision was used, activity should be limited for 6 weeks. COMPLICATIONSThe overall morbidity rate of appendicitis is approximately 10%. Most perioperative morbidity is caused by infectious complications. Wound infections occur in approximately 5% of all appendectomies; however, incidence of this complication is related to the stage of appendicitis. The wound infection rate is 1.4% for nonacute appendicitis, 3% for acute appendicitis, and 10-15% for perforated or gangrenous appendicitis. Formation of intra-abdominal or pelvic abscess following appendectomy occurs in 2-5% of patients. The incidence is higher for gangrenous or perforated appendicitis (6-8%) compared to early or suppurative appendicitis (1-2%) (Lee, 2001). Other complications include persistent ileus, small bowel obstruction, and pulmonary complications such as atelectasis and pneumonia. Deep venous thrombosis, pulmonary embolism, and myocardial infarction have also occurred in the early postoperative period. OUTCOME AND PROGNOSISThe outcome following appendectomy for acute or suppurative appendicitis is excellent. Most patients return to full activity within 2 weeks; however, when perforated appendicitis is encountered, prolonged hospitalization and additional diagnostic and therapeutic procedures may be required. The prognosis for all stages of appendicitis is excellent, with a mortality rate of less than 1%. This low mortality rate is largely the result of early diagnosis and treatment, antibiotics, and improved anesthesia care. FUTURE AND CONTROVERSIESControversy continues over the most accurate, cost-effective, and rapid method of making the diagnosis of atypical appendicitis. Surgical consultation remains the most effective method of determining what additional diagnostic tools are needed. REFERENCES
Article Last Updated: Mar 10, 2006 |