eMedicine Specialties > General Surgery > Abdomen

Vermiform Appendix

Steven L Lee, MD, Chief, Pediatric Surgery, Department of Surgery, Kaiser-Permanente, Los Angeles Medical Center
Shant Shekherdimian, MD, Consulting Surgeon, Department of Surgery, Kaiser Foundation Hospital; Jeffrey J DuBois, MD, Consulting Staff, Division of Pediatric Surgery, Kaiser Permanente, North Sacramento Medical Center

Updated: Nov 24, 2008

Introduction

In 1886, Reginald H. Fitz, a Harvard pathologist, first described the clinical condition of acute appendicitis.¹ 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.²

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.³ 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 Procedure

The 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.⁴

Problem

Acute 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; therefore, an accurate and timely diagnosis of atypical appendicitis 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.⁶

Frequency

In 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.¹

The peak incidence of acute appendicitis has gradually declined to about half of its peak incidence in the early 20^th century, with the current annual incidence of 1 per 1000 population in the United States and 86 cases for every 100,000 persons worldwide.^7,8

Acute appendicitis is less common in Africa and in parts of Asia because of the high-residue diets of the inhabitants.

Etiology

Appendicitis 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%).⁹

Pathophysiology

The 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 mucous 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.⁹ 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.

Presentation

The 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.³

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.³

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.⁹

Indications

Indications 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.³

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.³

Relevant Anatomy

Embryologically, 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.¹

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.¹

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.⁹

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.⁹

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.

Contraindications

No 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 plus PO antibiotics for 7-10 d) with consideration for interval appendectomy in 6 weeks.¹⁰

Workup

Laboratory Studies

• Complete blood cell (CBC) count with manual differential
  • The WBC count is often mildly elevated, and a left shift is present. When an extremely elevated WBC count is present, either the patient has a perforated appendix, or another process, such as a viral illness, is responsible.
  • Both pediatric patients and adult patients do not always manifest an elevated WBC count.³ Thus, an increased percentage of bands on manual cellular differential may be just as reliable. Because an accurate history and physical is often more difficult to obtain, a persistently elevated percentage of bands may be the only objective finding of appendicitis in the pediatric patient.
• Urinalysis (UA): Although not mandatory, a UA is often obtained to rule out urinary tract infections; however, pyuria (WBCs in the urine) is commonly observed in appendicitis because the inflammatory process may lie adjacent to the right ureter.
• Electrolyte and renal panel: This test is not required but may be useful to help guide electrolyte resuscitation prior to appendectomy.

Imaging Studies

• No imaging studies are needed in patients with classic appendicitis. This has been confirmed by a retrospective study determining predictive values for appendicitis (Alvarado score) based on history and physical findings. Prospective comparison of the accuracy of the Alvarado score with ultrasound findings was similar.¹¹
• Additional imaging studies may be required in the workup of atypical appendicitis. Controversy exists as to the most accurate, rapid, and cost-effective method of diagnosing atypical appendicitis while avoiding delays that may increase morbidity.
• Plain abdominal radiographs - Abdominal series
  • For the most part, abdominal roentgenograms are not helpful in making the diagnosis of appendicitis. Roughly 85% of radiograph findings are normal, and 10% have nonspecific findings.³
  • The 2 most common nonspecific findings associated with appendicitis are ileus and small bowel obstruction. A more specific abnormality is a fecalith in the RLQ, but this is observed in only 4-5% of radiographs.
  • Rarely, free air under the diaphragm may also be present in patients with perforated appendicitis.
• Abdominal/pelvic ultrasound
  • Ultrasound is an ideal noninvasive means to visualize the abdominal cavity. It is inexpensive and portable, and it can be rapidly performed with little or no patient preparation. Most importantly, it poses no ionizing radiation risk to the patient; therefore, it is particularly safe to use in children and pregnant women. On the other hand, it is operator-dependent, which means that it requires some experience and expertise to produce consistent quality results.
  • The wall elements of the appendix have a typical "target" appearance and can be visualized using graded ultrasonography compressive technique with a high resolution transducer, occasionally with supplement of color Doppler.
  • Appendicitis is suspected when the study demonstrates wall thickening (>8-10 mm), luminal distention, and lack of compressibility. In addition, ultrasound is useful in detecting free intraperitoneal fluid and fluid collections consistent with abscess formation.
  • Prospective studies have shown excellent results, with an average sensitivity of 86% and a specificity of 94% under the conditions of well-controlled clinical trials, namely in the hands of experienced examiners.¹² In addition, many reported studies included patients with classic appendicitis instead of patients with equivocal clinical histories and physical findings. Such good results reported in prospective clinical trials were not frequently duplicated in routine clinical conditions. In fact, the accuracy of ultrasonography was no better than that based on clinical evaluation by the surgeons, and low sensitivity and high false-negative rates have been reported.^3,13,14
  • Ultrasound is most useful for excluding other diagnoses. In women, pelvic pathology, such as pelvic inflammatory disease, ruptured Graafian follicle, twisted ovarian cyst or tumor, endometriosis, and ruptured ectopic pregnancy, can be readily detected by ultrasonography.
• Contrast-enhanced CT scans
  • CT scan findings become more prominent with enhanced disease. Specific findings include an edematous, thick-walled appendix, inflammatory streaking of surrounding fat, and the presence of an appendicolith. Abscess formation, a small amount of free air in the RLQ, and a pericecal phlegmon suggest a perforated appendix.
  • In most clinical trials, CT appears superior to ultrasonography in the evaluation of the acute abdomen. Since CT scans have shown to yield precise information, it has increasingly become a screening tool for acute appendicitis in the emergency department. In well-conducted clinical trials, CT scans have excellent sensitivity and specificity, in the range of 87-100% and 91-97%, respectively.^15,16,17 Again, such good results reported in prospective clinical trials were not frequently duplicated in routine clinical conditions. Use of CT scans in patients who have acute appendicitis had risen from 25% to 68% over a 5-year period and yet the rate of negative appendectomy remained largely unchanged, suggesting the information obtained from the imaging studies may not have much influence on the clinical decision-making process.¹⁸
  • One of the potential clinical dilemmas involves the failure of CT scan to identify a normal appendix. The difficulty in identifying the normal appendix by CT scan ranges from 44-51% in asymptomatic patients.^19,20 It is probably unsafe to assume that nonvisualization of the appendix excludes the diagnosis of acute appendicitis unless there is a collaborating history or physical findings. In a patient who has no evidence of inflammation in the ileocecal region and the appendix is not visualized, there is a chance that the patient indeed still has acute appendicitis.
• Tc-labeled WBC scan: Despite a reported sensitivity of 98% and specificity of 95%, the time required for performing the scan and its lack of around-the-clock availability make this a less-than-ideal diagnostic test for appendicitis.²¹
• Barium contrast studies
  • Historically, a single-contrast barium enema was used to diagnose patients with atypical signs and symptoms. The goal was to assess the patency of the appendiceal lumen. In addition, the colonic wall could be examined for extrinsic mass effects caused by appendicitis.
  • Although this remains a simple, inexpensive, and safe study, it has been largely replaced by ultrasound and CT scanning and is rarely used today.

Diagnostic Procedures

• The only diagnostic procedure for acute appendicitis short of open exploration is diagnostic laparoscopy.

Histologic Findings

A 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.³

Staging

Appendicitis progresses through the following stages: acute or focal appendicitis, suppurative appendicitis, gangrenous appendicitis, and perforated appendicitis.⁹

Treatment

Medical Therapy

No medical treatment exists for acute appendicitis.

Surgical Therapy

A 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 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%).⁵  

The benefits of a laparoscopic approach seem to be more pronounced among obese patients, where a recent study found a significantly shorter length of hospital stay (lap = 3.4 d vs open = 5.5 d) and a higher wound closure rate (lap = 90% vs open = 68%).²²

Preoperative Details

All 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, and they are at least as effective as the traditional triple therapy.²³

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.³

Intraoperative Details

The basic technique for open and laparoscopic appendectomy is described below and is individualized to the authors' preference.⁵ Other approaches, suture materials, or techniques may be used 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 mucous 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 either immediate operative intervention or initial nonoperative management. Although there are some proponents of immediate surgical intervention, it has been associated with significantly higher morbidity (odds ratio 3.3) than nonsurgical treatment in a meta-analysis of 19 studies by Andersson et al.²⁴  

With nonoperative management, patients are initially treated with broad-spectrum, intravenous antibiotics alone or in combination with percutaneous aspiration of the abscess and/or drain placement.²⁵ 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.^10,26

Postoperative Details

If 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.²⁷

Follow-up

The 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.

Complications

The 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%).³

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 Prognosis

The 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 Controversies

Controversy 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

1. Condon RE, Telford GL. Appendicitis. In: Townsend CM, eds. Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 14^th ed. Philadelphia, Pa: WB Saunders and Co; 1991:884-898.

2. Fitz RH. Perforating inflammation of the vermiform appendix; with special reference to its early diagnosis and treatment. Am J Med Sci. 1886;92:321-346.

3. Lee SL, Walsh AJ, Ho HS. Computed tomography and ultrasonography do not improve and may delay the diagnosis and treatment of acute appendicitis. Arch Surg. May 2001;136(5):556-62. [Medline].

4. Herrinton JL Jr. The vermiform appendix: its surgical history. Contemp Surg. 1991;39:36-44.

5. Ho HS. Appendectomy. Scientific American Surgery. 1999;1-18.

6. Lewis FR, Holcroft JW, Boey J, et al. Appendicitis. A critical review of diagnosis and treatment in 1,000 cases. Arch Surg. May 1975;110(5):677-84. [Medline].

7. Carr NJ. The pathology of acute appendicitis. Ann Diagn Pathol. Feb 2000;4(1):46-58. [Medline].

8. Korner H, Sondenaa K, Soreide JA, et al. Incidence of acute nonperforated and perforated appendicitis: age-specific and sex-specific analysis. World J Surg. Mar-Apr 1997;21(3):313-7. [Medline].

9. Liu CD, McFadden DW. Acute abdomen and appendix. In: Greenfield LJ, Mulholland MW, eds. Surgery: Scientific Principles and Practice. 2^nd ed. Baltimore, Md: Williams & Wilkins; 1997:1246-1261.

10. Kaminski A, Liu IL, Applebaum H, et al. Routine interval appendectomy is not justified after initial nonoperative treatment of acute appendicitis. Arch Surg. Sep 2005;140(9):897-901. [Medline].

11. Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med. May 1986;15(5):557-64. [Medline].

12. Franke C, Bohner H, Yang Q, et al. Ultrasonography for diagnosis of acute appendicitis: results of a prospective multicenter trial.Acute Abdominal Pain Study Group. World J Surg. Feb 1999;23(2):141-6. [Medline].

13. Ford RD, Passinault WJ, Morse ME, et al. Diagnostic ultrasound for suspected appendicitis: does the added cost produce a better outcome?. Am Surg. Nov 1994;60(11):895-8. [Medline].

14. Douglas CD, Macpherson NE, Davidson PM, et al. Randomised controlled trial of ultrasonography in diagnosis of acute appendicitis, incorporating the Alvarado score. BMJ. Oct 14 2000;321(7266):919-22. [Medline].

15. 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. Jan 15 1998;338(3):141-6. [Medline].

16. Horton MD, Counter SF, Florence MG, et al. A prospective trial of computed tomography and ultrasonography for diagnosing appendicitis in the atypical patient. Am J Surg. May 2000;179(5):379-81. [Medline].

17. Malone AJ Jr, Wolf CR, Malmed AS, et al. Diagnosis of acute appendicitis: value of unenhanced CT. AJR Am J Roentgenol. Apr 1993;160(4):763-6. [Medline].

18. Weyant MJ, Eachempati SR, Maluccio MA, et al. Interpretation of computed tomography does not correlate with laboratory or pathologic findings in surgically confirmed acute appendicitis. Surgery. Aug 2000;128(2):145-52. [Medline].

19. Grosskreutz S, Goff WB 2nd, Balsara Z, et al. CT of the normal appendix. J Comput Assist Tomogr. Jul-Aug 1991;15(4):575-7. [Medline].

20. Scatarige JC, DiSantis DJ, Allen HA 3rd, et al. CT demonstration of the appendix in asymptomatic adults. Gastrointest Radiol. Summer 1989;14(3):271-3. [Medline].

21. Rypins EB, Evans DG, Hinrichs W, et al. Tc-99m-HMPAO white blood cell scan for diagnosis of acute appendicitis in patients with equivocal clinical presentation. Ann Surg. Jul 1997;226(1):58-65. [Medline].

22. Corneille MG, Steigelman MB, Myers JG, et al. Laparoscopic appendectomy is superior to open appendectomy in obese patients. Am J Surg. Dec 2007;194(6):877-80; discussion 880-1. [Medline].

23. Goldin AB, Sawin RS, Garrison MM, et al. Aminoglycoside-based triple-antibiotic therapy versus monotherapy for children with ruptured appendicitis. Pediatrics. May 2007;119(5):905-11. [Medline].

24. Andersson RE, Petzold MG. Nonsurgical treatment of appendiceal abscess or phlegmon: a systematic review and meta-analysis. Ann Surg. Nov 2007;246(5):741-8. [Medline].

25. Oliak D, Yamini D, Udani VM, et al. Initial nonoperative management for periappendiceal abscess. Dis Colon Rectum. Jul 2001;44(7):936-41. [Medline].

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Keywords

vermiform appendix, acute appendicitis, suppurative appendicitis, gangrenous appendicitis, perforated appendicitis, lymphoid hyperplasia, fecaliths, fecal stasis

Contributor Information and Disclosures

Author

Steven L Lee, MD, Chief, Pediatric Surgery, Department of Surgery, Kaiser-Permanente, Los Angeles Medical Center
Steven L Lee, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American College of Surgeons, American Pediatric Surgical Association, Association for Academic Surgery, Society of American Gastrointestinal and Endoscopic Surgeons, and Society of Laparoendoscopic Surgeons
Disclosure: Nothing to disclose.

Coauthor(s)

Shant Shekherdimian, MD, Consulting Surgeon, Department of Surgery, Kaiser Foundation Hospital
Disclosure: Nothing to disclose.

Jeffrey J DuBois, MD, Consulting Staff, Division of Pediatric Surgery, Kaiser Permanente, North Sacramento Medical Center
Jeffrey J DuBois, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American College of Surgeons, American Pediatric Surgical Association, Association for Academic Surgery, California Medical Association, Society for Surgery of the Alimentary Tract, Society of American Gastrointestinal and Endoscopic Surgeons, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

Medical Editor

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
Brian James Daley, MD, MBA, FACS is a member of the following medical societies: American Association for the Surgery of Trauma, American College of Chest Physicians, American College of Surgeons, American Medical Association, Association for Academic Surgery, Association for Surgical Education, Eastern Association for the Surgery of Trauma, Shock Society, Society of Critical Care Medicine, Southeastern Surgical Congress, and Tennessee Medical Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

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
David Chelmow, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Medical Association, Association of Professors of Gynecology and Obstetrics, Massachusetts Medical Society, Phi Beta Kappa, Sigma Xi, Society for Gynecologic Investigation, and Society for Medical Decision Making
Disclosure: Nothing to disclose.

CME Editor

Frederick B Gaupp, MD, Consulting Staff, Department of Family Practice, Hancock Medical Center
Frederick B Gaupp, MD is a member of the following medical societies: American Academy of Family Physicians
Disclosure: Nothing to disclose.

Chief Editor

John Geibel, MD, DSc, MA, Vice Chairman, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital
John Geibel, MD, DSc, MA is a member of the following medical societies: American Gastroenterological Association, American Physiological Society, American Society of Nephrology, Association for Academic Surgery, International Society of Nephrology, New York Academy of Sciences, and Society for Surgery of the Alimentary Tract
Disclosure: AMGEN Royalty Other; AstraZeneca Grant/research funds Other

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