The ability to diagnose appendicitis accurately in a child continues to be one of the most fundamental skills that a pediatric surgeon has to master, although making the diagnosis often is difficult in young patients. The surgeon ultimately is responsible for deciding whether a child is taken to the operating room for appendectomy; however, a primary care physician often is the first person to evaluate the patient who complains of abdominal pain. Pediatricians with expertise in infectious diseases frequently are involved in the care of children who present with subtle or atypical manifestations of appendicitis, have unusual microorganisms recovered from their appendices, or have complications as a result of appendiceal rupture, such as the development of wound infections, sepsis, peritonitis, intraabdominal abscesses, and pelvic abscesses.
Epidemiology
Reported incidences of acute appendicitis vary widely, depending on where the studies were performed and what methodologies were used. The number of cases of acute appendicitis had been decreasing until the 1990s, when the rate began to rise. It is estimated that more than 70,000 children are diagnosed with appendicitis each year in the United States. Although appendicitis occurs in all age groups, the highest incidence occurs during the second decade of life. Appendicitis is an uncommon event in children younger than 5 years of age and occurs extremely rarely in infants younger than 6 months old. Patients with acquired immunodeficiency syndrome (AIDS) may have a higher incidence of appendicitis than the general population.
The peak rates of appendicitis occur during the summer months, whereas the lowest rates occur during the winter months. Most studies show a modest increase in incidence of appendicitis in males compared with females. The rate of appendicitis in whites is higher than that of blacks and Asians. Hispanics have the highest rate of appendicitis-related hospitalizations in the United States. Whether the reported racial differences are due to errors of measurement, sociodemographic factors, environmental factors, factors related to body constitution, or genetic factors remains unclear. Children with appendicitis more frequently have a history of family members who previously have had appendicitis, suggesting that genetic background plays a role in the susceptibility to appendicitis. Previous breastfeeding, decreased dietary fiber, ingestion of refined carbohydrates, and atopy have all been suggested to increase the risk for developing appendicitis. Higher perforation rates have been observed in obese individuals and tobacco smokers.
Pathophysiology
The initial event in the development of most cases of appendicitis is thought to be obstruction of the appendiceal lumen. Microorganisms rarely invade the appendiceal mucosa and initiate the inflammatory process. Appendiceal obstruction can be caused by inspissated feces (fecalith), hypertrophied lymphoid tissue that develops during a systemic viral infection or bacterial enterocolitis, parasitic infestation, appendiceal wall hemorrhage associated with anaphylactic purpura, inspissated barium, or ingested seeds. Continued production of mucus by the appendiceal mucosa distal to the obstruction causes the appendix to distend. Vascular congestion and ischemia occur as the increased intraluminal pressure of the appendix becomes greater than the venous pressure, and edema develops as lymphatic flow becomes obstructed.
Stasis of intestinal flow and intestinal ischemia allow the microorganisms in the appendix to invade the tissues, enhancing the already developing inflammatory response. Bacteria then may translocate across the appendiceal wall and reach the peritoneal cavity. If the process is severe and arteriolar blood flow to the appendix is obstructed, transmural infarction occurs and the appendix ruptures. Microorganisms are liberated into the peritoneal cavity, causing generalized peritonitis and formation of an abscess. Animal studies have suggested that synergism occurring between enteric aerobes, such as Escherichia coli, and anaerobes, such as Bacteroides fragilis, is important in the development of intraabdominal and pelvic abscesses after perforation. An association between the development of an abscess after appendiceal perforation and the presence of Streptococcus milleri also exists.
As the appendix distends in the early stages of appendicitis, the visceral afferent autonomic nerves that enter the spinal cord at T8 to T10 are stimulated, referring the pain to the epigastric and periumbilical areas of the abdomen. When the inflammatory response reaches the serosal surface of the appendix, the parietal peritoneum is stimulated and the pain intensifies in the right lower quadrant. If perforation occurs, the peritoneal inflammatory response causes more generalized abdominal tenderness.
Although appendiceal obstruction may play an important role in the early stages of most cases of appendicitis, not all obstructed appendices become inflamed. Ten percent of normal appendices removed during abdominal surgical procedures contain inspissated fecal material. Also, children may develop recurrent, crampy abdominal pain, possibly from intermittent appendiceal obstruction.
The classic description of the pathophysiology of appendicitis does not easily explain many epidemiologic features of this disease, including its higher incidence in males and certain races. The amount and reactivity of the lymphoid tissue in the wall of the appendix have been suggested to be key determinants to the development of appendicitis. The amount of lymphoid tissue in the appendix is greatest during adolescence when the disease process is most prevalent and the amount most likely is controlled genetically.
In a case-control study from Italy, prolonged breastfeeding during infancy was associated with a decreased risk for developing acute appendicitis later in life. The investigators hypothesized that breastfeeding may have decreased the amount of stimulation to intestinal lymphocytes by microbial and food antigens early in life, so that appendiceal lymphoid tissues were less reactive to antigenic challenge during adolescence and adulthood. Appendicitis may be observed less frequently during infancy and the neonatal period because the appendix is more funnel shaped, the diet is primarily liquid, recumbent posture is maintained for prolonged periods, and gastrointestinal and respiratory tract infections develop less frequently during this time.
Clinical Manifestations
In school-aged children and adolescents with appendicitis, the median duration of symptoms before the time of hospital admission is 24 to 48 hours. Pain in the right iliac fossa is the most common sign of appendicitis, occurring in 88% in almost all patients. Pain shifts from the periumbilical area to the right lower quadrant of the abdomen in approximately two-thirds of children with appendicitis. The pain usually worsens during movement. The characteristics of the abdominal pain do not always predict accurately which children have appendicitis. Of children found to have mesenteric adenitis at laparotomy, 25% report a shift in their abdominal pain to the right iliac fossa, and 33% experience worsening of their pain during movement.
Nausea and vomiting are also commonly observed in children with appendicitis. Vomiting usually occurs after the onset of abdominal pain but may precede pain in nearly 20% of cases. Anorexia occurs less commonly in children than in adults. Complaints of diarrhea, constipation, and dysuria occasionally can be elicited from children with appendicitis.
Fever is a useful diagnostic sign of appendicitis in children with right lower quadrant abdominal pain. A temperature greater than 37.5°C (99.5°F) is found in most but not all cases. Very high temperatures (>39°C [102.2°F]) suggest that perforation already has occurred or that another intraabdominal process is present. Rarely children present with erythema and tenderness of the scrotum or a scrotal or inguinal mass as the only manifestation of acute appendicitis.
During the physical examination, tenderness in the right iliac fossa is the most sensitive sign of appendicitis. The psoas muscle may become irritated from the inflamed appendix, causing the child to feel increased pain when the right hip is flexed actively. Likewise if the obturator internus muscle is involved, pain is elicited when the flexed thigh is rotated internally. Guarding is found in most cases of appendicitis, compared with half of cases of mesenteric adenitis and 8% of cases of nonspecific abdominal pain. Similarly, rebound tenderness is found more commonly in children with appendicitis than with acute mesenteric adenitis or nonspecific abdominal pain; its presence triples the odds of the child having appendicitis.
The development of diffuse abdominal tenderness and the absence of bowel sounds usually indicate perforation. Extremely hyperactive bowel sounds suggest that the patient may not have appendicitis. Occasionally a mass can be palpated in the right lower quadrant of the abdomen in children with appendicitis who are relaxed or well sedated. Rectal tenderness is present more commonly in children with appendicitis than with other causes of abdominal pain; however findings during the rectal examination seldom alter the clinical decision of the surgeon.
In preschool-aged children, the diagnosis of appendicitis is more difficult to establish because of the inability of young children to express their symptoms and because they often do not cooperate during the physical examination. Young children with appendicitis are often seen early in the course of their symptoms and are prescribed antibiotics, antihistamines, or antipyretics. By the time one realizes that the child has appendicitis, the appendix usually is perforated (50% to 90%). In contrast to older children, vomiting is the initial symptom of appendicitis most frequently observed, and abdominal pain may be absent or may never localize in the right iliac fossa. Sleep disturbances, irritability, restlessness, and crying are common manifestations of appendicitis in this age group. The preschool-aged child is more likely to have a palpable inflammatory mass at presentation.
During the newborn period, appendicitis is an extremely rare occurrence, although most cases are found when prematurity exists. Symptoms of neonatal appendicitis include abdominal distention; vomiting; irritability; diarrhea; erythema, edema, or cellulitis of the abdominal wall; gastrointestinal hemorrhage; abdominal rigidity; lethargy; and jaundice. Usually the symptoms of neonatal appendicitis are indistinguishable from those of necrotizing enterocolitis. Underlying conditions such as total colonic Hirschsprung disease, meconium plugs, esophageal atresia, or hernias may predispose the neonate to develop this condition.
In children who are undergoing chemotherapy for leukemia, acute appendicitis may present as only vague abdominal pain, abdominal distention, lack of abdominal guarding, fever, dehydration, diarrhea, or unusual symptoms such as gastrointestinal bleeding. Symptoms of appendicitis in immunocompromised patients may be identical to those of typhlitis.
Diagnosis
A great emphasis has been placed on using various laboratory tests to help clinicians diagnose the appendicitis accurately. Patients who have received prior oral antibiotics may have milder symptoms and signs of classic appendicitis, necessitating further diagnostic studies.
For decades, physicians have valued peripheral blood leukocyte counts, neutrophil counts, C-reactive protein concentrations, and erythrocyte sedimentation rates to help them distinguish appendicitis from other causes of abdominal pain. When properly evaluated, these tests have been found to be too insensitive to use as reliable tools for diagnosing appendicitis. Normal results do not rule out the possibility that the child has appendicitis, although these tests help to confirm a physician’s suspicions when results are positive. When the nonspecific tests are elevated, often perforation or abscess formation has occurred. Hyperbilirubinemia and increased serum procalcitonin levels also are signs of probable perforation. Certain groups of patients commonly have normal leukocyte counts despite having acute appendicitis. African-American patients with acute appendicitis frequently do not develop leukocytosis. Patients with AIDS who develop appendicitis also frequently do not have elevated white blood cell counts.
Routine radiographic studies for the diagnosis of appendicitis in children no longer are suggested. Radiographs of the abdomen are neither sensitive nor specific enough for diagnosing childhood appendicitis. Graded compression ultrasonography is increasingly becoming the diagnostic procedure of choice when evaluating a patient with possible appendicitis. A noncompressible, enlarged (>6 mm in diameter in adolescents) appendix or a fecalith is the major criterion used for diagnosing appendicitis by ultrasonography. Interruption in the continuity of the echogenic submucosa suggests necrosis of the appendiceal wall and impending perforation. An echogenic periappendiceal mass indicates inflammation of the mesenteric or omental fat. Loculated or generalized fluid collections suggest that perforation already has occurred.
Because graded compression ultrasonography is highly operator-dependent, a meta-analysis has demonstrated that the procedure is 88% sensitive and 94% specific in diagnosing acute appendicitis in children. False-positive ultrasound results occur in obese patients who have noncompressible appendices because of overlying fat and in children who have inflamed appendices caused by Crohn disease, ulcerative colitis, or adjacent salpingitis. False-negative results occur if retrocecally located appendices are not visualized properly; if the cecum is filled with gas or feces and is not compressed adequately; or if perforation has occurred, allowing the appendix to be compressible. In one study, a noncompressible appendix was identified in only 38% of pediatric patients with perforated appendicitis, thus rendering the other ultrasound findings of appendicitis important in diagnosing the disease. The examination should be directed to diagnose other causes of abdominal pain that can mimic appendicitis when a normal appendix is found during the evaluation.
The advantages of using ultrasonography over computed tomography (CT) are that it is relatively inexpensive, is safe, does not require sedation, lacks radiation exposure, and is widely available. It is especially useful in adolescent girls with abdominal pain because gynecologic causes of the pain can be evaluated easily at the time of appendiceal examination. Bedside ultrasound in the emergency department is currently being used to identify children with appendicitis.
High-resolution CT has higher sensitivity (94%) and similar specificity (95%) compared to ultrasonography in diagnosing appendicitis, and it is less operator dependent. Intravenous contrast agents and high-resolution, thin-section scanning techniques must be used to visualize the appendix adequately. An enlarged appendix with a circumferentially and symmetrically thickened bowel wall is the most common CT finding in appendicitis. Periappendiceal inflammatory reaction or fluid collections may be identified. If the appendix is not well visualized, the presence of a fecalith, along with pericecal inflammatory changes, strongly suggests appendicitis. Fecaliths can be visualized in normal appendices by CT, however, and are of no clinical significance unless other inflammatory changes are present.
Helical or multidetector CT techniques using rectal or no contrast have been shown to be very accurate in diagnosing appendicitis. By using a focused right lower quadrant approach, helical CT may be completed more rapidly. Waiting for a CT scan may delay a surgical consultation and increase the rate of perforation before surgery. Also CT is expensive and uses significant amounts of ionizing radiation in children who have greater radiosensitivity of organs and tissues compared with adults. Many medical centers have implemented protocols that initially use ultrasonography as the first diagnostic procedure for possible appendicitis and only use CT when the ultrasound results are equivocal to reduce cost and radiation exposure.
Whether the increasing use of ultrasonography and CT to diagnose appendicitis in children has decreased, the misdiagnosis of the disease and subsequent negative appendectomy rate in hospitals is unclear.
Radiolabeled autologous leukocyte scans also have been used to diagnose appendicitis in children; however, this modality should be reserved for atypical presentations of disease when localizing signs are not present. Magnetic resonance imaging may be considered in patients with nondiagnostic ultrasound tests and concerns about radiation exposure.
Microbiology
Numerous microorganisms have been implicated as a cause of acute appendicitis; however, considerable debate has ensued as to whether simply isolating an organism from the appendiceal lumen is sufficient proof to define causation ( Box 51.1 ).
Anaerobes
Bacteroides spp.
Bilophila wadsworthia
Catabacter hongkongensis
Clostridium spp., including C. difficile
Fusobacterium spp.
Peptostreptococcus spp .
Pigmented bile-resistant, gram-negative rods
Turicibacter sanguinis
Enteric Aerobes and Facultative Anaerobes
Aeromonas spp.
Campylobacter spp.
Citrobacter spp.
Enterobacter spp.
Enterococcus spp.
Escherichia coli
Klebsiella spp.
Morganella morganii
Proteus spp.
Providencia rettgeri
Salmonella spp.
Shigella spp.
Streptococcus anginosus (formerly milleri ) group
Yersinia spp.
Other Bacteria
Actinomyces spp.
Atypical mycobacteria (in patients with AIDS)
Chromobacterium violaceum
Corynebacterium appendicis
Eikenella corrodens
Haemophilus spp.
Ehrlichia chaffeensis
Kluyvera ascorbata
Pasteurella multocida
Pseudomonas spp.
Staphylococcus spp.
Streptococcus pneumoniae
Streptococcus pyogenes
Parasites
Angiostrongylus costaricensis
Anisakis spp.
Ascaris lumbricoides
Balantidium coli
Cryptosporidium parvum
Entamoeba histolytica
Enterobius vermicularis
Schistosoma spp.
Strongyloides stercoralis
Taenia spp.
Trichuris trichiura
Viruses
Adenoviruses
Coxsackievirus B
Cytomegalovirus
Epstein-Barr virus
Measles virus
Fungi
Candida albicans
Coccidioides immitis
Mucor spp.
Histoplasma capsulatum
Bacteria
In most cases of appendicitis, bacteria do not appear to be involved directly in the initial stages of the inflammatory process. Microorganisms that normally inhabit the appendix are liberated into the peritoneal cavity when appendiceal perforation occurs or when translocation through the inflamed tissues is present, and polymicrobial infections develop as a complication of the disease process. In a study of 30 adolescents and adults with nonperforated and perforated appendicitis, 223 different anaerobes and 82 aerobes were recovered from cultures of their appendiceal tissues, peritoneal fluid, and contents of abscesses. An average of 10 different organisms were isolated per specimen collected. In a recent microbiome study, 12 taxa were found to be increased from inflamed appendices compared to normal appendices.
In most culture-based studies of appendiceal tissues and peritoneal fluid specimens from patients with appendicitis, B. fragilis is the strict anaerobe isolated most frequently, occurring in more than 70% of patients. Other anaerobes that are isolated frequently include Bacteroides spp., Bilophila wadsworthia, Peptostreptococcus spp., Fusobacterium spp., and Clostridium spp. A gram-negative anaerobic rod that develops a pigment in culture and is bile resistant also has been identified frequently. Anaerobes such as Turicibacter sanguinis and Catabacter hongkongensis continue to be newly described from patients with appendicitis. Rarely acute appendicitis has been seen in the setting of Clostridium difficile colitis, although the role of the anaerobe’s toxins in causing the appendiceal inflammation is unknown.
E. coli is the aerobic or facultative anaerobic bacteria isolated most frequently from children with appendicitis. E. coli is found in more than 75% of patients. Certain E. coli strains with type 1C fimbriae may contribute to the development of appendiceal inflammation. Enterohemorrhagic E. coli O157:H7 and O111:H have been isolated infrequently from the stools and peritoneal fluid of children with appendicitis.
Viridans streptococci of the S. anginosus group, especially S. milleri , can be found in more than 60% of cultures from children with appendicitis. Group D streptococci are isolated in 20% to 30% of patients with appendicitis. Pseudomonas spp. are isolated slightly less frequently, although they may be found more frequently in young children. Other aerobes or facultative anaerobes that can be isolated from appendiceal tissues, abscesses, or blood include Citrobacter spp., Klebsiella spp., Enterobacter spp., Proteus spp., Morganella morganii, Providencia rettgeri , Eikenella corrodens , non–group A β-hemolytic streptococci, and staphylococci.
Rarely encapsulated organisms, such as Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus segnis, and Aggregatibacter aphrophilus have been isolated from appendiceal tissues or peritoneal fluid of children with appendicitis, and often these organisms have been isolated in pure culture. Very rarely organisms such as Pasteurella multocida, Streptococcus pyogenes, and Actinomyces spp. have been cultured from patients with appendicitis. Shigella, Salmonella, Campylobacter, Yersinia, and Aeromonas spp. also have been isolated occasionally from appendiceal tissues or peritoneal fluid of patients with nonperforated and perforated appendicitis, but, again, whether they played a role in the pathogenesis of disease is unknown. Much more commonly, these organisms cause enterocolitis or mesenteric adenitis, with symptoms mimicking appendicitis.
Appendicitis has occurred during systemic infections caused by Brucella melitensis and Ehrlichia chaffeensis. Rarely Kluyvera ascorbata, Arcobacter butzleri, and Chromobacterium violaceum have been isolated from individuals with appendicitis, as well as newly described aerobes and facultative anaerobes, such as Corynebacterium appendicis.
Rarely isolated primary tuberculosis can occur in children. The progression of disease is usually rapid; thus one should be suspicious when caseating granulomas are observed in histopathologic sections of the appendix.
Adults and children with appendicitis usually are not bacteremic at the time they are diagnosed, especially if the appendix is not perforated. Occasionally Klebsiella pneumoniae, E. coli, B. fragilis, and B. wadsworthia are isolated from the blood of patients with nonperforated appendicitis. In a review of 1000 children and adults with appendicitis, 10% of patients with perforation had positive blood cultures, whereas none of the patients without perforation had bacteremia. A higher rate of bacteremia may occur when laparoscopic surgery is performed because of the air that is forced into the peritoneum, although the clinical significance of the induced bacteremia is unknown.
In immunocompromised patients who develop appendicitis, the microorganisms that are isolated from appendiceal tissues or peritoneal cultures usually are identical to those found in immunocompetent patients. Patients with AIDS who have gastrointestinal Mycobacterium avium complex or Mycobacterium tuberculosis infections may develop symptoms that mimic appendicitis. Atypical mycobacteria have been isolated from an appendiceal abscess from a child with AIDS.
Parasites
In Turkey, parasites were found to be the cause of appendicitis in 1.4% of cases. Roundworms, such as Ascaris lumbricoides, may obstruct the appendiceal lumen occasionally and initiate the cascade of inflammatory events leading to perforated appendicitis. Parasites such as Enterobius vermicularis can be identified in the lumen of 1% to 12% of surgically removed appendices obtained from patients living in highly endemic areas. Pinworms have been found more frequently, however, in appendices with no evidence of appendiceal inflammation in some studies, suggesting that pinworms probably are a part of the normal appendiceal flora and do not play a role in the pathogenesis of appendicitis. Whether some parasites may cause abdominal pain that mimics the symptoms of appendicitis necessitating surgical intervention remains unclear.
Scattered reports from mostly developing nations describe other worms, including Taenia spp., Anisakis spp., Trichuris trichiura, Strongyloides stercoralis, Schistosoma spp., and Angiostrongylus costaricensis, that have been identified in the lumen of appendices from patients with appendicitis. Similarly, protozoa such as Balantidium coli, Entamoeba histolytica, and Cryptosporidium parvum have been found in inflamed appendices of immunocompromised and immunocompetent patients, but whether they play a role in the pathogenesis of disease is unknown.
Viruses
The role that viruses play in causing appendicitis also has been debated. One suggestion is that a systemic viral infection may induce hypertrophied lymphoid aggregates that obstruct the appendiceal lumen. In the 1960s, elevated levels of antibodies against group B coxsackieviruses and adenoviruses were found in the sera of some children with appendicitis. A later study, however, could not confirm this finding. Six adolescents with infectious mononucleosis have developed appendicitis; cytomegalovirus has occasionally been observed in immunodeficient and otherwise healthy patients’ inflamed appendices; and a child with acute varicella had virus demonstrated in the appendix following surgery for appendicitis. Other children have had histologic evidence of measles virus or adenovirus infection in the appendix. Because of the rarity of documented simultaneous viral infections and appendicitis, whether these viruses play a major role in the pathogenesis of acute appendicitis is doubtful.
Fungi
Rarely Candida albicans is isolated from inflamed appendices or abscess cultures, but its role in pathogenesis of disease is unknown. Perforation of the appendix from intestinal mucormycosis has occurred in granulocytopenic patients and premature newborns. Also, appendicitis has been described in individuals with histoplasmosis, coccidioidomycosis, and aspergillosis.
Treatment
Nonperforated Appendicitis
In previously healthy children with signs of acute appendicitis, nasogastric suctioning should be established and imbalances in fluid and electrolyte concentrations should be corrected quickly. In the United States, most children are taken to the operating room. However, many hospitals now perform appendectomies only during day and evening hours because of limitations on resident work hours and decreased services available at night. No differences have been noted in perforation rates, lengths of stay, or complication rates in children who are diagnosed with appendicitis at night and given analgesics until a scheduled morning surgery if the delay time is less than 12 hours. Morphine is often used to reduce the severity of abdominal pain in children with appendicitis, although there is no evidence that morphine reduces appendiceal pain compared with placebo.
Prophylactic antibiotics given perioperatively decrease the rate of postoperative wound infection even in noncomplicated cases of childhood appendicitis. No consensus exists concerning the appropriate antimicrobial agent or agents that should be used to reduce the complication rate. Prospective, randomized studies demonstrate that a single perioperative dose of proper antibiotic(s) with antimicrobial activity against E. coli and enteric anaerobes is as effective as continuing the antibiotic(s) for 1 to 5 days after surgery. Few data support the routine intraoperative collection of peritoneal fluid or appendiceal cultures in children with nonperforated appendicitis, although immunocompromised patients should undergo intraoperative cultures, including cultures for mycobacteria and cytomegalovirus.
Most surgeons are now performing laparoscopic appendectomies in children with nonperforated and perforated appendicitis. Advantages of the procedure are a reduction in wound infection, reduction in scarring, less postoperative pain at 24 hours, shorter hospital stay, and earlier return to normal activity, although the procedure must be performed by a surgeon experienced in laparoscopic technique. The mean total cost of a laparoscopic appendectomy is higher than that of open appendectomy, and meta-analyses have determined that there is increased operative time and a small increase in the risk for developing a postoperative abscess using the laparoscopic technique. Newer single-incision laparoscopic techniques reduce the length of hospital stay in children with appendicitis. There are now some centers that discharge children with uncomplicated appendicitis on the same day as surgery.
Outside the United States and in a few places within the United States, children with nonperforated appendicitis are treated initially with intravenous fluids and antibiotics. In France, a trial of oral amoxicillin-clavulanic acid versus appendectomy in adults was not inferior in outcome. Proponents of initial conservative management consider that the complication rate is significantly lower than when a procedure is done during the acute stage of disease. More than 70% of patients are treated successfully without surgery. When the child does not clinically improve or a walled-off abscess develops, drainage of the area and appendectomy are performed. The presence of intraluminal appendiceal fluid appears to predict recurrent appendicitis after initial nonoperative management, although many surgeons do an interval appendectomy 6 to 8 weeks after resolution of the symptoms to prevent future complications even though most children do well.
Perforated Appendicitis
Most surgeons advocate early intervention when perforation has occurred to prevent severe complications such as fistula formation, abscess rupture, and death, despite the high chance of developing postoperative complications. Surgeons are increasingly performing primary closures without drains in children. A randomized prospective trial of appendiceal drains in children with perforated appendicitis showed no benefit compared with primary wound closure. Appendectomy wounds can be closed with continuous, absorbable sutures even in complicated cases. If incisions are not primarily closed, simple daily wound probing may decrease the incidence of wound infection. Recent studies demonstrate that extensive irrigation of the peritoneum with saline or antibiotics does not reduce the rate of postoperative complications in children with perforated appendicitis who are receiving systemic antibiotics. Ranitidine or diphenhydramine given to children with perforated appendicitis may increase the risk for developing a postoperative abscess.
Antimicrobial agents should be administered routinely to children when perforation or appendiceal abscess is suggested or discovered during surgery. Antibiotics active against aerobes and anaerobes that normally inhabit the intestinal tract have been effective in treating children with perforated appendicitis. Treatment failures occur most commonly when B. fragilis or Pseudomonas spp. are isolated from intraoperative cultures and antimicrobial agents without activity against these organisms are used. Controversy continues regarding the value of obtaining routine intraoperative peritoneal cultures in cases of perforated appendicitis, although most studies demonstrate that culture results seldom change the clinical management of patients.
The antimicrobial combination of ampicillin, gentamicin, and clindamycin has been the gold standard of therapy since the 1970s. The importance of including ampicillin in the regimen for adequate enterococcal coverage continues to be controversial. Animal studies and clinical trials using antibiotics with poor enterococcal activity have shown that ampicillin probably is not required in the treatment of perforated appendicitis. Because of the increasing problem of ampicillin resistance in enterococci, ampicillin probably should be reserved for the rare child with enterococcal bacteremia or with persistent intraabdominal infection in which enterococci have been isolated. Some medical centers use metronidazole instead of clindamycin because of its broader activity against enteric anaerobes, whereas other institutions substitute cefotaxime or ceftriaxone for gentamicin. In a small study, once-daily dosing of ceftriaxone and metronidazole was comparable in efficacy to standard three-drug therapy in children with perforated appendicitis.
Single-agent antibiotic therapy for perforated appendicitis may offer improvement in terms of pharmacy and hospital costs. Agents that have been shown to be effective in treating children with perforated appendicitis include cefoxitin, imipenem-cilastatin, ticarcillin-clavulanate, piperacillin-tazobactam, ampicillin-sulbactam, meropenem, and ertapenem. In a few medical centers, nearly 50% of B. fragilis isolates are resistant to cefoxitin, raising the question as to whether cefoxitin should be used routinely as a single agent in these institutions. Generally, the convenience of monotherapy does not outweigh the potential development of resistance to these broad-spectrum agents. They may be useful in the treatment of appendicitis in children with renal disease or hearing loss when avoiding the use of gentamicin is prudent.
Limiting the duration of antibiotic use to 3 days after surgery does not lead to higher rates of wound infections or intraabdominal abscesses in children who are afebrile and eating. Efforts have been made to shorten the hospital stay of children with perforated appendicitis. Some institutions have set criteria for hospital discharge and discontinuation of antibiotics, such as absence of fever for 24 hours, ability to eat well, and less than 3% band forms on the white blood cell differential. Many surgeons will switch to oral antibiotics at home after 3 to 5 days of intravenous antibiotics in the hospital, although the benefit of adding prolonged oral antibiotics has not been shown. Providing home single-intravenous antimicrobial therapy also can reduce costs and hasten hospital discharge in selected children with perforated appendicitis.
Similar to nonperforated appendicitis, some controversy exists regarding whether immediate appendectomy should be performed on children in whom a palpable mass is associated with their appendicitis or who show evidence of appendiceal rupture with or without abscess formation at the time of presentation. Similarly there is a lack of prospective studies to determine if interval appendectomy is required after successful nonoperative treatment of an appendiceal mass in children. Families do experience more stress when nonoperative management of perforated appendicitis is implemented.
Prognosis and Complications
Currently in the United States, the risk of dying of appendicitis is very low. The mortality rate is higher in the rare newborn or premature infant who develops appendicitis. Also, factors contributing to the death of children rarely may include delay in establishing diagnosis, inadequate fluid replacement, immunodeficiency, and postoperative vascular or infectious complications.
The most predictive factor of postoperative morbidity occurring from appendicitis is perforation. Age, obesity, duration of the surgical procedure, and nutritional status also are risk factors for the development of complications. Wound infection rates in children who receive perioperative antibiotics should be less than 7%; infections generally are caused by the same organisms that are isolated in cultures obtained during the appendectomy. Occasionally children develop peritonitis, intraabdominal abscesses, psoas abscesses, fistulas, pyelophlebitis of the portal vein, scrotal abscesses, empyema, or pneumoperitoneum during the course of treatment of appendicitis.
CT can be successfully used to detect postoperative abscesses even in the first week after surgery. If complications occur, another surgical procedure often is performed and antibiotic treatment is prolonged. Abscesses may be treated successfully with antibiotics alone and without surgical drainage in stable patients after appendectomy.
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