Acute appendicitis in children: Management

INTRODUCTION — This topic will review the management of appendicitis in children. The evaluation, diagnosis, and diagnostic imaging of acute appendicitis in children and management of appendicitis in adults are discussed separately:

●(See "Acute appendicitis in children: Clinical manifestations and diagnosis".)

●(See "Acute appendicitis in children: Diagnostic imaging".)

●(See "Management of acute appendicitis in adults".)

DIAGNOSIS — The diagnostic approach to children with suspected appendicitis is provided in the algorithm (algorithm 1) and is discussed separately. (See "Acute appendicitis in children: Clinical manifestations and diagnosis" and "Acute appendicitis in children: Diagnostic imaging".)

APPROACH — Once appendicitis is diagnosed, further management is determined by whether the appendix is intact, has undergone perforation (advanced appendicitis), or has developed into an appendiceal mass (phlegmon) or abscess. All children with appendicitis warrant fluid resuscitation as determined by their degree of dehydration, intravenous (IV) antibiotics targeting gut flora, and analgesia. Once stabilized as needed, most patients with early appendicitis and all patients with advanced appendicitis warrant urgent appendectomy, as do ill-appearing patients with an appendiceal mass or abscess. Well-appearing patients with an appendiceal mass or phlegmon may initially be managed nonoperatively or undergo appendectomy. (See 'Early appendicitis' below and 'Advanced appendicitis' below and 'Appendiceal mass or abscess' below.)

The status of the appendix (intact, perforated, localized mass [phlegmon], or abscess) is determined by clinical findings as follows:

●Patients with early appendicitis typically have a recent onset (one to two days) of abdominal pain that, over time, has migrated from the periumbilical region to the right lower quadrant (RLQ) with one or more of the following (see "Acute appendicitis in children: Clinical manifestations and diagnosis", section on 'Clinical suspicion'):

•Low-grade fever, vomiting, and anorexia associated with RLQ tenderness on physical examination

•Elevation of white blood cell (WBC) count, absolute neutrophil count, and/or C-reactive protein

•Some patients with early appendicitis may have equivocal findings of appendicitis by history and physical examination but have diagnostic imaging that confirms the diagnosis (see "Acute appendicitis in children: Diagnostic imaging", section on 'Imaging approach')

●The combination of clinical findings of appendicitis as described above for early appendicitis with additional findings of peritonitis (eg, fever, rebound, guarding, or rigid abdomen) and evidence of perforation on diagnostic imaging (eg, ultrasound, computed tomography [CT], or magnetic resonance imaging [MRI]) can frequently establish the presence of advanced appendicitis prior to surgical removal [1]. However, in some patients, perforation is only discovered intraoperatively.

●Children with an appendiceal mass (phlegmon) or abscess have a delayed presentation (at least five to seven days), and evidence of a periappendiceal mass or abscess on physical examination and diagnostic imaging [2].

EARLY APPENDICITIS — Early appendicitis is defined as appendicitis without evidence of perforation.

Appendectomy — For children with early appendicitis who have risk factors for perforation, we recommend appendectomy. Risk factors for perforation include any one of the following:

●Abdominal pain for ≥48 hours

●White blood cell (WBC) count >18,000/microL

●Elevated C-reactive protein

●Appendicolith present on imaging

●Appendix diameter >1.1 cm on imaging

●Preoperative concern for rupture based upon clinical findings

We also suggest appendectomy for patients without any of these risk factors (approximately 20 percent of children who are diagnosed with appendicitis). However, nonoperative management (NOM) with systemic antibiotics is a reasonable alternative for low-risk patients if preferred by the caregiver after shared decision-making as described in the algorithm (algorithm 2). (See 'Nonoperative management' below.)

The rationale for timely removal of an inflamed appendix is that it prevents progression to rupture with peritonitis in some children and is curative [3-5]. Perforated appendicitis is associated with a substantially increased risk of morbidity (eg, surgical site infections, paralytic ileus) and mortality (see 'Post-appendectomy complications' below). Timely appendectomy substantially reduces these risks and has been the standard approach since the 1890s [6].

Appendectomy also permits direct pathologic examination of the appendix and diagnosis of rare but important coexisting conditions such as a carcinoid tumor or alternative diagnoses such as terminal ileitis or ovarian torsion that change subsequent management [7].

Laparoscopic appendectomy is a safe procedure with children experiencing less morbidity than adults [8]. (See 'Post-appendectomy complications' below.)

Preoperative care — Key aspects of preoperative care for children with early appendicitis include fluid therapy, analgesia, and antibiotic prophylaxis:

●Fluid therapy and analgesia – Intravenous (IV) hydration and analgesia should be provided. Any identified electrolyte abnormalities should be corrected before surgery. Rehydration can be accomplished by giving 20 mL/kg boluses of isotonic crystalloid until the signs of dehydration have resolved and the patient has voided. Once euvolemia has been established, the child should receive lactated Ringer's with 10 to 20 mEq/L of potassium chloride at 1 to 1.5 maintenance and additional fluid losses (eg, vomiting) should be replaced. (See "Treatment of hypovolemia (dehydration) in children".)

Pain control is also an important component of preoperative care of children with acute appendicitis, both before and after the diagnosis is made. Pain management should be guided by the patient's self-assessment of pain severity whenever possible. IV opioids (eg, morphine) are typically the best choice. Ketorolac is an excellent choice for postoperative pain medication, and does not significantly increase the patient's bleeding risk. (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Severity assessment' and "Pain in children: Approach to pain assessment and overview of management principles", section on 'Opioids'.)

●Antibiotic treatment – Antibiotics should be administered as soon as the diagnosis of appendicitis is established and at least 30 to 60 minutes before the incision is made [9]. We recommend that children with nonperforated appendicitis receive a single prophylactic dose of a broad-spectrum antibiotic before operation rather than no treatment. Acceptable antibiotic choices include:

•Cefoxitin

•Ceftriaxone and metronidazole

•Cefotetan

•Ciprofloxacin and metronidazole in patients allergic to penicillins and cephalosporins

•Piperacillin and tazobactam

The inclusion of piperacillin and tazobactam for prophylaxis of uncomplicated appendicitis in children differs from joint guidelines for prophylaxis for simple appendectomy proposed by the Infectious Diseases Society of America, the Surgical Infection Society, The American Society of Health-System Pharmacists, and the Society for Healthcare Epidemiology of America [10] but is consistent with guidelines proposed by the American Pediatric Surgical Association [11]. The use of piperacillin and tazobactam for such patients is based upon the frequent difficulty in identifying whether the appendix is perforated in children based on imaging prior to operation. However, in an observational study of almost 18,000 children with uncomplicated appendicitis, of whom one-third received extended-spectrum antibiotics (primarily piperacillin and tazobactam), treatment failure, defined as readmission within 30 days related to a complication of appendicitis, occurred in approximately 1 percent of all patients and was not reduced in the patients receiving extended-spectrum antibiotics (adjusted odds ratio [aOR] 1.32, 95% CI 0.9-2.0) [12].

Patients with simple appendicitis do not require further doses of antibiotics after appendectomy. By contrast, antibiotics should be continued postoperatively in children with perforated appendicitis. (See 'Antibiotics' below.)

The effectiveness of prophylactic antibiotics in patients with early appendicitis is supported by a meta-analysis of 45 trials that noted a significant reduction in wound infections (5 versus 11 percent, odds ratio [OR] 0.37) and intra-abdominal abscesses (0.6 versus 1.4 percent, OR 0.46) among adults and children undergoing appendectomy who received antibiotic prophylaxis [13]. Whether any additional doses of antibiotics are beneficial in these patients was not addressed by this meta-analysis. However, a systematic review by the American Pediatric Surgical Association concluded that evidence is lacking to support postoperative antibiotics in children with nonperforated appendicitis, and most experts agree that additional doses of antibiotics in these patients are unnecessary [11].

Timing of operation — In the past, appendicitis has been considered a surgical emergency that requires prompt appendectomy to avoid perforation and other complications. However, evidence from observational studies suggests that adverse outcomes (eg, perforation, complications, or operating time) are not increased for children who receive timely administration of antibiotics and undergo appendectomy less than 24 hours after diagnosis [14-17]. For example, in a multicenter, prospective, observational study of almost 1000 children 3 to 18 years of age with appendicitis, duration of time ≤24 hours between emergency department evaluation and operation was not associated with a significant increase in appendiceal perforation on adjusted analysis, including children without perforation on CT of the abdomen during initial evaluation [15]. A retrospective observational study of over 2400 children undergoing appendectomy at 23 children's hospitals also found no association between time to appendectomy ≤24 hours and complicated appendicitis or postoperative complications [16]. On the other hand, operative delay beyond 48 hours after admission has been associated with increased risk for surgical site infections and 30-day complications [14]. By contrast, a retrospective study had found an increased risk of perforation based upon time from emergency department diagnosis to surgery [18]. However, the duration of symptoms was not considered.

Of note, limiting the total time of symptoms prior to appendectomy rather than the time from diagnosis to surgery appears to be of greatest importance in preventing perforation and other adverse outcomes [19,20]. As an example, in a prospective observational study that evaluated 230 children who underwent appendectomy, patients with symptoms greater than 48 hours had a significantly higher rate of perforation when compared with patients with symptoms ≤48 hours (46 versus 12 to 18 percent) [19]. When evaluated according to time from diagnosis, the perforation rate, length of stay, and operating time were not significantly different.

Laparoscopic or open approach — We recommend that children with early appendicitis undergo appendectomy with a laparoscopic approach rather than an open approach.

Evidence supporting this recommendation for laparoscopic appendectomy includes the following:

●Two meta-analyses that compared laparoscopic with open surgery for acute appendicitis in children noted that laparoscopic procedures were associated with a significantly decreased hospital length of stay (mean difference 0.5 to 0.6 days) and risk of wound infection (1 to 2 versus 5 to 6 percent, odds ratio [OR] 0.20 to 0.45) [21,22]. The mean difference in operative time was 7 to 11 minutes longer for laparoscopy, which is of marginal clinical significance. Intra-abdominal abscess was more common after laparoscopy in one meta-analysis that included observational studies and randomized trials [21] but was of low frequency and could not be analyzed in the other meta-analysis of seven trials [22].

Good evidence to support decreased postoperative pain and earlier return to normal activities after laparoscopic appendectomy in children is lacking. However, the decrease in hospital length of stay provides indirect evidence for these benefits of the laparoscopic approach and is consistent with our experience.

●In a systematic review of almost 75,000 children undergoing appendectomy for uncomplicated appendicitis, laparoscopic appendectomy was associated with a reduced length of hospital stay and no significant difference in postoperative complications such as wound infection or intra-abdominal abscess when compared with open appendectomy [23].

Laparoscopic appendectomy may be performed using a three port (three incisions) or single incision technique [24,25]. In a prospective observational study of 186 children with early appendicitis, 96 percent successfully completed the procedure using single incision laparoscopic surgery.

Intraoperative considerations — Important intraoperative considerations arise based upon the appearance of the appendix or discovery of a carcinoid tumor as follows:

●Abnormal but intact appendix – The following surgical principles should be followed [26]:

•A segment of omentum that is firmly attached to the appendix should be divided a few centimeters away and removed with the appendix.

•The base of the appendix should be ligated close to the cecum. There is no proven benefit to inversion of the stump.

•All purulent fluid should be aspirated.

•All incisions and trocar sites that are larger than 5 mm should be closed primarily.

●Perforated appendix – In some patients thought to have early appendicitis based upon preoperative clinical findings, a perforated appendix will be encountered. Intraoperative considerations for patients with advanced (perforated) appendicitis are discussed separately. (See 'Intraoperative considerations' below.)

●Normal appendix – When an apparently normal appendix is found, it should be removed. Removal of an appendix that appears grossly normal is generally recommended because microscopic inflammation may be noted on pathologic examination [27]. Removal of the appendix will also significantly diminish concern for the diagnosis of appendicitis if the patient develops another episode of abdominal pain, although stump appendicitis remains possible. (See 'Small bowel obstruction' below.)

Evidence for other possible causes of abdominal pain, including Meckel's diverticulitis, terminal ileitis, mesenteric adenitis, omental torsion, renal mass or obstruction, cholecystitis, or tubal or ovarian pathology should be sought if the appendix appears to be normal.

●Carcinoid tumor – Rarely, a carcinoid tumor will be seen or palpated in the appendix at the time of appendectomy [28]. Simple appendectomy is sufficient treatment for most cases of appendiceal carcinoid. On the other hand, a right hemicolectomy is indicated if the tumor is greater than 2 cm in diameter, if the tumor invades through the wall of the appendix, or if the adjacent mesenteric nodes are involved. (See "Staging, treatment, and post-treatment surveillance of non-metastatic, well-differentiated gastrointestinal tract neuroendocrine (carcinoid) tumors", section on 'Appendix'.)

Postoperative care — The principal management issues after appendectomy in children with early appendicitis include adequate pain control and resumption of oral intake as follows:

●Analgesia – Evidence is lacking to guide optimal post-appendectomy pain management, and practice varies widely [29]. Close attention to pain assessment and resolution of pain is essential, regardless of the regimen chosen. (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Severity assessment'.)

In our experience, adequate pain control is frequently achieved by wound blocks at the time of surgery and postoperative parenteral or oral nonsteroidal antiinflammatory drugs (NSAIDs) with opioid medication reserved for rescue therapy. This approach is especially appropriate for patients undergoing minimally invasive surgery with same-day discharge and avoids side effects such as drowsiness and constipation. In an observational study of over 260 children post appendectomy, a protocol consisting of cold therapy to incision sites in the post-anesthesia care unit, prompt pain assessment upon arrival to the acute care ward, and a pain regimen alternating acetaminophen and ibuprofen with oxycodone for rescue therapy reduced post-operative oral opioid use, number of prescribed opioid doses at discharge, and return visits for pain or constipation compared with historical controls [30].

In the past, use of NSAIDs was discouraged because of the theoretical risk of bleeding. However, in studies of their use after other operations where hemorrhage is more likely to occur (eg, tonsillectomy), NSAIDs have not been associated with increased bleeding [31]. In one observational study of 186 children undergoing appendectomy for early appendicitis using a single-incisional laparoscopic technique, pain control with oral NSAIDs was adequate for most patients [24].

●Oral intake and diet – Oral fluids can be introduced as soon as the child is awake. Diet may be advanced to solid food as tolerated. If admitted, most children are able to go home within 24 to 48 hours. Some centers now discharge patients on the day of surgery once adequate pain control and ability to tolerate liquids and solids are confirmed. Longer lengths of stay to permit continued treatment with antibiotics is necessary if the appendix was gangrenous or perforated. (See 'Antibiotics' below.)

Same-day discharge — Evidence suggests that selected children with early appendicitis may be discharged on the same day of surgery with high caregiver satisfaction and without an increase in complications, urgent revisits, or readmissions when compared with overnight hospitalization [24,32,33].

Nonoperative management — Appendectomy for early appendicitis remains the treatment of choice for most children diagnosed with appendicitis (see 'Appendectomy' above). However, the use of nonoperative management (NOM) in children may be increasing. In a retrospective study of a United States hospital administrative database of >73,500 children treated for nonperforated appendicitis over nine years, 14 percent were managed nonoperatively with an increase from 3 percent in the first quarter of 2011 to 33 percent in the first quarter of 2020 [34].

Patient selection for NOM and sample antibiotic regimens are provided in the algorithm (algorithm 2). NOM may be appropriate in selected children and according to patient and caregiver preference after shared decision-making [35,36]. Specifically, it may be safe and effective for older children who can better describe their symptoms (over seven years of age) and meet all of the following criteria [35]:

●Abdominal pain for <48 hours

●White blood cell (WBC) count ≤18,000/microL

●Normal C-reactive protein

●No appendicolith present on imaging

●Appendix diameter ≤1.1 cm on imaging

●No preoperative concern for rupture based upon clinical findings

NOM should only be performed by a surgeon with pediatric expertise. Only a minority of children diagnosed with appendicitis are potential candidates for NOM. For example, in one large, nonrandomized, multicenter trial, approximately 20 percent of children presenting with appendicitis met similar criteria [36]. However, NOM may be especially appropriate in children who meet the above criteria and who have comorbidities that raise the risk of appendectomy.

Antibiotic protocols vary widely but typically include one to two days of inpatient broad spectrum IV therapy (eg, piperacillin-tazobactam, ceftriaxone and metronidazole, or ciprofloxacin and metronidazole) until resolution of symptoms and normalization of WBC count occur followed by oral antibiotics (eg, amoxicillin-clavulanic acid or ciprofloxacin and metronidazole) as an outpatient [37].

Prospective, nonrandomized, and randomized trials in children report early and one-year success rates for NOM (ie, resolution of symptoms, no surgery during initial hospitalization, and no recurrent appendicitis) of 85 to 91 percent and 67 to 87 percent, respectively [34,36,38,39], with the highest success rates achieved when strict criteria for NOM are used [39]. In the largest of these studies, a prospective, multicenter, nonrandomized controlled trial of 1068 children with appendicitis (370 who received NOM per caregiver preference), complication-free treatment success was 85 percent during early NOM at initial admission and 67 percent at one-year follow-up [36]. Compared with surgery, children undergoing NOM had fewer days of disability at one year (7 versus 11 days) but higher rates of emergency department visits (25 versus 7 percent) and readmissions (23 versus 3 percent). The negative appendectomy rate was 7.5 percent in the surgical group and 1.4 percent in children receiving NOM who underwent surgery after initial hospitalization. However, the generalizability of this study is limited by high loss to follow-up in both treatment groups.

Additional potential risks of NOM were noted in a large, retrospective study of >7,400 children reported to a national hospital database and undergoing NOM. In this study, 18 percent had early failure (within 14 days of initial presentation) and 2 percent had late failure (median time 4.2 years) [34]. At the time of failure, 46 percent had a diagnosis of perforated appendicitis, which was higher than the proportion of children undergoing appendectomy at the index visit (38 percent). Patients undergoing NOM also had higher rates of emergency department visits and hospitalizations. Because this study relied on diagnosis codes from an administrative database, these rates may not be accurate. The higher rates of revisits and hospital admissions in children undergoing NOM are consistent with the prospective trial discussed below. Further data from a prospective trial is necessary to confirm the risk of perforated appendicitis in children who fail NOM.

With respect to caregiver values and preferences, one online survey of over 1700 parents found that 85 percent of caregivers would prefer surgery over nonoperative management if their child had appendicitis, primarily due to concerns about the potential for perforation and death [40]. However, in another study, when presented with education and treatment options, especially the low risk of perforation and mortality if nonoperative management is used, only about 60 percent of caregivers still preferred surgery [41].

Thus, NOM appears to be a safe option for older children with early appendicitis and imaging that shows an appendiceal diameter ≤1.1 cm and no appendicolith although the risk of perforated appendicitis in children who fail NOM may be higher [34]. NOM may be preferred by a significant number of caregivers, which makes discussion of this option appropriate in selected patients. More evidence, preferably from large randomized trials, is desirable to provide further guidance as to the optimal selection criteria for NOM in children and the outcomes of specific antibiotic treatment regimens [42,43].

ADVANCED APPENDICITIS — Appendicitis is considered advanced when perforation or gangrene has developed. When possible, advanced appendicitis in infants and young children should be managed by a pediatric surgeon [44].

Appendectomy — We recommend that children with advanced appendicitis and without an appendiceal mass or abscess, undergo urgent appendectomy rather than delayed appendectomy. Timely appendectomy for patients with advanced appendicitis has been the standard approach since the 1890s [6]. Appendectomy may prevent progression to sepsis and septic shock and also permits aspiration of pus and irrigation of the abdominal cavity. It is a safe procedure with children experiencing less morbidity than adults [8]. Wound infection, intra-abdominal abscess, and paralytic ileus are the primary early complications of appendectomy and occur in up to 9 percent, 5 percent, and 2 percent of patients, respectively [3]. Since the advent of antibiotics for preoperative treatment and an emphasis on early removal, mortality following appendectomy for advanced appendicitis is very rare [6]. The major life-threatening complication consists of late small bowel obstruction due to adhesions and occurs in <1 percent of patients. (See 'Post-appendectomy complications' below.)

Initial nonoperative management followed by interval appendectomy may result in better outcomes than early appendectomy for children with a delayed presentation of appendicitis associated with an appendiceal mass (phlegmon) or abscess. However, the presence of an appendicolith at initial evaluation is associated with failure of nonoperative management [45]. (See 'Appendiceal mass or abscess' below.)

Preoperative care — Adequate preoperative preparation is of paramount importance in patients with complicated appendicitis and includes the following measures:

●Replacement and maintenance fluid therapy should be provided and adjusted for serum sodium and potassium. (See "Treatment of hypovolemia (dehydration) in children" and "Maintenance intravenous fluid therapy in children".)

●A nasogastric tube should be inserted if the child has persistent vomiting. All measured gastric drainage should be replaced with 10 to 20 mEq/L of potassium chloride in isotonic or half normal saline. Routine use of nasogastric tube drainage does not appear to improve the postoperative course [46].

●A urethral catheter should be inserted to monitor urine production when the child is severely dehydrated. An hourly urine output of 1 to 2 mL/kg is a sign that the intravascular volume has been restored and the patient is fit for surgery.

●All patients should receive preoperative antibiotics. We generally use piperacillin and tazobactam when gangrene or perforation is suspected pre-operatively as recommended by the American Pediatric Surgical Association guidelines [11].

The optimal prophylactic regimen is not clear and acceptable alternatives to piperacillin and tazobactam include:

•Cefoxitin

•Ceftriaxone and metronidazole

•Cefotetan

•Ciprofloxacin and metronidazole in patients allergic to penicillins and cephalosporins

The initial dose or doses of antibiotics should be completed as soon as possible and ideally at least 30 to 60 minutes before the operation. (See 'Preoperative care' above.)

In an observational study of over 7000 children with advanced appendicitis of whom two-thirds received extended spectrum antibiotics (primarily piperacillin and tazobactam), treatment failure, defined as readmission within 30 days related to a complication of appendicitis, occurred in approximately 6 percent of all patients with advanced appendicitis and was increased in patients who received extended spectrum antibiotics (adjusted odds ratio [aOR] 1.4; 95% CI 1.1-1.9) [12].

Clinical trials are needed to determine the best empiric antibiotic regimen for these patients.

Laparoscopic or open approach — We suggest that children with appendiceal perforation undergo appendectomy by a laparoscopic approach when surgeons who are well trained in this technique are available. Open laparotomy for neonatal appendicitis is suggested for newborn infants with abdominal distension and sepsis who show no signs of necrotizing enterocolitis on imaging or who display perforation or obstruction on plain abdominal radiographs [47]. (See "Acute appendicitis in children: Clinical manifestations and diagnosis", section on 'Neonates (0 to 30 days)' and "Neonatal necrotizing enterocolitis: Clinical features and diagnosis".)

Evidence supporting laparoscopic appendectomy in patients with advanced appendicitis includes the following:

●In a meta-analysis of 16 comparative studies and 3 trials published since 2000 (34,474 children with complicated appendicitis of whom 10,965 underwent laparoscopic appendectomy), laparoscopic appendectomy when compared with open appendectomy was associated with significantly reduced hospital length of stay (mean reduction 0.7 days), lower risk of wound infection (3.3 versus 4.1 percent), lower risk of bowel obstruction (1.2 versus 1.5 percent), longer operative time (range of mean excess time 2 to 50 minutes), and a higher risk for intra-abdominal abscess (3.7 versus 2.6 percent) [23]. However, there was significant heterogeneity for most pooled results.

●In an unblinded randomized trial not included in the above meta-analysis, of 131 children younger than 18 years of age with a clinical diagnosis of perforated appendicitis and no mass or phlegmon, early appendectomy was associated with a significantly shorter time to return to normal activities (mean number of days: 14 versus 19) and reduced adverse events (eg, abscess, small bowel obstruction, or unplanned readmission, 30 versus 55 percent) than initial treatment with antibiotics alone followed by interval appendectomy six to eight weeks later [48]. In addition, hospital charges and costs were significantly lower for children who had an early appendectomy [49].

●In an observational study not included in the above meta-analysis and that utilized a national database, 660 children undergoing laparoscopic appendectomy had an overall complication rate of 12 percent [50]. This rate was not significantly different for the 169 obese children undergoing the procedure.

Taken together, these studies suggest that laparoscopic appendectomy in children with advanced appendicitis is associated with overall lower postoperative morbidity than open appendectomy with a slight increase in the risk of intra-abdominal abscess but a shorter length of hospital stay.

Intraoperative considerations — Variation exists among pediatric surgeons regarding the intraoperative management of advanced appendicitis in children [51]. We, along with most others, follow these general principles [26]:

●A search should be made for an appendicolith in the pelvis or periappendiceal area when the appendix is grossly perforated, especially if one was noted on the preoperative imaging.

●We do not routinely culture the stump, free pus, or peritoneal fluid because the results almost never alter treatment.

●As in simple appendicitis, the base of the appendix should be ligated close to the cecum.

●A drain should be inserted if there is a well-formed abscess cavity or if the stump closure is tenuous.

●Aspiration of obvious purulent material is recommended for children with perforated appendicitis, but data are conflicting as to whether or not the addition of intraoperative irrigation is effective in reducing postoperative abscess formation and/or wound infection [52-55].

●The wound(s) should be irrigated generously and closed primarily.

●A peripherally placed central venous line (PICC) may be inserted at the time of surgery to facilitate outpatient management of intravenous (IV) antibiotics, obtaining blood for laboratory studies, and, if required, parenteral nutrition, but this is seldom necessary.

It is unclear whether routine irrigation in patients with advanced appendicitis is beneficial. One observational study found no increase in adverse outcomes (wound infection or dehiscence, intra-abdominal abscess, prolonged ileus, or small bowel obstruction) when irrigation and drainage was not performed [52]. However, a subsequent randomized trial of 100 children with perforated appendicitis found a lower rate of intra-abdominal abscess in children irrigated with povidone iodine versus no irrigation (12 versus 16 percent, respectively), although the difference was not significant [56].

Postoperative care

Antibiotics — We recommend that children receive IV antibiotics after appendectomy for advanced appendicitis until they are tolerating a regular diet and are afebrile. Children who are still febrile, have a white blood cell (WBC) count ≥12,000/mm³, and/or are unable to tolerate a regular diet five to seven days after surgery warrant diagnostic imaging studies to search for an abdominal or pelvic abscess [57].

●Immediate postoperative period – Based upon a meta-analysis of 45 studies, initial treatment with IV antibiotics significantly reduces wound infection and intra-abdominal abscess formation for patients with gangrenous or perforated appendicitis compared with no treatment although data in children are limited [13]. We use piperacillin/tazobactam as recommended for perforated appendicitis by the American Pediatric Surgical Association guidelines [11]. In retrospective series, therapy with a single antibiotic (such as piperacillin/tazobactam, cefoxitin, or ceftriaxone) appears to be as effective as multiple antibiotic therapy (such as ampicillin, gentamicin, and metronidazole) for preventing complications of perforated appendicitis, as measured by length of hospital stay and readmission rates and is more cost effective [11,58,59].

In a prospective randomized controlled trial of 98 children with perforated appendicitis, metronidazole (30 mg/kg as a single daily dose) and ceftriaxone (50 mg/kg as a single daily dose) was as effective as standard multiple daily doses of ampicillin, gentamicin, and clindamycin in preventing abscess or wound infection and is a reasonable alternative to piperacillin/tazobactam [60]. In a separate retrospective observational study, metronidazole and ceftriaxone once daily was equivalent to ertapenem alone or combined with cefoxitin in terms of abscess or other postoperative complications but was markedly less costly [61]. Length of hospitalization was similar between groups. However, patients who received the simplified regimen incurred significantly lower antibiotic charges.

In a separate observational study of over 7000 children with complicated appendicitis, treatment failure, defined as readmission within 30 days related to a complication of appendicitis, occurred in approximately 6 percent of all patients with complicated appendicitis and was increased in patients who received extended spectrum antibiotics [12].

Thus, the benefits of extended-spectrum antibiotics are not clear. Clinical trials are needed to determine the optimal antibiotic regimen.

●Duration of antibiotics and use of oral antibiotics – Our approach is to continue IV antibiotics in children with advanced appendicitis until they meet the following criteria:

•Afebrile

•Pain well controlled on oral analgesics

•Tolerating a regular diet

•Ambulating

•Benign abdominal examination (no mass or tenderness)

We discharge patients with advanced appendicitis when they meet our discharge criteria even if they have been treated for fewer than five days. Although a minimum of five days of IV antibiotics is recommended by the American Pediatric Surgical Association (APSA) guidelines, [11,62], as noted below, several studies published after these guidelines have reported good outcomes with durations of IV antibiotics <5 days in selected patients. In addition, evidence suggests that no oral antibiotics may need to be prescribed at discharge [63-65]. For example, in an observational study of 510 children with complicated appendicitis, length of stay, abscess, and readmission rates were not significantly different for patients who met the above clinical criteria but did not receive oral antibiotics at discharge [65]. In a prospective observational study of 540 children before and after antibiotic regimen change in a single institution, the over 150 patients who met discharge criteria prior to completion of five days of IV antibiotics and who were discharged without oral antibiotics had similar rates of postoperative abscess after discharge when compared with patients who received oral antibiotics to complete a seven-day course (8 versus 6 percent, respectively) [64]. A systematic review of postoperative antibiotic duration for children with advanced appendicitis noted that children treated with IV antibiotics for three days did not have an increased number of infectious complications compared with those treated for longer periods [66].

In addition to the above clinical criteria, some pediatric surgeons also use normalization of WBCs to discontinue IV antibiotics, and this approach is endorsed by the APSA [11,62]. In a prospective trial of 100 children with perforated appendicitis, normalization of WBCs at day five was used to determine further care; 42 percent of patients underwent discharge on oral antibiotics (amoxicillin and clavulanate potassium, Augmentin) to complete a seven-day course of antibiotics prior to postoperative day five without an increased risk of postoperative abscesses [67]. The remaining patients were either not tolerating a regular diet or remained febrile on postoperative day five.

In some of these patients, fever on the third postoperative day may be a predictor of intraperitoneal infection [68].

Pain control — Postoperative pain should be initially controlled with parenteral opioid analgesics (eg, morphine). Patient-controlled analgesia is preferable, when possible. Opioid analgesia may be supplemented with parenteral ketorolac or acetaminophen. Dosing for these agents is discussed in more detail separately. (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Opioids' and "Pain in children: Approach to pain assessment and overview of management principles", section on 'Nonopioid analgesics'.)

Administration of IV acetaminophen has been associated with tenfold dosing errors and toxicity that occur when the dose in mg is administered as the volume in mL. When ordering IV acetaminophen in children, both the dose in mg and volume in mL should be specified along with the other recommended parameters for drug order safety (ie, mg/kg, the child’s weight in kg, and the maximum accumulated amount for 24 hours). (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Acetaminophen' and "Clinical manifestations and diagnosis of acetaminophen (paracetamol) poisoning in children and adolescents", section on 'Iatrogenic IV overdose' and "Management of acetaminophen (paracetamol) poisoning in children and adolescents", section on 'Iatrogenic intravenous overdose'.)

Oral analgesics (eg, ibuprofen, acetaminophen, hydrocodone, or oxycodone) can be substituted once the child is drinking well.

Intestinal dysfunction — Many patients with advanced appendicitis have a paralytic ileus or a mechanical intestinal obstruction from fibrinous adhesions. Nasogastric drainage should be instituted for patients with persistent vomiting or abdominal distension and not routinely.

Once intraperitoneal inflammation and infection have improved and the ileus has resolved, oral fluids can be introduced. The diet may then be advanced to solid food as tolerated. Many pediatric surgeons will start patients on a regular diet immediately following laparoscopic appendectomy for both simple and perforated appendicitis.

Nutrition — Parenteral nutrition support is usually not needed in children with advanced appendicitis. However, it is indicated in previously healthy children who are unable to eat after one week [69]. Those who are already malnourished should begin parenteral nutrition within 48 to 72 hours following surgery. (See "Parenteral nutrition in infants and children".)

APPENDICEAL MASS OR ABSCESS — The approach to patients with an appendiceal mass or abscess depends upon their clinical appearance.

Ill-appearing — Ill-appearing patients with evidence of an appendiceal mass or abscess warrant early appendectomy as for advanced appendicitis. (See 'Appendectomy' above.)

Well-appearing — Patients who present late (more than five to seven days from the onset of the illness) with a well-localized abscess or inflammatory mass (phlegmon) may initially be treated nonoperatively [2,70-72]. However, some experts still prefer to perform early appendectomy in these patients. Current evidence is insufficient to determine which approach is better. For example, a small trial of 40 children with a well-defined abdominal abscess on CT found no difference in total length of hospitalization, recurrent abscess rates, or overall charges between patients who received initial laparoscopic appendectomy or those treated with initial nonoperative therapy (percutaneous drainage, antibiotic administration) followed by interval appendectomy approximately 10 to 12 weeks later [73]. However, in a separate, retrospective study of over 200 children with advanced appendicitis of whom over two-thirds had an intra-abdominal abscess at presentation, medical management was associated with significantly greater post-admission complications (eg, bowel obstruction and recurrent appendicitis), total length of hospitalization, and greater utilization of health care resources (eg, more imaging, longer duration of total parenteral nutrition, and more unscheduled repeat hospitalizations) [74].

If nonoperative treatment (ie, intravenous [IV] antibiotics with or without percutaneous drainage) is chosen, the surgeon must carefully monitor the patient’s clinical progress. There should be steady improvement in abdominal pain, fever, appetite and intestinal function. If not, conversion to operative treatment may be warranted.

The ideal patient for initial nonoperative management is not ill appearing and has a well localized, tender mass in the right lower quadrant without signs of generalized peritonitis. The rationale for initial nonoperative treatment was illustrated in a meta-analysis of 61 observational and small randomized trials that included 55,593 adult and pediatric patients with acute appendicitis, 4 percent of whom had appendiceal abscess or phlegmon [2]. Thirty-six percent of 886 patients with abscess or phlegmon who underwent immediate surgery had morbidity, including postoperative infection, intestinal fistula, small bowel obstruction, and recurrence. This frequency of complications was significantly higher than for the 14 percent of 895 patients who initially were managed nonoperatively (odds ratio [OR] 3.4; 95% CI 2.0-5.6).

Nonoperative treatment includes the following:

●IV fluids should be administered. Oral intake may be resumed as tolerated.

●Parenteral nutrition is indicated if the child is unable to eat after one week or earlier if the child is already malnourished.

●Antibiotics should be prescribed (as for advanced appendicitis) and continued until the child is afebrile, tolerating a regular diet, and has a normal white blood cell (WBC) count.

●Appropriate pain management.

A CT scan should be obtained upon admission in all cases selected for nonoperative management to identify candidates for image-guided percutaneous drainage. Significant abscesses (>3 to 4 cm in diameter) should be drained under image guidance (ultrasound or CT) by aspiration or placement of an indwelling catheter. Even multiple intra-abdominal abscesses may be managed in this fashion [75]. Smaller abscesses and those not amenable to percutaneous drainage can be treated with antibiotics, at least initially.

Percutaneous drainage or laparotomy may be indicated in patients initially selected for nonoperative management. Indications for intervention include lack of clinical improvement within 24 to 48 hours, continued fever, worsening of localized tenderness, or increased abdominal mass size.

Although continued nonoperative management is advocated by some experts, we suggest interval appendectomy 10 to 12 weeks following resolution of the initial episode, particularly for children with an appendicolith. An interval appendectomy is often performed 8 to 12 weeks following resolution of the initial episode of appendicitis in patients with appendiceal mass/phlegmon. The purpose of delay is to avoid the morbidity of immediate appendectomy in these patients while definitively treating the underlying appendicitis.

Evidence regarding the benefit of interval appendectomy is limited and conflicting:

●In a multicenter trial of 102 children randomized to observation after evaluation for appendiceal mass for patients without an appendicolith or interval appendectomy, 77 percent of patients did not have recurrent appendicitis within one year of enrollment [76]. Significant complications (eg, wound infection, intestinal perforation, abscess formation, postoperative small bowel obstruction, or prolonged ileus) occurred in 6 percent of patients undergoing interval appendectomy. No patient underwent early appendectomy in this study.

●In one systematic review the frequency of morbidity (eg, postoperative infection, intestinal fistula, small bowel obstruction) associated with interval appendectomy was not substantially different than the risk of recurrence in patients who did not undergo interval appendectomy (11 versus 7 percent, respectively) [2]. Most recurrences developed within six months of hospital discharge. Of those patients not undergoing interval appendectomy, 20 percent required percutaneous abscess drainage. Nonoperative treatment delayed the diagnosis of Crohn disease and cancer in approximately 2 percent of patients; delayed diagnosis was more common in adult patients.

●Another systematic review of 127 cases reported in three retrospective observational studies found that the pooled risk of recurrent appendicitis among children not undergoing interval appendectomy after an appendiceal mass was 21 percent. However, there was significant heterogeneity among the studies for the risk of recurrent appendicitis (range 0 to 42 percent) [77]. The incidence of complications after interval appendectomy in 1247 children was 3.4 percent. Among the 955 children for whom histopathologic findings were reported, 0.9 percent had a carcinoid tumor. In one study included in this analysis, the recurrence of appendicitis was not influenced by age, sex, type of appendicitis, or abscess drainage [78]. In another study included in this review, the rate of recurrence in children with an appendicolith was significantly higher than in those without an appendicolith (76 versus 26 percent, respectively) [45].

Thus, the need for interval appendectomy after initial nonoperative management of appendiceal abscess/phlegmon is unclear. Many surgeons still recommend interval appendectomy. A strategy of interval appendectomy or observation should be considered on a case by case basis after discussing the risks and benefits of each approach.

DISCHARGE CRITERIA (ALL PATIENTS) — In general and for all different "types" of appendicitis (simple, advanced, or perforated with local abscess or phlegmon), timing of discharge is based on the clinical condition of the patient. Children who are afebrile, tolerating a regular diet, and free of pain or well controlled on non-narcotic analgesics are ready for discharge. This typically requires a longer stay for advanced cases, but the criteria are similar.

Patients who meet these criteria appear to be at lower risk for post-appendectomy complications. For example, in a case-control study comparing children with perforated appendicitis who developed intra-abdominal abscesses with those who did not, none of the patients who were afebrile and eating on the third postoperative day developed intra-abdominal abscesses [79].

POST-APPENDECTOMY COMPLICATIONS — Children with simple appendicitis have a risk of wound infection or abscess of approximately 1 to 5 percent depending upon the surgical approach [21,22]. Up to 55 percent of children with advanced appendicitis have a complication, such as infection, bowel obstruction, or unplanned hospital admission [48]. The most common complications are infectious. Risk factors for postoperative abscess formation include [80,81]:

●Older age

●High body mass index

●History of diarrhea at presentation

●Fever on or after the third postoperative day

●Leukocytosis on or after the fifth postoperative day

Early

Infections — Infections that occur after appendectomy include wound abscesses, intra-abdominal abscesses, and pelvic abscesses. Subphrenic abscesses, which were very common before we had effective anti-microbials, are now extremely rare. Infectious complications are more likely after operation for advanced appendicitis. With good surgical technique and appropriate use of antibiotics, wound abscesses occur in approximately 2 to 9 percent of cases, even when the appendix is gangrenous or perforated [82,83]. Intra-abdominal and pelvic abscesses occur in about 5 percent of patients with appendicitis [66,84].

The typical symptoms of postoperative infection are fever, anorexia, inability to tolerate a normal diet more than three to five days after operation, continued weight loss, and pain in and around the incision site(s) or in the abdomen and pelvis. Patients with these symptoms should be seen promptly, preferably in consultation with the surgeon or surgical service who performed the appendectomy. If there is no obvious wound infection on physical examination, an abdominal and pelvic ultrasound should be obtained. Once the presence of an abscess is identified, a CT scan of the abdomen and pelvis is often indicated to precisely define the problem (because there may be more than one purulent collection) and to serve as a guide to the feasibility of image-guided drainage.

Wound abscesses are treated by opening the wound to permit drainage and healing by secondary intention.

Most abdominal and pelvic abscesses can be treated by percutaneous drainage under ultrasound or CT guidance. Pelvic abscesses, which point into the rectum, may be treated by transrectal drainage.

Intestinal dysfunction — Intestinal dysfunction is the second most common complication of appendicitis [26]. Causes include paralytic ileus, constipation, mechanical obstruction, and rarely, intussusception. In the first few days after appendectomy, intestinal dysfunction is usually caused by a combination of paralytic ileus from peritonitis and mechanical obstruction from fibrinous adhesions. Most of these early bowel "obstructions" resolve with gut rest including nasogastric suction and intravenous (IV) fluids. Antibiotics may also be helpful. Parenteral nutrition support is indicated if the patient is unable to eat for more than five to seven days [69]. (See 'Postoperative care' above.)

Constipation typically occurs later than paralytic ileus, often after discharge. Multiple factors may contribute, including reduced appetite, changes in diet, reduced physical activity, and narcotic drugs. A presumptive diagnosis of constipation can be established by phone conversation, and treatment can be initiated on an outpatient basis, but if intake is poor, especially if accompanied by vomiting, the child should be seen promptly for a thorough clinical assessment.

Plain abdominal radiographs are very useful in distinguishing paralytic ileus from constipation. In paralytic ileus, radiographs show diffuse bowel dilation. With constipation, excess stool and gas can be seen in the colon with little small bowel dilation.

In rare cases, a large bowel to large bowel or ceco-colic intussusception starting from the inverted appendiceal stump may also occur, causing early mechanical obstruction [85]. This is often preceded by a brief period where the gastrointestinal tract seems to be "open." The diagnosis can be established with ultrasonography. Reoperation is usually required. (See "Intussusception in children".)

Late

Small bowel obstruction — Mechanical small bowel obstruction from postoperative and postinflammatory adhesions occurs in less than 1 percent of children [86]. Most patients who present to the hospital with a complete bowel obstruction more than a month after an appendectomy will require a laparotomy and enterolysis.

Stump appendicitis — Stump appendicitis refers to the inflammation of residual appendiceal tissue months to years after an appendectomy [87-89]. This rare condition has been attributed to incomplete appendectomy that leaves an excessively long stump after open or laparoscopic surgery. Clinical findings are similar to acute appendicitis, and the diagnosis should be considered in any patient with right lower quadrant pain despite the prior history of appendectomy.

A retrospective observational report found three patients out of 2185 developed stump appendicitis following primary appendectomy [89]. Ultrasound or CT of the abdomen with contrast assists in establishing the diagnosis. A review of 36 case reports found that the median time to presentation is one year after initial operation with a range of four months to 50 years [88]. Perforation occurred in 70 percent of patients.

Mortality — Fatal complications of appendicitis are rare (<0.1 percent) [90]. Most deaths occur in very young children and in those with complicated perforating appendicitis who undergo surgery before they are adequately resuscitated or who develop uncontrolled postoperative sepsis [91].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Appendicitis in children".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Appendicitis in adults (The Basics)" and "Patient education: Appendicitis in children (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Early appendicitis

•For children with early appendicitis and risk factors for perforation, we recommend appendectomy within 24 hours of diagnosis (Grade 1B). (See 'Appendectomy' above and 'Timing of operation' above.)

Risk factors for perforation include any one of the following:

-Abdominal pain for ≥48 hours

-White blood cell (WBC) count >18,000/microL

-Elevated C-reactive protein

-Appendicolith present on imaging

-Appendix diameter >1.1 cm on imaging

-Preoperative concern for rupture based upon clinical findings

We also suggest appendectomy for children with early appendicitis without any of these risk factors (Grade 2C). However, nonoperative management (NOM) is a reasonable alternative for low-risk patients, depending upon caregiver preference after shared decision-making as described in the algorithm (algorithm 2). (See 'Nonoperative management' above.)

•Preoperative management includes intravenous (IV) rehydration, correction of electrolyte abnormalities, and timely administration of prophylactic antibiotics. (See 'Preoperative care' above.)

•We recommend that children with nonperforated appendicitis receive a prophylactic dose of a broad spectrum antibiotic (eg, cefoxitin, piperacillin and tazobactam, or ceftriaxone and metronidazole) as soon as the diagnosis is established and at least 30 to 60 minutes before operation rather than no treatment (Grade 1A). (See 'Preoperative care' above.)

•We recommend that children with early appendicitis undergo laparoscopic appendectomy rather than open appendectomy (Grade 1B). (See 'Laparoscopic or open approach' above.)

•At operation, an apparently normal appendix requires removal. A careful search for other causes of abdominal pain including tubo-ovarian pathology in girls should be performed. (See 'Intraoperative considerations' above.)

•Following surgery, oral fluids may be offered as soon as the child is awake. Analgesia may be given orally as well. Most children are able to go home within 24 hours. (See 'Postoperative care' above.)

●Advanced appendicitis

•We recommend that children with perforated or gangrenous appendicitis, that do not have an appendiceal mass or abscess, undergo urgent appendectomy rather than delayed appendectomy (Grade 1B).

•Preoperative management of children with advanced appendicitis includes replacement and maintenance fluid therapy and IV antibiotics. In addition, the clinician should place a nasogastric tube in vomiting children and a urinary catheter to monitor urine output in children with severe dehydration. (See 'Preoperative care' above.)

•We suggest that children with appendiceal perforation undergo laparoscopic appendectomy rather than an open technique when surgeons who are well trained in laparoscopy are available (Grade 2B). (See 'Laparoscopic or open approach' above.)

•We recommend that children receive IV antibiotics after appendectomy for advanced appendicitis until they are tolerating a regular diet and are afebrile (Grade 1B). Children who are still febrile and/or unable to tolerate a regular diet 7 to 10 days after surgery may have an abdominal or pelvic abscess and should have diagnostic imaging studies. Other issues that must be addressed in the postoperative period include pain control, nutrition, and management of intestinal dysfunction. (See 'Postoperative care' above.)

●Appendiceal mass/phlegmon

•Ill-appearing patients with an appendiceal mass or phlegmon warrant early appendectomy. Patients who present more than five to seven days from the onset of the illness with a well-localized abscess or inflammatory mass (phlegmon), but are otherwise well-appearing, may initially be treated nonoperatively. (See 'Appendiceal mass or abscess' above.)

•Although continued nonoperative management is advocated by some experts, we suggest interval appendectomy 10 to 12 weeks following resolution of the initial episode, particularly for children with an appendicolith (Grade 2C). In children without an appendicolith, clinicians and parents may want to weigh the risk of morbidity versus recurrence when making the decision. (See 'Appendiceal mass or abscess' above.)

●Post-appendectomy complications

•Post-appendectomy complications include wound infection, intra-abdominal or pelvic abscess, constipation, paralytic ileus, intussusception, small bowel obstruction, and stump appendicitis. Mortality is rare. (See 'Post-appendectomy complications' above.)

•Signs of complications include fever, anorexia, vomiting, inability to tolerate a normal diet more than three to five days after operation, continued weight loss, or pain in and around the incision site(s) or in the abdomen and pelvis. Patients with any one of these symptoms warrant prompt evaluation for the underlying cause. (See 'Post-appendectomy complications' above.)

●Discharge criteria

•Children who are afebrile, tolerating a regular diet, and free of pain or well controlled on non-narcotic analgesics are ready for discharge. (See 'Discharge criteria (all patients)' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges David E Wesson, MD, who contributed to earlier versions of this topic review.