Acute Appendicitis in Children
From The Child's Doctor, Spring 2011
- Jessica A. Naiditch, MD
- Research Fellow, Pediatric Surgery, Children's Memorial Hospital
- Disclosure: Dr. Naiditch has no industry relationships to disclose and does not refer to products
that are still investigational or not labeled for the use in discussion.
- Marybeth Browne, MD
- Attending physician, Pediatric Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago; Assistant professor of Surgery, Northwestern University Feinberg School of Medicine
- Disclosure: Dr. Browne has no industry relationships to disclose and does not refer to products
that are still investigational or not labeled for the use in discussion.
Other Disclosure Information
At the conclusion of this activity, participants will be able to:
Weigh the risks and benefits of ultrasound vs. CT scan in identifying patients with an atypical presentation of appendicitis
Explain the rationale behind urgent appendectomy and interval appendectomy
Discuss the safety and effectiveness of laparoscopic appendectomy
Changing approaches to diagnosis and treatment of acute appendicitis create new questions for pediatricians. Should ultrasound or computed tomography (CT) be the first-line imaging choice for identifying appendicitis? How soon should surgery occur? How safe and effective is laparoscopic appendectomy vs. open surgery? This article will consider these issues in light of the literature on the current options for diagnosis and treatment of appendicitis.
Appendicitis is the most common indication for emergency abdominal surgery in children, with 80,000 cases diagnosed per year and a lifetime risk for developing appendicitis of 7%. Whereas historically the operation would occur emergently within 6 hours of diagnosis, now appendectomy tends to be performed urgently, during daylight hours. In some cases, interval appendectomy is considered.
Appendicitis is thought to occur when luminal obstruction of the appendix, usually due to lymphoid hyperplasia, results in a buildup of secretions in the appendix, leading to increased intra-luminal pressure. This then leads to inflammation, with possible necrosis and perforation if left unaddressed in a timely fashion. Perforation results in either a well-circumscribed contained abscess, poorly defined phlegmon, or diffuse peritonitis and sepsis.
Clinical presentation and diagnosis
The classic clinical presentation of appendicitis is that of migrating abdominal pain that starts as a vague discomfort in the peri-umbilical region and then migrates to the right lower quadrant of abdomen, becoming more somatic, sharp, and well-localized. Patients often present with fever, anorexia, and vomiting. Examination may reveal focal peritonitis with pain, guarding or rebound at McBurney’s point, or generalized peritonitis if free rupture has occurred. Leukocytosis is generally present with a neutrophil predominance.
Previous research assessed the precision and accuracy of symptoms and signs, and basic lab tests for evaluating children with possible appendicitis. The likelihood of appendicitis increased with migrating pain (likelihood ratio, LR 1.9-3.1), fever (LR 3.4), rebound tenderness (LR 3.0), and the classic signs of appendicitis, including the psoas sign, obturator sign, and Rovsing sign (LR 2.0, 2.0, 2.0, respectively). A white blood cell count less than 10,000 cells/mm3 decreased the likelihood of appendicitis (LR 0.22) and less than 8,850 cells/mm3 decreased it even more (LR 0.06). Other lab studies, such as c-reactive protein test (CRP) and erythrocyte sedimentation rate (ESR), increased the LR when elevated and decreased the LR when normal. The use of prospectively validated scoring systems and scoring clinical parameters (eg, presence of fever, anorexia, vomiting, and leukocytosis) to help diagnose appendicitis[3-7] can be considered, but is not generally utilized in our practice.
Imaging for appendicitis
Unfortunately, up to one-third of children have an atypical presentation, making the diagnosis more challenging. Given this high occurrence of varied presentations of appendicitis, diagnostic imaging with ultrasound (US) or computed tomography (CT) has come to play a key role in helping identify patients with appendicitis that do not fit the classic presentation.
US findings in appendicitis may include a dilated, non-compressible appendix with a hyperemic wall. US is a low-cost study that does not require ionizing radiation, is noninvasive with no need for patient preparation or sedation, and provides dynamic information. Overall sensitivity and specificity are 88% and 94%, respectively. US is said to be operator dependant with less diagnostic sensitivity in the hands of less experienced ultrasonographers.[10-12] US has limitations in large or obese patients. A recent study has shown that the sensitivity, specificity and positive predictive value of US in detecting appendicitis are significantly diminished in very obese children (BMI>99th percentile). US can also be limited through the presence of abundant bowel gas, guarding by the patient, or an anomalous location of the appendix.
CT scan has higher sensitivity and specificity for appendicitis, at 94% and 95%, respectively. CT allows for multiplanar imaging, is better able to image the retrocecal appendix, and is unchanged in quality of imaging in the presence of bowel, obesity or severe abdominal pain. However, the risks of ionizing radiation in the pediatric population should not be underestimated. When compared with adult patients, children have an increased risk of developing cancer because of the increased dose over time and their longer expected lifespan, increasing time over which a malignancy can develop. In addition, although operating without radiological confirmation for appendicitis can be associated with a significant negative appendectomy rate, liberal use of CT scan has not been demonstrated to decrease the rate of negative appendectomy.[15-18]
Weighing the risks and benefits of these imaging strategies must be done in the context of the patient who may have appendicitis. Wan and colleagues used a Markov decision analysis and determined that the most cost-effective method of imaging pediatric appendicitis was to start with a US study and follow each negative US with a CT exam, as this would avoid 53% of CT scans, and therefore, the future risk for lethal malignancy.
All patients diagnosed with appendicitis are kept npo (nil per os), supplemented with maintenance intravenous fluid infusion after initial fluid resuscitation, and given antibiotics with anaerobic, gram negative, and gram positive coverage for intestinal flora.
Historically, appendicitis has been treated with emergency surgical intervention initiated within 6 hours of diagnosis. Pediatric surgeons have recently transitioned care to an urgent philosophy with operation during daytime hours or intervention with catheter drainage of well-formed abscesses in perforated appendicitis with a plan for interval appendectomy.
Emergent vs. urgent surgery: Surana and Colleagues performed a retrospective analysis of their data on children that underwent appendectomy, comparing those who had emergent surgery within 6 hours of diagnosis with those that were delayed beyond 6 hours, up to 24 hours after diagnosis. Their study of 695 pediatric patients showed a similar length of stay, complication rate, and rate of perforation between these 2 demographically similar groups. Yardeni and colleagues published their experience with delayed appendectomy for patients diagnosed during the late evening and early morning hours in a similar fashion and confirmed the findings of Surana et al. They also demonstrated no significant difference in the rate of perforation, length of stay, or complications. This allows greater efficiency and effective use of physician and hospital resources by allowing patients diagnosed with appendicitis in the evening and early morning hours to delay their surgery until the daytime hours.
Urgent vs. interval appendectomy: The rate of perforation at presentation is as high as 20%. For the patients with perforation that are overtly ill, deteriorating, or have generalized peritonitis, urgent operation is necessary. In patients that present with a well-formed abscess, intervention with catheter drainage with a plan for appendectomy in the future is a viable option. The reasoning for considering this option is the decreased risk of intra-operative complications at the interval operation, once the inflammation has resolved. Recently, a prospective randomized trial demonstrated no difference in terms of total hospitalization, recurrent abscess rate or total costs when comparing immediate appendectomy with catheter drainage and interval appendectomy. Drainage was shown to result in faster return to regular diet and a shorter operative time at the interval operation. However, operating at presentation resulted in the need for fewer CT scans and healthcare visits.
Laparoscopic appendectomy (LA): LA has increased in popularity over the past 20 years since it was first performed by Semm in 1983. Studies in the pediatric population up to this time have had varied results when trying to determine if operative technique, LA vs. open appendectomy (OA), affects outcomes. Studies show that outcomes are comparable between OA and LA. One of the largest pediatric studies was a randomized trial of 517 children undergoing OA or LA. This study showed no significant difference in outcomes, with overall complication rates of 11.2% in OA and 9.9% in LA (P NS). Results demonstrated no significant difference in operating time, length of stay, wound infection or postoperative abscess. We recommend LA as a safe and effective procedure in treating appendicitis.
The diagnosis of appendicitis can be made clinically in patients with classic presentations and may be aided by clinical scoring systems. When children present with atypical signs and symptoms, they may require imaging to aid in the diagnosis of appendicitis and differentiation from other common causes of abdominal pain in children. US is a first-line imaging choice in children, as it can offer high sensitivity in diagnosing appendicitis and help decrease the need for a CT scan; and, therefore, decrease exposure to ionizing radiation and the risk of future malignancy. Appendectomy is now an urgent surgical intervention, performed within 24 hours of presentation with no increase in the rate of perforation. Drainage of abscess in perforated appendicitis with the plan for an interval appendectomy is an option that has equivalent outcomes when compared to immediate operation. Lastly, laparoscopic appendectomy is as safe and effective as open appendectomy.
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