Lab tests and ultrasounds identify children who need surgical treatment for appendicitis
Data from two standard diagnostic tests commonly obtained in children evaluated for abdominal pain - when combined - can improve the ability of emergency department physicians and pediatric surgeons to identify those patients who should be sent to the operating room for prompt removal of an inflamed appendix; those who may be admitted for observation; and those who may safely be discharged home, according to a new study published online as an “article in press” in the Journal of the American College of Surgeons (JACS). The study will appear in a print edition of the Journal this spring.
The researchers from Boston Children’s Hospital retrospectively examined major categories of ultrasound findings in children with suspected appendicitis in conjunction with blood tests that signal bacterial infection in 845 children seen in the emergency department between 2010 and 2012. It is believed to be the one of the first studies to show that the addition of the white blood count (WBC) and polymorphonuclear leukocyte differential (PMN%) data can significantly improve the clinical value of ultrasound in diagnosing appendicitis in children, according to the study authors.
“Ninety percent of all hospitals perform laboratory studies and ultrasound when there is a reasonable suspicion of appendicitis in children. Hospitals tend to look at the results of these studies independently, however, and the improved diagnostic value of using these in a complimentary fashion has not yet been reported. The diagnostic evaluation approach in this study can be used by other institutions as a diagnostic tool to help emergency department physicians and surgeons provide better care by avoiding treatment delay in very high-risk patients and unnecessary admissions for very low risk patients,” according to lead study author and pediatric surgeon Shawn J. Rangel, MD, MSCE, FACS, at Boston Children’s Hospital.
Emergency physicians and surgeons typically order ultrasound scans to obtain images of the appendix and the surrounding tissues in children with acute abdominal pain to look for evidence of appendicitis. Sonographic scans often do not lead to a definitive conclusion about the presence or absence of appendicitis, however. In the Boston Children’s Hospital study, a radiologist could not identify a normal appendix or any evidence of appendicitis on sonogram in more than half of all patients with suspected appendicitis. This relatively high rate of equivocal studies is not uncommon in children, however, and has been reported at other hospitals that also routinely evaluate children with abdominal pain.
A Rapid Blood Test to Quickly Rule Out Appendicitis?
A new rapid blood test to rule out appendicitis among the 8 million patients who come to U.S. emergency rooms with abdominal pain each year may save patients from unnecessary radiation from a diagnostic CT scan, eliminate extra tests and hours of hospital observation, and cut costs in the process. The test, which is currently being studied at two Penn Medicine hospitals and 11 other sites, screens for a novel biomarker of inflammation, and is designed to be used along with other common blood tests used to detect appendicitis. Young women and children are expected to benefit most from the test, since their reproductive organs are especially sensitive to radiation from imaging studies.
“Abdominal pain is the number-one reason people come to the emergency department, and appendicitis is one of the most commonly performed emergency surgeries in the United States,” says Angela Mills, MD, an assistant professor of Emergency Medicine at the Perelman School of Medicine. “People wind up getting a lot of tests, and waiting a long time, in order for us to be sure they don’t have this condition. This test may help us limit unnecessary radiation to patients, and cut the costs and emergency room crowding associated with waiting for answers from standard tests.”
Mills is leading the study at the Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center, which will enroll about 110 of the study’s 800 patients. The test, which was developed by AspenBio Pharma, is a simple blood draw which is taken along with other labs ordered by physicians to evaluate a patient’s condition, including those that check for signs of infection like elevated white blood cell counts. Eventually, Mills said, the test is expected to be administered as a standalone test at the bedside, saving even more time by eliminating the need to send the blood to a hospital lab for analysis - similar to how chest pain patients’ cardiac enzymes can be rapidly tested to determine if they may have had a heart attack.
An elevated WBC and a shift in the PMN% differential tend to be sensitive indicators of appendicitis. However, these changes are not always present in children with appendicitis, and such changes may be abnormal even in children who do not have the disease. Of the 845 children in this study, 393 (46.5 percent) had appendicitis. An elevated WBC count was found in 348 (62.1 percent) of these patients, and a PMN% shift was found in 340 (58.5 percent). In children who did not have appendicitis, the WBC was elevated in 212 (37.9 percent), and the PMN% shift occurred in 241 (41.5 percent).
The ability to identify children with and without appendicitis was significantly improved when sonographic and laboratory findings were paired. The risk of appendicitis rose from 79.1 percent to 91.3 percent when laboratory studies indicated a bacterial infection and sonography showed primary signs of appendicitis, such as increased blood flow or a thickening in the wall of the appendix. The risk of appendicitis rose from 89.1 percent to 96.8 percent when laboratory results were abnormal and the sonogram showed secondary signs of appendicitis, e.g., fat near the appendix.
The ability to single out children who did not have appendicitis also was substantially improved, the researchers noted. In children where the ultrasound showed neither a normal appendix nor evidence of appendicitis (the largest single category of ultrasound findings), the percentage of children who did not have appendicitis rose from 46.0 percent to 98.2 percent when laboratory studies were within normal ranges.
The approach outlined in this study differs from other methods of assessing the risk that a child may have appendicitis. The Pediatric Appendicitis and Alvarado Scores typically combine a child’s clinical presentation and laboratory data to determine whether a child has a high-, medium-, or low-risk of appendicitis. The scores have not been proven to be reliable in a clinical setting in a number of prospective studies, however, and do not take into account the important diagnostic information provided by ultrasound.
Tests and diagnosis
To help diagnose appendicitis, your doctor will likely take a history of your signs and symptoms and examine your abdomen.
Tests and procedures used to diagnose appendicitis include:
Physical exam to assess your pain. Your doctor may apply gentle pressure on the painful area. When the pressure is suddenly released, appendicitis pain will often feel worse, signaling that the adjacent peritoneum is inflamed.
Your doctor also may look for abdominal rigidity and a tendency for you to stiffen your abdominal muscles in response to pressure over the inflamed appendix (guarding).
Your doctor may use a lubricated, gloved finger to examine your lower rectum (digital rectal exam). Women of childbearing age may be given a pelvic exam to check for possible gynecological problems that could be causing the pain.
Blood test. This allows your doctor to check for a high white blood cell count, which may indicate an infection.
Urine test. Your doctor may want you to have a urinalysis to make sure that a urinary tract infection or a kidney stone isn’t causing your pain.
Imaging tests. Your doctor may also recommend an abdominal X-ray, an abdominal ultrasound or a computerized tomography (CT) scan to help confirm appendicitis or find other causes for your pain.
The approach followed in the Boston Children’s Hospital study can be adapted to individual settings. “Any institution can read our study and readily reproduce what we did,” Dr. Rangel said. “We are not advocating that other hospitals adopt our sonographic categories or laboratory value cut-offs for WBC and PMN values, but rather to work collaboratively with their radiologists and emergency room physicians to develop their own approach for categorizing sonographic findings in their patients with suspected appendicitis, and then develop risk profiles that are tailor-made for their patients after incorporation of their institution’s laboratory data. Institutions can use the risk profiles as educational vehicles and clinical guidelines decision tools to help emergency department physicians and surgeons avoid unnecessary computed tomography (CT) scans and admissions for observation for very low-risk patients, and avoid treatment delays in very high-risk patients,” he concluded.
Other study participants were Seema Anandalwar, MD; Michael Callahan, MD; Richard G Bachur, MD; Christina Feng, MD; Feroze Sidhwa, MD; Mahima Karki, BA; and George A Taylor, MD.
Citation: Use of White Blood Cell Count and Polymorphonuclear Leukocyte Differential to Improve the Predictive Value of Ultrasound for Suspected Appendicitis in Children. Journal of the American College of Surgeons. DOI: http://dx.doi.org/10.1016/j.jamcollsurg.2015.01.039
About the American College of Surgeons
The American College of Surgeons is a scientific and educational organization of surgeons that was founded in 1913 to raise the standards of surgical practice and improve the quality of care for surgical patients. The College is dedicated to the ethical and competent practice of surgery. Its achievements have significantly influenced the course of scientific surgery in America and have established it as an important advocate for all surgical patients. The College has more than 80,000 members and is the largest organization of surgeons in the world.