Diagnosing appendicitis without radiation
Physicians develop safer, more efficient diagnostic pathway
Pediatric Emergency Specialist Jay Pershad, MD, has seen more than 500 cases of appendicitis in his 16-year career at Le Bonheur Children’s Hospital.
While the diagnosis is one of the most common emergencies requiring surgery in children, clinical diagnosis is elusive, and no test is perfect – yet. In an effort to find the most accurate and safest way to diagnose appendicitis, Pershad and his surgical colleagues have developed a novel pathway for diagnosing appendicitis. Results of a study evaluating this new diagnostic pathway – a combination of the Samuel’s pediatric appendicitis score (PAS, Figure 1) and selective ultrasonography – were published in the journal Pediatrics in January 2014.
“We’ve come to rely on advanced imaging for diagnosing appendicitis,” said Pershad. “Now, we are learning more about radiation exposure from CT and how it increases a child’s lifetime risk of cancer. We want to provide the safest care we can for children.”
Computerized tomography (CT) has rapidly become the modality of choice for diagnosing appendicitis. The technology is very sensitive, allowing for relatively expedient diagnosis. In fact, the use of CT for diagnosing appendicitis has increased from 0.9 percent in 1998 to 15.4 percent in 2008, according to National Ambulatory Medical Care Survey data.
But the high quality of CT images doesn’t come without a cost. CT scanning exposes patients to higher doses of radiation – one abdominal CT with IV contrast is the equivalent of 150 chest X-rays. Radiation exposure is especially concerning in children who have smaller bodies than adults and are, therefore, more susceptible to the harmful effects of radiation.
“Each imaging tool has its plusses and minuses,” said Harris L. Cohen, MD, radiologist-in-chief at Le Bonheur Children’s Hospital. “Ultrasound has proven to be excellent for imaging an abnormal appendix without any radiation risk. It’s the first modality we should use in a child or teen suspected of having appendicitis.”
A new model
For patients with suspected appendicitis, receiving an early, accurate diagnosis makes all the difference. Most clinicians rely on various combinations of clinical exam, laboratory tests, two published clinical scores – the Alvarado and Samuel’s pediatric appendicitis score – and advanced diagnostic imaging. The more time between symptom onset and treatment, the higher the risk for perforated appendicitis and infection, says Pershad, who also serves as medical director of Pedi-Flite transport and the hospital’s Transfer Center. Rates of perforated appendicitis are especially high in the pediatric population because its presentation overlaps with many other childhood illnesses that cause abdominal pain.
Le Bonheur researchers hypothesized that a clinical pathway (Figure 2) combining Samuel’s PAS, a grading system developed in 2002, and selective use of ultrasonography, or ultrasound, would provide the safest and most accurate way to diagnosis acute appendicitis.
To test the hypothesis, the team enrolled 216 patients in an 11-month period ages 3 to 17 years who presented with abdominal pain and suspicion of appendicitis based on initial evaluation by the emergency medicine physician. After a period of observation, intravenous hydration and receipt of basic laboratory tests, the ED physician assigned the patient a PAS score.
- Patients with a PAS of 1 to 3 (low probability of appendicitis) were either discharged from the hospital and received a follow-up phone call within 24 hours or admitted to general pediatrics services with an alternate diagnosis.
- Patients with a PAS of 4 to 7 (intermediate probability of appendicitis) received a right lower quadrant ultrasound. If the ultrasound was positive for appendicitis, surgical consultation was sought. If the ultrasound was negative, patients were discharged or admitted for observation, depending on ongoing clinical suspicion of appendicitis.
- For participants with a PAS of 8 to 10 (high probability of appendicitis), pediatric surgery was consulted for further management.
Results of the study were promising. The combination yielded a sensitivity of 92 percent and specificity of 95 percent. Even more, creating an effective diagnostic process helped Le Bonheur streamline and expedite care, reducing risk of perforation.
Despite having to bring in ultrasound technologists from home for after-hours imaging requests (43 percent of the sample came in after 5 p.m.), the mean ED length-of-stay for patients with suspected appendicitis did not increase.
“When we develop a consistent practice, everyone works together and knows exactly what to do and when – from the ED to radiology to surgery,” said Pershad.
Another key finding of the study was the cost effectiveness of the new pathway.
“Although we can ultrasound every patient with suspected appendicitis, we found that by first assigning a PAS score, then using ultrasound if necessary, our diagnoses were more accurate,” said Pediatric Surgeon Eunice Huang, MD, a co-author of the study. “We were less likely to miss any cases of appendicitis, which is good because missing the correct diagnosis can lead to a late diagnosis of perforated appendicitis; that means more complex and expensive treatments.”
Using ultrasound alone without the additional score required of the Le Bonheur pathway cost about $500 less per patient, but also resulted in a 5 percent increase in diagnostic error. Though the pathway takes an investment in resources and buy-in from multiple hospital departments, finding the best way to care for children is the right thing to do, says Pershad.
“As physicians, we have a responsibility to do what we can to ensure that our patients are getting the safest, best care possible and that we’re using resources in the most effective way.”
Appendicitis score eliminates radiation exposure for Sydney
When 9-year-old Sydney Howell first complained of stomach pain, her parents thought she might have pulled a muscle. She had been jumping on a trampoline with friends the day before. Then, the pain worsened.
“She was doubled over in pain and inconsolable. She wouldn’t even eat breakfast, and we knew something was wrong,” said Wyatt Howell, Sydney’s father.
Her mother, Beth, took her to see her pediatrician, who suspected Sydney had appendicitis and sent her to Le Bonheur Children’s Hospital. From there, the Emergency Department team worked quickly to confirm the diagnosis and get Sydney the care she needed. Following the newly defined pathway, her Le Bonheur physician assessed Sydney, ordered basic lab tests and assigned her a pediatric appendicitis score (PAS).
“Sydney’s PAS score placed her into the range of intermediate probability of suspected appendicitis, so we ordered an ultrasound,” said Jay Pershad, MD, medical director of Pedi-Flite Transport and Le Bonheur’s Transfer Center.
Once the ultrasound confirmed that Sydney’s appendix was inflamed, she was admitted and underwent surgery to remove her appendix.
“She recovered well and only stayed the night,” said Wyatt. Sydney, who loves to dance, was able to return to ballet within two weeks.
“It’s good to know that Le Bonheur is mindful of children’s exposure to radiation and using different diagnostic tools to reduce the risk,” said Wyatt. “Had they told us she needed a CT, we wouldn’t have questioned it.”