SonoStudy: Ultrasound differentiating perforated from non-perforated appendicitis #FOAMed #FOAMus

In a study published in AJR, a very hot topic was reviewed. 2 centers. 160 kids. Ultrasound and appendectomy with comparison to operative report. Do I have your attention now? This is a tough one, ultrasound for appendicitis is being recommended by pediatricians, radiologists, emergency physicians and surgeons. A big limitation was thought that ultrasound is not great for differentiating perforated from non-perforated appendicitis…. in addition to other limitations including bowel gas scatter limiting view of the entire appendix, and variations in appendix size that may have a false positive for appendicitis if diameter size alone is used as the indicator. Well, it isnt perfect – we know that.

Now, to review, appendicitis is diagnosed by applying the linear (or curvilinear if added depth is needed) probe to the area where the patient points to noting maximal pain, with the indicator toward the patient’s right side. Graded compression is then performed in that region which should displace and flatten bowel, identifying the psoas muscle and the transverse view of the iliac vessels. The appendix usually is located just anterior to these structures coming off of the cecum, and is normally compressible without being more than 6mm in diameter. It may be in its transverse or longitudinal view depending on anatomy. The entire appendix should be viewed, including to its tip. Be sure to view it in two orthogonal planes (rotate probe 90 degrees) to ensure it is the appendix, as a lymph node may look very similar to a transverse appendix but will not elongate into a tubular structure when viewed in its longitudinal plane. Here are some views of a positive appendicitis (absence of compressibility with attempts, dilated appendix):

APPENDICITIS WITH MEASUREMENTS_crop

Appendicitis by Ultrasound: A greater than 6mm in diameter, aperistaltic, non-compressible appendix +/- appendecolith.

Ultrasound Podcast posted a great video a year ago on the “how-to” for appendix ultrasound and why to go to ultrasound first in the work up of appendicitis:

Let’s go back to the study:

“OBJECTIVE. Acute appendicitis is the most common condition requiring emergency surgery in children. Differentiation of perforated from nonperforated appendicitis is important because perforated appendicitis may initially be managed conservatively whereas nonperforated appendicitis requires immediate surgical intervention. CT has been proved effective in identifying appendiceal perforation. The purpose of this study was to determine whether perforated and nonperforated appendicitis in children can be similarly differentiated with ultrasound.

MATERIALS AND METHODS. This retrospective study included 161 consecutively registered children from two centers who had acute appendicitis and had undergone ultra-sound and appendectomy. Ultrasound images were reviewed for appendiceal size, appearance of the appendiceal wall, changes in periappendiceal fat, and presence of free fluid, abscess, or appendicolith. The surgical report served as the reference standard for determining whether perforation was present. The specificity and sensitivity of each ultrasound finding were determined, and binary models were generated.

RESULTS. The patients included were 94 boys and 67 girls (age range, 1-20 years; mean, 11 ± 4.4 [SD] years) The appendiceal perforation rate was significantly higher in children younger than 8 years (62.5%) compared with older children (29.5%). Sonographic findings associated with perforation included abscess (sensitivity, 36.2%; specificity, 99%), loss of the echogenic submucosal layer of the appendix in a child younger than 8 years (sensitivity, 100%; specificity, 72.7%), and presence of an appendicolith in a child younger than 8 years (sensitivity, 68.4%; specificity, 91.7%).

CONCLUSION. Ultrasound is effective for differentiation of perforated from nonperforated appendicitis in children.”

Interestingly, a multi-organizational group came together for guidelines published in a study in Pediatric Emergency Care. : abstract below:

“The objective of this study was to compare usage of computed tomography (CT) scan for evaluation of appendicitis in a children’s hospital emergency department before and after implementation of a clinical practice guideline focused on early surgical consultation before obtaining advanced imaging.

METHODS:

A multidisciplinary team met to create a pathway to formalize the evaluation of pediatric patients with abdominal pain. Computed tomography scan utilization rates were studied before and after pathway implementation.

RESULTS:

Among patients who had appendectomy in the year before implementation (n = 70), 90% had CT scans, 6.9% had ultrasound, and 5.7% had no imaging. The negative appendectomy rate before implementation was 5.7%. In patients undergoing appendectomy in the postimplementation cohort (n = 96), 48% underwent CT, 39.6% underwent ultrasound, and 15.6% had no imaging. The negative appendectomy rate was 5.2%. We demonstrated a 41% decrease in CT use for patients undergoing appendectomy at our institution without an increase in the negative appendectomy rate or missed appendectomy. The results were even more striking when comparing the rate of CT scan use in the subset of patients undergoing appendectomy without imaging from an outside hospital. In these patients, CT scan utilization decreased from 82% to 20%, a 76% reduction in CT use in our facility after protocol implementation.

CONCLUSIONS:

Implementation of a clinical evaluation pathway emphasizing examination, early surgeon involvement, and utilization of ultrasound as the initial imaging modality for evaluation of abdominal pain concerning for appendicitis resulted in a marked decrease in the reliance on CT scanning without loss of diagnostic accuracy.”

Why talk about this? Well, there is ALWAYS, always, ALWAYS press about how ultrasound can and should be used for appendicitis evaluation in pediatric patient for radiation exposure minimization. It does have false negatives and false positives though – as with all thing ultrasound, you must know it’s strengths and weaknesses….and correlate clinically :)

SonoStudy: CT vs Ultrasound, Community vs Academic Ctr – kids evaluated for appendicitis

In a recent Mescape news article, a topic near and dear to my heart (and, yes, I know I have a lot of them – but decreasing radiation exposure, length of stay, and health care cost are a few), there was a study highlighted that compared community practice versus academic practice in the evaluation of children with abdominal pain that required imaging for ruling out appendicitis. It basically states that community practice do more CT scans and the results are less sensitive. Ive copied the article below, but it got me thinking…. there are quite a few factors that are different in community practice from academic practice and I wonder if they bias these results. Some community practice groups do perform published research studies, but academic centers are well known for being the research hub – does that mean they are more in tune with the talk around town? or that they are more progressive? Well, that can be argued as quite a few academic centers may seem like they are resistant to change. Also, is ultrasound available 24/7? Many community practice centers do not have access to ultrasound outside of business hours, and I know that a few academic centers are also ultrasound-openic overnight. The radiologists who read these studies may not even be in the same country as out-sourcing has become more common than ever before. Would that decrease the sensitivity? It’s hard to say, but I doubt they would be in demand if they made that many mistakes. Surgeons are more reluctant to take a patient to the operating room without a CT-proven appendicitis and emergency physicians are less likely to discharge a patient without a clear diagnosis for right lower quadrant pain. Do any of these factors play into this? Hmmmm…..well, in a prior post about a study done on ultrasound versus CT, the numbers suggest that change is needed…. somewhere along the line of the work up.

“Community hospitals are more than 4 times more likely than pediatric institutions to use radiation-exposing computed tomography (CT) scans and 80% less likely to use ultrasound for pre-appendectomy evaluations in children, study results suggest. Jacqueline M. Saito, MD, MSCI, and colleagues from Washington University School of Medicine in St. Louis, Missouri, also found that both diagnostic tools were less sensitive for appendicitis in the community hospital setting. As previously reported by Medscape Medical News, CT screening of children with abdominal pain has skyrocketed while appendicitis rates remain unchanged, adding to growing concerns regarding the link between excessive radiation exposure and cancer risk later in life. “Broadly-applicable strategies to systematically maximize diagnostic accuracy for childhood appendicitis, while minimizing ionizing radiation exposure, are urgently needed,” the authors write, noting that evaluations may be streamlined by using algorithms developed with broad validity to decrease reliance on preoperative imaging and radiation exposure while avoiding unnecessary hospital transfers, admissions, operations, and missed diagnoses. The retrospective study was published online December 24 in Pediatrics.

For the study, researchers reviewed the records of 423 children who had undergone surgery for presumed appendicitis. Preoperative imaging was performed in 93.4% of cases; final diagnoses included acute appendicitis (69.0%), perforated appendicitis (23.6%), and normal appendix (7.3%). After adjusting for age, sex, race/ethnicity, body mass index, symptom duration, and white blood cell count, researchers found that children initially evaluated at a community hospital were 4.4 times more likely to have undergone a preoperative CT scan (odds ratio [OR], 4.37; 95% confidence interval [CI], 1.70 – 11.19; P = .002) and 80% less likely to have had an ultrasound performed (OR, 0.20; 95% CI, 0.07 – 0.58; P = .003) than those at a pediatric facility. About 15.1% of children underwent both ultrasound and CT before surgery, particularly if they were girls (OR, 4.51; 95% CI, 1.47 – 13.82; P = .008) or had a lower body mass index percentile (OR, 0.98; 95% CI, 0.96 – 1.00; P = .03), longer symptom duration (OR, 1.81; 95% CI, 1.15 – 2.86; P = .01), or lower white blood cell count (OR, 0.87; 95% CI, 0.78 – 0.97; P = .01). Most children undergoing both tests had the ultrasound first (46/64, 71.9%), and normal/indeterminate results were followed up with CT (OR, 17; 95% CI, 7.7 – 37.0). Although high overall, CT scans performed at pediatric hospitals tended to be more sensitive for any appendicitis and for perforated appendicitis than those done at community hospitals (98.8% vs 93.4% [P = .07] and 75.0% vs 49.0% [ P = .045], respectively). Sensitivities were highest for older children (aged 13 – 18 years) and those not obese; insufficient numbers of underweight children were available for analysis. Accuracy of ultrasound for diagnosing appendicitis was found to be moderate in the pediatric hospital setting (weighted κ, 0.36; 95% CI, 0.24 – 0.48) and highest among older children (aged 13 – 18 years; weighted κ, 0.38; 95% CI, 0.22 – 0.54) and boys (weighted κ, 0.40; 95% CI, 0.21 – 0.55); rarity of use in community hospitals precluded any evaluation of ultrasound sensitivity in this setting. “Variation in diagnostic imaging use for pediatric appendicitis by initial evaluation location might stem from multiple factors, such as availability of imaging or the perceived need for diagnosis confirmation,” the authors comment, noting that ultrasound may be less available in community hospitals and that emergency physicians may have low risk tolerance for pediatric diagnostic errors and malpractice claims, preferring to place their confidence in CT scans.” Pediatrics. Published online December 24, 2012. Abstract

SonoStudies: Ultrasound First for Appendicitis, the gift that keeps on giving….

I know I harp on this quite a bit – or at least Ive been found guilty of doing it, but it’s important, relevant, and radiation /cost saving. Ive spoken about US and appendicitis in a prior post when talking about who we should or should not CT. There have been quite a few studies lately about appendicitis and ultrasound’s role in it’s diagnosis. I trained when it was a “clinical” diagnosis – loved those days – ask them where the pain is, they point to the right lower quadrant, it’s tender there with a fever history, I call the surgeon and they come down and decide whether to observe or take to the OR. I do miss those days, but now we live in a more litiginous world, where surgeons records of missed/false diagnoses are public and the prior accepted 20% false rate for appendicitis no longer exists. Continue reading

SonoStudy: “US equivocal for appy” To scan or not to scan? THAT is the question…

Interesting topic of discussion and I wonder what the usual plan is at your facilities with regard to US “equivocal and cannot see the appendix”. Apparently, we order too many CTs after that result, and might want to think about an alternative to radiation: observation period. According to one of our Radiology colleagues who is a guru with US, Dr Brooke Jeffrey, and studied this extensively with a goal to minimize radiation: 400 pediatric and adult patients had US to evaluate for appendicitis. Continue reading