Appendicitis is a common presentation in the Emergency Department. Dilemmas arise when deciding whether to image patients with equivocal symptoms and WBC lab results. Given the risk of ionizing radiation with CT scans, we should ideally minimize the number of CT scans ordered in these patients without mistakenly sending patients home with an early appendicitis. A perforated appendix places the patient at risk for bowel obstruction, infertility (in women), and sepsis.
Where does the American College of Emergency Physicians (ACEP) stand on the critical issues surrounding the evaluation of appendicitis?
This installment of the Paucis Verbis (In a Few Words) e-card series reviews the ACEP Clinical Policy on Appendicitis. In the end, the policy conjures up more questions than answers, but a comprehensive presentation of the literature to date and helpful risk-stratification data are provided.
I'm curious, what protocol do you use for your CT scans for ruling out appendicitis? What combinations of PO, IV, and PR contrast do you use, if any? At our site, we use PO and IV contrast.
Looking at the last line, based off of the Kharbanda study, it didn't make sense (to me) as written (i.e. presence of the features listed would increase my pre-test prob, LR). From Kharbanda's abstract:
ReplyDelete"...a second low-risk decision rule was developed consisting of absolute neutrophil count of <6.75x10^3/uL, absence of nausea, and absence of maximal tenderness in the right lower quadrant. This rule had a sensitivity of 98.1% (95% CI: 90.1–99.9), NPV of 97.5% (95% CI: 86.8–99.9), and negative likelihood ratio of 0.058 (95% CI: 0.008–0.411) in the validation set. Theoretical application of the low-risk rules would have resulted in a 20% reduction in CT."
There was another rule derived in the paper that looked at ANCs > 6.75, but that didn't have the same NLR of 0.058.
I'm not a statistician, but it is my understanding that there are Positive and Negative LR's. Positive LRs predict the accuracy of a POSITIVE test for the disease. Negative LRs predict the accuracy of a NEGATIVE test for the disease. So in the example, if you have 0 of the 5 criteria (nausea, RLQ pain, difficulty walking, RT, and PMN >6,750), it is very unlikely that you have an appy with a LR of 0.058. I hope that answers your question.
ReplyDeleteThat makes more sense. Thank you for the clarification.
ReplyDelete