Back to the Basics: A Clinical Approach to Excluding Acute Appendicitis
Review by Jane G. Buss, MD
Kharbanda AB, Taylor GA, Fishman SJ, et al. A clinical decision rule to identify children at low risk for appendicitis. Pediatrics. 2005;116(3):709-16.
Appendicitis is the most common condition requiring emergency abdominal surgery in the pediatric population. To diagnosis appendicitis, clinicians typically utilize clinical findings, imaging studies, and laboratory testing. The use of clinical scoring systems to improve the diagnosis of appendicitis in children has been limited, mostly resulting from unacceptably low sensitivities/specificities, or the lack of validation. The use of CT scan to aid in the evaluation of children with appendicitis has become widespread. Concerns remain, however, regarding long-term radiation effects and increased healthcare costs associated with this approach.
The authors of this study sought to develop clinical scores for children to predict which of those with acute abdominal pain do not have appendicitis. Additionally, they hoped to lessen the use of CT scanning. Their goal was to identify those groups of children who have significant abdominal pain without appendicitis who could be safely observed without CT scan or possible surgery.
This prospective cohort study enrolled 601 eligible children ages three to 18 with suspected appendicitis who presented to the emergency department over a 15-month period. Two low-risk clinical decision rules were developed using logistic regression and recursive partitioning. Using logistic regression, six factors were identified from analysis of 425 patients in the derivation set significantly associated with an increased likelihood of appendicitis. The score components include:
- Nausea (2 points);
- History of focal right lower quadrant pain (RLQ) (2 points);
- Migration of pain (1 point);
- Difficulty walking (1 point);
- Rebound tenderness (2 points); and
- Absolute neutrophil count (ANC) >6.75 x 103/uL (6 points).
When tested with data from the 176 patients in the validation set, a score of less than or equal to five had a sensitivity of 96.3%, and a negative predictive value of 95.6% for excluding appendicitis.
The authors then derived a second clinical low-risk decision rule by recursive partitioning. They determined that a combination of ANC <6.75 X 10 to the third/microliter, absence of nausea (or emesis or anorexia), and absence of maximal tenderness in the RLQ essentially excluded appendicitis in the derivation and validation groups. This rule had a sensitivity of 98.1%, and a negative predictive value of 97.5%.
In summary, these authors derived two clinical decision rules giving the clinician the option of a clinical score (logistic regression) or a decision tree (recursive partitioning) to identify children at low risk for appendicitis. Their findings suggest application of either low-risk rule would lead to decreased reliance on CT scan. Applying these clinical rules to their patients could have reduced the rate of CT scan by 20%. They conclude that pediatric patients who have suspected appendicitis and are at low risk by either model should be considered for observation rather than undergo CT scan or operative care.
Epidemiology of Fungal Infection in the Tertiary Care Inpatient Setting
Review by Brandan P. Kennedy, MD
Abelson, JA, Moore T, Bruckner D, et al. Frequency of fungemia in hospitalized pediatric inpatients over 11 years at a tertiary care institution. Pediatrics. 2005;116(1):611-617.
Fungal organisms are relatively uncommon causes of blood infections in the pediatric population. When they do occur, they cause significant morbidity and mortality. The incidence of fungal blood infections appears to be rising at a faster rate than that of other pathogens. Authors from the University of California performed this study to describe those rate changes, and to evaluate whether treatment has improved in the past 11 years.