From the Journals

Negative chest x-ray to rule out pediatric pneumonia

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Chest radiograph for pneumonia ‘not good enough’

While the results of this study offer reassurance that chest radiograph for suspected pneumonia in children has a high negative predictive value, perhaps a more important question is the accuracy of chest radiography at ruling in bacterial pneumonia – its positive predictive value.

There are reasons to suspect that the positive predictive value of chest radiography may not be as high as the negative predictive value found in this study. This is particularly important given that questions have been raised about the utility of antibiotic therapy in treating Mycoplasma pneumonia infection in children.

Leaving out chest radiography altogether in children with a low clinical suspicion for pneumonia would decreased radi-ation use, cost, and perhaps also unnecessary antibiotic prescriptions.

Matthew D. Garber, MD, is from the department of pediatrics at the University of Florida College of Medicine in Jacksonville and Ricardo A. Quinonez, MD, is from the department of pediatrics at the Baylor College of Medicine and Texas Children’s Hospital. These comments are taken from an accompanying editorial (Pediatrics 2018, 142(3): e20182025. No conflicts of interest were declared.



A negative chest radiograph can be used to rule out the possibility of pneumonia in children suspected of having the disease, and therefore reduce antibiotic use, researchers say.

In a paper published in the September issue of Pediatrics, researchers report the results of a prospective cohort study in 683 children – with a median age of 3.1 years – presenting to emergency departments with suspected pneumonia.

Dr. Susan C. Lipsett, from the division of emergency medicine at Boston Children’s Hospital, and co-authors, wrote that the use of chest radiograph to diagnose pneumonia is thought to have limitations such as its inability to distinguish between bacteria and viral infection, and the possible absence of radiographic presentations early in the disease in patients with dehydration.

In this study, 457 (72.8%) of the children had negative chest radiographs. Of these, 44 were clinically diagnosed with pneumonia, despite the radiograph results, and prescribed antibiotics. These children were more likely to have rales or respiratory distress and less likely to have wheezing compared with the children with negative radiographs who were not initially diagnosed with pneumonia.

Among the remaining 411 children with negative radiographs – who were not prescribed antibiotics – five (1.2%) were subsequently diagnosed with pneumonia within 2 weeks of the radiograph. These five children were all under 3 years of age, but none had been treated with intravenous fluids for dehydration. Only one had radiographic findings of pneumonia on a follow-up visit.

Counting the 44 children diagnosed with pneumonia despite the negative x-ray, chest radiography showed a negative predictive value of 89.2% (95% confidence interval, 85.9%-91.9%). Without those children, the negative predictive value was 98.8% (95% CI, 97%-99.6%).

There were also 113 children (16.5%) with positive chest radiographs, and 72 (10.7%) with equivocal radiographs.

The authors said their results showed that most children with negative chest radiograph would recover fully without needing antibiotics, and argued there was a place for chest radiography in the diagnostic process, to rule out bacterial pneumonia.

“Most clinicians caring for children in the outpatient setting rely on clinical signs and symptoms to determine whether to prescribe an antibiotic for the treatment of pneumonia,” they wrote. “However, given recent literature in which the poor reliability and validity of physical examination findings are cited, reliance on physical examination alone may lead to the overdiagnosis of pneumonia.”

They acknowledged that the lack of a universally accepted gold standard for the diagnosis of pneumonia in children was a significant limitation of the research. In addition, the lack of systematic radiographs meant some children who initially had a negative result and recovered without antibiotics may have shown a positive result on a second scan.

No conflicts of interest were declared.

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