Simple clinical signs of lower respiratory infection.

We studied the reliability of some simple clinical signs in the diagnosis of paediatric lower respiratory infection (LRI). Seventy infants and 148 children attending the outpatient department for cough of less than 15 days duration were studied. These children were examined by a paediatrician, and a proforma of simple clinical signs of LRI was filled in. A chest X-ray was taken on the same day and interpreted by a radiologist who did not know the clinical features of the patient. Clinical signs were then compared with X-ray changes, the latter being taken to indicate the presence of LRI. Respiratory rates of greater than 40/min in infants and greater than 30/min in older children were found to be the best indicators of LRI as revealed by a receiver-operating-characteristic curve. Chest indrawing and nasal flaring were found to be associated with moderate and severe disease.