Clinical signs of pneumonia in infants under 2 months.

To determine clinical signs that can predict pneumonia (confirmed by radiography) in infants under 2 months of age, 101 infants with pneumonia and 150 with an upper respiratory infection (but not pneumonia) were studied. Ten infants with pneumonia and 15 with an upper respiratory infection did not have the cough and/or difficult (or rapid) breathing that are recommended as 'entry criteria' by the World Health Organisation (WHO). The remaining infants met WHO entry criteria; in them sensitivity and specificity of respiratory rate > or = 60/min and/or severe chest indrawing to diagnose pneumonia was 85% and 97% respectively. Addition of four non-specific signs (stopped feeding well, looked sick, temperature < or = 38 degrees C, and abdominal distension) to respiratory rate > or = 60/min and/or chest indrawing for case identification resulted in a 7% gain in sensitivity but 22% loss of specificity. Addition of nasal flaring improved the sensitivity by 6% without loss of specificity. However, the non-specific signs were the only clue to diagnosis in five infants weighing < or = 2500 g. At age < 7 days, a weight < or = 2500 g and cyanosis were associated with significantly higher risk of mortality. These findings support the use of a respiratory rate > or = 60/min and/or chest indrawing for identification of pneumonia, and suggest addition of nasal flaring to the criteria for case identification in infants under 2 months with cough and/or difficult or rapid breathing.