In developing countries (Nigeria inclusive), the operational
definition of pneumonia adopted by WHO is
based on the presence of (easily recognisable) clinical parameters like fast breathing (tachypnoea) or chest
indrawing/retraction, in a child with cough and/or
difficult breathing of more than 28 days. The clinical
value of this diagnostic strategy (in which the focal
clinical signs are tachypnoea and chest indrawing) is
underscored by the reported sensitivity and specificity
of 74% and 67%.3 An equally noteworthy operational
definition peculiar to the ‘high pneumonia incidence’
countries of the developing world is the preferred use
of the term ‘acute lower respiratory infections (ALRI)’
as a synonym for pneumonia,4 partly in view of the
overwhelming proportion (over 75%) of ALRI attributable
to pneumonia, the understandable difficulties in
accomplishing the prerequisites of the microbiologic or
radiologic diagnosis, as well as the significant symptom
overlap between pneumonia and the less common ALRI
syndromes.