Purpose of review: Babies with cystic fibrosis are born with essentially normal lungs but rapidly develop inflammation and infection. Evaluation is generally based on history and physical examination until school age, when children become able to perform spirometry. In these 'silent years', however, unrecognized lung damage can occur. Recently, techniques to improve the evaluation of preschool children have been developed, and an assessment of where they fit into clinical and research practice is now needed. This is particularly urgent to select groups of children for new, phenotype-specific therapies, and monitor their effects.
Recent findings: The techniques in which there have been major recent advances include physiologic methods, particularly indices of gas mixing; imaging techniques, especially high-resolution computed tomographic scanning; and bronchoscopic studies. The clinical roles of these techniques need to be explored, as do comparisons between techniques.
Summary: The preschool years need no longer be silent. Some simple techniques such as spirometry can be performed in much younger children than conventionally believed to be practical. Others currently require sophisticated apparatus (lung clearance index) or carry potential risks (radiation, high-resolution computed tomographic scanning). We need good long-term, prospective comparisons of these techniques, with measurement of inflammatory markers. We also need to know which are sufficiently reproducible, and indicative of prognosis, for use as endpoints in clinical trials.