Clinical, morphological and functional features of primary ciliary dyskinesia children in southeast Spain

Abstract

Introduction: Congenital central hypoventilation syndrome (CCHS) is a disorder of the respiratory center at medulla oblongata. Responsiveness of the respiratory center is measured by relating the increase in minute ventilation induced by an increase in inhaled CO2, known as the Ventilatory Response to CO2 (VRCO2). The VRCO2 is useful because it can be evaluated quantitatively. We measured the VRCO2 in CCHS and compared the results with normal children. Method: Records of VRCO2 in 6 children with CCHS between January 1989 and December 2012 were reviewed. Demographic data, time of diagnosis and type of PHOX2B gene abnormality were analyzed. The VRCO2 was measured using a pulmonary function measuring system made by Aivision Japan and Read’s rebreathing technique in which a mixture of 95% O2 and 5% CO2 was inhaled in a closed circuit. Result: The VRCO2 was measured 7 times. Five measurements were taken in infancy, others in adolescence. The average VRCO2 was 0.037ml/mm/min/mmHg (−0.035 to 0.013). It was extremely low compared with normal children (0.64±0.23) at our institution. In a child with repeated measurements at 5 months and 18 years of age, the VRCO2 did not improve. There was no correlation between the VRCO2, type of PHOX2B gene abnormality, and time of diagnosis. Conclusion: These data demonstrate that the VRCO2 in CCHS is extremely low compared with normal children and does not improve with age. Therefore, the VRCO2 is very useful in the diagnosis of CCHS.