Pulmonary function in adolescents with ataxia telangiectasia.
BACKGROUND
Pulmonary complications are common in adolescents with ataxia telangiectasia (A-T), however objective measurements of lung function may be difficult to obtain because of underlying bulbar weakness, tremors, and difficulty coordinating voluntary respiratory maneuvers. To increase the reliability of pulmonary testing, minor adjustments were made to stabilize the head and to minimize leaks in the system. Fifteen A-T adolescents completed lung volume measurements by helium dilution. To assess for reproducibility of spirometry testing, 10 A-T adolescents performed spirometry on three separate occasions.


RESULTS
Total lung capacity (TLC) was normal or just mildly decreased in 12/15 adolescents tested. TLC correlated positively with functional residual capacity (FRC), a measurement independent of patient effort (R2=0.71). The majority of individuals had residual volumes (RV) greater than 120% predicted (10/15) and slow vital capacities (VC) less than 70% predicted (9/15). By spirometry, force vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) values were reproducible in the 10 individuals who underwent testing on three separate occasions (R=0.97 and 0.96 respectively). Seven of the 10 adolescents had FEV1/FVC ratios>90%.


CONCLUSIONS
Lung volume measurements from A-T adolescents revealed near normal TLC values with increased RV and decreased VC values. These findings indicate a decreased ability to expire to residual volume rather then a restrictive defect. Spirometry was also found to be reproducible in A-T adolescents suggesting that spirometry testing may be useful for tracking changes in pulmonary function over time in this population.
Division of Pediatric Pulmonology, Department of Pediatrics, The Johns Hopkins Medical Institution, Baltimore, Maryland 21287-2533, USA. smorrow@jhmi.edu
Sharon
S
McGrath-Morrow
Maureen
M
Lefton-Greif
Karen
K
Rosquist
Thomas
T
Crawford
Amber
A
Kelly
Pamela
P
Zeitlin
Kathryn A
KA
Carson
Howard M
HM
Lederman
D000293:Adolescent; D000328:Adult; D001260:Ataxia Telangiectasia / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods