Pulmonary dysfunction and reduced exercise capacity in patients with myelomeningocele.
OBJECTIVE
To evaluate pulmonary function and exercise capacity in children with myelomeningocele.


METHODS
Prospective evaluation in a randomly selected cohort of 12 subjects (10 to 17 years of age) with myelomeningocele and 12 control subjects matched for age, sex, and arm span.


METHODS
Spirometry, lung volumes, maximum respiratory pressures, maximum oxygen expenditure during arm ergometry, and anaerobic threshold were measured.


RESULTS
Mean total lung capacity and fractional lung volumes were significantly lower in case subjects than control subjects. Eleven subjects (92%) had a reduced forced vital capacity; seven (58%) had restrictive disease as evidenced by reductions in total lung capacity with normal or increased forced expiratory volume in 1 second/forced vital capacity ratio. Nine subjects (75%) had respiratory muscle weakness as evidenced by reduced maximum respiratory pressures or a low maximum voluntary ventilation. Exercise capacity was reduced as evidenced by a lower maximum oxygen consumption at peak exercise (13.8 +/- 4.8 vs 21.3 +/- 7.5 ml/min per kilogram of body weight; p < 0.02) and a lower anaerobic threshold (12.4 +/- 5.1 vs 17.3 +/- 4.2 ml/min per kilogram; p < 0.01) than the control group. Though the majority of subjects with myelomeningocele had a significant degree of restrictive disease, respiratory muscle weakness, or both, only one subject had pulmonary symptoms during exercise.


CONCLUSIONS
Though most subjects with myelomeningocele had a significant degree of restrictive lung disease, respiratory muscle weakness, or both, exercise capacity was mostly limited by arm weakness. Skeletal muscle weakness may mask the symptoms of an underlying pulmonary abnormality, which may not be evident unless a pathologic cause of increased ventilation is present. Pulmonary function testing is suggested to screen for these abnormalities.
Sherman
M S
MS
Department of Medicine, MCP Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania, USA.
Kaplan
J M
JM
Effgen
S
S
Campbell
D
D
Dold
F
F
D000293:Adolescent; D015308:Anaerobic Threshold; D001835:Body Weight; D016022:Case-Control Studies; D002648:Child; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000209:etiology*; D008297:Male; D008591:Meningomyelocele / Q000150:complications* / Q000503:physiopathology*; D010101:Oxygen Consumption; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000209:etiology*; D014797:Vital Capacity