Impact of surgical treatment on respiratory muscle dysfunction in symptomatic hyperparathyroidism

HYPOTHESIS: We hypothesized that surgical treatment would improve respiratory muscle strength in symptomatic hyperparathyroidism (HPT). DESIGN: Prospective clinical trial. SETTING: A tertiary referral center. PATIENTS: Fifteen consecutive patients with symptomatic HPT and 10 with euthyroid multinodular goiter (control group) without a history of obstructive or restrictive lung disease. INTERVENTIONS: Forced vital capacity and forced expiratory volume in 1 second were measured before and 6 months after surgery to estimate respiratory muscle involvement. These measurements were compared with the reference values estimated individually in each patient. Mann-Whitney and Wilcoxon signed rank tests were used for statistical analysis, and P<.05 was considered statistically significant. MAIN OUTCOME MEASURES: Respiratory dysfunction in patients with symptomatic HPT, pulmonary function after parathyroidectomy, and the correlation between the preoperative serum parathyroid hormone and total serum calcium values and the impairment in pulmonary function. RESULTS: Preoperative forced vital capacity and forced expiratory volume in 1 second measurements were below the reference values in 11 (73%) and 9 (60%) patients, respectively. All the patients were normocalcemic, and forced vital capacity and forced expiratory volume in 1 second measurements significantly improved at postoperative month 6 (P = .001). No significant difference was detected in the control group. Improvement in pulmonary function correlated with preoperative serum calcium and parathyroid hormone values in patients with HPT (P<.05 and P<.001, respectively). CONCLUSIONS: Symptomatic HPT impairs inspiratory and expiratory components of respiratory function, and normalization of serum calcium levels after surgical treatment is associated with a significant improvement in lung function.