Pulmonary manifestations in lysinuric protein intolerance

Abstract

Study objectives: To evaluate the pulmonary manifestations and the course of acute respiratory insufficiency associated with lysinuric protein intolerance (LPI).

Design: Retrospective review of clinical data and chest radiographs (total 225) obtained during the lifetime follow-up of 31 LPI patients. About half of the 25 patients without respiratory symptoms underwent high-resolution computed tomography (HRCT) of the lungs, radionuclide perfusion imaging, whole body plethysmography, and diffusing capacity measurements.

Patients: Thirty-one Finnish patients with LPI.

Results: During the follow-up period, four children with LPI died in respiratory insufficiency, 1 adult had an episode of respiratory insufficiency, and another had chronic symptoms, whereas 25 patients remained symptom-free. The radiologic findings in acute progressive respiratory insufficiency were uniform: at first, reticulonodular interstitial densities and, later on, progressive airspace disease. At autopsy, three patients showed pulmonary alveolar proteinosis and one had pulmonary hemorrhage and cholesterol granulomas. One adult had reversible respiratory insufficiency with signs of bronchiolitis obliterans, another adult had recurrent episodes of chest pain, dyspnea, and hypoxia. Of the symptom-free patients, one third (8 of 25) had signs suggestive of pulmonary fibrosis evidenced on chest radiographs and two thirds (8 of 14) had signs evidenced by HRCT films. Most symptom-free patients showed mild abnormalities either in perfusion imaging (9 of 12) or in function tests (8 of 12).

Conclusion: In childhood, patients with LPI are highly predisposed to develop pulmonary hemorrhages and alveolar proteinosis. Interstitial lung densities may precede the acute phase. Most adult LPI patients show radiologic signs of interstitial lung disease but only a few show clinical impairment.