EARLY DETECTION OF LUNG INVOLVEMENT IN LYSINURIC PROTEIN INTOLERANCE - ROLE OF HIGH-RESOLUTION COMPUTED-TOMOGRAPHY AND RADIOISOTOPIC METHODS

Pulmonary disease of unknown etiology is a potentially fatal complicat ion in patients with lysinuric protein intolerance (LPI), an autosomal recessive disorder caused by the defective transport of cationic amin o acids. Lung involvement was investigated in nine Italian LPI patient s through pulmonary function tests and lung imaging studies consisting of conventional chest radiography, high-resolution computed tomograph y (HRCT), and perfusion and ventilation scintigraphy. One 10-yr-old pa tient died of severe respiratory insufficiency from alveolar proteinos is. All of the remaining patients were asymptomatic at the time of the study, although HRCT scans revealed signs of lung involvement defined by the presence of acinar nodules, inter- and/or intralobular thicken ing of the interstitial septa, and subpleural cysts in five of the pat ients. Radioisotope studies showed an uneven distribution of perfusion and ventilation, and confirmed the presence of seg mental and/or diff use pulmonary functional defects. No abnormalities of pulmonary functi on were evident, and answers to a questionnaire excluded primary coexi sting lung disease. In patients with LPI, including those without clin ical and functional impairment, HRCT and radioisotopic studies appear to be the most sensitive methods for the early diagnosis of lung disea se and correct assessment of its progression.