Pulmonary alveolar proteinosis during a 30-year observation. Diagnosis and treatment

Pulmonary alveolar proteinosis (PAP) is a rare disease characterised by the abnormal accumulation of surfactant-like material in macrophages within the alveolar spaces and distal bronchioles. The course of the disease is variable and the prognosis is often good. However, progressive disease in some patients can cause respiratory dysfunction and can be life threatening. In this situation, the only effective treatment is whole lung lavage. The objective of the study was to present the characteristics and the course of pulmonary alveolar proteinosis in our own material, the diagnostic methods used, the indications for treatment and the treatment efficacy.

Retrospective analysis included 17 patients: 6 women and 11 men, aged from 32 to 56 years, who were observed in the Third Lung Department of Pneumonology at the National Institute of Tuberculosis and Lung Diseases between 1984 and 2013. In all patients chest X-ray, pulmonary function test and blood gases were performed. In 15 patients, high-resolution computed tomography (HRCT) was obtained. Bronchoscopy was performed in all of the patients, and in 7/17, bronchoalveolar lavage (BAL) was carried out. Fourteen patients underwent open lung biopsy. The indications for whole lung lavage (WLL) were progression of dyspnoea with restriction of daily activity and/or hypoxaemia.

In most of the patients (13/17) the diagnosis was established outside our institute. Patients were referred to our department to establish further procedures. The criteria of diagnosis of PAP in most patients (16/17) was the histological examination of lung tissue, obtained by open lung biopsy (14 cases) and transbronchial lung biopsy (TBLB) (2 cases). Only in one patient the diagnosis was established on the basis of BAL. HRCT imaging was characteristic of proteinosis in 11/15 patients, and BAL examination in 6/7 patients, in whom BAL was performed. In four patients, who had been exposed to injurious factors for many years, secondary proteinosis was recognised; in other patients, no exposure or no other disease was found, and primary alveolar proteinosis was diagnosed. In one patient granulocyte macrophage colony stimulating factor autoantibody was detected. The majority of patients (10/17) had clinical symptoms at the diagnosis. The most commonly reported was dyspnoea, followed by respiratory tract infections. The most common abnormality (12/17) in pulmonary lung test was a decrease of diffusing capacity of the lung for carbon monoxide (DLCO). Respiratory distress at rest was found in two patients. Patients were observed for the period of 6 months to 19 years. Spontaneous partial remission was observed in 10 out of 13 untreated patients, including one complete remission; in 3 cases stabilisation was found in radiological examinations; and in other 4 patients, whole lung lavagewas used, resulting in clinical improvement with partial resolution of lesions in radiological examinations in 3 patients. In one patient, despite WLL being repeated three times, improvement was not achieved.

Pulmonary alveolar proteinosis is a rare interstitial disease with a mild course in most cases. In 13/17 patients diagnosis was based on histological examination of samples from open lung biopsy. The presented patients were observed in the years 1984-2004, and at that time histologic examination was the main diagnostic method. The most common abnormality in pulmonary function tests was decrease of DLCO. In most cases, spontaneous remission of the disease was observed. In four patients with severe course of PAP, WLL was performed with subjective, functional and radiological improvement in 3 of them.