Radiology
Chest radiographs of patients with PAM usually reveal bilateral diffuse micronodular calcifications, producing a "sandstorm” appearance that first involves the inferior portions and then the middle and upper portions of the lungs. High-resolution computed tomography
The most common findings on HRCT are diffuse hyperdense ground-glass attenuation and subpleural linear calcifications, often most predominant in the inferior and posterior portions of the lungs. Additionally, the medial aspects of the lungs appear to be more heavily involved than the lateral aspects. Ground-glass opacities, probably due to small calculi in the air space, are the most common finding in children and in patients with early-stage PAM. Magnetic resonance imaging
On magnetic resonance imaging (MRI), the calcific lesions usually show hypointensity or a signal void on T1- and T2-weighted images. Pulmonary function studies
Pulmonary function tests, arterial blood gases, ventilation perfusion relationships, and O2 diffusing capacity are normal in the initial stages of PAM. As the disease progresses, pulmonary function tests reveal typical features of a restrictive defect with reduced forced vital capacity (FVC) and elevated forced expiratory volume in FEV1/FVC. Treatment
To date, no treatment has been proven to effectively reverse or prevent the progression of PAM. Lung transplantation is an option for end stage disease, but is typically only recommended as a last resort when quality of life is significantly impaired.Etidronate is a bisphosphonate and can reduce the formation of calcium hydroxyapatite crystals. It has led to clinical and radiological improvements in few cases. Epidemiology
Since the disease was first described in 1918, over 500 case reports have appeared in the literature.
PAM is associated with consanguinity. The incidence is higher in Turkey, Japan, India and Italy. The disease affects both men and women equally, and it has been associated with intermarriage within families. The mean age at diagnosis is 35 years based on the cases reported in the literature. Society
PAM is one of the rare lung diseases currently being studied by the Rare Lung Diseases Consortium (RLDC). Pulmonary Alveolar Microlithiasis patients, families, and caregivers are encouraged to join the NIH Rare Lung Diseases Consortium Contact Registry. This is a privacy protected site that provides up-to-date information for individuals interested in the latest scientific news, trials, and treatments related to rare lung diseases. References


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