Response to Disodium Etidronate Treatment in Three Siblings with Pulmonary Alveolar Microlithiasis.

Pulmonary alveolar microlithiasis (PAM) is a rare chronic genetic lung disease in childhood with no proven therapy. It is characterized by the deposition of calcium phosphate microliths within the alveolar air spaces. The effect of disodium etidronate (DE) treatment on PAM is controversial. We report 3 siblings (an 11-year-old boy and 4-year-old twin girls) with PAM diagnosed by chest X-ray, thoracic high-resolution computed tomography, technetium-99m bone scan and bronchoalveolar lavage fluid findings. After the administration of DE (200 mg/day) for a 1-year period, 2 siblings showed radiological improvement, while 1 sibling did not. No drug side effects were observed within the treatment period.