Effect of Disodium Etidronate in Patient With Pulmonary Alveolar Microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive lung disease. It is characterized by the accumulation of calculi called microliths. There is no definitive treatment. Disodium etidronate has been administered due to its alleged calcium phosphate precipitation-reducing effect; however, its effectiveness is controversial. Case; A 13-year-old male referred because of the reticulonodular opacities in chest X-ray detected during evaluation for upper respiratory tract infection. Pulmonary function test results showed a mild restrictive pattern. Findings on computed tomographic (CT) images were consistent with interstitial lung disease. Open lung biopsy confirmed a diagnosis of PAM. The patient started disodium etidronate treatment. Sandstorm-like appearance on chest x-ray decrease and restrictive pattern in pulmonary function test improved after six months of treatment. There was no significant change in CT. After cessation of treatment, the patient remains stable clinically. His asymptomatic sister also screened and similar mutation in SLC34A2 detected. However, because of his sister asymptomatic and younger, she is followed without treatment and remained stable clinically. Conclusion: Currently, there is no consensus on the treatment of PAM. The number of the report describes the beneficial effects of long-term treatment with disodium etidronate, but in a certain case, it seems ineffective. Our patient9s chest X-ray and pulmonary function improved after six months of disodium etidronate treatment. However, there was no major change in CT. He remains asymptomatic after discontinuation of treatment. Therefore, the effectiveness of disodium etidronate still remains controversial.