Case series of Pulmonary Alveolar Microlithiasis from India

Abstract

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterised by calcific deposits in lung parenchyma. PAM being a progressive disease with dissociation between severity of clinical symptoms and radiological picture, it is often detected incidentally. Mutations in the SLC34A2 gene encoding the type IIb sodium phosphate cotransporter in alveolar type II cells are considered to be involved in the pathogenesis of PAM. The majority of the patients are diagnosed usually between the ages of 20 and 40 years, although paediatric PAM has also been reported. Diagnosis is confirmed by combination of radiological features, bronchial lavage and histopathological testing. At present, lung transplant is the only definitive treatment available. Though rare, the prevalence of PAM is worldwide. Till June 2018, 86 cases have been reported from India and 1042 cases have been reported worldwide. We report three cases from India, including a student, cement factory worker and a tailor, which will highlight the varied clinical and radiological presentations of this rare disease along with the response to treatment.

Pulmonary alveolar microlithiasis

“…Disodium etidronate treatment was attempted in an 18-year-old and 51-year-old man who did not symptomatically benefit after 2 years and 6 months of therapy, respectively and who self-discontinued therapy [25]. Weekly alendronate was administered over 6 and 12 months to two adult men in their fifth decade with symptomatic improvement, although radiographs were unchanged [96].…”

An Unusual Case of Pulmonary Alveolar Microlithiasis Masquerading as Pulmonary Tuberculosis

“…Till June 2018¬, 86 cases were reported from India and 1042 cases reported worldwide. [2] It is characterized by deposition of intra-alveolar calcium and phosphate throughout the lung parenchyma. The etiopathogenesis of PAM is not very well understood however the SLC34A2 gene coding for the sodium-phosphate co-transporter in type II pneumocytes is deemed responsible for the disease.…”

“…First case from India was reported by Vishwanathan in 1962 and 86 cases have been reported since then. [2] PAM presents with clinical symptoms of varied severity that at times mimic those of more common disease like tuberculosis. [3] The case reported here was initially referred to Chest Medicine Department of Tertiary Care Hospital as that of Multi Drug Resistant Tuberculosis (MDR-TB) with superadded acute lung infection.…”

An “Orphan” in search of a treatment: Pulmonary alveolar microlithiasis

“…However, when symptomatic cough and breathlessness are the primary complaints, the former likely attributable to stimulation of unmyelinated c fibers in bronchial tree by microliths. [5]…”

“…Since then, 27 cases have been reported, of which ten are from India, including the present case. [5910] With an increasing proportion of cases being reported from India, a national registry of this “orphan” disease will help us better study the trends and improve management by having timely referrals for lung transplant.…”