Pulmonary Hypertension and Polycythemia Secondary to Pulmonary Alveolar Microlithiasis Treated with Sequential Bilateral Lung Transplant: A Case Study and Literature Review

Abstract

BACKGROUND Pulmonary alveolar microlithiasis is an autosomal recessive disease in which a mutation in the SLC34A2 gene that codes for a sodium phosphate type IIb transporter protein (expressed in human epithelial tissues and functions in the clearance of phosphate ions) leads to the formation of extensive pulmonary intra-alveolar microliths. The subsequent characteristic clinical features of dyspnea and hypoxia are a manifestation of these microliths. There have been fewer than 1000 cases of pulmonary alveolar microlithiasis reported worldwide, and there have been 19 reported lung-transplanted patients. CASE REPORT A 49-year-old Saudi male patient presented with longstanding history of easy fatigability and tiredness on exertion since he was 16 years old. Throughout his follow-up in different hospitals (1986-1989), tuberculosis and pulmonary fibrosis were suspected. The patient was lost to follow-up between 1989 and 2001. In 2002, he presented to the emergency room with coughing, shortness of breath on exertion, abdominal swelling, and pedal edema. An investigation with chest x-rays, CT scan, electrocardiogram, and an echocardiogram was conducted. After referral to a tertiary care center, the patient was diagnosed with pulmonary alveolar microlithiasis. He subsequently developed pulmonary hypertension and polycythemia and therefore received a bilateral lung transplant in 2016. Following the lung transplant, he developed a mild reperfusion injury and tonic-clonic seizures, requiring ICU admission. After a successful extubatation with stable vitals and good recovery, he was discharged home in stable condition with planned follow-up. CONCLUSIONS We report a case of pulmonary alveolar microlithiasis successfully treated with a bilateral lung transplant. Although pulmonary alveolar microlithiasis is a rare entity, healthcare providers should consider it in the differential diagnoses of parenchymal lung diseases and differentiate it from tuberculosis and pulmonary fibrosis.

Figure 1.

Summarizes the patient’s history from 1986 to 2016.

Figure 2.

Shows diffuse opacification on chest, which appears dense; the appearance is compatible with pulmonary calcinosis. The visualized bony thorax appears grossly unremarkable on X-ray (A). CT scan shows diffused opacification of both lungs, with calcific densities involving the entire lungs. The calcific densities predominantly involve the middle lobe and lingula more extensively. The tracheobronchial tree appears grossly unremarkable. There is enlargemt in the pulmonary trunk, compatible with pulmonary hypertension (B, C).