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

Objective: Rare disease 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.