Single Lung Transplantation In A Patient With Pulmonary Alveolar Microlithiasis Exacerbated By Pneumothorax:A Case Report And Literature Review

Objective To improve the understanding of PAM disease by the analysis of a patient with pulmonary alveolar microlithiasis(PAM)and pneumothorax,received single lung transplantation,and literature review.Methods We retrospectively analyze and follow-up a case of PAM and pneumothorax in the Department of Respiratory and Critical Care Medicine,the First Affiliated Hospital of Soochow University,describe the epidemiology,pathogenesis,clinical features,imaging features and treatment methods of the PAM disease,as well as conduct literature review.Results The patient,male,51 years old,was admitted because of "recurrent cough and expectoration for 30 years,chest tightness for 1 month,aggravated for 3 days",his brother has a history of PAM.The early symptoms were mild and non-specific and the disease progress was slow but irreversible.Chest CT scan showed diffuse sand-like high-density shadows with regional fusion in lung and bilateral pneumothorax.However,the spontaneously recurrent pneumothorax was persisted and worsened under closed thoracic drainage treatment.Therefore,the left lung transplantation was performed and lung tissue showed pathologically a large amount of calcium phosphate deposition in the alveoli.The postoperative quality of life was significantly improved,and there was no recurrence one year later.We searched for documents in Pubmed with "Pulmonary Alveolar Microlithiasis" as key word from Jan,2000 to Jun,2019,and found 119 articles including 184 cases,with "Lung transplantation,Pulmonary Alveolar Microlithiasis" as keywords from Jan,1900 to Jun,2019,and found 23 articles including 18 cases.The clinical characteristics of these patients were further analyzed,and the results were as follows:1.Among the 184 patients,apart from 25 patients that did not describe the clinical symptoms at the time of onset,the most common symptom among the remaining 159 patients was dyspnea in 76 cases(47.8%),which started as dyspnea after activity and presented progressive aggravation;This was followed by 48 cases(30.2%)of cough,8 cases(5.0%)of chest pain,6 cases(3.8%)of fever,6 cases(3.8%)of fatigue,5 cases(3.1%)of hemoptysis,and 30 cases(18.9%)of asymptomatic patients.2.In addition to the 10 patients with unknown diagnostic records,95(54.6%)of the 174 patients were clearly diagnosed by lung biopsy,including 35 cases of surgical lung biopsy(20.1%),57 cases of bronchoscopy lung biopsy(32.8%),2 cases of ct-guided percutaneous lung biopsy(1.1%),and 1 case of autopsy(0.6%).Among the remaining 79 cases,40 cases(23.0%)were diagnosed by chest imaging combined with clinical manifestations,20 cases(11.5%)were detected micronodules by bronchoalveolar lavage fluid(BALF)under fiberoptic bronchoscopy,18 cases(10.3%)were diagnosed by 99mTc pulmonary uptake imaging,and 1 case(0.6%)was detected micronodules in sputum.3.Lung transplantation is the only effective treatment in the terminal stage of PAM patients.A total of 13 lung transplant centers in the world recorded a total of 18 end-stage PAM patients who completed lung transplantation.The average age of lung transplantation was 48.7 years,including 14 cases double lung transplantation,4 cases of single lung transplantation.Fourteen patients survived for a long time,including 11 cases of double lung transplantation and 3 cases of single lung transplantation.The longest survival time in the report was 90 months.Four deaths occurred,including three double lung transplants and one single lung transplant.Five of the 14 surviving patients had complications after surgery.The probability of complications was 35.7%.Important complications include massive pulmonary vascular rupture(surgical associated pulmonary vessel rupture),acute rejection,anastomotic stricture,reperfusion syndrome,shock,and reperfusion,edema,atrial fibrillation,etc.All 4 deaths had postoperative complications,with a probability of 100%.The four complications were massive bleeding;infection;hemodynamic instability,reperfusion edema;loss of lung function from primary transplant,Sepsis.Conclusions 1.PAM is a rare autosomal recessive genetic disease with familial aggregation;the pathogenesis is believed to be related to the mutation of SLC34A2 gene.2.Clinical manifestations of PAM include cough and progressive dyspnea;The imaging features were diffuse ground glass shadow and small nodules in the two lungs,showing"sandstorm" like changes.3.The "gold standard" for the diagnosis of PAM is the micronodules of calcium phosphate deposition found in lung biopsy.4.Lung transplantation is the only effective treatment for PAM,and the type and timing of the operation are unclear.