Hu, Xiaowen

Background Birt–Hogg–Dubé syndrome (BHD) is a rare autosomal dominant disease characterised by the development of lung cysts, skin fibrofolliculomas and an increased risk for renal cancer. The progression of cystic lung disease with ageing in BHD has not been well characterised. Objectives To assess the severity of lung involvement in patients with BHD aged 50 years or older. Methods A retrospective computer-assisted search was performed to identify patients with BHD seen at Mayo Clinic in Rochester, Minnesota and the First Affiliated Hospital of University of Science and Technology of China from January 2000 to May 2023. Demographic, clinical, pulmonary function and radiological parameters were extracted and analysed. Results Among 82 patients with BHD aged 50 years or older, 49 (59%) were female and the median age was 57 years (range, 50–79) at baseline. Pneumothorax occurred in 46 patients (56%). Lung cysts were observed on CT in 77 patients (94%) and were bilateral in nearly all cases. The number of cysts was≥10 for most patients (84%) and the median size of the largest cyst was 31 mm (range, 4–160 mm). Median (range) % predicted values of forced vital capacity, forced expiratory volume in 1 s and diffusion capacity of the lung for carbon monoxide were 98 (62–147), 92 (56–145) and 85 (61–133), respectively, for those with data available. During follow-up (median, 41 months; range, 3–259), 35% of patients manifested worsening in pulmonary function or cystic lung disease. Conclusion Lung involvement in older patients with BHD manifests varying severity of cystic lung disease with relatively mild functional impairment, if any, and indolent progression.

Abstract Aspiration-related syndromes comprise a broad spectrum of diseases affecting the airways and lung parenchyma resulting from inadvertent entry of oropharyngeal or gastric contents into the respiratory tract. The diagnosis can be challenging given lack of self-reported symptoms and unwitnessed or silent aspiration events. Aspiration is a common finding in healthy individuals suggesting that host defenses play a critical role in the pathophysiology. In the absence of strict criterion, a high index of suspicion is necessary based on recognition of established risk factors and identification of characteristic imaging findings. Conditions predisposing to altered levels of consciousness and neuromuscular weakness can lead to dysphagia, impaired cough reflux, and subsequent aspiration. The most salient feature on imaging is the anatomic location of the abnormalities, with the superior segments of the lower lobes and posterior segments of upper lobes involved in the recumbent position, and basilar segments of lower lobes in the upright position. Acute syndromes include pneumonia, pneumonitis, and foreign body aspiration. In the more indolent form of aspiration, bronchiectasis, diffuse bronchiolitis, and interstitial lung disease can develop. A detailed understanding of associated radiographic findings for these syndromes can help to implicate aspiration as the cause for imaging abnormalities and ultimately optimize patient management.

Abstract Background: Diagnosis of rare diseases remains a challenge in China. We describe our experience with Birt-Hogg-Dubé syndrome (BHDS) encountered at a Rare Lung Disease Clinic recently established in China.Methods: After the first patient with BHDS was recognized in 2017, a Rare Lung Disease Clinic with a multidisciplinary team of specialists was established. We retrospectively analyzed the data of consecutive patients with BHDS encountered from inception to December 2021.Results: There were 1, 1, 15, 12 and 21 cases with BHDS diagnosed from year 2017 to 2021, respectively. All 50 patients (34 women) were of Han race with a mean age of 47.3 years. The common manifestations were pulmonary cysts (98%), pneumothorax (54%) and skin lesions (68%). Renal cancer was detected in two patients and renal angiomyolipoma in four other patients. The main presentations leading to diagnosis were pneumothorax (42%), family screening (36%) and lung cysts identified on radiologic imaging (20%). The average delay in diagnosis was 8.3 years, and 4.7 years in patients with only pulmonary cysts. The most frequent pathogenic variant was c.1285del/dup on exon 11 (23%) among 44 patients confirmed by genetic testing. Renal cancer has not been found on follow-up surveillance thus far.Conclusions: There has been increasing number of patients with BHDS recognized in China, facilitated by establishment of a Rare Lung Disease Clinic. Pulmonary cysts and pneumothorax were commonly encountered features, but skin lesions appeared to be more prevalent in Chinese subjects than previously reported in other Asian countries.

Abstract An ongoing outbreak of Coronavirus Disease 2019 (COVID-19) has spread around the world. However, the clinical characteristics and outcomes of patients with COVID-19 related to different modes of exposure have not been well defined. We aimed to explore the clinical features and outcomes of COVID-19 related to one-time community exposure versus continuous household exposure. Retrospective case–control study involving COVID-19 patients admitted to a tertiary designated center in China was performed. Patients were enrolled if they had known exposure history of one-time community exposure or continuous household exposure. Twenty patients were compared in terms of demographic characteristics, clinical presentation, chest CT images, laboratory results, treatments, and clinical outcomes at 1-month follow-up. There were 10 patients in one-time community and continuous household exposure groups respectively. Males compromised 80% and 40% while the median ages were 37.5 and 51 years old in the 2 groups, respectively. Fever and cough were most common symptoms. Ground-glass opacities were presented on chest CT scan in 90% and 70% of the patients, and the median CT scores were 7 and 16 on admission, respectively. Three patients ranked severe in the community exposure group while 7 patients were severe or critical in household exposure group. On 1-month follow-up, all patients were improved clinically but COVID-19 IgG antibody detected positive. Median follow-up CT scores were 0 and 13 while pulmonary function test abnormalities were 0/9 and 2/7 in the 2 groups, respectively. COVID-19 patients with one-time community exposure tended to be mild in severity and had better outcomes, comparing to those with continuous household exposure.

OBJECTIVE: Aspiration can cause a variety of pulmonary syndromes, some of which are not well recognized. The objective of this study was to assess the demographic, clinical, radiological, and histopathological correlates of diffuse aspiration bronchiolitis (DAB), a bronchiolocentric disorder caused by recurrent aspiration. METHODS: This was a retrospective study of 20 consecutive patients with DAB seen at the Mayo Clinic in Rochester, Minnesota, between January 1, 1998 and June 30, 2014. RESULTS: The median age of the patients was 56.5 years (range, 22-76 years), and the male/female ratio was 2.3:1.0. In 18 patients, the diagnosis of DAB was based on the results of a lung biopsy; in the 2 remaining patients, it was based on clinical and radiological features, together with documented aspiration observed in a videofluoroscopic swallow study. In 19 patients (95%), we identified predisposing factors for aspiration, including gastroesophageal reflux disease (GERD), drug abuse, and dysphagia. Common presenting features included cough, sputum production, dyspnea, and fever. Twelve patients (60%) had a history of recurrent pneumonia. In all of the patients, chest CT revealed bilateral pulmonary infiltrates consisting of micronodules and tree-in-bud opacities. In the majority of patients, interventions aimed at preventing recurrent aspiration (e.g., anti-GERD therapies) led to improvement in the symptoms of DAB. CONCLUSIONS: Young to middle-aged subjects with recognizable predisposing factors for aspiration and who report a history of recurrent pneumonia are at increased risk for DAB. Although DAB is not well recognized, certain chest CT features are characteristic of the disorder.