Multiple spontaneous pneumothoraces revealing Birt-Hogg-Dube syndrome

The Birt-Hogg-Dubé (BHD) syndrome is associated with cutaneous disorders including fibrofolliculomas and trichodiscomas, and also lung pneumatocysts and kidney tumours. The BHD syndrome occurs as a consequence of an autosomal dominantly inherited genodermatosis, linked to multiple germline mutations in the 14 exons of the BHD gene, mapped on 17p11.2 and encoding for folliculin (FLCN). The size and number of lung pneumatocysts are extremely variable and the cysts are surrounded by normal pulmonary tissue. In the absence of smoking lung function is usually unimpaired. The lung cysts are frequently complicated by the development of recurrent pneumothoraces. Treatment of pneumothorax in patients with the BHD syndrome is similar to the approach taken for patients with spontaneous pneumothorax. Lung cysts in the BHD syndrome are a rare cause of cystic pulmonary lesions. However, they must be systematically evaluated since kidney tumours occur in one third of patients. We report a case of classical BHD syndrome with specific cutaneous involvement, recurrent pneumothoraces complicating lung cysts, an exon 12 germline mutation on BHD gene and a familial history suggesting other related cases. This observation allows us to update this orphan disease, to consider BHD in the differential diagnosis of lung cysts and, above all, to highlight the high frequency and the prognostic significance of associated kidney tumours.     

Spontaneous pneumothorax due to Birt-Hogg-Dube syndrome in a Chinese family

A Chinese woman presented with a spontaneous pneumothorax and a family history suggestive of the autosomal dominant transmission of pneumothorax. The patient also had skin fibrofolliculomas and folliculin gene deletion, compatible with Birt-Hogg-Dube (BHD) syndrome. The importance of BHD syndrome and other familial spontaneous pneumothoraces is discussed.     

Obstructive lung disease in Behcet's syndrome

Obstructive lung disease in two patients with Behcet's syndrome is presented. In both cases increased airways resistance, impaired PEF and FEV1.0 were found. In addition, diffusion capacity was slightly decreased in spite of enlarged total lung capacity and increased residual volumes. Both patients had mild hypoxaemia despite slight hyperventilation; a normal chest X-ray, and a decreased serum complement C3 level. Corticosteroids had a beneficial effect on VC in one of the two cases but failed to have any significant effect on the impaired ventilatory function in the other.     

Cystic fibrosis lung disease: the role of nitric oxide

This review summarizes current knowledge about the role of nitric oxide (NO) in cystic fibrosis (CF) lung disease. NO is endogenously produced by a group of enzymes, the NO synthases (NOSs). There are three isoforms of NOS, each encoded by different genes: neuronal (nNOS), immune or inducible (iNOS), and endothelial (eNOS) nitric oxide synthase.(1) They all form NO and L-citrulline by enzymatic oxidation of L-arginine. This reaction requires a number of cosubstrates, including molecular oxygen and tetrahydrobiopterin. It is now known whether all three isoenzymes are constitutively expressed in cells of the respiratory tract and that their gene expression is inducible.(2,3) NO production by iNOS, the "high-output" NOS, is stimulated by bacterial lipopolysaccharide (LPS) as well as proinflammatory cytokines such as interleukin (IL)-1gamma, IL-2, interferon (IFN)-gamma, and tumor necrosis factor (TNF). In contrast to nNOS and eNOS, activation of iNOS does not require an increase in intracellular Ca(2+) concentration.     

Chronic lung disease in the sleep apnea syndrome

Several well controlled epidemiologic and hemodynamic studies suggest that about 20% of sleep apnea syndrome (SAS) patients will have chronic obstructive pulmonary disease (COPD), and the majority of these patients (with combined diseases) will have pulmonary hypertension. Indeed it has been suggested that only patients with underlying hypoxemia, such as that from COPD, will develop right heart failure in the OSA setting. Experience shows that apnea/COPD patients will have severe hypersomnolence associated with the OSA, cough and dyspnea with the airways disease, and edema and plethora related to chronic hypoxemia. Many patients present with respiratory failure and are diagnosed at the time of initial intubation and mechanical ventilation. Episodic nocturnal hypoxemia may be worsened by a steeper rate of desaturation due to lower alveolar and blood oxygen stores, and longer apneas perhaps contributed to by depressed chemosensitivity. Daytime hypoxemia may also add to the severe hemodynamic disturbances. Since COPD cannot be cured, aggressive treatment of SAS is critical. Past studies have shown that tracheostomy or nasal CPAP in this setting not only leads to resolution of episodic nocturnal desaturation but may lead to rapid improvement in daytime oxygenation in many patients. Pulmonary hypertension and other measures of cardiopulmonary function improve when apnea is cured. Elimination of the SAS may disclose nonapneic REM related desaturation that could require supplemental oxygen therapy in addition to tracheostomy or nasal CPAP. Pulmonary function testing in SAS patients with smoking histories, followed by aggressive treatment of SAS, is recommended.     

The folliculin-FNIP1 pathway deleted in human Birt-Hogg-Dube syndrome is required for murine B-cell development

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disorder characterized by cutaneous fibrofolliculomas, pulmonary cysts, and kidney malignancies. Affected individuals carry germ line mutations in folliculin (FLCN), a tumor suppressor gene that becomes biallelically inactivated in kidney tumors by second-hit mutations. Similar to other factors implicated in kidney cancer, FLCN has been shown to modulate activation of mammalian target of rapamycin (mTOR). However, its precise in vivo function is largely unknown because germ line deletion of Flcn results in early embryonic lethality in animal models. Here, we describe mice deficient in the newly characterized folliculin-interacting protein 1 (Fnip1). In contrast to Flcn, Fnip1(-/-) mice develop normally, are not susceptible to kidney neoplasia, but display a striking pro-B cell block that is entirely independent of mTOR activity. We show that this developmental arrest results from rapid caspase-induced pre-B cell death, and that a Bcl2 transgene reconstitutes mature B-cell populations, respectively. We also demonstrate that conditional deletion of Flcn recapitulates the pro-B cell arrest of Fnip1(-/-) mice. Our studies thus demonstrate that the FLCN-FNIP complex deregulated in BHD syndrome is absolutely required for B-cell differentiation, and that it functions through both mTOR-dependent and independent pathways.     

Shrinking lung syndrome and systemic auto-immune disease

INTRODUCTION: Shrinking lung syndrome usually manifest in dyspnea, decreased lung volume associated with elevated diaphragm. It reports with systemic autoimmune disease and physiopathological mechanism is controversial. EXEGESIS: We report three shrinking lung syndrome observations in which two cases were diagnosed at the time to onset of autoimmune disease. The three patients were treated with corticosteroid, two of them necessitated theophylline. Review of the literature highlight 60 cases and permit to discuss physiopathological mechanisms which remain uncertain. Diaphragmatic dysfunction (because of myositis or neuropathy) represented by abnormal transdiaphragmatic pressures is actually discussed. CONCLUSION: Shrinking lung syndrome is rare but must be considered in patient with autoimmune disease and dyspnea. The diagnosis can be difficult because of clinical, pathological and functional features which are controversial. The optimum treatment is unknown.     

Mounier-Kuhn syndrome masquerading as obstructive lung disease

Chronic obstructive pulmonary disease (COPD) is present in 10.1% of the population and is the fourth leading cause of death in the United States while the prevalence of asthma in adults is 6.7%.¹ Patients presenting to primary care offices with lower respiratory tract symptoms like dyspnea and wheezing are often diagnosed with COPD or asthma and started on treatment. There are uncommon conditions like Mounier-Kuhn syndrome (MKS) that can present with similar symptoms and it is important for the primary care physician to keep them in mind when evaluating patients. It is important to identify MKS, as early recognition can lead to better management and prevention of complications. We describe a case of an older gentleman with recurrent symptoms of shortness of breath and intermittent spells of productive sputum who was misdiagnosed with COPD for years. Our diagnosis was supported by a clinical history and confirmed by radiographic evidence.     

Xerotrachea and interstitial lung disease in primary Sjogren's syndrome

22 patients with primary Sjogren's syndrome were prospectively studied for respiratory system involvement with clinical, roentgenological and functional parameters. 12 patients (55%) had respiratory manifestations. In 10/12 (83%), respiratory symptoms occurred before or concomitantly with the classical symptoms of Sjogren's syndrome. There were two distinct forms of respiratory involvement: xerotrachea, manifested by dry cough without other symptoms and negative roentgenological and functional evaluation and diffuse interstitial lung disease manifested by dyspnea with or without dry cough with bibasilar rales, compatible chest roentgenogram, restrictive pattern in spirometry and/or hypoxemia. Xerotrachea was more common in patients with glandular form of Sjogren's syndrome (3/10) and diffuse interstitial lung disease in patients with extraglandular form (6/12). None of the 22 patients had pleurisy or other forms of respiratory involvement. Antibodies to Ro (SSA) and La (SSB) antigens were more common in patients with the extraglandular form of the syndrome but did not correlate with diffuse interstitial lung disease.     

Cystic fibrosis-associated liver disease

Liver disease is increasingly common in cystic fibrosis (CF). As new therapeutic options emerge, life expectancy increases and common hepatobiliary manifestations impact on quality of life and survival of CF patients. Hepatobiliary abnormalities in CF vary in nature and range from defects attributable to the underlying CFTR gene defect to those related to systemic disease and malnutrition. Today complications of liver disease represent the third most frequent cause of disease-related death in patients with CF. Here we review molecular and clinical genetics of CF, including genetic modifiers of CF-associated liver disease, and provide practical recommendations for genetic testing, diagnosis and treatment of hepatobiliary manifestations in CF.