Tag: visualeditor-wikitext |
|
| Line 1: |
Line 1: |
| {{Use dmy dates|date=August 2018}}
| | {{Infobox medical condition |
| {{Infobox medical condition (new) | | | name = Diffuse Panbronchiolitis |
| | name = Diffuse panbronchiolitis | | | image = |
| | image = HRCT scans of diffuse panbronchiolitisCropped.jpg | | | caption = |
| | caption = [[High-resolution computed tomography]] images of the lower chest in a 16-year-old boy with diffuse panbronchiolitis | | | field = [[Pulmonology]] |
| | pronounce =
| | | symptoms = [[Cough]], [[sputum production]], [[dyspnea]] |
| | field = [[Pulmonology]] | | | complications = [[Respiratory failure]], [[cor pulmonale]] |
| | synonyms =
| | | onset = Typically in [[adulthood]] |
| | symptoms = | | | duration = Chronic |
| | complications = | | | causes = Unknown, possibly [[genetic]] |
| | onset = | | | risks = [[Asian descent]], [[HLA-B54]] |
| | duration = | | | diagnosis = [[Clinical evaluation]], [[CT scan]], [[lung biopsy]] |
| | types =
| | | treatment = [[Macrolide antibiotics]] |
| | causes = | | | prognosis = Variable, improved with treatment |
| | risks = | |
| | diagnosis = | |
| | differential =
| |
| | prevention =
| |
| | treatment = | |
| | medication =
| |
| | prognosis = | |
| | frequency =
| |
| | deaths =
| |
| }} | | }} |
| '''Diffuse panbronchiolitis''' ('''DPB''') is an [[inflammation|inflammatory]] [[lung disease]] of unknown cause. It is a severe, progressive form of [[bronchiolitis]], an inflammatory condition of the [[bronchiole]]s (small air passages in the lungs). The term ''diffuse'' signifies that [[lesion]]s appear throughout both lungs, while ''panbronchiolitis'' refers to inflammation found in all layers of the [[respiratory bronchioles]] (those involved in [[gas exchange]]). DPB causes severe inflammation and [[Nodule (medicine)|nodule]]-like lesions of [[terminal bronchiole]]s, chronic [[sinusitis]], and intense coughing with large amounts of [[sputum]] production.
| |
|
| |
|
| The disease is believed to occur when there is susceptibility, or a lack of [[immune system]] resistance, to DPB-causing bacteria or viruses, caused by several genes that are found predominantly in individuals of [[East Asian people|East Asian]] descent. The highest [[Incidence (epidemiology)|incidence]] occurs among [[Japanese people]], followed by [[Koreans]]. DPB occurs more often in males, and usually begins around age 40. It was recognized as a distinct new disease in the early 1960s, and was formally named ''diffuse panbronchiolitis'' in 1969.
| | '''Diffuse Panbronchiolitis''' (DPB) is a chronic inflammatory lung disease primarily affecting the [[bronchioles]]. It is characterized by chronic [[sinusitis]], [[productive cough]], and [[dyspnea]]. The condition is most commonly observed in individuals of [[East Asian]] descent, particularly in [[Japan]] and [[Korea]]. |
|
| |
|
| If left untreated, DPB progresses to [[bronchiectasis]], an irreversible lung condition that involves enlargement of the bronchioles, and pooling of [[mucus]] in the bronchiolar passages. Daily treatment of DPB with [[macrolide]] [[antibiotic]]s such as [[erythromycin]] eases symptoms and increases survival time, but the disease currently has no known cure. The eventual result of DPB can be [[respiratory failure]] and heart problems.
| | ==Epidemiology== |
| | Diffuse Panbronchiolitis is predominantly seen in [[East Asian]] populations, with a higher prevalence in [[Japan]]. The disease is rare in other ethnic groups. The exact prevalence is not well-documented, but it is considered a rare disease outside of Asia. |
|
| |
|
| == Classification == | | ==Etiology== |
| | The exact cause of Diffuse Panbronchiolitis is unknown. However, there is a strong association with certain [[genetic]] markers, particularly the [[HLA-B54]] antigen, suggesting a genetic predisposition. Environmental factors have not been clearly identified. |
|
| |
|
| The term "bronchiolitis" generally refers to inflammation of the bronchioles.<ref name=br1/> DPB is classified as a form of "primary bronchiolitis", which means that the underlying cause of bronchiolitis is originating from or is confined to the bronchioles.<ref name=bronc/><ref name=classbronc/> Along with DPB, additional forms of primary bronchiolitis include [[bronchiolitis obliterans]], follicular bronchiolitis, [[Respiratory bronchiolitis interstitial lung disease|respiratory bronchiolitis]], [[mineral dust airway disease]], and a number of others.<ref name=bronc/> Unlike DPB, bronchiolitis that is not considered "primary" would be associated with diseases of the larger airways, such as [[Bronchitis#Chronic_bronchitis|chronic bronchitis]].<ref name=bronc/><ref name=classbronc/> | | ==Pathophysiology== |
| | The disease is characterized by chronic inflammation of the [[bronchioles]], leading to the formation of [[lymphoid follicles]] and [[infiltration]] of [[neutrophils]] and [[lymphocytes]]. This results in obstruction of the small airways and impaired [[mucociliary clearance]], contributing to [[chronic infection]] and [[bronchiectasis]]. |
|
| |
|
| == Signs and symptoms == | | ==Clinical Features== |
| | Patients with Diffuse Panbronchiolitis typically present with: |
| | * [[Chronic cough]] |
| | * [[Sputum production]] |
| | * [[Dyspnea]] on exertion |
| | * [[Chronic sinusitis]] |
|
| |
|
| Symptoms of DPB include [[chronic sinusitis]] (inflamed [[paranasal sinus]]es), wheezing, [[rales|crackles]] ([[respiratory sounds]] made by obstructions such as phlegm and [[secretion]]s in the lungs), [[dyspnea]] (shortness of breath), and a severe cough that yields large amounts of sputum (coughed-up phlegm). There may be [[pus]] in the sputum, and affected individuals may have fever. Typical signs of DPB progression include [[Wiktionary:dilation|dilation]] (enlargement) of the bronchiolar passages and [[hypoxemia]] (low levels of oxygen in the blood). If DPB is left untreated, bronchiectasis will occur; it is characterized by dilation and thickening of the walls of the bronchioles, inflammatory damage to respiratory and [[terminal bronchiole]]s, and pooling of mucus in the lungs.<ref name=dpb06/><ref name=path/> DPB is associated with progressive [[respiratory failure]], [[hypercapnia]] (increased levels of carbon dioxide in the blood), and can eventually lead to [[pulmonary hypertension]] (high blood pressure in the [[pulmonary vein]] and [[pulmonary artery|artery]]) and [[cor pulmonale]] (dilation of the [[right ventricle]] of the heart, or "right heart failure").<ref name=dpb/><ref name=dpb09far/>
| | As the disease progresses, patients may develop [[respiratory failure]] and [[cor pulmonale]]. |
|
| |
|
| == Cause == | | ==Diagnosis== |
| [[File:HLA.svg|thumb|right|200px|The genes for human HLA are located on chromosome 6.]] | | The diagnosis of Diffuse Panbronchiolitis is based on clinical evaluation, imaging studies, and sometimes [[lung biopsy]]. |
|
| |
|
| DPB is [[idiopathic]], which means an exact [[physiological]], [[Environment (biophysical)|environment]]al, or [[pathogen]]ic cause of the disease is unknown. However, several factors are suspected to be involved with its [[pathogenesis]] (the way in which the disease works).<ref name=dpb06/>
| | ===Imaging=== |
| | A [[CT scan]] of the chest typically shows diffuse [[nodular opacities]] and [[bronchiectasis]], particularly in the [[lower lobes]]. |
|
| |
|
| The [[major histocompatibility complex]] (MHC) is a large [[genome|genomic]] region found in most [[vertebrate]]s that is associated with the immune system. It is located on [[chromosome 6]] in humans. A subset of MHC in humans is [[human leukocyte antigen]] (HLA), which controls the [[antigen presentation|antigen-presenting system]], as part of [[adaptive immunity]] against pathogens such as [[bacteria]] and [[virus]]es. When human cells are infected by a pathogen, some of them can present parts of the pathogen's proteins on their surfaces; this is called "antigen presentation". The infected cells then become targets for types of [[cytotoxic T-cell]]s, which kill the infected cells so they can be removed from the body.<ref name=mhcb/>
| | ===Biopsy=== |
| | A [[lung biopsy]] may be performed to confirm the diagnosis, showing characteristic [[histopathological]] features such as [[lymphoid hyperplasia]] and [[inflammatory cell infiltration]]. |
|
| |
|
| Genetic predisposition for DPB susceptibility has been localized to two HLA [[haplotype]]s (a [[nucleotide]] or gene sequence difference between [[Homologous chromosome|paired chromosomes]], that is more likely to occur among a common ethnicity or trait) common to people of East Asian descent. [[HLA-B54]] is associated with DPB in the Japanese, while [[HLA-A11]] is associated with the disease in Koreans.<ref name=dpb11/> Several genes within this region of [[human leukocyte antigen|class I HLA]] are believed to be responsible for DPB, by allowing increased susceptibility to the disease.<ref name=dpb09far/><ref name=dpbo/> The common genetic background and similarities in the HLA profile of affected Japanese and Korean individuals were considered in the search for a DPB gene.<ref name=dpbo/> It was suggested that a mutation of a suspected disease-susceptibility gene located somewhere between [[HLA-B]]<ref name=ohlab/> and [[HLA-A]]<ref name=ohlaa/> had occurred on an ancestral chromosome carrying both HLA-B54 and HLA-A11. Further, it is possible that a number of [[genetic recombination]] events around the disease [[locus (genetics)|locus]] (location on a chromosome) could have resulted in the disease being associated with HLA-B54 in the Japanese and HLA-A11 in Koreans. After further study, it was concluded that a DPB susceptibility gene is located near the HLA-B locus at chromosome 6p21.3. Within this area, the search for a genetic cause of the disease has continued.<ref name=dpb11/><ref name=dpbo/>
| | ==Treatment== |
| | The mainstay of treatment for Diffuse Panbronchiolitis is long-term [[macrolide antibiotic]] therapy, such as [[erythromycin]] or [[clarithromycin]]. These antibiotics have anti-inflammatory properties that help reduce airway inflammation and improve symptoms. |
|
| |
|
| Because many genes belonging to HLA remain unidentified, [[Genetic screen#Positional cloning|positional cloning]] (a method used to identify a specific gene, when only its location on a chromosome is known) has been used to determine that a [[mucin|mucin-like]] gene is associated with DPB. In addition, diseases caused by identified HLA genes in the DPB-susceptibility region have been investigated. One of these, [[Bare lymphocyte syndrome#BLS I|bare lymphocyte syndrome I]] (BLS I), exhibits a number of similarities with DPB in those affected, including chronic sinusitis, bronchiolar inflammation and nodules, and the presence of ''H. influenzae''. Also like DPB, BLS I responds favorably to erythromycin therapy by showing a resolution of symptoms. The similarities between these two diseases, the corresponding success with the same mode of treatment, and the fact that the gene responsible for BLS I is located within the DPB-causing area of HLA narrows the establishment of a gene responsible for DPB.<ref name=dpb11/> Environmental factors such as inhaling toxic fumes and cigarette smoking are not believed to play a role in DPB, and unknown environmental and other non-genetic causes—such as unidentified bacteria or viruses—have not been ruled out.<ref name=dpb06/><ref name=dpb/><ref name=dpb09far/>
| | ==Prognosis== |
| | With appropriate treatment, the prognosis for patients with Diffuse Panbronchiolitis has improved significantly. Long-term macrolide therapy can lead to stabilization or improvement of lung function and symptoms. |
|
| |
|
| [[Cystic fibrosis]] (CF), a progressive multi-system lung disease, has been considered in the search for a genetic cause of DPB. This is for a number of reasons. CF, like DPB, causes severe lung inflammation, abundant mucus production, infection, and shows a genetic predominance among Caucasians of one geographic group to the rarity of others; whereas DPB dominates among East Asians, CF mainly affects individuals of European descent. While no gene has been implicated as the cause of DPB, mutation in a specific gene—much more likely to occur in Europeans—causes CF. This mutation in the [[Cystic fibrosis transmembrane conductance regulator|CF-causing gene]] is not a factor in DPB, but a unique [[genetic polymorphism|polymorphism]] (variation) in this gene is known to occur in many Asians not necessarily affected by either disease. It is being investigated whether this gene in any state of mutation could contribute to DPB.<ref name=dpb06/><ref name=dpb11/> | | ==See Also== |
| | * [[Bronchiectasis]] |
| | * [[Chronic obstructive pulmonary disease]] |
| | * [[Interstitial lung disease]] |
|
| |
|
| == Pathophysiology == | | ==External Links== |
| | * [https://www.wikimd.com/wiki/Diffuse_panbronchiolitis WikiMD: Diffuse Panbronchiolitis] |
|
| |
|
| Inflammation is a normal part of the human immune response, whereby [[leukocyte]]s (white blood cells), including [[neutrophil]]s (white blood cells that specialize in causing inflammation), gather, and [[chemokine]]s (proteins released from certain cells, which activate or elicit a response from other cells) accumulate at any location in the body where bacterial or viral infections occur. Inflammation interferes with the activity of bacteria and viruses, and serves to clear them from the body. In DPB, bacteria such as ''[[Haemophilus influenzae]]'' and ''[[Pseudomonas aeruginosa]]'' can cause the proliferation of inflammatory cells into the bronchiolar tissues. However, when neither bacteria are present with DPB, the inflammation continues for an as yet unknown reason.<ref name=dpb06/><ref name=path/> In either circumstance, inflammation in DPB can be so severe that nodules containing inflammatory cells form in the walls of the bronchioles.<ref name=dpb06/><ref name=inf03/> The presence of inflammation and infection in the airways also results in the production of excess mucus, which must be coughed up as sputum.<ref name=dpb06/><ref name=dpb/> The combination of inflammation, nodule development, infection, mucus, and frequent cough contributes to the breathing difficulties in DPB.<ref name=dpb06/><ref name=path/>
| | {{Pulmonology}} |
| | {{Respiratory diseases}} |
|
| |
|
| The fact that inflammation in DPB persists with or without the presence of ''P. aeruginosa'' and ''H. influenzae'' provides a means to determine several mechanisms of DPB pathogenesis.<ref name=path/> [[Leukotriene]]s are [[eicosanoid]]s, [[lipid signaling|signaling molecules]] made from [[essential fatty acid]]s, which play a role in many lung diseases by causing the proliferation of inflammatory cells and excess mucus production in the airways.<ref name=leuk/> In DPB and other lung diseases, the predominant mediator of neutrophil-related inflammation is [[leukotriene B4]], which specializes in neutrophil proliferation via [[chemotaxis]] (the movement of some types of cells toward or away from certain molecules).<ref name=dpb06/><ref name=dpb11/>
| | [[Category:Respiratory diseases]] |
| | | [[Category:Pulmonology]] |
| Inflammation in DPB is also caused by the chemokine [[CCL4|MIP-1alpha]] and its involvement with [[CD8|CD8<sup>+</sup>]] [[T cell]]s. [[Beta defensin]]s, a family of [[antimicrobial]] [[peptide]]s found in the respiratory tract, are responsible for further inflammation in DPB when a pathogen such as ''P. aeruginosa'' is present. If present with DPB, the [[human T-lymphotropic virus|human T-lymphotropic virus, type I]], a [[retrovirus]], modifies DPB pathogenesis by infecting [[T helper cell]]s and altering their effectiveness in recognizing the presence of known or unknown pathogens involved with DPB.<ref name=dpb06/><ref name=dpb11/>
| |
| | |
| == Diagnosis ==
| |
| [[File:HRCT scans of diffuse panbronchiolitis.jpg|thumb|400px|left|High resolution computed tomography (HRCT) images of the lower chest in a 16-year-old boy initially diagnosed with DPB (''left''), and 8 weeks later (''right'') after a 6-week course of treatment with erythromycin. The bilateral bronchiectasis and prominent centri-lobular nodules with a "tree-in-bud" pattern shows noticeable improvement.]]
| |
| The diagnosis of DPB requires [[medical test|analysis]] of the lungs and bronchiolar tissues, which can require a lung [[biopsy]], or the more preferred [[high resolution computed tomography]] (HRCT) scan of the lungs.<ref name=dpb09far/> The diagnostic criteria include severe inflammation in all layers of the respiratory bronchioles and lung tissue lesions that appear as nodules within the [[terminal bronchiole|terminal]] and respiratory bronchioles in both lungs.<ref name=dpb06/> The nodules in DPB appear as [[Opacity (optics)|opaque]] lumps when viewed on [[X-ray]]s of the lung, and can cause [[airway obstruction]], which is evaluated by a [[spirometry|pulmonary function test]], or PFT.<ref name=dpb/> Lung X-rays can also reveal dilation of the bronchiolar passages, another sign of DBP. HRCT scans often show blockages of some bronchiolar passages with mucus, which is referred to as the [[tree-in-bud sign|"tree-in-bud"]] pattern.<ref name=dpb09far/> Hypoxemia, another sign of breathing difficulty, is revealed by measuring the oxygen and carbon dioxide content of the blood, using a blood test called [[arterial blood gas]]. Other findings observed with DPB include the proliferation of [[lymphocyte]]s ([[white blood cell]]s that fight infection), neutrophils, and [[histiocyte|foamy histiocytes]] (tissue [[macrophage]]s) in the lung [[lumen (anatomy)|lining]]. Bacteria such as ''H. influenzae'' and ''P. aeruginosa'' are also detectable, with the latter becoming more prominent as the disease progresses.<ref name=dpb06/><ref name=path/> The white blood, bacterial and other cellular content of the blood can be measured by taking a [[complete blood count]] (CBC). Elevated levels of [[IgG]] and [[IgA]] (classes of [[immunoglobulin]]s) may be seen, as well as the presence of [[rheumatoid factor]] (an indicator of [[autoimmunity]]). [[Hemagglutination]], a clumping of red blood cells in response to the presence of [[antibodies]] in the blood, may also occur. Neutrophils, beta-defensins, leukotrienes, and chemokines can also be detected in [[bronchoalveolar lavage]] fluid injected then removed from the bronchiolar airways of individuals with DPB, for evaluation.<ref name=dpb06/><ref name=dpb11/>
| |
| | |
| === Differential diagnosis ===
| |
| | |
| In the [[differential diagnosis]] (finding the correct diagnosis between diseases that have overlapping features) of some obstructive lung diseases, DPB is often considered. A number of DPB symptoms resemble those found with other obstructive lung diseases such as [[asthma]], [[Bronchitis#Chronic_bronchitis|chronic bronchitis]], and [[emphysema]]. [[Wheeze|Wheezing]], coughing with [[sputum]] production, and shortness of breath are common symptoms in such diseases, and obstructive respiratory functional impairment is found on [[pulmonary function testing]].<ref name=dpb/> Cystic fibrosis, like DPB, causes severe lung inflammation, excess mucus production, and infection; but DPB does not cause disturbances of the pancreas nor the [[electrolyte]]s, as does CF, so the two diseases are different and probably unrelated.<ref name=dpb06/><ref name=dpb11/> DPB is distinguished by the presence of lesions that appear on X-rays as nodules in the bronchioles of both lungs; inflammation in all [[tissue (biology)|tissue]] layers of the respiratory bronchioles; and its higher prevalence among individuals with East Asian lineage.<ref name=dpb06/>
| |
| | |
| DPB and [[bronchiolitis obliterans]] are two forms of primary bronchiolitis.<ref name=bronc/> Specific overlapping features of both diseases include strong cough with large amounts of often pus-filled sputum; nodules viewable on lung X-rays in the lower bronchi and bronchiolar area; and chronic sinusitis. In DPB, the nodules are more restricted to the respiratory bronchioles, while in OB they are often found in the membranous bronchioles (the initial non-cartilaginous section of the bronchiole, that divides from the [[tertiary bronchus]]) up to the [[secondary bronchus]]. OB is a bronchiolar disease with worldwide prevalence, while DPB has more localized prevalence, predominantly in Japan.<ref name=bronc/><ref name=dpb/> Prior to clinical recognition of DPB in recent years, it was often misdiagnosed as [[bronchiectasia]], [[COPD]], [[Idiopathic pulmonary fibrosis|IPF]], [[phthisis miliaris]], [[sarcoidosis]] or [[bronchioloalveolar carcinoma|alveolar cell carcinoma]].<ref name="Huiping Li" />
| |
| | |
| == Treatment ==
| |
| [[File:Erythromycin A.svg|thumb|Molecular structure of Erythromycin A, an antibiotic used to treat DPB]]
| |
| [[Macrolide]] antibiotics, such as [[erythromycin]], are an effective treatment for DPB when taken regularly over an extended period of time.<ref name=mac/><ref name=mac08/><ref>{{cite journal |last1=Lin |first1=Xiufang |last2=Lu |first2=Jing |last3=Yang |first3=Ming |last4=Dong |first4=Bi Rong |last5=Wu |first5=Hong Mei |title=Macrolides for diffuse panbronchiolitis |journal=Cochrane Database of Systematic Reviews |date=25 January 2015 |doi=10.1002/14651858.CD007716.pub4|pmc=6464977 }}</ref> [[Clarithromycin]] or [[roxithromycin]] are also commonly used.<ref name=AJRM/> The successful results of macrolides in DPB and similar lung diseases stems from managing certain symptoms through [[Immunotherapy|immunomodulation]] (adjusting the immune response),<ref name=mac08/> which can be achieved by taking the antibiotics in low [[dosing|doses]]. Treatment consists of daily oral administration of erythromycin<ref name=dpb09far/> for two to three years, an extended period that has been shown to dramatically improve the effects of DPB. This is apparent when an individual undergoing treatment for DPB, among a number of disease-related remission criteria, has a normal neutrophil count detected in BAL fluid, and [[arterial blood gas|blood gas]] (an [[artery|arterial]] [[blood test]] that measures the amount of oxygen and carbon dioxide in the blood) readings show that free oxygen in the blood is within the normal range.<ref name=mac/><ref name=mac08/><ref name=mac04/> Allowing a temporary break from erythromycin therapy in these instances has been suggested, to reduce the formation of macrolide-resistant ''P. aeruginosa''.<ref name=mac/> However, DPB symptoms usually return, and treatment would need to be resumed. Although highly effective, erythromycin may not prove successful in all individuals with the disease, particularly if macrolide-resistant ''P. aeruginosa'' is present or previously untreated DPB has progressed to the point where respiratory failure is occurring.<ref name=mac08/><ref name=mac04/>
| |
| | |
| With erythromycin therapy in DPB, great reduction in bronchiolar inflammation and damage is achieved through suppression of not only [[neutrophil]] proliferation, but also lymphocyte activity and obstructive mucus and water [[secretion]]s in airways.<ref name=mac/> The antibiotic effects of macrolides are not involved in their beneficial effects toward reducing inflammation in DPB.<ref name=mac04/> This is evident because the treatment dosage is much too low to fight infection, and in DPB cases with the occurrence of macrolide-resistant ''P. aeruginosa'', erythromycin therapy still reduces inflammation.<ref name=mac/>
| |
| | |
| A number of factors are involved in suppression of inflammation by erythromycin and other macrolides. They are especially effective at inhibiting the proliferation of neutrophils, by diminishing the ability of [[interleukin 8]] and [[leukotriene B4]] to attract them.<ref name=clinf/> Macrolides also reduce the efficiency of [[cell adhesion|adhesion molecules]] that allow neutrophils to stick to bronchiolar tissue linings. Mucus production in the airways is a major culprit in the morbidity and mortality of DPB and other respiratory diseases. The significant reduction of inflammation in DPB attributed to erythromycin therapy also helps to inhibit the production of excess mucus.<ref name=clinf/>
| |
| | |
| == Prognosis ==
| |
| Untreated DPB leads to bronchiectasis, respiratory failure, and death. A journal report from 1983 indicated that untreated DPB had a five-year survival rate of 62.1%, while the 10-year survival rate was 33.2%.<ref name=dpb/> With erythromycin treatment, individuals with DPB now have a much longer life expectancy due to better management of symptoms, delay of progression, and prevention of associated infections like ''P. aeruginosa''.<ref name=mac04/> The 10-year survival rate for treated DPB is about 90%.<ref name=dpb06/> In DPB cases where treatment has resulted in significant improvement, which sometimes happens after about two years, treatment has been allowed to end for a while. However, individuals allowed to stop treatment during this time are closely monitored. As DPB has been proven to recur, erythromycin therapy must be promptly resumed once disease symptoms begin to reappear. In spite of the improved prognosis when treated, DPB currently has no known cure.<ref name=dpb06/><ref name=dpb11/>
| |
| | |
| == Epidemiology ==
| |
| DPB has its highest [[prevalence]] among the Japanese, at 11 per 100,000 population.<ref name=dpb06/> Korean,<ref name=kor/> Chinese,<ref name=chitwo/> and Thai<ref name=thai/> individuals with the disease have been reported as well. A genetic predisposition among East Asians is suggested.<ref name=dpb11/> The disease is more common in males,<ref name=ew/> with the male to female ratio at 1.4–2:1 (or about 5 men to 3 women).<ref name=dpb06/> The average onset of the disease is around age 40, and two-thirds of those affected are non-smokers, although smoking is not believed to be a cause.<ref name=dpb09far/> The presence of HLA-Bw54 increases the risk of diffuse panbronchiolitis 13.3-fold.<ref>{{Cite book | author=Lazarus SC | title=Murray and Nadel's Textbook of Respiratory Medicine | publisher=WB Saunders | year=2005 | page=1300 | edition=4th | isbn=978-0-7216-0327-8 | url-access=registration | url=https://archive.org/details/murraynadelstext0000unse }}</ref>
| |
| | |
| In Europe and the Americas, a relatively small number of DPB cases have been reported in Asian immigrants and residents, as well as in individuals of non-Asian ancestry.<ref name=usa/><ref name=lat/><ref name=can/> Misdiagnosis has occurred in the West owing to less recognition of the disease than in Asian countries. Relative to the large number of Asians living in the west, the small number of them thought to be affected by DPB suggests non-genetic factors may play some role in its cause. This rarity seen in Western Asians may also be partly associated with misdiagnosis.<ref name=dpb09far/><ref name=dpbai/>
| |
| | |
| == History ==
| |
| In the early 1960s, a relatively new chronic lung disease was being observed and described by physicians in Japan. In 1969,<ref name=dpb69/> the name "diffuse panbronchiolitis" was introduced to distinguish it from chronic bronchitis, emphysema, [[Extrinsic allergic alveolitis|alveolitis]], and other obstructive lung disease with inflammation. Between 1978 and 1980, results of a nationwide survey initiated by the Ministry of Health and Welfare of Japan revealed more than 1,000 probable cases of DPB, with 82 histologically confirmed. By the 1980s, it was internationally recognized as a distinct disease of the lungs.<ref name=dpb06/><ref name=dpb/>
| |
| | |
| Before the 1980s, the prognosis or expected outcome of DPB was poor, especially in cases with [[superinfection]] (the emergence of a new viral or bacterial infection, in addition to the currently occurring infection) by ''P. aeruginosa''.<ref name=inf03/> DPB continued to have a very high mortality rate before generalized antibiotic treatment and [[oxygen therapy]] were beginning to be used routinely in the effort to manage symptoms. Around 1985, when long-term treatment with the antibiotic erythromycin became the standard for managing DPB, the prognosis significantly improved.<ref name=mac04/> In 1990, the association of DPB with HLA was initially asserted.<ref name=dpb11/>
| |
| | |
| == External links ==
| |
| {{Medical resources
| |
| | DiseasesDB = 3804
| |
| | ICD10 = {{ICD10|J|21|9|j|21}}
| |
| | ICD9 = {{ICD9|466.1}}
| |
| | ICDO =
| |
| | OMIM = 604809
| |
| | MedlinePlus =
| |
| | eMedicineSubj =
| |
| | eMedicineTopic =
| |
| | MeshID =
| |
| }}
| |
| {{Respiratory pathology}}
| |
| {{featured article}}
| |
| | |
| [[Category:Genetic disorders with OMIM but no gene]] | |
| [[Category:Rare diseases]] | | [[Category:Rare diseases]] |
| [[Category:Respiratory diseases]] | | [[Category:Genetic disorders]] |
Diffuse Panbronchiolitis (DPB) is a chronic inflammatory lung disease primarily affecting the bronchioles. It is characterized by chronic sinusitis, productive cough, and dyspnea. The condition is most commonly observed in individuals of East Asian descent, particularly in Japan and Korea.
Epidemiology
Diffuse Panbronchiolitis is predominantly seen in East Asian populations, with a higher prevalence in Japan. The disease is rare in other ethnic groups. The exact prevalence is not well-documented, but it is considered a rare disease outside of Asia.
Etiology
The exact cause of Diffuse Panbronchiolitis is unknown. However, there is a strong association with certain genetic markers, particularly the HLA-B54 antigen, suggesting a genetic predisposition. Environmental factors have not been clearly identified.
Pathophysiology
The disease is characterized by chronic inflammation of the bronchioles, leading to the formation of lymphoid follicles and infiltration of neutrophils and lymphocytes. This results in obstruction of the small airways and impaired mucociliary clearance, contributing to chronic infection and bronchiectasis.
Clinical Features
Patients with Diffuse Panbronchiolitis typically present with:
As the disease progresses, patients may develop respiratory failure and cor pulmonale.
Diagnosis
The diagnosis of Diffuse Panbronchiolitis is based on clinical evaluation, imaging studies, and sometimes lung biopsy.
Imaging
A CT scan of the chest typically shows diffuse nodular opacities and bronchiectasis, particularly in the lower lobes.
Biopsy
A lung biopsy may be performed to confirm the diagnosis, showing characteristic histopathological features such as lymphoid hyperplasia and inflammatory cell infiltration.
Treatment
The mainstay of treatment for Diffuse Panbronchiolitis is long-term macrolide antibiotic therapy, such as erythromycin or clarithromycin. These antibiotics have anti-inflammatory properties that help reduce airway inflammation and improve symptoms.
Prognosis
With appropriate treatment, the prognosis for patients with Diffuse Panbronchiolitis has improved significantly. Long-term macrolide therapy can lead to stabilization or improvement of lung function and symptoms.
See Also
External Links
| Pulmonology topics |
| Diseases | |
| Diagnostic | |
| Treatments | |
| Related fields | |
| Professionals | |
This pulmonology-related article is a stub. You can help WikiMD by expanding it.
|
| Respiratory diseases |
| Upper respiratory tract | |
| Lower respiratory tract | |
| Pleural cavity | |
| Pulmonary vascular diseases | |
| Related conditions and diseases | |
This respiratory disease-related article is a stub. |
