Diffuse panbronchiolitis
Severe progressive bronchiolitis of unknown cause, mainly in East Asians.
Diffuse panbronchiolitis (DPB) is a serious, progressive inflammatory lung condition with no known cause. It is a severe type of bronchiolitis, meaning it affects the tiny air passages in the lungs called bronchioles. The word "diffuse" indicates that the damage is spread throughout both lungs, while "panbronchiolitis" means that all layers of the respiratory bronchioles—the ones responsible for gas exchange—are inflamed. The disease leads to intense inflammation, nodule-like growths in the terminal bronchioles, chronic sinusitis, and a heavy cough that produces large amounts of phlegm.
The condition is thought to arise when the immune system lacks resistance to certain bacteria or viruses, likely due to genetic factors found mostly in people of East Asian descent. It is most common in Japan, followed by Korea, and affects men more often than women, typically starting around age 40. DPB was first identified as a distinct illness in the early 1960s and officially named in 1969.
Without treatment, DPB leads to bronchiectasis, an irreversible condition where the bronchioles become enlarged and mucus pools in the airways. Daily use of macrolide antibiotics like erythromycin can ease symptoms and extend survival, but there is no cure. Eventually, DPB can result in respiratory failure and heart complications.
DPB is classified as a primary bronchiolitis, meaning the inflammation originates in the bronchioles themselves, rather than being linked to diseases of the larger airways like chronic bronchitis. Other forms of primary bronchiolitis include bronchiolitis obliterans, follicular bronchiolitis, respiratory bronchiolitis, and mineral dust airway disease.
Symptoms include chronic sinusitis, wheezing, crackling sounds in the lungs, shortness of breath, and a severe cough with large amounts of sputum, which may contain pus. Fever can also occur. As the disease progresses, the bronchiolar passages widen, and oxygen levels in the blood drop. If untreated, bronchiectasis develops, marked by thickened, dilated bronchioles, inflammatory damage, and mucus buildup. Advanced DPB can lead to respiratory failure, high carbon dioxide levels in the blood, pulmonary hypertension, and right heart failure.
The exact cause of DPB is unknown, but several factors are suspected.
Quick Facts
- Field
- Pulmonology
Facts from the source article.
Lore & Background
Diffuse panbronchiolitis was recognized as a distinct new disease in the early 1960s and was formally named in 1969. It 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 found predominantly in individuals of East Asian descent. Genetic predisposition has been localized to two HLA haplotypes: HLA-B54 is associated with DPB in the Japanese, while HLA-A11 is associated with the disease in Koreans. A DPB susceptibility gene is thought to be located near the HLA-B locus at chromosome 6p21.3.
Reader's Guide
Diffuse panbronchiolitis is significant as a distinct, progressive lung disease that primarily affects East Asian populations, with the highest incidence among Japanese and Koreans. Its recognition in the 1960s and formal naming in 1969 established it as a separate entity from other bronchiolitis forms. The disease is idiopathic, but genetic factors involving HLA haplotypes are strongly implicated. If left untreated, DPB progresses to bronchiectasis, respiratory failure, and heart problems. Daily treatment with macrolide antibiotics such as erythromycin eases symptoms and increases survival time, but there is no known cure. The disease's genetic basis and response to therapy have informed research into similar conditions like bare lymphocyte syndrome I and cystic fibrosis, though the exact cause remains unknown.
Did You Know?
- DPB was formally named in 1969.
- The highest incidence occurs among Japanese people, followed by Koreans.
- If left untreated, DPB progresses to bronchiectasis, an irreversible lung condition.
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