000 Respiratory Bronchiolitis, ILD

  • Buzz words
    • Respiratory bronchiolitis
      • All smokers
      • Usually symptomatic and no clinical significance
    • Respiratory bronchiolitis ILD

Etiology Cigarette Smoke

Difference between RB , RB ILD and desquamative interstitial pneumonia (DIP) is that RB has centrilobular findings while RB ILD has centrilobular changes and ground glass changes and DIP has centrilobular findings ground glass changes and cysts.

A “smoker’s macrophage”, with yellow to light brown and finely granular cytoplasmic pigment.
Courtesy Wiki
web lungs 437
Photomicrograph (original magnification, x100; hematoxylin-eosin stain) showing the characteristic histologic features of RB-ILD. Pigmented macrophages in a terminal bronchiole and the adjacent alveoli (arrows), and moderate peribronchiolar inflammation and fibrosis (arrowhead) are present. *Mueller-Mang C, Grosse C, Schmid K, et al.: What every radiologist should know about idiopathic interstitial pneumonias. Radiographics 2007, 27:595–615.
Prior permission from The Radiological Society of North America.
Sieminska A, et al  Respiratory bronchiolitis-interstitial lung disease Orphanet Journal of Rare Diseases volume 9: 106 (2014)
Macrophages, wall and lumen of bronchiole, and centrilobular nodules
Histopathology of respiratory bronchiolitis: Smoker’s macrophages (arrow); mild interstitial lymphocytic infiltrate and mild fibrosis (arrowhead)[
Courtesy Wiki
web lungs 438
Axial HRCT shows ill-defined centrilobular ground-glass nodules image in the upper lobes. The patient had a mild cough and dyspnea with exercise.
Courtesy Radiology Key
Coronal HRCT reconstruction shows faint centrilobular nodules image in the upper lobes sparing the lower lung zones in this asymptomatic patient with a 40 pack-year smoking history. Courtesy Radiology key

 

High-resolution computer tomography in respiratory bronchiolitis-associated interstitial lung disease. Bronchiolocentric interstitial ground-glass opacifications, accentuated in the upper part of the lung.
Smoking-Related Interstitial Lung Disease
January 2015Deutsches Ärzteblatt International 112(4):43-50 Hagmeyer L et al
RB-ILD in a 32-year-old man with a 17 pack-year history of smoking who presented with a cough, restrictive PFT results, and reduced diffusion capacity. (a) High-resolution CT image obtained through the upper lungs shows bilateral centrilobular ground-glass nodules (arrow).
Attili, A.K etal  Smoking-related Interstitial Lung Disease: Radiologic-Clinical-Pathologic Correlation RadioGraphics Vol. 28, No. 5  2008
Photomicrograph of a surgical lung biopsy specimen shows a bronchiolocentric collection of pigmented macrophages (arrow).
Attili, A.K etal  Smoking-related Interstitial Lung Disease: Radiologic-Clinical-Pathologic Correlation RadioGraphics Vol. 28, No. 5  2008
  • Histopathology characterized by
      • pigmented macrophages and
      • respiratory bronchioles and alveoli
        • mild interstitial inflammatory
        • alveolar septa in the peribronchial may be mildly thickened
        • no significant fibrosis

DIP is similar to RB-ILD,

    •  DIP and  RB-ILD are a spectrum
    • differing in compartments involved
    • DIP not bronchiolocentric.
    • hyperplasia of the alveolar type II cells
    • distribution pattern more homogeneous a
    • mild peribronchial fibrosis

Buzz

Use your words

respiratory bronchiolitis = inflammation of the respiratory bronchioles.

dirty lung appearance

centrilobular lung nodules

ground glass

air trapping

emphysema

Respiratory Bronchiole

The diagram shows the structure of the airways and alveoli at the level of the secondary lobule. The terminal bronchiole (tb- pink) enters the secondary lobule and terminates in the respiratory bronchiole (rb – purple) which lies in the center of the the secondary lobule (centrilobular). It gives rise to the alveolar duct (ad,  yellow)which gives rise to the alveolar sac (as, teal blue. Finally the alveolar sac terminates in the alveoli (a white).
Courtesy Ashley Davidoff MD
lungs-0028-low res

 

The arteriole and bronchiole lie in the center of the lobule.
Pulmonary venules (red) and lymphatics (yellow). lie in the periphery of the lobule
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Davidoff Art Courtesy Ashley Davidoff MD

 

Secondary Lobule

Inhalation – Upper Lobes

centrilobular ground glass nodules

References and Links
Attili, A.K etal  Smoking-related Interstitial Lung Disease: Radiologic-Clinical-Pathologic Correlation RadioGraphics Vol. 28, No. 5Gupta et al Diffuse Cystic Lung Disease: Part I  American Journal of Respiratory and Critical Care Medicine 191(12)  April 2015Sieminska A, et al  Respiratory bronchiolitis-interstitial lung disease Orphanet Journal of Rare Diseases volume 9: 106 (2014)Wiki