Upper Lung Zone Disease Distribution

Upper Lung Zone Disease Distribution
Jud W. Gurney, MD, FACR
DIFFERENTIAL DIAGNOSIS
Common
  • Post-Primary Tuberculosis
  • Sarcoidosis
  • Centrilobular Emphysema
  • Bronchiolitis, Respiratory
  • Langerhans Cell Histiocytosis
Less Common
  • Silicosis/Coal Worker’s Pneumoconiosis
  • Chronic Hypersensitivity Pneumonitis
  • Cystic Fibrosis
  • Chronic Eosinophilic Pneumonia
  • Allergic Bronchopulmonary Aspergillosis
Rare but Important
  • Neurogenic Pulmonary Edema
  • Smoke Inhalation
  • Metastatic Pulmonary Calcification
  • Ankylosing Spondylitis
  • Chronic Lung Allograft Rejection
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
  • Pneumonic: CHEST CASES
    • Cystic fibrosis, Histiocytosis X or Hypersensitivity pneumonitis, Emphysema, Sarcoidosis, Tuberculosis
    • Calcification-metastatic pulmonary, ABPA or Ankylosing spondylitis, Silicosis, Eosinophilic pneumonia, Smoke inhalation
  • Normal physiologic gradients in upright lung create zones or regions of lung that differ in terms of blood flow, ventilation, lymphatic function, stress, and concentration of inhaled gases
    • Consider lung as a map, with zones not defined by anatomy but by regional differences produced by physiology
    • End result of interaction between pathologic process with its environment
    • Soil and seed concept: Seeds (pathologic process) finds certain soils (physiologic regions) more conducive to growth
  • Distribution of disease usually readily apparent from frontal radiograph
    • Caveats: Normally lung much thicker at base than at apex
      • Truly uniform distribution of pathology will be more apparent in lower lung zones due to summation across greater thickness of lower lobes
      • Uniform radiographic distribution may actually be more profuse in upper lung zones pathologically due to less summation across thinner upper lobes
Helpful Clues for Common Diagnoses
  • Post-Primary Tuberculosis
    • Proclivity for apical posterior segments of upper lobes
    • Cavitary disease combined with consolidation and bronchial wall thickening
  • Sarcoidosis
    • Chronic granulomatous process of unknown etiology
    • Peribronchial and perilymphatic nodules
    • Identical findings in berylliosis
  • Centrilobular Emphysema
    • Sequelae of long-term smoking
    • Punched out holes in centrilobular distribution
  • Bronchiolitis, Respiratory
    • Clustered “dirty” macrophages in and around respiratory bronchioles from cigarette smoking
    • Faint, ill-defined centrilobular nodules in upper lung zones
    • May be precursor of centrilobular emphysema
  • Langerhans Cell Histiocytosis
    • Granulomas contain Langerhans cell (that processes antigen)
    • Seen almost exclusively in smokers
    • Probably allergic reaction to constituent of cigarette smoke
    • Centrilobular nodules that eventually evolve into bizarre-shaped cysts, paracicatricial emphysema
Helpful Clues for Less Common Diagnoses
  • Silicosis/Coal Worker’s Pneumoconiosis
    • Long-term exposure to occupational dusts
    • Simple (nodular interstitial thickening) may progress to progressive massive fibrosis (PMF)
    • Nodules follow lung lymphatics, tends to be more profuse in dorsal upper lung
  • Chronic Hypersensitivity Pneumonitis
    • History of inhaled organic antigen exposure
    • Upper lung zone distribution, especially common in those with intermittent exposure (like farmer’s lung)
      • Midlung predominance seen in many other antigen exposures that occur continuously (like bird breeder’s lung)
    • Centrilobular ground-glass nodules and hyperinflated lobules (head-cheese sign) evolves into peribronchial fibrosis
  • Cystic Fibrosis
    • Autosomal recessive gene disorder that results in thick viscous secretions
    • Primary pathology occurs in airways
    • Bronchiectasis more severe in upper lobes, especially right upper lobe
  • Chronic Eosinophilic Pneumonia
    • Predominant involvement in upper peripheral lung (“photographic negative” of pulmonary edema)
    • Ground-glass opacities and consolidation
      • Opacities resolve from periphery, leaving lines (inner edge) paralleling chest wall
    • Rapid response to corticosteroid therapy
  • Allergic Bronchopulmonary Aspergillosis
    • Asthma history, abnormal hypersensitivity reaction to Aspergillus organisms
    • Central upper lobe bronchiectasis with peripheral sparing
Helpful Clues for Rare Diagnoses
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Aug 8, 2016 | Posted by in CARDIOLOGY | Comments Off on Upper Lung Zone Disease Distribution

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