Patterns of Disease in the Lung

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Patterns of Disease in the Lung
2015-02-24 16:09:48
Lung Disease Pneumonia Neoplasia

Vet Med - Module 9
Show Answers:

  1. What are the four pathogen routes of entry into the lungs?
    • Aerogenous (including aspiration)
    • Haematogenous
    • Direct entry
    • Lymphatic spread
  2. What are the four basic classifications of pneumonia?
    Bronchopneumonia, interstitial pneumonia, granulomatous pneumonia, and embolic pneumonia
  3. What are the four subclasses of bronchopneumonia?
    Enzootic, suppurative, fibrinous and aspiration
  4. Describe the pathogenesis of bronchopneumonia
    Inhaled agents --> inflammation at the bronchoalveolar junction --> acute inflammatory response --> exudation of fluid and plasma proteins into bronchioles and alveoli --> recruitment of alveolar macrophages and emigration of neutrophils
  5. What type of distribution does bronchopneumonia have?
    Cranioventral distribution
  6. What are the different causes of bronchopneumonia?
    • Bacteria eg Pasteurella multocidaMannheimia haemolytica, Bordatella bronchispetica
    • Mycoplasmas
    • Aspirated food/gut contents
    • Viruses + secondary bacterial infection
  7. What is the route of entry for bronchopneumonia?
    Inhaled (aerogenous)
  8. What is the main cause of enzootic pneumonia?
  9. What is another term for enzootic pneumonia?
    Cuffing pneumonia, atypical pneumonia, chronic nonprogressive pneumonia
  10. What can be seen on gross and histological appearance of enzootic pneumonia?
    • Gross: cranioventral distribution, dark red, sharply demarcated, combination of collapse and consolidation
    • Histology: peribronchial cuffing of lymphocytes and plasma cells
  11. What is the main cause of suppurative pneumonia?
  12. What is the main cell type found in suppurative pneumonia?
    Neutrophils, typically degenerate
  13. What is the distribution of suppurative pneumonia?
  14. What substances are present in fibrinous pneumonia?
    Fibrin, oedema, neutrophils (degenerate) and necrosis
  15. What are the causes of fibrinous pneumonia?
    • Mannheimia haemolytica (shipping fever), Histophilus somni - cattle
    • Actinobacillus pleuropneumoniae - pigs
    • Aspiration of gut contents
  16. What is the distribution of fibrinous pneumonia?
  17. What can be seen on the gross surface of lungs with fibrinous pneumonia?
    Fibrinous pleural surface and marked expansion of interlobular septae
  18. What does Mannheimia haemolytica produce that causes tissue necrosis and fibrinous bronchopneumonia?
  19. What is aspiration pneumonia?
    When feed contents are found in the airways/alveoli in the middle of inflammation
  20. What are the predisposing causes of aspiration pneumonia?
    • Handfeeding neonatal animals
    • Megaoesophagus from any cause
    • Cleft palate/congenital abnormalities
    • Down animals e.g. anaesthesia
    • Iatrogenic e.g. putting feeding tube into lungs
  21. What can be seen on gross inspection of aspiration pneumonia?
    Often has a green/brown/black discolouration, perhaps foul smelling
  22. What does BALT stand for?
    Bronchial associated lymphoid tissue
  23. What is the distribution of interstitial pneumonia?
  24. What can be seen on gross inspection of lungs with interstitial pneumonia?
    Large lungs that do not deflate, rib impressions, rubbery/meaty texture
  25. What are the different causes of interstitial pneumonia?
    • Viral (canine distemper, IBR, EVR, Maedi)
    • Inhaled toxins/gases
    • Toxic metabolites locally generated
    • Acute respiratory distress syndrome (ARDS)
    • Ventilator induced injury
  26. What does PRRS stand for?
    Porcine reproductive respiratory syndrome
  27. What is the distribution of granulomatous pneumonia?
    Multifocal, any lobe
  28. What can be seen on histology with granulomatous pneumonia?
    Macrophages plus multinucleate giant cells arranged as discrete granulomas or in sheets
  29. What is the route of entry for granulomatous pneumonia?
    Aerogenous, haematogenous or lymphatic spread
  30. What are some possible causes of granulomatous pneumonia?
    Fungal pneumonias, bacteria, parasites
  31. Give an example of a parasite that can cause pneumonia
    Dictyocaulus viviparus/filaria
  32. What type of parasite in sheep causes 'lead shot lesions'?
    Muelleris capillaris
  33. What is the distribution of embolic pneumonia?
    Multifocal, random
  34. What is the route of entry for embolic pneumonia?
  35. What are the possible causes of embolic pneumonia?
    Vegetative valvular endocarditis, hepatic abscesses, any septicaemia
  36. What is the difference between primary and metastatic lung neoplasms?
    Primary neoplasms originate in the lung whereas metastatic neoplasms have moved to the lung from another site (as the lung is a popular metastatic site due to its massive blood flow and capillary bed)
  37. Primary lung neoplasms are commonly ... in origin?
  38. What is the malignant/non-malignant form of epithelial neoplasms?
    • Malignant - carcinoma
    • Non-malignant - adenoma
  39. What are the other cancer cell types?
    Round cell and mesenchymal
  40. What is feline 'lung-digit' syndrome?
    This is when pulmonary carcinomas have a tendency to metastasise to multiple digits on multiple limbs.  It is typically the first clinical sign in these cases.
  41. What is the name of the virus that causes lung neoplasia in sheep?  How does it do this?
    Jaagsiekte or ovine pulmonary adenocarcinoma.  This virus transforms alveolar epithelial cells (type II pneumocytes and clara cells) into a neoplastic population.
  42. What test can be used to diagnose Jaagsiekte?
    A wheelbarrow test - tip the sheep forward on its front legs and fluid will drip out of its nose
  43. Give examples of areas where metastatic lung tumours come from
    • Haemangiosarcoma (speen or right atrium)
    • Osteosarcoma
    • Mammary carcinomas