23. Chronic Pulmonary Infections Fungal Pneumonia - Cox

• Chronic pneumonias usually caused by slow-growing organisms

  • last more than 6 weeks
• General Pathophysiology for fungal pulmonary infection

  1. inhaled fungal spores - reaching deep lung tissue
  2. pneumonia
  3. fungemia - typically with IC pts
• General mechanism of fungal infection - Steps

  1. fungal spores sticks to host cell or ECM
  2. fungi penetrate host tissue by
  3. direct invasion
  4. phagocytosis
  5. endocytosis
  6. fungus use host nutrients to grow
• Fungus can enter blood stream and cause extrapulmonary dissemination
• How the host deal with the fungus once infected?

  • Host immune system starts inflammatory response
  • can lead to clearance
  • clearance
  • tissue damage --> further fungi invasion
  • Evade host by
  • modulation immune response
  • secretion of virulence factors
• disseminated fungal disease is common with?

  IC pts
• Disseminated fungal disease is when fungus enter bloodstream and invade any organs
• Mechanism of extrapulmonary dissemination

  1. fungi hijack phagocyte (trojan horse)
  2. direct invasion
  3. transcytosis - receptor mediated translocation
  4. paracellular cross - protease disrupt barriers
• Blasto endemic to?

  • Mississippi river
  • Ohio river
  • great lakes
• Blasto - conidia are phagocytized by bronchopulmonary cells

  • convert to yeast form - increase survival rate by
  • increase size and thickness
• Blasto - description

  • thick walled yeast cells with broad based budding
• Coccidio - common cause of community acquired pneumonia in the southwest
• Coccidio life cycle

  1. inhalation of spores
  2. in lung - forms spherule
  3. spherule undergo division and ruptures to form endospores
  4. disseminate throughout lung
• crypto found in

  • pigeon or bat poop
• Histo - IC pts no granuloma
• Allergic bronchopulmonary aspergillosis

  • non-invasive bc hyphae do not breach mucosa
  • allergic reaction - elevate IgE and IgG
  • necrotizing granulomatous inflammation
• ** Allergic bronchopulmonary aspergillosis can cause necrotizing granulomatous

  • will destroy wall of bronchi leading to bronchiectasis
•  Chronic pulmonary aspergillosis

  • non-invasion - fungi forms a ball leading to ischemic necrosis by occluding vessels
•  Chronic pulmonary aspergillosis occur when the fungus colonize a preexisting lung cavity
• invasive aspergillosis - subacute or chronic necrotizing apsergillosis

  • occur in
  • COPD
  • diabetes
  • alcoholism
  • corticosteroid
• invasive aspergillosis - airway invasive

  • occur in
  • IC or AID/HIV
• invasive aspergillosis - angioinvasive

  • occur in severely IC patients
• Subacute invasive pulmonary aspergillosis - form its own with central necrosis
• Mucor

  • larger spores will lodge in upper respiratory tract
  • smaller reach distal alveolar spaces
• Mucor will cause angioinvasion leading to hemorrhagic necrosis
• Mucor is right angle hyphae
• Mucor will invade pulmonary blood vessels causing massive hemorrhage
• PJP is considered AIDS defining disease


  • Pneumocystis jirovecii Pneumonia
• CMV infects endothelial or alveolar cells