This video is part of the series of videos discussing restrictive lung diseases. 
We will discuss hypersensitivity pneumonitis in this talk.

• Definition
  • Alveolitis due to inhaled external allergens. 
  • Involves smaller airways and the respiratory zones instead of the large airways.
• The difference of this disease from asthma.
  • This is a mixture of type III and type IV allergies.
• Pathophysiology of the hypersensitivity pneumonitis
  • Macrophages
  • Allergen presentation to T and B cells in the lymph nodes.
  • Interleukins released.
• Phases
  • Acute and Chronic.
  • Role of neutrophils and T cells in the acute phase.
  • Granuloma formation in the chronic phase.
  • Why hypersensitivity pneumonitis is also classified as a granulomatous disease.
  • IL4, IL5, IL12, C5a
• Scarring of the respiratory zones.
• Clinical Presentation
  • Fever, dyspnea, cough, lethargy, malaise, restrictive lung disease.
  • FEV1 reduced
  • FEV1/FVC increased due to increased elasticity and rapid expulsion.
  • Monday morning blues experienced by the patients.
• Industries/tasks that can cause this disease
  • Fungi and bacteria from farming work - farmers lungs. 
  • Micropolyspora fanny and bagassosis. 
  • Thermophilic actinomycetes.Cheese workers - moldy cheese. 
  • Penicillium casey.
  • Miller's lungs. 
  • Dusty grain.Animal products, pigeon breeder's lungs. 
  • Pigeon droppings have pigeon serum proteins.
  • Other chemical industry workers.