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Hypersensitivity Pneumonitis

Duration: 16:35

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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.

In this video we will learn about :

1. Definition of hypersensitivity pneumonitis. 

2. Pneumonitis vs. Asthma. 

3. Pathogenesis of acute and chronic reaction. 

4. Type III and IV hypersensitivity reaction. 

5. Effect on capacities and volumes. 

6. Clinical signs and symptoms 

7. Predisposed population. 



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Dr. Mobeen Syed

Dr. Mobeen Syed

MD., MSc., MSc., BSc

Mobeen Syed is the CEO of DrBeen Corp, a modern online medical education marketplace. Mobeen is a medical doctor and a software engineer. He graduated from the prestigious King Edward Medical University Lahore. He has been teaching medicine since 1994. Mobeen is also a software engineer and engineering leader. In this role, Mobeen has run teams consisting of hundreds of engineers and millions of dollars of budgets. Mobeen loves music, teaching, and doing business. He lives in Cupertino CA.

Respiratory System

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