CSIM 1.69: Respiratory Disease 1 Flashcards
What is an acinus?
A unit composed of: • A terminal bronchiole • Respiratory bronchioles • Alveolar ducts • Alveolar sacs • Alveoli
What is a lung lobule?
A unit composed of 4-5 acini
Describe the blood supply of the lungs
Dual blood supply (pulmonary and bronchial arteries)
What are the defence mechanisms of the lungs?
- Cough reflex
- Mucociliary apparatus
- IgA
- Alveolar macrophages
- Pneumocytes
Describe bronchopneumonia
Acute inflammation around bronchi and bronchioles. Exudate fills the air spaces, in a process called consolidation - organisation may follow
How is consolidation detected?
- Solid sound on percussion
* Changes on X-ray
Describe lobar pneumonia
As with bronchopneumonia, but involves a larger portion of lung (e.g. entire lobe)
• Acute inflammation
• Exudate
• Possible organisation
Describe the pathological stages of pneumonia
1) Hyperaemia
• An excess of blood in the vessels
2) Red hepatisation
• Red blood cells, neutrophils, and fibrin in the pulmonary alveolus/ alveoli
3) Grey hepatisation
• Red cells have been broken down leaving a fibrinosuppurative exudate
• This is the cause of consolidation
MAY progress to:
Septicaemia, empyema, abscess, fibrosis (organising pneumonia)
What is atypical pneumonia and how is it differentiated?
Pneumonia caused by viruses or mycoplasma, chlamydia or legionella
• No consolidation or suppuration
• Interstitial pneumonitis with oedema in alveoli and mononuclear infiltrate
• Development of hyaline membranes (fibrin lining the alveolar walls)
What are the main causes of atypical pneumonia in the IMMUNOCOMPETENT and the IMMUNOCOMPROMISED?
Immunocompetent: • Varicella zoster virus • Mycoplasma • Chamydia • Legionella
Immunocompromised: • Pneumocystis carinii • Aspergillus • Candida • Cytomegalovirus • Herpes simplex • Varicella zoster
In which patients can recurrent pneumonias occur in?
- Cystic fibrosis
- Bronchial obstruction
- Immunosuppression
Describe what is seen in a lung abscesses. Which lung is it more common in?
An enclosed region of localised suppurative necrosis.
More common in the right lung
What pathogen causes tuberculosis?
Describe what happens in primary and secodary pulmonary tuberculosis.
Mycobacterium tuberculosis
Primary TB:
• Asymptomatic
• Necrotising granulomatous response
• Single granulomatous lesion formed called a GHON FOCUS
• This spreads to the draining lymph node forming a GHON COMPLEX
• Heals with calcification and a scar
Secondary TB:
• Reactivation of bacterium ‘walled off’ by necrotising granulomatosis
• Occurs in the APICES of the lungs
• Destruction of tissue with cavitating lesions
• Fever and night sweats
• Productive cough and haemoptysis
• Weight loss
How can Mycobacterium tuberculosis be detected
Ziehl-Nielsen stain on biopsy
• M. tuberculosis shows up red
(IMG 170)
What is PROGRESSIVE TB?
Bronchopneumonia and miliary tuberculosis which MAY follow from a primary or secondary tuberculosis infection
