L13 Pneumonia and Bronchiectasis Flashcards
Classification of Pneumonia?
Pneumonia is an inflammatory process of the lung c aused by an infectious agent: (bacterial, viral or fungal)
(1) Clinical circumstances
- Community acquired (typical/atypical)
- Hospital acquired (nosocomial)
- Opportunistic
(2) Etiological agent
- Bacterial
- Viral
- Fungal
- Other
(3) Anatomical pattern
Bronchopneumonia
Characteristics?
Demographics?
Micro-characteristics?
Bronchopneumonia
- Patchy consolidated areas of acute suppurative (pus) inflammation
- Centered on bronchioles and bronchi - Often multilobar and bilateral
- Infancy and old age
- Arises from chronic debilitating illness
- Neutrophil-rich exudate, fills the bronchi, bronchioles and alveola
Lobar Pneumonia
Characteristics
Demographics
Cause?
Stages?
Lobar Pneumonia
Affects a large part of lobe or entire lobe
Typically affects otherwise healthy adults
Rarer now w/ antibiotics
Strep. Pneumoniae (90%)
Stages:
1. Congestion
2. Red Hepatization
3. Gray Hepatization
4. Resolution
Stages of Lobar Pneumonia?
1. Congestion
- Vascular engorgement
- Intra-alveolar proteinaceous fluid
- numerous bacteria in alveoli
- Lung heavy, boggy, red
2. Red Hepatization
- Massive congestion of lung parenchyma
- Neutrophils and fibrin fill alveolar spaces
- Lung appears red, firm, airless, liver-like
3. Gray Hepatization
- Disintegration of RBCs
- Fibrosuppurative exudate
- Gray/brown, dry surface
4. Resolution
- Occurs at 8-10 days
- Enzymatic digestion of consolidated exudate
- Produces semisolid debris
- Resorbed
- Ingested by macrophages
- Coughed up
- Produces semisolid debris
- Pleural fibrinous reaction may similarly resolve or undergo organization leaving permanent fibrous adhesions
Host Pneumonia Defence Mechanisms?
When does pneumonia infection occur?
Infection results when:
- Defect in host immunity (intrinsic factor)
- Particularly virulent organism (extrinsic)
- Evasion of muco-ciliary clearance
- Evasion of macrophage-induced killing
- Overwhelming inoculum of infecting organism (extrinsic)
Predisposing Host Factors for Pneumonia (7)
• Loss of cough reflex
– Neuromuscular disorders
– Cerebrovascular accident
– Coma
• Damage to muco-ciliary apparatus
– Smoking
– Kartagener syndrome
– I_mmotile cilia syndrome_
• Accumulation of secretions
– COPD
– Bronchiectasis (CF)
• Pulmonary congestion and oedema
• Decreased alveolar macrophage function
– Alcohol
– Smoking
• Drugs
– Immunosuppressants
– H2 antagonists
• Bronchial obstruction
– Bronchogenic carcinoma
– Foreign body
__________: Chronic necrotizing infection of the bronchi and bronchioles
=> associated with ___________________ of these airways
Bronchiectasis: Chronic necrotizing infection of the bronchi and bronchioles
=> associated with abnormal, irreversible dilation of these airways
Weakening/dilatation of lumen of airway => once dilated, does not return to normal
Airways are dilated, up to 4x normal diameter and filled with pus
Bronchietasis is a secondary diesase due to?
It is a secondary disease, due to
(1) Obstruction
(2) Persistent severe infection
What part of the lung is usually affected by bronchiectasis?
Typically affects Lower Lobes Bilaterally
Pathophysiology of Bronchiectasis (5 Steps)
2 main requirements:
– Impaired drainage, airway obstruction or defect in host defense
– Infectious insult
Clinical Features of Bronchiectasis
Clinical Features:
Symptoms:
- Severe persistent cough
- Production of large volumes of mucopurulent sputum
Signs:
- Crepitations
- Wheeze
- Clubbing of the fingers
- Cor pulmonale (right ventricular failure)
Investigations of Bronchiectasis?
Investigations
Blood tests (Not diagnostic) – Raised WCC and CRP if infective exacerbation
Radiology– CXR/CT thorax
Microbiology– Sputum C+S (Pseudomonas sp)
What causes cystic fibrosis?
Multi-system disease caused by a(recessive) genetic mutation in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein on Chr. 7q31
=>Thick, viscous secretions in lungs, pancreas, liver, intestine, reproductive tract
Presentation of cystic fibrosis in Adults vs. Children?
Presentation in infancy:
–Common mutations in CFTR gene
–Meconium ileus (blockage of the small intestine)
–Respiratory symptoms
–Failure to thrive
Presentation in adulthood
–Rare mutations in CFTR gene
–Gastrointestinal symptoms
–Diabetes mellitus
–infertility
