Respiratory III
Dr Basu MD
Part I
• Bacterial Pneumonia
• Community-Acquired Atypical
Pneumonia
• Lung Abscess
Part II
• Tuberculosis
Part I
Bacterial Pneumonia : general features
•
Definition of Pneumonia:
– Consolidation of lung
– Inflammation by infective agents.
•
Morphological types of Bacterial pneumonia:
1. Lobar pneumonia
2. Bronchopneumonia
Lobar pneumonia: acute pneumonia
• Agent: Streptococcus pneumoniae, or
pneumococcus ( diplococcic), kelbsiella.
• Age : elderly, malnourished, debilitated person.
• Features:
– involve the entire lobe
– Formation of intra alveolar exudates ( plenty ).
Bacterial Pneumonia
Streptococcus
pneumoniae, or
pneumococcus
Lobar pneumonia
•
4 morphological stages (seen if no
antibiotic is used):
1. Congestion.
2. Red hepatization (consistency like liver, red
due to RBC).
3. Gray hepatization ( consistency like liver.
Gray due to exudates in alveolus).
4. Complete Resolution ( complete restoration
of normal histology of lung).
This is a : Lobar pneumonia: locate the area
Streptococcus Pneumoniae Pneumonia An
entire love is involved. All Neutrophils in
alveolous.
Broncho-pneumonia.
• Patchy
• Age: extreme age group ( very old and child)
• Organism: Staphylococcous aureas, H.
influenzae, K.Pneumoniae, streptocossous
pyogens.
• Infection spread from bronchi to adjacent alveoli.
Broncho-pneumonia
Broncho-pneumonia
Patchy bronchopneumonia with areas of
tan-yellow consolidation.
Bronchopneumonia: Patchy area of alveoli that are
filled with PMNs AND EXTEDED INTO ADJACENT
BRONCHI.
Complication of pneumonia
•
•
•
•
Abscess formation.
Pleural empyema
Sepsis→ ARDS
Fibrous pleural scar,
Organized pneumonia.
Alveolar fibrosis: Organized
pneumonia
( lung become solid)
Clinical course
• High fever
• Chest pain
• Cough productive of mucopurulent sputum
( rust color ..if blood present)
Community-Acquired Atypical Pneumonias
• Other name: Interstitial pneumonia.
• Age: children and young adult.
• Clinical Presentation is different from typical
bacterial pneumonia:
– Cough with no or mild to moderate sputum
production.
– No physical finding of consolidation.
Community-Acquired Atypical Pneumonias
• Agents:
• Chlamydia, Mycoplasma, virus
• Viruses:
– Respiratory syncytial virus,
– parainfluenza virus (children);
– influenza A and B (adults);
– adenovirus (military recruits);
– SARS* virus
Common morphology of all Acquired
Atypical Pneumonias
• The interstitium in the alveolar wall is the main
location of inflammation ( lymphocytes and
plasma cells) with or without an intra-alveolar
exudate.
Mycoplasma pneumonia (most common form
of ATYPICAL PNEUMONIA)
• Cause: Mycoplasma infection.
• Lab: Elevation of titers of cold agglutinins
(IgM) in Mycoplasmal infection (in 50% of
cases).
• PCR for mycoplasma DNA is available.
lymphocytes and plasma cells in interstitial area and no
exudates in the alveolar space
Mycoplasma pneumonia
Any question please?
Lung Abscess
• Definition: localized collection of Neutrophils
and necrotic lung tissue.
• Cause:
– Bronchiectasis
– Aspiration of gastric content
– Bacterial pneumonia- septic emboli.
• Risk group:
– Loss of consciousness ( drug, alcohol)
– General anesthesia
– Bad oral/dental hygiene
Lung Abscess
• Anaerobic / Aerobic bacteria : etiology is oral
cavity disease.
• Aerobic organisms frequently isolated:
– Staphylococcous aureus, β hemolytic
streptococci = Pneumonia.
– Pseudomonas, Kelbsiella = Pneumonia.
Morphology of Lung Abscess
• Location:
• Aspiration abscess:
• Right > left lung.
• Pneumonia or bronchiectasis abscesses:
– Basal.
• X- ray : air fluid level
Lung Abscess : x ray : ‘air fluid level’
Lung abscess:
liquefactive necrosis
Clinical course of Lung Abscess
• Cough  copious amounts of
foul-smelling, purulent sputum.
• Striking fever.
Part II
Tuberculosis
Tuberculosis
• Definition of tuberculosis:
– Communicable Granulomatous disease
caused by Mycobacterium Tuberculosis.
– [M. avium-intracellulare  10-30% of
patients with AIDS]
Tuberculosis
Epidemiology
• TB in the US is a disease of:
– The elderly.
– The urban poor.
– The immuno-suppressed (AIDS).
Tuberculosis
Epidemiology
• Certain disease states increase the
risk.
– Diabetes mellitus, silicosis,
– Malnutrition or Alcoholism.
– Immunouppression (HIV).
Type of tuberculosis
1. Primary
1. Lung
2. Lymph nodes (cervical)
3. GIT
2. Secondary
Pathogenesis of granuloma formation
APC
CD4
APC activated CD4 cells
through MHC II and TCR
complex
Activated CD4 cell produce
INF-gamma
Collection of many epitheloid
cells= Granuloma
Caseation necrosis
Modify (activate) the
macrophage = epitheloid
cells
Activated macrophage kill
bacteria by NO
Primary tuberculosis
• Definition of primary tuberculosis:
– The disease that develop in a previously
unexposed (unsensitized) persons.
• Morphology: Ghon complex
• Focus of primary TB: Lung, Intestine,
lympnnodes (Cervical LN).
The Ghon complex: subpleural granuloma + marked
hilar lymphadenopathy.
Most often in children.
.
Primary Tuberculosis: Caseating granuloma with
Langhans giant cells: this may calcify.
Implications of Primary
Tuberculosis
1. It may resolve
2. It may progress to progressive
primary tuberculosis.
3. Some bacilli harbor in the apex of
lung for survival (due to high Oxygen
level).
Secondary TB
• DEF: disease that arises in a previously
sensitized host .
• Type:
– Reactivation of dormant primary
lesions.
– Exogenous re-infection.
Secondary Tuberculosis
(location)
• Location of
lesions: classically
localized to the
apex of one or both
upper lobes.
Pattern of Secondary
Tuberculosis
Early lesion
Small focus of consolidation Near the
apical pleura
Patterns of secondary TB: cavity formation
in lung
Progressive pulmonary tuberculosis
Endobronchial, endotracheal, and
laryngeal tuberculosis
Early lesion: in the
apex
Miliary pulmonary disease
Systemic miliary tuberculosis
Isolated-organ tuberculosis + Pleura
Progressive pulmonary tuberculosis
• Seen in the elderly and immunosuppressed. Both
lung involved with cavitary lesion.
• This may progress to spread to various organs.
Micro: Caseating granuloma
Progression of Sec. progressive TB
Erosion of Bronchus, lymphatic or blood vessels by
granuloma
Release of caseation
in bronchus
Lymphatic spread:
pulmonary miliary TB
Seeding to
Spread by Blood vessels:
systemic miliary TB and
hemoptysis
trachea and
bronchus
Miliary pulmonary tuberculosis
Caseating granuloma : size of Millet seeds.
Clinical Course of Tuberculosis
1.
2.
3.
4.
5.
Low grade fever (remitting).
Night sweats.
Malaise.
Anorexia.
Weight loss.
Clinical Course of Tuberculosis
• Diagnosis:
– Acid-fast smears and culture of the sputum.
– PCR amplification of M. tuberculosis.
Tuberculosis
Mantoux skin testing
• False negative (skin test anergy) maybe
produced by:
– Sarcoidosis.
– Immunosuppression.
– Overwhelming active tuberculosis.
– Hodgkin disease.
• False positive results  atypical
mycobacterium.
Nontuberculous Mycobacterial
Disease
• Stains implicated in the US are:
– M. avium-intracellulare.
– M. Kansasii.
– M. abscessus.
• Can mimic typical tuberculosis in
presentation  upper lobe cavitary
disease.
Risk factors for Nontuberculous
Mycobacterial Disease
• COPD, cystic fibrosis, and
pneumoconiosis.
• Immuno-suppression: In AIDS  M. avium
complex  disseminated disease with
systemic symptoms.
Clinical course
• Similar to classic TB but more aggressive
due to immunosuppression.
Thank you