Lec 2 pulmonary inf I Flashcards
Definition of pneumonia:
pathological:Infection of lung parenchyma distal to the terminal bronchioles
Clinically: at least one opacity on chest x-ray
The histologic spectrum of pneumonia:
- fibrinopurulent alveolar exudate- acute bacterial pneumonia
- Mononuclear interstitial infiltrate- viral and atypical pneumonia
- Granulomas and cavitation: chronic pneumonia
Lobar pneumonia:
-part or all of a lobe
-Streptococcus pneumonia responsible for more than 90%
The best way to classify pneumonias:
1) identifying etiological agents
2)By tracking the clinical signs of the patient
Pathogenic factors of pneumonia:
microbial
Capsule
IgA protease
ciliostatic factor
important
Pathogenic factors of pneumonia: host factors
-hypogammaglobulinemia
-phagocytic or cilliary dysfunction
-neutropenia
-lymphopenia
in the exam he can put hypergamma to trick you!
Impairment to defense mechanisms:
(ones that are likely to be mentioned)
1)Injury to mucocilliary blanket: due to smoking, alchohol etc
2)Decrease in macrophage function; due to smoking and alcohol
3)immune deficincies
4)Exisisting pulmonary disease
important
Smoking and alcohol:
Smoking: impair cilliary blanket and defect macrophage activity
Alcoholl:Impairs cough and epiglottic reflexes increasing risk of aspiration
also interferes with neutrophil infiltration.
Diagnosis of pneumonia:
3 main ways
Blood picture: CBC(leukocytosis) and acute phase reactants
-Isolation of microbe: sputum, blood culture, serology
Chest x ray- patchy or lobar?
Community acquired Acute pneumonia:
typical and Atypical
Typical; Strep pneumonia
Hemophilus influenza
Staph aureus
enterobacteriacae
Atypical: Mycoplasma pneumonia
Chlamidiya, Parainfluenza, adenovirus
Pneumococcal pneumonia: Consolidation
-hardening of lung parenchyma due to prescence of exudate in alveoli.
-acute onset of fever and rust colored sputum with chest pain especially with pleural involvment
-Usually lobar
Pneumococcal pneumonia: 1)Congestional Evolution
Congestion phase:1-2 days
-Heavy red lungs
- severe vascular congestion
- intra alveolar exudate with neutrophil
- Wartery sputum
- Bacteria +++
pneumococcal pneumonia:
3) Grey hepatization phase
Grey hepatization(4-8 days)
- -Dry grey brown cut surface
- -increased alveolar fibrin and macrophages
- -Disentegrating neutrophils, decreased RBC’s
Pneumococcal pneumonia:
2)Red hepatization.
Red hepatization(2-4 days)
- firm airless liver like lung
- Fibrinopurulent pleuritis
- Intra alveolar exudate
- Cells: erythrocytes, neutrophils, fibrin, rusty color sputum
pneumococcal pneumonia:
4) Resolution
Resolution (8-9days)
-enzymatic digestion of exudate
-Phagocytosis
Bronchopneumonia:
-patchy consolidation
-Neutrophilic exudate spreading to adjacent alveoli
Clinical manifestations of bronchopneumonia:
- fever cough
- chills and rigors
- pleuritic chest pain
Physical signs: TACHYPNEA, is a measure of severity
dullness to percussion
Other causes of pneumonias in the community:
-H.influenza- COPD
-S.Aureus-secondary infection
-k.pneumonia- chronic alcoholics
-P.aeruginosa-seen in ppl eith neutropenia and cystic fibrosis
-L.pneumophilia-in organ transplant patients
Community acquired Atypical pneumonia:
which is most common? and how often does it occur?
-Mycoplasma is most common
-Occurs sporadically or as local epidemics
Pathology of community acquired pneumonia:
-Involves the interstitium
-May be patchy or diffuse
-alveolar septa contain infiltrate of lymphocytes
-Alveolar capillary block caused by exudate and edema
has little exudate
Clinical picture of Community atypical pneumonia:
-insidous onset of minimal cough, minimal WBC, no Consolidation
-Radiological picture: Transient ill defined patches in lower lobes.
-viral inclusions can be seen in viral form
-In mycoplasma: cold agglutinin test positive.
Hospital acquired (Nosocomial) pneumonia
occurs at within at least 48 hours after hospital admission
G-ve bacilli mostly: P.aeruginosa , K.pneumonia
G+ve : staph aureus in US
Pathogenisis of Nosocomial pneumonia:
from prolonged use of antibiotics
-Endotracheal intubation
Pseudomonas aeruginosa pneumonia:
bronchopneumonia with high mortality
-Patients: neutropenic cancer patient/ burn patients/ ventilator associated
-pathology: abcess formation and empyema with prominent vascular invasion—- vasculitis
-Necrosis
Staphylococcal pneumonia:
Severe abcessing pneumonia
Risk: cystic fibrotic patients, COPD, IV Drug addicts
Aspiration pneumonia:
Aspiration of oropharyngeal secretions or gastric contents
Patient:Weak sensation of hypopharynx, + consolidation
microaspiration does nottt lead to pneumonia
Lung abcesses:
localized area of supparative necrosis within pulmonary parenchyma
In aspiration cases: more in right, single, upper area
In pneumonia cases: More basal and multiple
Fate and complication of lung abcesses
1)healing by fibrosis leaving a sterile cavity
2)Rupture with partial drainage of material:
-Radiological- Air fluid level
-rupture into pleura:empyema
-rupture into bronchus:bronchopneumonia
3)Bronchopleural fistula; pneumothorax
Complications of bacterial pneumonias:
1)Pleural effusion
2)fibrosis
3)abcess formation
4)bacterimic dissemenation
5)empyema
6)atelectasis
note:
atypical pneumonias are characterized by resp distress
