Lower Respiratory Infections Flashcards
What are the 3 components of the triad of infectious disease?
- Host
- Environment
- Pathogen
What would be considered to fall under the category of “Host”?
- Anatomic Defenses
- Innate Immunity
- Acquired Immunity
- Humoral
- Cell-mediated
What would fall under the category of “environment”?
- Humans
- Animals
- Occupational
- Travel
- Setting
- Inoculum
What would fall under the category “pathogen”?
- Bacteria
- Mycobacteria
- Fungi
- Viruses
- Protozoa
- Metazoans
What is virulence?
The ability to cause disease
What is required for the diagnoses of pneumonia?
Chest X-Ray showing parenchymal infiltrates
What are the divisions of Acute pneumonia?
- Typical
- Atypical
- Aspiration
- Viral
Describe Typical Acute pneumonia
- Community-Acquired usually (CAP)
- Measured in hours to days
- Onset with chills, fever and wet cough
- Lobar consolidation or segmental or sub-segmental bronchopneumonia
- Pleura often involved giving chest pain with inspiration (pleuritis)
- Micro-aspiration of upper respiratory tract colonizing bacteria
- Most often due to Streptococcus pneumoniae
Name the 4 points derived from the compilation of US and UK studies on the etiologies of community-acquired pneumonia
- Pneumococcus most common pathogen
- Haemophilus has largely disappeared
- Gram (-) pneumonia is uncommon but consider Klebsiella pneumoniae
- Viral pneumonia is often seen in children (respiratory viruses) and during influenza epidemics
According to US/UK studies, what are the most common pneumonia causing bacteria?
- Streptococcus pneumonia
2 . Hemophilus influenzae (but its far behind #1)
Name two types of atypical pheumonias
- Walking pneumonia
2. Environmentally acquired acute pneumonias
What are the antibiotics required for atypical pneumonias?
Non-beta-lactam antibiotics
Macrolides, Fluroquinolones, teteracyclines
What bacteria are involved in Walking pneumonia?
Mycoplamsma pneumoniae and Chlamydophila pneumoniae
What bacteria are involved in Environmentally acquired acute pneumonias?
- Legionella pneumophilia
- Coxiella burnetii
- Chlamydophila psittaci
What are some symptoms/characteristics of Aspiration pneumonia?
- Setting: stupor, coma, or seizures
- Focal infiltrates
- Dependent portions of lung
- Oropharyngeal flora
What is the microbiology of community acquired aspiration pneumonia?
Community acquired:
- Gram (+)
- Anaerobes (up to 20%)
What is the microbio of hospital acquired aspiration pneumonia?
Hospital-acquired:
-Gram (-), S. aureus
What might complicate Aspiration Pneumonia?
Chronic pneumonia with lung abscess formation
What is involved in the Trans-tracheal aspiration method?
Aspiration taken with needle inserted into the trachea
List the 4 types of oral anaerobic bacteria
- Gram (+) cocci
- Gram (+) Bacilli
- Gram (-) cocci
- Gram (-) bacilli
Give an example of Gram + cocci in oral anaerobic bacteria
Peptostreptococcus
Give an example of Gram + bacilli in oral anaerobic bacteria
- Actinomyces
- Eubacterium
- Leptotrichia
Give an example of Gram - cocci in oral anaerobic bacteria
Veillonella
Give an example of Gram - bacilli in oral anaerobic bacteria
- Fusobacteriuim
- Prevotella
- Porphyromonas
Describe Actinomyces sps.
- Cause of Pulmonary Actinomycosis
- Anaerobic/microaerophic GM + bacillus
- Oral Flora–Especially carious teeth and gingivitis
- Aspiration pneumonia often with unconsciousness
- This organism knows no tissue barrier–penetrating infection
What medications would you use to treat Pulmonary Actinomycosis (Actinomyces)?
- Requires long term Rx (6-12 mo)
- penicillin IV then PO or clindamycin
Name 4 examples of Viral Pneumonia
- Human respiratory viruses
- Hantavirus (Sin Nombre V.)
- Coronavirus (SARS, MERS)
- Bacterial pneumonia with or in the wake of influenza
What are 3 complications of acute bacterial pneumonia?
- Necrotizing pneumonitis
- Lung abscess
- Empyema
What is Necrotizing pneumonitis?
Death of lung parenchyma
What is a lung abscess?
Excavation of lung parenchyma
What is Empyema?
Spread of infection into potential space between parietal and visceral pleura, requires drainage as part of management
- Pleural space infection
- Invasion from lung parenchyma
- Diagnostic thoracentesis
- drainage via chest tube hooked to water seal
- management critical to prevent lung “entrapment”
Give some examples of Human Respiratory viruses
- Influenza
- Parinfluenza
- RSV
- Adenovirus
- Metapneumovirus
- Enterovirus
- Paraechovirus
Give 2 examples of Coronavirus
- SARS
2. MERS
Describe Chronic Pneumonia
- Weeks to months–not days
- Differential diagnosis
- Many non-infectious diseases
- NO empiric treatment
- Requires diagnosis by bronchoscopy or lung biopsy
Nodules in the lungs are indicative of what?
Chronic Pneumonia
Describe Tuberculosis based on this lecture
- Slow-growing acid-fast human pathogen
- Cough generates droplet nuclei
- Inhaled into alveolar space
- Replicates relentlessly and spreads to lymph nodes and then systemic circulation
- Becomes dormant as host cell mediated immunity develops
- Host at jeopardy for primary and post-primary disease
- Public health issues
In an immunocompromised host, what is required to investigate possible environmental factors for exposure?
Complete history
Name the infectious agents that typically cause Chronic Pneumonia
- Bacteria and Actinomyces (e.g. Anaerobes, nocardia)
- Mycobacterium (TB)
- Fungi (cocci, histo, crypto)
- Protozoa (todo, entamoeba)
- Metazoa (paragonimus)
How can you manage acute pneumonia?
- In most cases microbial diagnosis is not possible
- Nevertheless the possible pathogens of acute pneumonia are well established from previous studies going way back in medical history
- The development of broad-spectrum antibiotics to cover most possible pathogens makes empiric therapy possible in most cases
- Exceptions have arisen due to antibiotic resistance including the pneumococcus, the leading pathogen for lobar and bronchopneumonia
Name noninfectious causes of chronic pneumonia.
- Neoplasia
- Sarcoidosis
- Vasculitis
- Chemicals, drug, or inhalation
- Radiation
- Recurrent pulmonary emboli
- Bronchial obstruction (e.g., foreign body)
- Pulmonary eosinophilia
- Pneumoconiosis
- Allergic Alveolitis
- Idiopathic Causes
What are the idiopathic (non infectious) causes of chronic pneumonia?
- BOOP
- CIP, UIP, DIP, LIP, GIP
- Eosinophilic granuloma
- Lymphangioleiomyomatosis
- Goodpasteur Syndrome
- Alveolar proteinosis
- Pulmonary Hemosiderosis
- Angiocentric immunoproliferative lesions
Don’t forget to memorize the different chronic and non-infectious pathogens
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