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95 Cards in this Set
- Front
- Back
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What is pneumonia? |
An infection of the lung parenchyma |
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What is the most important clinical point when diagnosing pneumonia? |
Identifying the pathogen |
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What diagnostic tool is required in order to diagnose pneumonia? |
Chest x-ray |
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What is a blood marker that can be elevated to suggest pneumonia? |
procalcitonin |
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How does the nose defend the lung from infection? |
It can trap and clear organisms that are breathed in. |
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After the nose, what protects the lungs from infection? |
Tracheobronchial clearance by the mucociliary escalator |
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What protects the alveoli from pathogens? |
Alveolar macrophages |
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Why is an intubated patient at increased risk for pneumonia? |
Their nose and tracheobronchial lining are no longer involved in protecting the lungs from pathogens |
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Why are smokers at increased risk for pneumonia? |
They destroy their mucociliary escalator |
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Why are COPD patients on treatment at increased risk for pneumonia? |
Steroids decrease function of alveolar macrophages |
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What are 5 ways by which pneumonia is acquired? |
- Aspirated into lungs during sleep - Breathing it in from a coughing patient - Hematogenous spread - Direct penetration (knife wound) - Direct extension from infection of nearby tissue |
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How large must an organism be to be acquired by inhalation? |
1-10 microns |
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What 3 pathogens use aerosol as their major route of lung entry? |
- TB - Influenza - Histoplasmosis |
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What do bronchopneumonia and lobar pneumonia imply about the infection? |
That it is bacterial |
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What does lobar pneumonia involve? |
Infection in the alveolar spaces of a specific lobe of the lung |
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What does bronchopneumonia involve? |
Infection in the alveolar spaces arranged around specific bronchi |
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What pathogen is responsible for ~95% of lobar pneumonia cases? |
Pneumococcus |
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What are the 4 classic stages seen in lobar pneumonia?
Describe them |
Stage 1: Congestion - capillaries become engorged and leaky Stage 2: Red hepatization - lung lobe becomes full of RBCs and pus Stage 3: Gray hepatization - as RBCs break down, lobe remains hard but becomes gray Stage 4: Resolution - lobe returns to normal as pus is expectorated |
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What does a lobar pneumonia chest x-ray look like? |
A single lung lobe becomes opaque and defined as it is full of pus |
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What is notable in lobar pneumonia on a patient history?
Physical exam? |
Patient Hx: productive cough
PE: dull percussion over infected lobe |
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Describe the organization of lesions in bronchopneumonia? |
Patchy consolidation along bronchi in more than one lobe about 3-4cm in diameter |
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Describe bronchopneumonia histology? |
Alveolar space will be full of PMNs and progressively less infected the further away from lesions |
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What pathogen does interstitial pneumonitis imply?
Why? |
Non-bacterial (virus, fungus, or intracellular bacterium)
Infection occurs in the alveolar wall |
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What are the most common pathogens associated with interstitial pneumonitis? (2) |
- Viruses - Mycoplasma (intracellular bacterium) |
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Is there consolidation (filling of fluid) in interstitial pneumonitis on gross view or chest x-ray? |
No |
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How does a gross view of a lung with interstitial pneumonitis appear?
Chest x-ray? |
Gross view: looks normal
Chest x-ray: diffuse haziness all throughout |
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Why is there diffuse haziness on chest x-ray of lungs with interstitial pneumonitis? |
Alveolar walls are widened |
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Describe the cough of patients with interstitial pneumonitis? |
nonproductive, dry cough |
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What are some pathologic complications associated with pneumonia? (4) |
- Lung abscesses - Organization (scarring) - Bacteremia to heart valves, joints, brain - Empyema (pus in pleural space) |
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How do abscesses appear on x-ray? |
a large hole in the lung |
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What 3 pathogens are most associated with lung abscesses? |
- Strep - Klebsiella - Staph |
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What is an empyema? |
Pus that has penetrated the visceral pleura and fills the pleural space; must be drained. |
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Why must an empyema be drained ASAP? |
It can cause scarring and adhesion of the pleura |
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What is an organizing pneumonia? |
Pus in the alveolar space becomes scar tissue and no longer can exchange gasses. |
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Where can bacteria from pneumonia go to hematogenously? (3) |
- Heart valves (endocarditis) - Joints - Brain (meningitis) |
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What are the 3 classifications of pneumonia? |
- Community-acquired - Hospital-acquired - Immunocompromised |
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What pathogen would constitute a typical community-acquired pneumonia? |
Pneumococcus |
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What are the signs and symptoms of a typical pneumonia? (3) |
- High fever - Productive cough - Consolidation on PE and CXR |
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What pathogen would constitute most of atypical community-acquired pneumonia? |
Mycoplasma |
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What are the symptoms of atypical pneumonia? |
- Low-grade fever - dry, hacking cough - No consolidation on PE nor CXR |
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What makes Streptococcus pneumonia a rapidly progressing disease? |
Antiphagocytic capsule pneumolysin allows it to move quickly through lung parenchyma. |
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What cells are present in the alveolar space in Strep pneumo infection? |
PMNs |
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Which type of Haemophilus influenza is most common? |
Type B |
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How does H. influenza differ in its presentation of pneumonia in children? |
Laryngotracheobronchitis causes destruction of lining in trachea to bronchi, which becomes necrotic and sloughs off. |
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What is the gross presentation of H. influenza pneumonia? |
Usually bronchopneumonia, but can be lobar too |
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What is seen in the alveolar space of patients with H. influenza pneumonia? |
PMNs |
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In children, how serious is H. influenza pneumonia? |
Pediatric emergency |
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In what reservoirs does Legionella colonize? |
Air conditioners |
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What makes Legionella particularly virulent in the lungs? |
It can survive inside alveolar macrophages by blocking the phagolysosome formation and rupture out via pore toxins. |
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What does the gross pathology look like in Legionella infection? |
bronchopneumonia consolidation pattern |
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What is seen in the alveolar space of patients with Legionnaire's disease? |
PMNs and macrophages |
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How is Legionnaire's disease diagnosed? |
Urine antigen testing |
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What do the symptoms of Legionella pneumonia look like?
What is the fever called? |
Similar to the flu
Pontiac fever |
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What patients have difficulty clearing Legionella infections? |
Patients with COPD on long-term steroids |
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What are some examples of anerobic bacteria that can cause community-acquired pneumonia? (4) |
- Bacteroides - Fusobacteria - Actinomyces - Microaerophilic cocci |
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What do patients with anerobic pneumonia have in common? |
Bad teeth (infection is due to aspiration) |
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How can an anerobic pneumonia occur in the aerobic environment of the lung alveoli? |
Since aspiration of anerobes is from the mouth, aerobes can be aspirated with them and consume all the oxygen. |
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What do aerobes that are aspirated with anaerobic pneumonia cause? |
Abscesses |
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What is seen in the alveolar space of anerobic pneumonia? |
PMNs |
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How does community-acquired MRSA that leads to pneumonia compare to hospital-acquired MRSA? |
Less virulent, but still deadly |
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What makes community-acquired MRSA a likely cause for pneumonia? |
Young, healthy patient with bilateral, necrotizing pneumonia and abscesses |
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What other pathogenesis can community-acquired mycoplasma have besides pneumonia? (2) |
- Interference with cilia and desquamation of tracheal epithelium |
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What is seen in the alveolar space of mycoplasma pneumonia? |
Nothing, inflammation is in alveolar wall |
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What is the gold standard for diagnosis of mycoplasma pneumonia? |
PCR |
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Describe the cough of a patient with mycoplasma pneumonia? |
dry, non-productive cough |
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What is a unique characteristic about chlamydia pneumoniae?
What causes inflammation |
Intracellular
Lipopolysaccharide |
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Where does the inflammation of C. pneumoniae occur? |
Alveolar wall |
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What clinical presentation precedes the dry, hacking cough associated with C. pneumoniae? |
Sore throat (pharyngitis) |
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What is the gold standard for diagnosing C. pneumoniae? |
PCR |
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What 3 viruses can cause community-acquired pneumonia? |
- Flu - Adenovirus - RSV |
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What makes flu infection so deadly? |
Influenza destroys the mucociliary escalator and allows for a bacterial superinfection to occur |
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What is seen in the alveolar space in flu pneumonia? |
Nothing, infection is in alveolar wall |
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What are histocytes? |
Cells derived from monocytes |
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How is flu diagnosed? |
PCR |
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What 3 pathogens compose much of hospital-acquired pneumonia cases? |
- Pseudomonas - Gram negative enteric bacteria - Staphylococcal pneumonia |
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What is seen on gross view of pseudomonas pneumonia? |
Bronchopneumonia |
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What is seen in the alveolar space of pseudomonas infection? |
PMNs |
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What is the clinical presentation of pseudomonas pneumonia? |
Patient admitted to the hospital for unrelated problem and then comes down with fever, productive cough, dyspnea |
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How is pseudomonas pneumonia diagnosed? (2) |
Sputum and blood cultures |
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What are 3 examples of gram negative enteric bacteria that can cause hospital-acquired pneumonia? |
- Klebsiella - Serratia - Enterobacter |
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What is the gross presentation of gram negative enteric pneumonia? |
Bronchopneumonia (Some Klebsiella can be lobar and produces abscesses) |
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What kind of cough will gram negative enteric pneumonia produce? |
Productive cough |
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How is gram negative enteric pneumonia diagnosed? (2) |
Sputum and blood cultures |
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What may influence the presence of rales over the lungs in patients with gram negative enteric pneumonia? |
Hydration (if no rales, hydrate pt) |
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What are routes of administration for staphylococcal pneumoniae? (2) |
- Aspiration - IV catheter (hematogenous spread) |
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What is the gross view for staph pneumonia? (3) |
Bronchopneumonia, lobar, or abscess |
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In a patient with HIV, what can pulmonary infiltrates be if they are not infection? |
Kaposi's sarcoma |
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What pathogen is likely in an HIV positive patient with a CD4 count above 200?
CD4 count: 50-200?
CD4 count: <50? |
>200 = Bacterial pneumonia 50-200 = CMV <50 = Pneumocystis carinii |
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What is in the alveolar space of HIV positive patients with pneumocystis pneumonia? |
Foam of bacteria |
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How is pneumocystis confirmed? |
Broncho-alveolar lavage (BAL) with silver stain |
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What is the gross view of CMV pneumonia in immunocompromised patients? |
Patchy or diffuse infiltrate on CXR |
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What is seen in the alveolar space of immunocompromised patients with CMV pneumonia? |
Nothing, infection is in the alveolar wall and patient cannot mount an immune response |
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What are the symptoms for histoplasmosis pneumonia in immunocompromised patients? (3) |
- Fever - Night sweats - Weight loss |
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How is histoplasmosis diagnosed? (2) |
Urine antigen testing or culture |
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If a patient were not immunocompromised, what would be seen under histology for histoplasmosis infection? |
Granulomas |
