Lung B38 Pulmonary infections (except tuberculosis) Flashcards
What are the clinical types of pneumonia? (7)
- Community Acquired Acute
- Community Acquired Atypical
- Nosocomial Pneumonia
- Aspiration Pneumonia
- Chronic Pneumonia
- Necrotizing Pneumonia with Abscesses
- Immunocompromised Patient Pneumonia.
What pathogens cause community acquired acute pnemonia? (7)
- Streptococcus pneumonia, aka pneumococcus causes 90%
- Hemophilus influenzae (especially immune compromised and children)
- Moraxella catarrhalis (elderly)
- Staph aureus (secondary infections after viral resp infection, high rates of abscess and empyema)
- Klebsiella (most frequent gram negative pneumonia and hospital acquired type of debilitated and malnourished patients, especially alcoholics)
- Pseudomonas aeruginosa (also very common nosocomial, especially in neutropenia patients)
- Legionella
What are the characteristics of atypical pneumonia,
What pathogens cause it (8)
- Moderate to little sputum production and lower leukocytosis than seen in typical pneumonias.
- Patients are typically less debilitated than normal lobar/bronchopneumonia, but symptoms can range from nearly asymptomatic, to rapidly disseminating, fulminant sepsis and death (pseudomonas in immunocomp’d)
- Patchy infiltrations in lung
- It lacks the alveolar immune cell exudate
- Inflammatory infiltratate is confined to within the septa, which are edematous and widened.
- The edema can cause severe respiratory distress, that is not in proportion to radiologic findings.
- So, it can be disproportionately severe dyspnea, or dysporoptionately mildsymptoms depending on the specific agent and infection.
Causes:
- Mycoplasma pneumoniae - the most common, especially in young adults in close quarters (military recruits and colleges)
- Chlamydia pneumonia
- Coxiella Burnetii
- Influenza A
- Influenza B
- Adenoviruses
- Rubeola virus
- Varicella virus
What are the major infections that exacerbate COPD?
Haemophilus influenzae 60%
Moraxella catarrhjalis 30%
What major causes of pneumonia are also the most frequent causes of Otitis Media?
Streptococcus pneumonia 30%
- Haemophilus influenzae 25%*
- Moraxella Catarrhalis 20%*
What are the microbes causing nosocomial pneumonias?
- Enterobacteriaceae species (mainly Klebsiella, Serratia, Enterobacter, and E Coli)
- Psuedomonas aeurginosa
- Staphylococcus Aureus.
What causes aspiration pneumonia?
Aspiration of gastric contents usually during severe bouts of vomitting, or while unconcious
Gastric acid and GI bacteria get into lung and often create infected abscesses.
The Right lung is more commonly affected, due to its more descending bronchus.
The acid and bacteria are both important components of damage. It is generally a mixed infection, and can contain anaerobic or aerobic bacteria.
It usually only occurs in debilitated patients and causes severe, often life threatening infections that may become invasive.
What are causes of lung abscesses?
- Aspiration of infectious pathogens from teeth or oral cavity.
- severe oral caries
- from sinusitis or tonsilitis
- during oral surgery
- during anesthesia
- during coma
- alcoholic intoxication
- in patients with depressed cough reflex.
- Gastric Aspiration
- Necrotizing bacterial pneumonias
- S. aureus
- S. pyogenes
- K. pneumoniae
- Pseudomonas
- Type 3 streptococcus pneumoniae
- Mycotic infections
- Bronciectasis
- Cystic fibrosis
- Bronchial obstruction
- Septic embolism
- A septic embolism breaking off infective endocarditis
- Septic thrombophlebitis
- Hematogenously spread bacteria of a disseminated pyogenic infection
- Usually staphylococcus,
- S. aureus
- S. hemolyticus
- often generates multiple abscesses if spread hematogenously
- brochogenic carcinomas
What types of bacteria are present in lung abscesses
Anaerobic bacteria are almost always present in lung abscesses. They are frequently exclusively colonized by anaerobes.
Even though certain aerobic infections may cause the initial abscess formation.
Most frequently:
- Prevotella
- Fusobacterium
- Bacteroides
- Peptostreptococcus
- Microaerophilic streptococci
How does the location and nubmer of an abscess correspond to different abscess forming processes?
Aspiration abscesses are usually on the right side.
Bronchiectasis or pneumonia causes multiple absceses, near the base of the lung.
Septic emboli and hematogenously spread necrotizing infections can affect any lung region.
What can be the consequences of lung abscesses?
- As they enlarge they almost always rupture into the airways and thus produce the flat line of pus/fluid seen by radiology
- They may also rupture through the pleura, causing pneumothorax and empyema.
- They may generate further septic emboli**, generating **brain abscesses** or **meningitis.
- Secondary amyloidosis in chronic abscesses. (secondary amyloidosis is of the SAA type, due to chronic inflammation and elevated SAA levels).
Clinical symptoms of lung abscesses?
Similar to bronchietasis,
- strong cough
- producing very smelly, purulent or bloody sputum.
- spiking fever
- malaise
- weight loss
- Clubbing of the digits
- anemia (of chronic disease)
What are the causes of pneumonia in immunocomppromised patients?
First, the same agents that cause it in healthy people: Strep pneumo (pneumococcus) is still #1, Hemophilus influenza, Moraxella catarrhalis, Staph aureus, Klebsiella
Immunocompromised pneumonias
- Pseudomonas aeruginosa
-
Opportunisitc fungal infections
- Candidiasis
- Aspergillus, Invasive aspergillosis specifically.
- Pneumocystis jirovecii
- Klebsiella, Serratia, Enterobacter
T-cell deficient pneumonias:
- Mycobacteria
- Strongloides
- HSV, Cytomegalovirus
- Aspergillus
- Mucor
- Cryptococcus
- Nocardia
- Toxoplasma
