Pneumonia Flashcards
Cough +/- sputum Chest pain Fever Fatigue Shortness of breath Crackles Elevated WBC Abnormal CXR
signs/symptoms of pneumonia
Most common route of bacterial infection in the lung is…
Aspiration (from oral microflora or GI)
Smoking Meds Intubation Leukemia/Lymphoma COPD Viral infection AIDS Immunosuppression
Things that can cause a weakening of natural lung defenses
What are the steps to diagnostic evaluation for CAP
- Establish the diagnosis of pneumonia
- based on clinical signs/symptoms and lab/xray results - Identify the pathogen (if possible)
- s. pneumo is the most likely
- Gram stains/culture/blood maybe used
- patient history can help - Assess the severity of illness
- based on demographics, clinical findings, lab and x ray results
- CURB-65
- decide outpatient or inpatient
Typical vs. atypical pneumonia: rapid, ill, high fever, chest pain and sputum; consolidation and crackles; lobar infiltrate
typical
Typical vs. atypical pneumonia: slow, less ill, milder fever, headache and cough; crackles with no consolidation; patchy infiltrates (interstitial)
atypical
“Typical” pneumonia is usually caused by what organisms?
S. pneumoniae
S. aureus
GN bacilli
“Atypical” pneumonia is usually caused by what organisms?
Mycoplasma
Chlamydia
P. jiroveci
Viruses
Interstitial (atypical) pneumonia looks like what in a CXR?
Diffuse, stringy infiltrates (like a spider web)
Typical pneumonia looks like what in a CXR?
lobar
Most common bacterial cause of pneumonia (either ambulatory, hospitalized or severe/ICU)
Streptococcus pneumoniae
Drug resistant pneumoniae is typically found in what populations?
Age >65
Daycare
- why they get vaccinated maybe
P. aeruginosa infection is typically found in what populations?
CF
Bronchiectasis
H. influenzae infection is typically found in what populations?
Smokers
COPD
What factors increase the severity of pneumonia?
- age >60
- abnormal vital signs (low BP/RR, high HR)
- WBC>30k or <4k
- multilobar on cxr
Initial treatments for pneumonia are nearly always empiric
True (tests take time and 50% of time you’ll never know)
Which etiologic agents of pneumonia typically need hospitalization?
Legionella
S. aureus
Gram- bacilli
Outpatients with pneumonia typically receive what treatment?
Macrolides or doxycycline
Outpatients with DRSP, or inpatients not in the ICU, with pneumonia typically receive what treatment?
Beta-lactam + macrolide
OR
Respiratory fluoroquinolone
Inpatients in the ICU with pneumonia typically receive what treatment?
Beta-lactam + azithromycin or fluoroquinolone
Empiric drug therapy for CAP in children is dependent on
age
You know your chosen treatment for pneumonia was effective if..
better within 24-48 hours
When to suspect an atypical (other) cause of pneumonia?
Upper lobe infiltrate (TB) Indolent Non-resolving with treatment Outdoors (Blastomycosis) SW (Coccidioides)
What are the steps to diagnostic evaluation for HAP
Basically the same as CAP
Hospital Acquired Pneumonia (HAP) affects 1% of hospitalized patients, has a mortality of 33%, and is highest in…
intubated patients
Typical Hospital Acquired Pneumonia pathogens
Gram- bacilli P. aeruginosa Enterobacter E. coli MRSA Klebsiella
Treatment for HAP is based upon
local hospital flora
Typical Hospital Acquired Pneumonia pathogens
Gram- (P. aeruginosa, E. coli, MRSA, Klebsiella)
- HAP more likely to be polymicrobial
What pathogens are not covered by empiric CAP therapy so must be included with HAP empiric therapy?
MRSA (Vacomycin)
P. aeruginosa (gentamicin)
*CAP empiric therapy includes E.coli and klebsiella)
Wider variety of pathogens (fungal) should be considered for HAP patients that are
immunocompromised
What opportunistic pathogen should be considered for AIDS patients with pneumonia if their CD4 count is < 200?
Pneumocystis
- bacterial pneumonia still remains the most likely culprit
What clinical presentation is the prominent feature of AIDS patients with pneumocystis?
hypoxemia
Typical presentations (upper lobe cavitary infiltrates) are seen with AIDS patients with TB when they have
higher CD4 count
atypical presentations (lower zone infiltrates) are seen with AIDS patients with TB when they have
low CD4 count
Neutropenia can make you more susceptible to what infections?
Bacteria Opportunistic Pathogens (Candida & Aspergillus)
Splenectomy can make you more susceptible to what infections?
Encapsulated organisms
Neutrophils are involved in what type of inflammatory response?
Acute inflammation in alveolar SPACE in response to BACTERIA
Lymphocytes are involved in what type of inflammatory response?
Chronic inflammation in alveolar SEPTAE (interstitial) in response to VIRUSES
- alveolar space is clear
A granuloma is an inflammatory response to what pathogens?
in response to FUNGI and MYCOBACTERIA
What cells make up granulomas?
- Langhans giant cells
- Histiocytes (macrophages)
- Some lymphocytes & neutrophils
What are two major patterns of bacterial pneumonia?
- Bronchopneumonia
- scattered patchy foci of consolidation - Lobar Pneumonia
- complete consolidation of a lobe w/wo hepatization
- Strep. pneumo
Organisms causing bacterial pneumonia can be largely divided into
CAP or HAP
Describe pneumococcal pneumonia caused by Strep pneumo
- Pathogen: Strep pneumo
- Encapsulated gram + diplococci
- extracellular - Pathology
- Early: red hepatization (intra-alveolar neutrophils and RBCs)
- Later: grey hepatization (intra-alveolar macrophages) - Lobar pattern
Describe pneumonia caused by Anaerobic bacteria
Anaerobic bacteria often cause necrosis +/- abscess and foul-smelling sputum
- higher risk in alcholism
Describe pneumonia caused by Filamentous Bacteria
- Pathogens: gram +
- Nocardia (acid fast +)
- Actinomyces (acid fast -) - Abscesses
- Nocardia: abscesses in immunocompromised
- Actinomyces: abscesses with sulfur granules
Complications of bacterial pneumonias (3 total)
- Abscesses
- Pyothorax/empyema (infection of pleural fluid/space)
- Bacteremia (in blood)
Abscess vs. Granulomas: macrophages, lymphocytes, langhan cells surrounding necrotic center with neutrophils and bacteria
Granulomas + necrosis
Abscess vs. Granulomas: center full of neutrophils and bacteria and fibrosis surrounding the center
Abscess (pus)
Describe pneumonia caused by Mycoplasma
- Milder (chronic walking pneumonia) than usual bacterial pneumonia
- inflammation in the wall and lumen of bronchiole; alveoli is clean
Describe tuberculosis caused by Mycobacterium tuberculosis
- Primary TB
- inhalation of m. tuberculosis
- Ghon Complex (ghon focus + infected hilar lymph node)
- Granulomatous inflammation +/- necrosis
- 90% asymptomatic - Secondary TB
- reactivation of primary TB or new infection in sensitized/HIV patient
- Granulomas cavitary lesions in apex of upper lobes
- granulomas can deteriorate and disseminate hematogenously (miliary TB)
Complications of TB (4 total)
- Miliary TB (multiple small granulomas)
- Hemoptysis: angioinvasion of pulmonary artery
- Broncho-pleural fistula: erodes into pleural space leading to empyema
- Cavity formation: site for aspergilloma growth
Describe pneumonia caused by Fungi
- Pathogens: Histo, Blasto, Coccidioides; crypto
- often in immunocompromised patients
- Granulomatous host response
- silver stains for detection
What fungal pathogen is very small and found in bird droppings?
Histoplasma
- necrotizing granulomatous inflammation
- pomegranate shaped
What fungal pathogen is thick walled (double contoured) and had broad based budding?
Blastomyces
- dumbbell-shaped
What fungal pathogen is most found in SW US and has spherules (w/ endospores inside)
Coccidioides
- half-cut fig shaped
What fungal pathogen is found in pigeon droppings and has halo or narrow based budding?
Cryptococcus
type of fungus; seen in soil and decaying plant material; septate hyphae with acute (V-shaped) branching
Aspergillus
3 types of Aspergillosis disease
- Invasive aspergillosis
- invasion of blood vessel wall and lumen - Aspergilloma
- Mycetoma (fungal ball) in cavity from TB - Allergic Bronchopulmonary Aspergillosis (ABPA)
- allergic response to aspergillus
- high IgE and eosinophils
Describe pneumonia caused by Pneumocystis
- HIV/AIDS patients with <200 CD4 count at risk
- frothy exudates within alveolar spaces
- broncho-alveolar lavage useful for diagnosis (silver stain)
Describe pneumonia caused by Viruses
- Interstitial lymphocytes
- CMV (owl eye cells with large intra-nuclear inclusions)
- HSV (cells with 3 Ms: multinucleation, margination, molding)