Pulmonary infection Flashcards
Clinical classifications of pneumonia (5)
CAP, HAP, HCAP, VAP, Pneumonia in immunocompromised patient.
Communiy acquired pneumonia pathogens
- Most common
- Atypical pneumonia pathogens
- Elderly smokers
- Alcoholics and aspirators
- S. pneumonia
- mycoplasma, viral, chlamydia
- legionella (peripheral consolidations, progresses to lobar and multilobar)
- Klebsiella. Voluminous inflammaory exudates causing bulging fissure sign.
HAP and HCAP. Disctinction and pathogens
HAP in hospitalized patients. HCAP in patients in nursing homes or prior hospitalization.
Pathogens: MRSA, pseudomonas.
Opportunistic pathogens (4)
PCP, Aspergillus, nocardia, CMV.
radiographic patterns of infection (4)
Lobar
Lobular (bronchopneumonia) - patchy consolidation
Interstitial pneumonia (mycoplasma, chlamydia, pneumocystis)
Round pneumonia
Round pneumonia: most common pathogen. Why is infection confined?
Strep pneumo
Infection confined due to incomplete formation of pores of Kohn
Complications of pneumonia (6)
Pulmonary abscess, pulmonary gangrene, Empyema, Pneumatocele, Bronchopleural fistula, Empyema necessitans.
3 stages of empyema
Free flowing exudative effusion.
Development of fibrous strands
Fluid becomes solid and jelly like.
Bronchopleural fistula
What is it? Causes?
Can occur from rupture of visceral pleura as complication of pneumonia. But most common cause is Surgery. Other etiologies include lung abscess, empyema, and trauma.
Empyema necessitans. What is it, what are most common pathogens
Extension of empyema into chest wall. Most commonly due to TB, but also seen in Nocardia and actinomyces.
3 clinical scenarios of TB
1-2. Initial exposure to TB can lead to 2 clinical outcomes
- re-activation
- Contained disease (90%). (primary)
- Primary progressive TB (host cannot hold disease. Occurs in children and immunocompromised)
- re-activation
Primary TB. (Can be normal on CXR)
1, What are the 4 imaging manifestations
- 2 Classic imaging complexes
- Ill-defined consolidation, pleural effusion, lymphadenopathy, milliary disease.
- a. Ghon focus - parenchymal infection - calcified granuloma
b. Ranke complex - Ghon focus + lymphadenopathy.
In TB, when do you see cavitation, when do you see adenopathy?
Cavitation is seen more commonly in reactivation TB.
Adenopathy is more common in primary TB.
- Most common location for primary TB
- Most common location of reactivation TB
- Primary: RML, RLL
- reactivation - upper lobe apical and posterior segments.
Imaging of re-activation TB in immunocompetent patient and immunosuppressed patient.
Immunocompetent patient: cavitation, lack of adenopathy. Endobronchial spread (Tree-in-bud)
Immunocompromised: low attenuation adenopathy may be seen.