Pneumonia 101
Armaan Khalid
What the...
Definition of Pneumonia
An acute or chronic disease marked
by inflammation of the lung
parenchyma, that causes
consolidation of inflammatory
exudates
Main causes
Bacteria
Virus
Fungal & etc
Classification
Anatomical/Radiological
Lobar
Multi-focal/lobular (bronchopneumonia)
Interstitial (focal diffuse)
Location of Contraction
Community
Institutional (nursing home)
Nosocomial (hospital)
Precipitating Factors
Smoking (Smokers in household)
Previous lung pathology (COPD, CF)
EToH abuse
Immunosuppresion
Recent hospital admission
IVDU (S Aureus haematogenous
spread)
Recent exposure to pneumonia pts
Preceding viral infection
HIV
Causative Organisms
Atypical Pneumonia
Assoc w a milder form of pneumonia
Walking pneumonia
Considered atypical because
Inability to detect on gram stain
Inability to be cultivated in normal media
Examples
Mycoplasma
Chlamydophila species
Legionella
Coxiella burnetii (Q fever)
Bordetella pertussis (Whooping cough)
Clinical Presentation
Preceding Hx of viral illness
On Hx/Ex
Febrile/Pleuritic Pain/Dry cough
Sputum production
Malaise/Rigors/Chills
Tachypnoea/cardia
↓ chest movements
Use of accessory chest muscles
Sg of consolidation +/- pleural rub
History Taking
Impt to review pt’s:
Potential exposure
Envt/Work/Social factors
Aspiration risks
Seizure/EToH/GORD
Host factors
COPD/IVDU/Smoking/HIV
Sputum Characteristics
S Pneumoniae
Rust coloured sputum
Pseudomonas/Haemophilus &
Pneumococcal
Green sputum
Klebsiella species
Red currant jelly sputum
Anaerobic species
Foul smelling/Bad tasting sputum
Risk Stratification
How do you make the decision to Rx
the pt in a out/in-patient setting?
CURB-65 criteria
Pneumonia Severity Index (PSI)
PSI calculator online
http://pda.ahrq.gov/clinic/psi/psicalc.asp
CURB-65 criteria
C – Confusion
U – Uraemia, BUN > 20 mg/dL
R – Respiratory Rate > 30 bpm
B – Blood pressure < 90/60 mm Hg
65 – Age > 65 years old
Score 0-1:
Score 2:
Score 3-4:
Outpatient treatment
Admit to the wards
Admit to ICU
PSI Calculator
Differential Diagnosis
Asthma
Atelectasis
Bronchiectasis
COPD
Lung Abscess
Viral infection
Influenza
Workup
FBE/UNE/BUN/LFT/CRP/ESR
Blood cultures
Impt to get them before initiating
empirical therapy
Sputum (microscopy & culture)
ABG
? Pleural fluid tap
CXR (frontal & lateral)
Further Workup
Pneumococcal antigen
Counter-immunoelectrophoresis of
sputum, urine & serum
Mycoplasma antibodies
Legionella & Chlamydia antibodies
Immunoflurorescent tests
Legionella antigen
Urinary antigen test
Radiological Findings
General Characteristics
Affected tissue will appear denser
May contain air bronchogram(s)
Visibility of air in the bronchi
Sign of airway disease, not pathognomonic
for pneumonia
Airspace pneumonia appears fluffy &
their margins are indistinct
If it abuts a pleural surface, there will be a
sharp demarcation of the margins
Patterns of Appearance
Lobar
Segmental (Bronchopneumonia)
Interstitial
Round
Cavitary
I Spy With My Little Eye
Lobar Pneumonia
Patterns on CXR
Lobar Pneumonia
Common organism: S Pneumoniae
Homogenous consolidation w air
bronchogram
Silhouette sign present when in contact
with the heart, aorta or diaphragm
Segmental Pneumonia
Patterns on CXR
Segmental (Bronchopneumonia)
Common organisms: S Aureus & gramnegative bacteria
Affects the walls of the bronchioles
Spread centrifugally via tracheobronchial
tree to many foci @ the same time
Margins are fluffy & indistinct
Produces exudate that fills the bronchi
No air bronchograms present
May be assoc w atelectasis
Interstitial Pneumonia
Patterns on CXR
Interstitial Pneumonia
Common organisms: Mycoplasma, viral
pneumonia & PCP
Reticular interstitial disease w diffuse
spread throughout lungs in early disease
process
Frequently progresses to airspace
disease
Round Pneumonia
Patterns on CXR
Round Pneumonia
Common organisms: H influenzae, Strep
& Pneumococcus
Spherical pneumonia usually seen in the
lower lobes of children
May resemble a mass
Clinical presentation does not match w that
of a mass
Cavitary Pneumonia
Patterns on CXR
Cavitary Pneumonia
Common organism: M tuberculosis
Primary TB < Reactivation TB
Primary TB
Upper lobes > lower lobes
Assoc w ipsilateral hilar adenopathy & large
unilateral pleural effusions
Reactivation TB
Cavities are thin-walled, smooth inner
margin & usually no air-fluid level
Localised Lower Lobe Pathology
Spine Sign
On Lateral CXR, thoracic spine
vertebra are darker in diaphragm than
in shoulder girdle
CXR needs to penetrate more tissue in
the shoulder girdle than in diaphragm
With interstitial/airspace disease in
posterior lower lobe, vertebra would be
more opaque (brighter) than usual
Spine Sign!
Silhouette Sign
If 2 objects of the same radiographic
density touch each other, then their
edges disappear
Silhouette Sign
Valuable in localising lung pathology
Silhouette Sign Helpful Hints
Structure That Isn’t Visible
Disease Location
Ascending Aorta
Right Upper Lobe
Right Heart Border
Right Middle Lobe
Right Hemidiaphragm
Right Lower Lobe
Descending Aorta
Left Upper/Lower Lobe
Left Heart Border
Lingula of Left Upper Lobe
Left Hemidiaphragm
Left Lower Lobe
Management
Respiratory Support
O2 +/- bronchodilators
Fluid resuscitation
Empiric Abx Rx
Empiric Rx should initially be broad
Each hospital has it’s own guidelines
Empirical Rx of Pneumonia
Supportive Measures
Analgesia & anti-pyretics
Chest physiotherapy
IV fluids or diuretics
Positioning of patient (Aspiration risk)
Suctioning & bronchial hygiene
Clinical Resolution
Clinical response to Abx Rx
Improvement seen in 48-72 hrs
Abx shouldn’t be changed w/in 72hrs
Time required for Abx to act
Change if marked deterioration
Radiological resolution takes longer
than clinical resolution
Clinical Resolution (or lack thereof)
No resolution
Resistant to Abx
2° to complications (empyema/abscess)
Non-infectious cause (CHF/malignancy)
Viral aetiology
Consider
CT/MRI
Bronchoscopy
Lung biopsy
Consult ID physician
Viral Pneumonia
Common in children & the elderly
Prevalent in the immunosuppressed
Uncommon in adults
13-50% of all CAP
Influenza virus main offender (>50%)
Clinical findings similar to bacteria
May predispose & superimpose on a bacterial
pneumonia
Common during winter
Rx
Supportive Rx
Antiviral
Immunisations
References
Kumar & Clark, Clinical Medicine, 6th
edn, Chapter 14, Pneumonia, pp 922929
W Herring, Learning Radiology:
Recognizing The Basics, 1st edn,
Chapter 8 Recognizing Pneumonia, pp
60-67
Longmore et al, OHCM, 7th edn ,
Chapter 5, Chest Medicine, pp 152-153