PNEUMONIA
Prof T Rogers
THE IMPORTANCE OF
PNEUMONIA
• A major killer in both developed and
developing countries
• Accounts for more deaths than other
infectious diseases
• Mortality rates vary but can be as high as
25%
• A major cause of death in children in
developing countries
• Incidence here (?) 2-5/1000 population
PNEUMONIA
• Neither radiological or microbiological
criteria are specific for predicting the
cause of pneumonia
• A better approach is to first consider the
clinical circumstances under which
pneumonia acquired
• Add the clinical background of the
particular patient…
Classification of pneumonia
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Community-acquired
Hospital-acquired
Aspiration and anaerobic
Pneumonia in immunocompromised
AIDS-related
Geographically restricted
Recurrent
COMMUNITY-ACQUIRED PNEUMONIA:
INTRODUCTORY POINTS
• More common at the extremes of age
• Twice as common in winter months
• A General Practitioner is likely to see up to
10 cases per yr
• Represent <10% of all respiratory infection
cases prescribed antibiotics
• Most will be managed in the community
TYPES OF COMMUNITY ACQUIRED
PNEUMONIA
• In a previously healthy individual
• Here the infection may have been
acquired by droplet spread from another
• Alternatively, in patients with underlying
diseases endogenous colonizing bacteria
may be the cause
• These are more likely to be resistant to
first-line antibiotics
SYMPTOMS OF PATIENTS WITH
COMMUNITY-ACQUIRED PNEUMONIA(%)
[Mc Farlane unpublished]
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Cough
Fever
Breathlessness
Pleural pain
Headache
New sputum production
Muscle aches
Nausea/vomiting
92
86
67
62
55
54
44
48
British Thoracic Society CAP severity assessment:
CURB 65 score
• Any of: confusion, urea> 7mmol/l, respiratory
rate>30/min, blood pressure systolic <90mmHg
diastolic<60mmHg, age>65 years
• Low (0-1), moderate (2), high (3+) severity
• Will help determine where treated (home vs
hospital), and likely mortality.
• ICU admission indicated by CURB score of 4-5
COMMUNITY ACQUIRED PNEUMONIA:
WHAT’S CAUSING IT?
MICROBIOLOGICAL CAUSES (%) OF
COMMUNITY ACQUIRED PNEUMONIA FROM
HOSPITAL BASED STUDIES (N=3,000)
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No cause found
Pneumococcus
Influenza virus
Legionella spp*.
Haem. Influenzae
Other viruses
Psittacosis/Q fever
Gram neg. bacilli
Staph aureus*
CAP
Severe CAP
36
25
8
7
5
5
3
2.7
2
33
27
2.3
17
5
8
2
2
5
INVESTIGATIONS FOR DIAGNOSIS
OF PNEUMONIA
• Non-invasive: blood count, urea,
albumin,LFT’s, sputum gram, chest X-ray,
CT scan
• Culture of sputum, blood, pleural fluid
• Serology: pneumococcal, Legionella
antigen
• Invasive: induced sputum, bronchoscopy,
open lung biopsy
TYPICAL GRAM APPEARANCE OF
Strep pneumoniae IN SPUTUM
GRAM POSITIVE CHAINS
DIPLOCOCCI
Streptococcus pneumoniae
(pneumococcus)
• A gram positive coccus that grows in short
chains
• Alpha haemolytic on blood agar
• Identified by its susceptibility to optochin
• Polysaccharide capsule confers
pathogenicity-at least 80 serotypes
• There are multivalent vaccines for
prevention of pneumococcal disease
SOME COMPLICATIONS OF
PNEUMOCOCCAL SEPSIS
• Bacteraemia (10%+)
• Empyema (1%)
• Meningitis (<0.5%)
• Mortality rates of 10-25%
• Splenectomy or asplenia a major
risk factor
Pneumococcal vaccine is
recommended for:
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Age >65 years
Underlying chronic lung disease
Asplenia
Alcoholism
Diabetes mellitus
Chronic renal failure
HIV infection
VIRUSES THAT CAUSE COMMUNTIY
ACQUIRED PNEUMONIA
INFLUENZA
© March Issue of Epi-Insight, Vol 6, Issue 3,
Health Protection Surveillance Centre, Ireland
Pandemic influenza H1N1
• An acute respiratory illness
• Sudden onset of: fever (>38oC),
headache, cough, sore throat, muscle
aches, pneumonia
• Transmitted by respiratory droplets from
coughing, sneezing, and from “infected”
surfaces.
• 1,613 cases confirmed with 4 deaths in
Ireland up to 3rd October
Underlying diseases with an
increased risk of severe influenza
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Chronic lung, liver, CNS, conditions,
Immunosuppression
Diabetes mellitus
Asthma
Age <5 years or >65 years
Severely obese (BMI 40 or more)
Pregnancy
haemoglobinopathies
Preventing the spread of pandemic
(swine) influenza
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Wash hands with soap and water
Avoid unnecessary contact with cases
Avoid touching eyes, nose , mouth
Cover mouth and nose with tissue
Patients admitted to hospital who have a
confirmed diagnosis will be nursed in a
negative pressure room
• HCW’s wear protective clothing
Treatment and prevention of pandemic
influenza H1N1
• Oseltamivir treatment of severe cases
• Can also be considered as antiviral
prophylaxis in selected high risk patients
• Should be used prudently because of risk
of drug resistance
• Vaccine about to be issued, will include
provision for health care workers
A
V
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N
F
L
U
OTHER VIRAL CAUSES
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Respiratory syncytial virus (RSV)
Parainfluenza viruses
Enteroviruses
(Cytomegalovirus)
S
A
R
S
© July 2003 issue of Virus Alert,
bulletin of the National Virus Reference
Severe Acute Respiratory
Syndrome (SARS)
o Identified in Guangdong Province, China,
in November 2002
o Rapidly spread to Hong Kong, South East
Asia, North America..The World
o By the end of outbreak in June 2003 more
than 8,000 cases had occurred with >800
deaths
o Person to person transmission
demonstrated
CAUSES OF ‘ATYPICAL’
PNEUMONIA
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Mycoplasma pneumoniae
Chlamydia pneumoniae
Legionella pneumophila
Coxiella burnetii
Mycoplasma pneumoniae
• Has no cell wall, therefore doesn’t respond to
beta lactams
• Causes atypical pneumonia in adolescents and
young adults
• Dry hacking cough, low grade fever, headache
feature
• Isolation by culture of the organism is difficult
therefore diagnosis is confirmed by a high CFT
or rising titre of specific antibodies
• Cold agglutinins also typical
• Macrolides or tetracyclines most active
Chlamydia pneumoniae
• An obligate intracellular bacterium
• Causes mild pneumonia but may cause
protracted symptoms
• Sore throat, hoarseness, URT symptoms
feature
• Serological diagnosis rather than culture
• Tetracyclines, macrolides, quinolones
active
Legionnaires’ disease
• A severe pneumonia due to Legionella
pneumophila
• Can be community or hospital acquired
• Organism is acquired from environmental
sources eg, humidified air conditioning,
showers
• Usually attacks debilitated individuals
Radiology
Microbiology
Gram –ve, flagellated rod, aerobic
Facultative intracellular parasite in both
amoeba and human
monocytes/macrophages
RISK FACTORS
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Male sex
Advanced age
Cigarette smokers
Alcoholism
Chronic lung disease
Immmunosuppression, malignancy
Legionnaires’ disease
• Hyponatremia, confusion, nausea,
vomiting, abnormal LFT’s a feature
• Diagnosis often confirmed by urinary
antigen test (specific for serogroup 1)
• Can be cultured on special media
• Must be notified to Public Health as it can
cause outbreaks
• Most active antibiotics are: macrolides,
quinolones, rifampicin
Antibiotic Treatment of Community
Acquired Pneumonia
• The priority is to cover pneumococcus
• Penicillin, amoxycillin, cephalosporins,
new quinolones and macrolides have all
been used as monotherapy
• Choice will be influenced by local
resistance rates for pneumococcus
Examples of antibiotics for CAI
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Benzylpenicillin
Penicillin V
Ampicillin, amoxycillin, Augmentin
Cefuroxime, cefotaxime, ceftriaxone
Moxifloxacin (a quinolone)
Erythromycin, clarythromycin,
azithromycin
ACID ALCOHOL FAST RODS
SUGGESTING TUBERCULOSIS
KLEBSIELLA PNEUMONIA
(RARE)
COMMUNITY ACQUIRED PNEUMONIA IN
INFANTS AND CHILDREN
• Group B streptococcus and E coli cause
pneumonia in neonates
• RSV an important pathogen in infants
• Bordetella pertussis (cause of whooping
cough) important in young children
• As is Haemophilus influenzae type b
SOME FEATURES OF NOSOCOMIAL
PNEUMONIA
• Often ventilator associated, therefore seen
in ITU most commonly
• Due to both endogenous organisms and
others acquired by cross infection
• MRSA, gram negatives predominate
• High associated mortality because of comorbidity and antibiotic resistance
HOSPITAL ACQUIRED PNEUMONIA:
Pseudomonas aeruginosa
TREATMENT OF HOSPITAL
ACQUIRED PNEUMONIA
• Will depend on the local epidemiology of
the unit/hospital
• Often require good cover for MRSA and
gram negative enterobacteria
• Therefore vancomycin and carbapenem or
Tazocin may be used
PNEUMONIA IN THE
IMMUNOCOMPROMISED HOST
• Cause depends on the underlying
immunodeficiency
• More likely to present as a diffuse
interstitial pneumonia
• Treatment often empirical as establishing
the cause is often difficult
MAJOR CAUSES OF PNEUMONIA IN
IMMUNOCOMPROMISED
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Pneumocystis jiroveci (carinii)
Cytomegalovirus
Other respiratory viruses
Tuberculosis
Fungi
Pneumocystis jiroveci
(Lung biopsy)
Cyst stage
NOCARDIOSIS
(Cause: Nocardia asteroides, acid fast rod)
Geographically restricted
pneumonias
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Typhoid
Melioidosis
Brucellosis
Endemic mycoses: histoplasmosis
Helminthic: paragonimiasis
Recurrent pneumonia
• May be caused by local bronchial or pulmonary
abnormality
• Obstruction due to eg, foreign body, carcinoma,
lymph node
• Chronic obstructive lung disease: bronchiectasis
• Neurological disorders: motor neurone disease
• Structural: tracheo-oesophageal fistula
• Aspiration (alcoholics): anaerobic organisms
• Immunodeficiency state:
hypogammaglobulinaemia
EMPYEMA
• May arise as an acute complication of pneumonia
• Characterised by collection in pleural cavity, malaise,
fever, pleuritic pain, leucocytosis
• Chronic empyema usually occurs after failure to
diagnose or treat adequately an acute empyema
• May be loculated, or associated with a broncho-pleural
fistula
• Organisms are those causing the original pneumonia, or
anaerobes
• Treat by drainage of the collection and antibiotics after
microbiological findings