A/Prof Peter Wark
Department of Respiratory and Sleep
Medicine John Hunter Hospital

• Ms AN, 37 year old
• Previously well
• 3 day history
– Sore throat
– Dry cough
• Today
– Left sided sharp chest pain
– Felt hot and unwell, rigors

• Pneumonia
• Bronchitis
• Asthma
• Pulmonary embolus

• In US pneumonia
– 6 th leading cause of death
– Leading cause of death from an infectious disease
• Mortality
– 1-5%
– Up to 40%

Identifying a pathogen

• In clinical practice an organism is found in only 50%
• No single test is available that can identify all organisms
• History, clinical findings and X-ray changes are not diagnostic of a particular organism
• ? Mixed infection, especially viral and bacterial

• 20-60%, Strep Pneumoniae
• 3-37%, Mycoplasma Pneumoniae and
Chlamydia Pneumoniae
• 10% cases
– Viral (exceptions influenza, adenovirus)
– Staph Aureus (MSSA and MRSA)
– Gram neg organisms
– Legionella pneumophilia (3-10%)

• Risk is increased
– Nursing home resident
– Cardiorespiratory disease (COPD, CCF)
– Immunosuppression
– Alcoholism
– Recent antibiotic use
– Age > 65 years
• Cause
– more gram negative organisms or resistant pathogens
– Viral (CMV, VSZ, respiratory viruses
– PCP
– Fungal

• 20-50%, Strep Pneumoniae
• 10-30% E.Coli, K Pneumoniae, Enterobacter
• 3-10% Legionella pneumophilia (adm ICU)
• Staph Aureus
– MSSA
– MRSA
• Viral
• Pseudomonas Aerugniosa ?

• PCR improves detection
• Some series, accounts for up to 24%
• Not predicted by CXR or CRP
• Pathogens
– Influenza
– SARS
– RSV
– Rhinovirus (co-pathogen 35% severe CAP)
– Adenovirus

How to identify the pathogen?

• Sensitivity 10-54%
• “good sample” and cultured quickly
• Gram stain positive (esp Pneumococcus)
• Culture best with heavy growth and correlation with gram stain
• Special culture medium for Legionella, sensitivity 10-
80% (better with BAL), specificity 80%
• High false positive, especially Staph Aureus & GNB

• Sensitivity 7-16%, specificity 90% (depends on organism)
• Strep Pneumoniae,
– accounts for 2/3 positive blood cultures
– Pneumococcal bacteraemia, 1%, mortality 19% vs
4% hospitalised with pneumococcal pneumonia

• Detection of Strep Pneumoniae & Legionella
• Advantages
– Easily available
– Valid after antibiotics initiated
• Pneumococcus
– Sensitivity 82%, specificity 97% (bacteraemic)
• Legionella
– Sensitivity 70-80%, specificity 97%
– Only L. Pneumophilia

• CURB-65
– Confusion (1 point)
– Urea >7mmols (1)
– Respiratory rate >30 (1)
– BP, systolic <90 or diastolic < 60 (1)
– Age >65yrs
Score
0-1
2-3
3-5
Implication
Risk death <3%, OP
Risk death 9% hospitalise
Mortality 15-40% consider
ICU

Sex
M (0 points)
F (-10 points)
Demographic factors
Age (1 point for each year)
Nursing home resident (10 points)
Comorbid illnesses
Neoplastic disease (30 points)
Liver disease (20 points)
Congestive heart failure (10 points)
Cerebrovascular disease (10 points)
Renal disease (10 points)
Physical examination findings
Altered mental status (20 points)
Respiratory rate >= 30/minute (20 points)
Systolic blood pressure < 90 mmHg (20 points)
Temperature < 35 degrees C or >= 40 degrees C (15 points)
Pulse >= 125/minute (10 points)

Laboratory and radiographic findings
Arterial pH < 7.35 (30 points)
Blood urea nitrogen >= 30 mg/dL (11 mmol/L) (20 points)
Sodium < 130 mEq/L (20 points)
Glucose 14 mmol/L) (10 points)
Hematocrit < 30 percent (10 points)
Partial pressure of arterial oxygen < 60 mmHg or oxygen saturation < 90% (10 points)
Pleural effusion (10 points)
0-50 Points: Class I 0.1% Mortality
51-70 Points: Class II 0.6% Mortality
71-90 Points: Class III 0.9% Mortality
91-130 Points: Class IV 9.3% Mortality
131-395 Points: Class V 27.0% Mortality

• Age >65yrs
• Chronic disease
– COPD
– CCF
– Diabetes
– Liver disease
– Chronic renal failure
– Neoplasia
• Alcoholism
• Immunosuppression

• Altered mental state
• Tachypnoea (RR>30)
• Hypotension (systolic <90mmHg)
• Temperature <35 0 C or > 40 o C
• Tachycardia (125bpm)

• Electrolytes
– Na <130mmol
– Glucose >14mmol
• Renal impairment (Urea >11mmol/L)
• Gas exchange and acid base
– pH <7.35
– PaO
2
• CXR
<60mmHg
– Extent consolidation
– Presence of an effusion

Clinical
• Age 39 years
• No co-morbidities
• Altered mental state
• BP 100/50
• Temp, 39.5
• RR, 32bpm
• HR 125
Investigations
• pH 7.38
• pO2 68mmHg
• Na 135mmols
• HCT 32%
• Urea 8mmols
• BGL 8mmols
Class 4 mortality 9.3%

• Moderate
– Penicillin 1.2g 4hrly IV +
– Doxycycline or clarithromycin or azithromycin orally
– If gram negative, add gentamicin for 2-3 doses (7mg/kg/d)
• Severe
– Penicillin 1.2g IV 6hrly +
– Gentamicin IV 2-3 doses +
– Azithromycin 500mg IV
• Alternate
– Ceftriaxone 1g/d or
– Tazocin 4.5gm QID
– Moxifloxacin 400mg IV/PO daily

(Asadi et al Resp Med 2012
• 2973 patients mild pneumonia
• Those who received guideline based treatment, less likely to die, 6% v 1% (OR 0.23, 0.09 to
0.59)
• Those who received macrolides (as opposed to fluroquinolones) were less likely to die.

• 24-72 hrs, see stability
• Day 3,
– improvements in symptoms
– Defervescence by day 4 (most rapid Strep
Pneumoniae)
– Fall in WCC & CRP or 50% reduction PCT
• CXR
– Slow to resolve (60% some abnormality at 4 weeks)

• Switch to PO therapy
– Improvement in cough and dyspnoea
– Afebrile
– WCC & CRP improving
• Discharge
• No need to repeat CXR now, but 4-6 weeks post discharge

• PCT >0.25 mcg/L and decision to use antibiotics reduces unnecessary antibiotic use in 2 RCTs
– Improves diagnosis in those with heart failure
– Cost effective in ICU
• Higher PCT predicts the presence of bacteraemia
• Increase in PCT in first 72hrs was associated with reduced survival
• Fall in PCT by 50% indicates an ability to switch to PO antibiotics

24-72hrs clinical response
Early clinical response
Lack of clinical response
Switch to oral & discharge
Revaluate
Host
Pathogen
Complications
Deteriorating

Lack of response or deterioration
• Host factors
– Elderly
– Immunosuppressed
– Bacteraemia
– Chronic illness
– Diabetes
– Alcoholism
– Second nosocomial pneumonia
• Local factors
– Effusion/empyema
– Abscess
• Misdiagnosis
– Pulmonary embolus
– CCF
– Pulmonary haemorrhage
– Pulmonary vasculitis
– BOOP
– Acute interstitial pneumonitis
– Eosinophilic pneumonia
– Hypersensitivity pneumonitis

• Agitated and very breathless
• P 140, BP 90/50, RR 38, T 39 0 C
• ABGs (FiO
2
0.5)
– pH 7.32
– PaO
2
55mmHg
– PaCO
2
30mmHg
– HCO
3
16mmols

• Agitated and very breathless
• P 140, BP 90/50, RR 38, T 39 0 C
• ABGs (FiO
2
0.5)
– pH 7.32
– PaO
2
55mmHg
– PaCO
2
30mmHg
– HCO
3
16mmols

• Progression of pneumonia
• ARDS
• Bacteraemia
• Shock

• Suspect
– Persistent fever
– Pleuritic chest pain
– Organisms (pneumococcous, Strep Milleri, Staph Aureus)
• Clinical examination
• Image again

Lung abscess/necrotising pneumonia

1.
Clinical assessment
– Diagnosis with CXR
– Risk factors for poor outcomes
– Severity assessment
2.
Follow guidelines for empirical antibiotics
3.
Assess response
4.
Reassess if response is not typical