Pneumonia

Question 1

Sources of pneumonia

Answer 1

1. Community acquired
2. Aspiration pneumonia
3. Hospital acquired >48hrs of hospitalization
4. Ventilator acquired: 48hrs on ventilator

Question 2

Other differentials

Answer 2

1. Exacerbation of airway disease
2. Atelectasis due to prolong bedrest

Question 3

High risk patients

Answer 3

1. Elderly
2. Chronic co-morbidities
3. Viral co-infection
4. Impaired airway disease
5. Specific pathogens: TB and others

Question 4

Pathogens

Answer 4

1. No diagnosis in 50% of the process
2. Bacterial co-infection in 30% of patients with flu and RSV. 4% with covid
3. Strep pneumoniae is the most common bacteria followed with mycoplasma, legionella / staph aureus.
4. Pseudomonas is rare (hospital acquired mostly but rare)
5. Fungi is more common in travellers

Question 5

Diagnosis - physical findings, radiological, microbiological

Answer 5

1. Physical findings: Bronchial breathing, vocal fremitus and others.
   Atypical infection: confusion, diarrheoea, hyponatremia
2. CXR: focal infiltrates, lobar consolidation, loss of heart border
   CT chest (getting more common): new infiltrates/ consolidation. Better in picking up subtle changes compared to CXR in 43% of the cases
   USS: Getting more common: air bronchogram, lung hepatization
3. Microbiology: Unclear 50% of the time. Identification of new pathogenic flora with clinic correlation

Question 6

Hospital acquired pneumonia diagnosis and differential

Answer 6

1. New CXR changes + one of the following: fever, lymphocytosis, new/ worsening secretions, worsening gas exchange
2. Differentials include empymea, atelectasis and PE

Question 7

Tests to consider

Answer 7

1. Respiratory swab PCR
2. Sputum MCS
3. Blood culture
4. Pneumococcal/ legionella A urine antigen
5. biomarkers - crp, procalcitonin

Question 8

Screening for admission and severity of disease

Answer 8

1. CURB-65 (for admission)
   Confusion, uremia, resp rate, BP, age
   Point of 2 or more require admission
2. PSI - pneumonia severity index
3. SMART-COP: for risk stratification especially used in tropical australia - check for acinobacter and amiliyodosis coverage in wet season

Question 9

Management (low, moderate to severe)

Answer 9

Low-severity: Amoxicillin 1g TDS + doxycycline 100mg BD. For non-severe penicillin allergy, change amoxicillin to cefuroxime 500mg PO BD

Moderate to severe: Benzylpenicillin 1.2g QID + doxycycline 100mg PO BD OR Amoxicillin 1g IV QID + Clarithromycin 500mg PO BD. For non- severe penicillin allergy, change amoxicillin/ benzylpenicillin to ceftriaxone 1g OD IV

For severe allergy: Moxifloxacin 400mg PO OD

Question 10

Management in tropical pneumonia

Answer 10

Add ceftriaxone 2g IV OD + Gentamycin IV + doxycycline 100mg PO BD/ Clarithromycin 500mg PO BD

Question 11

High severity CAP management

Answer 11

Ceftriaxone 2g IV OD / 1g BD for patients in shock + azithromycin 500mg IV OD for 3 doses.

For non-severe penicillin allergy - use the regime above

For severe penicillin allergy: Moxifloxacin 400mg IV/PO OD

MRSA (unlikely in CAP): Vancomycin
Pseudomonas (more in HAP /necrotizing disease/ known prev pseudomonas infection): Tazosin 4.5g QID + azithromycin 500mg PO 3.7 +/- Gentamycin if septic shock

From tropical wet season: Meropenem 1g IV TDS + azithromycin 500mg IV OD 3/7

Question 12

Viral pneumonia management
- influenza

Answer 12

Influenza: oseltamivir
RSV: Roboviron under ID supervision in immunocompromised patients
Covid: IV remdesivir IV, dexamethasone. nirmatrelvir/ritonavir PO

Question 13

Adjuvant treatment in COVID

Answer 13

Corticosteroid
Covid: mortality benefit in hypoxic patient

No evidence in mortality in bacterial pneumonia. Greater risk of readmission. Not recommended other than covid

Question 14

Sequelae post pneumonia

Answer 14

• increase risk new-onset LV dysfunction and myocardial fibrosis due to bacterial translocation. cardiac implication needs to be further studied