Lobar Pneumonia

Question 1

How common is it?

Answer 1

5-11/1000 – incidence increased at the extremes of age.

Question 2

Who does it affect?

Answer 2

People at higher risk include: the elderly, the very young, and those with underlying health problems, such as chronic obstructive pulmonary disease (COPD), diabetes, congestive heart failure, sickle cell anemia, and the immunocompromised.

Question 3

What causes it?

Answer 3

Community-acquired Pneumonia (CAP)

• May be primary or secondary to underlying disease.
• Streptococcus pneumoniae = commonest cause.
• Other causes = Haemophilus influenzae, Mycoplasma pneumoniae (More common), Staphylococcus aureus, Legionella species, Moraxella catarrhalis and Chlamydia.
• Gram negative bacilli, Coxiella burnetii, anaerobes (rarer).
• Viruses account for up to 15%.
• Flu may be complicated by C-A MRSA pneumonia.

Hospital-acquired Pneumonia

• > 48h after hospital admission.
• Most commonly Gram negative enterobacteria or Staph. aureus.
• Also – Pseudomonas, Klebsiella Bacteroides and Clostridia.

Aspiration
- Those with stroke, myasthenia, bulbar palsies, ↓consciousness, oesophageal disease or poor dental hygiene risk aspirating oropharyngeal anaerobes.

Immunocompromised Patient

• Strep. Pneumoniae, H.influenzae, Staph. Aureus, M. catarrhalis, M. pneumoniae, gram –ve bacilli and Pneumocystis jiroveci.
• Other fungi, viruses (CMV, HSV) and mycobacteria.

Question 4

What risk factors are there (and how can they be reduced)?

Answer 4

• Certain chronic diseases, such as asthma, chronic obstructive pulmonary disease and heart disease
• Weakened or suppressed immune system, due to factors such as HIV/AIDS, organ transplant, chemotherapy for cancer or long-term steroid use
• Smoking, which damages your body’s natural defenses against the bacteria and viruses that cause pneumonia
• Being placed on a ventilator while hospitalized
• Long hospital stays

Question 5

How does it present?

Answer 5

Symptoms
- Fever, rigors, malaise, anorexia, dyspnoea, cough, purulent sputum, haemoptysis, and pleuritic pain.

Signs
- Pyrexia, cyanosis, confusion (can be only sign in elderly – may also be hypothermic), tachypnoea, tachycardia, hypotension, signs of consolidation (diminished expansion, dull percussion note, ↑tactile vocal fremitu/vocal resonance, bronchial breathing and a pleural rub.

Complications
- Pleural effusion, empyema, lung abscess, respiratory failure, septicaemia, brain abscess, pericarditis, myocarditis, cholestatic jaundice.

Question 6

Which other conditions may present similarly?

Answer 6

• • Asthma
• • Atelectasis
• • Bronchiectasis
• • Bronchiolitis
• • Bronchitis
• • Chronic Obstructive Pulmonary Disease
• • Foreign Body Aspiration
• • Lung Abscess
• • Pneumocystis Carinii Pneumonia
• • Pneumonia, Fungal
• • Pneumonia, Viral
• • Respiratory Failure

Question 7

How would you investigate the patient?

Answer 7

• Aim is to establish diagnosis, identify pathogen and assess severity.

CXR
- Lobar or multilobar infiltrates, cavitation or pleural effusion.

Assess oxygenation
- Oxygen saturation (ABGs if SaO2 7mmol/L
- Respiratory rate - >30/min
- BP - 65.
0-1 = Home
2 = Hospital therapy
>3 = Severe pneumonia indicates mortality 15-40% - consider ITU.

Question 8

What treatment/s would you consider? What risks and benefits of treatment are there?

Answer 8

Antibiotics – orally if not severe and not vomiting; severe give by IV. 
Empirical treatment (check local policy).
CAP – Oral amoxicillin or clarithromycin or doxycycline (mild – moderate, increased frequency). Severe – co-amoxiclav or cephalosporin in IV AND clarithromycin.

Hospital acquired – Aminoglycoside + antipseudomonal penicillin IV or 3rd gen cephalosporin IV.