Pneumonia

Question 1

Define:

Answer 1

Infection of distal lung parenchyma (acute lower respiratory tract illness) - LRTI WITH OPACIFICATION ON CHEST XRAY

It can be categorised in many ways: 
o	Community-acquired 
o	Hospital-acquired/nosocomial 
o	Aspiration pneumonia 
o	Pneumonia in the immunocompromised  
o	Typical 
o	Atypical (Mycoplasma, Chlamydia, Legionella)

Question 2

Aetiology:

Answer 2

Community-Acquired
o Most common: Streptococcus pneumoniae (70%)
o Haemophilus influenzae
o Mycoplasma pneumonia
o Moraxella catarrhalis (occurs in COPD patients)
o Chlamydia pneumonia
o Chlamydia psittaci (causes psittacosis)
o Legionella (can occur anywhere with air conditioning)
o Staphylococcus aureus
o Coxiella burnetii (causes Q fever)
o TB
o Viruses (15%)

Hospital-Acquired - >48h after hospital admission
o Most common: Gram-negative enterobacteria (Pseudomonas, Klebsiella) or S aureus

Aspiration pneumonia
o Those with stroke, myasthenia, bulbar palsies, reduced consciousness, oesophageal disease or poor dental hygiene risk aspirating oropharyngeal anaerobes

Immunocompromised patients
o	Strep pneumoniae
o	H influenza
o	S aureus
o	M catarrhalis
o	M pneumoniae
o	Gram –ve bacilli 
o	Pneumocystis jiroveci -FUNGI

Question 3

Epidemiology:

Answer 3

• 5-11/1000
• Community-acquired pneumonia is responsible for > 60,000 deaths per year in the UK
• High in very young or old
• Mortality: 21% in hospital

Question 4

Risk factors:

Answer 4

o	Age  
o	Smoking  
o	Alcohol 
o	Pre-existing lung disease (e.g. COPD)  
o	Immunodeficiency 
o	Contact with patients with pneumonia

Question 5

Symptoms of typical pneumonia:

Answer 5

• Fever
• Rigors
• Sweating
• Malaise
• Dyspnoea
• Cough
• Purulent Sputum
• Haemoptysis
• Pleuritic chest pain
• Weight loss
• Confusion (in severe cases or in the elderly)

Question 6

Symptoms of atypical pneumonia:

Answer 6

Headache
Myalgia
Diarrhoea/abdominal pain
DRY cough

Question 7

Signs:

Answer 7

• Pyrexia
• Respiratory distress
• Tachypnoea
• Tachycardia
• Hypotension
• Cyanosis

Signs of consolidation
o Decreased chest expansion
o Dull to percuss over affected area
o Increased tactile vocal fremitus/vocal resonance over affected area
o Bronchial breathing over affected area
o Coarse crackles on affected side

Chronic suppurative lung disease (empyema, abscess) –> clubbing

Confusion and may be hypothermic – elderly

Question 8

Investigations:

Answer 8

Bloods 
o	FBC - raised WCC 
o	U&Es 
o	LFT 
o	CRP
o	Blood cultures  
o	ABG (assess pulmonary function)  
o	Blood film - Mycoplasma causes red cell agglutination 

CXR
o Lobar or multilobar (patchy) shadowing
o Pleural effusion or cavitation
o NOTE: Klebsiella often affects upper lobes
o May detect complications (e.g. lung abscess)

Sputum/Pleural Fluid - MC&S

Urine - Pneumococcus and Legionella antigens – in severe cases, check for Legionella (sputum culture, urine antigen)

Atypical Viral Serology

Bronchoscopy and Bronchoalveolar Lavage - if Pneumocystis carinii pneumonia (immunocompromised) is suspected, or if pneumonia fails to resolve

Question 9

Management:

Answer 9

Assess severity CURB-65, validated scoring system
o 1 point for each:
 Confusion – abbreviated mental test <8
 Urea >7mmol/l
 Respiratory rate greater than or equal to 30
 BP < 90 systolic and/or 60 diastolix
 Age greater than/equal to 65
o 0 – 1: home treatment if possible
o 2: hospital therapy
o 3 or more: severe pneumonia – consider ICU

Assess using ABC
o Treat hypoxia (sats <88%) with oxygen, starting at 24-28% if history of COPD/hypercapnia
o Treat hypotension/shock from infection
o Assess for dehydration – give IV fluid support

Start empirical antibiotics
o Mild: oral amoxicillin
o Moderate: IV/oral amoxicillin + clarithromycin
o Severe: IV co-amoxiclav + clarithromycin

Question 10

Prevention:

Answer 10

o Pneumococcal vaccine
o Haemophilus influenzae type B vaccine
o These are only usually given to high risk groups (e.g. elderly, splenectomy)

Question 11

Supportive treatment:

Answer 11

o Oxygen
o IV fluids
o CPAP, BiPAP or ITU care for respiratory failure
o Surgical drainage may be needed for lung abscesses and empyema

Question 12

Complications:

Answer 12

• Pleural effusion
• Empyema

Localised suppuration (e.g. abscess) 
o	Symptoms of abscesses: 
	Swinging fever  
	Persistent pneumonia 
	Copious/foul-smelling sputum 

Septic shock  
•	ARDS 
•	Acute renal failure 
•	Pericarditis 
•	Myocarditis

Question 13

Prognosis:

Answer 13

• Most resolve within treatment within 1-3 weeks
• Severe pneumonia has a high mortality
• The CURB-65 score is used to assess the severity of pneumonia:
o Confusion < 8 AMTS
o Urea > 7 mmol/L
o Respiratory rate > 30/min
o Blood pressure: systolic < 90 mm Hg or diastolic < 60 mm Hg
o Age > 65 yrs