Pneumonia

Question 1

Define

Answer 1

Inflammation of the lungs with consolidation or interstitial lung infiltrates usually caused by bacteria. Acute lower respiratory tract infection.

Question 2

What’s the aetiology/risk factors?

Answer 2

• Community-acquired
o Typical organisms: Streptococcus pneumonia (commonest), Haemophilus influenzae, Moraxella catarrhalis
o Atypical organisms: Mycoplasma pneumonia, Staphylococcus aureus, legionella, chlamydia
o Gram negative bacilli, Coxiella burnetti and anaerobes are rarer
o Viruses (15%)
• Hospital-acquired
o Defined as acquired after 48hrs of admission to hospital
o Most commonly gram-negative enterobacteria, staph aureus
o Also pseudomonas, Klebsiella, bacteroides, clostridia
o Rare cause – viral pneumonia

• Aspiration
o Increased risk in stroke, myasthenia, bulbar palsies, decreased consciousness, esophageal disease
o Aspirate oropharyngeal anaerobes

• Immunocompromised
o Strep pneumonia, H. influenzae, staph aureus etc.
o Other fungi, viruses and mycobacteria

Question 3

Epidemiology

Answer 3

• 5-11/1000
• Increased risk in very young or old
• Mortality about 21% in hospitals

Question 4

What are the presenting symptoms?

Answer 4

• Fever
• Rigor
• Malaise
• Anorexia
• Dyspnea
• Cough
• Purulent septum
• Haemoptysis
• Pleuritic pain

Question 5

What are the signs?

Answer 5

• Pyrexia
• Cyanosis
• Confusion (may be the only sign in the elderly)
• Tachypnoea
• Tachycardia
• Hypotension
• Signs of consolidation
• Pleural rub

Question 6

How would you class severity?

Answer 6

CURB-65: 1 mark for each of the following

C – confusion (abbreviated mental test < or equal to 8)
U – urea (>7mmol/l)
R – respiratory rate (>30/min)
B – BP (<90/60)
>or equal to 65

0-1: home with antibiotic treatment
2: hospital therapy
>3: severe pneumonia increased mortality

Question 7

What are the appropriate investigations?

Answer 7

• The clinical history should enquire about:
o contact with birds (possible psittacosis)
o farm animals (Coxiella burnetii, causative organism of Q fever)
o recent stays in large hotels or institutions (Legionella pneumophila)
o chronic alcohol abuse (Mycobacterium tuberculosis, anaerobic organisms),
o intravenous drug abuse (S. aureus, M. tuberculosis)
o contact with other patients with pneumonia.
• Oxygenation
o Oxygen saturation
 ABG is <92% and BP
• Bloods
o FBC, U&E (may show raised urea and hyponatremia), LFT, CRP
o Blood culture
• CXR
o Lobar of multilobar infiltrates, cavitation, pleural effusion
• Sputum for culture and microscopy
• Atypical organisms/viral serology
• Urine antigen testing for legionella and pneumoccus
• Pleural fluid may be aspirated for culture
• If patient immunocompromised or ITU, bronchoscopy or bronchoalveolar lavage

Question 8

How would you manage hospital acquired pneumonia?

Answer 8

o Co-amoxiclav 625mg/ 3 times a day

o Severe – cefuroxime and gentamicin

Question 9

Who would you give metronidazole?

Answer 9

patients with increased risk of anaerobic infection

Question 10

What are the possible complications?

Answer 10

• Respiratory failure
o Type I resp failure common – treat with high flow oxygen. Check ABGs frequently.
• Hypotension
o May be due to dehydration and vasodilation due to sepsis
o If systolic <90, fluid challenge
o If BP does not rise, IV fluid through central line, request ITU assessment
• Atrial fibrillation
o Common in elderly
o Beta-blocker or digoxin may be required to slow ventricular response rate
• Pleural effusion
o If large, drainage may be required
• Empyema
o Pus in pleural space
o Suspected if patient with resolving pneumonia has recurrent fevers
o CXR- indicates pleural effusion
o Needs to be drained
• Lung abscess
o Localized area of infection within the lung
o Treat with antibiotics, postural drainage
• Septicaemia
o Bacterial spread to bloodstream
o Metastatic infection e.g. infective endocarditis, meningitis
• Pericarditis and myocarditis
• Jaundice
o Cholestatic - May be due to sepsis or secondary to antibiotic treatment (particularly flucloxacillin or coamoxiclav)

Question 11

What’s the prognosis?

Answer 11

Prognosis is determined by 3 major factors: age of the patient, general state of health (presence of comorbidities), and the setting where antibiotic treatment is given.

In general, the mortality rate in outpatients is <1%, while for hospitalised patients, mortality rate ranges from 5% to 15%, but increases to between 20% and 50% in patients requiring ICU admission.

Several risk factors, such as bacteraemia, ICU admission, comorbidities (especially neurological disease), and infection with a potentially multidrug-resistant pathogen (e.g., Staphylococcus aureus , Pseudomonas aeruginosa , Enterobacteriaceae), are associated with increased 30-day mortality.

Question 12

How would you manage community acquired pneumonia?

Answer 12

Mild:

• amoxicillin or erythromicin
• if doesn’t respond in 48hrs, CXR

Severe:
- CXR
- IV cefuroxime and clarithromycin
If S.aureus - add fluxcloxacillin 
If not - oral antibiotics