U13C2 CAP

Question 1

What is pneumonia and the different types?

Answer 1

Pathological definition:
• Inflammation of lung parenchyma leading to consolidation
• Doesn’t have to be infectious (e.g. cryptogenic organising pneumonia) or bacterial (e.g. viruses, fungi …)

• Infection of the air-space of the lung
• Symptoms of LRTI with CXR changes (usually consolidation)
• Usually treated as due to bacterial infection

Community-acquired pneumonia (CAP)- Pneumonia acquired outside hospital or healthcare facilities

Hospital acquired pneumonia (HAP)- Pneumonia acquired ≥ 48 hrs. into hospital admission that wasn’t incubating on admission. Recently hospitalised patients can be treated as CAP unless additional risk factors for MDR’s/HAP e.g. recent Ab use, severity. Most cases of hospital-acquired pneumonia are caused by bacteria, especially aerobic gram-negative bacilli, such as Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter MRSA

Question 2

What is the aetiology of pneumonia?

Answer 2

1. Typical
   • Streptococcus pneumoniae
   • Haemophilus influenza
   • Moraxella catarrhalis
   • Staphylococcus aureus
2. Atypical (less likely to respond to b-lactam penicillins)
   • Mycoplasma pneumoniae
   • Chlamydophila pnuemoniae
   • Chlamydia psittaci
   • Legionella pneumoniae
   - When to consider atypical pathogens:
   • Foreign travel (all atypicals)
   • Prior antibiotics, hyponatraemia (mycoplasma)
   • Air conditioning exposure,
   • diarrhoea,
   • abnormal LFT’s,
   • neurological symptoms,
   • prior Ab’s (legionella)
   • Headache (Chlamydophila pneumoniae)
   • Sub-acute presentation, weight loss, exposure or past history of TB
   • NH resident, swallowing issues, history of LoC with vomiting e.g. alcohol, seizure (aspiration pneumonia
   – gram –ve’s, anaerobes)
3. Others
   • Pseudomonas aeruginosa
   • Enterobacteriaceae
   • Group A Streptococcus
4. Viral pathogens
   • Influenza A
   • Influenza B
   • Parainfluenza
   • Rhinovirus

Question 3

What is CURB 65?

Answer 3

• Confusion (AMTS </= 8/10)
• Urea (> 7mmol/L)
• RR >/= 30 breaths/min `
• BP (SBP < 90 mmHg, DBP </= 60)
• Age > 65 years old
• Low severity: 0 to 1 = < 3%
• Moderate severity: 2 = 9%
• High severity 3 to 5 = 15 – 40%

Question 4

What would a history show for pneumonia?

Answer 4

• pain, haemoptysis, malaise, arthralgia, myalgia
• Elderly, immunocompromised – more subtle symptoms and signs
• Specific pathogens:
  • Legionella - confusion, GI upset, hyponatraemia, transaminitis,
  lymphopaenia
  • Mycoplasma – young, myringitis, uveitis, iritis, encephalitis,
  myocarditis
• Fever, Cyanosis, tachypnoea, dyspnoea, Tachycardia, hypotension - Sepsis / septic shock, Localising signs -dullness to percussion, bronchial breathing, crackles

Question 5

What is the ddx for pneumonia?

Answer 5

• Left ventricular failure
• Pulmonary embolus
• Infective exacerbation COPD
• Infective exacerbation bronchiectasis
• Acute asthma
• TB
• Empysema
• Lung neoplasm (primary or secondary)
• Oesophageal rupture

Question 6

What is the British Thoracic Society (BTS) Community Acquired Pneumonia Care Bundle?

Answer 6

1. Perform CXR within 4hrs of admission
2. Assess Oxygen Saturation and prescrube oxygen according to appropriate target range
3. Calculate CURB 65 in all patients where CXR demonstrates pneumonia
4. Adminster antibiotics within 4hrs of diagnosis appropriate to CURB 65 score

Question 7

What is the role of a microbiologist?

Answer 7

• Antimicrobial stewardship
• Infection control
• Monitoring of organ prevelence
• Antibiotic sensativity testing
• Antimicrobial advice
• A sounding board

Question 8

What would a V/Q ratio show in pneumonia?

Answer 8

Question 9

What is the pathophysiology of pneumonia?

Answer 9

Question 10

What are the histological changes in pneumonia?

Answer 10

Question 11

What are the signs symptoms of pneumonia?

Answer 11

Fever
Cough (with or without sputum or blood)
Dyspnoea
Fatigue
Pleuritic chest pain, malaise, arthralgia, myalgia

What causes the symptoms that present in pneumonia?

• Accumulation of fluid in alveoli and inflammation of the lower respiratory tract has a direct role to play in causing the symptoms of pneumonia.
• Exchange of O2/CO2 across the blood-gas barrier becomes impaired (feeling SOB as a result, tachypnoea to compensate, also contributes to fatigue)
• Cough is a reflex to remove infectious pathogens from the airways
• Temperature spikes as a result of the immune response (cardinal sign of inflammation)
• Inflammation of pleura surrounding the lungs causes pleuritic chest pain (cardinal sign of inflammation)
• In older adults, confusion can be caused by the decrease in blood oxygen, they are more susceptible to severe cases of pneumonia due to their age and immune system (other comorbidities may also contribute)

Low PaO2
High CRP

Question 12

What are the risk factors and complications of pneumonia?

Answer 12

• • Bacteraemia & Septic ShockIf bacteria caused the pneumonia, bacteria could get into your blood from the lungs and cause bacteraemia, and this can lead to sepsis if it is not treated
  • Lung AbscessesPneumonia can cause pockets of pus to build up in the lungs (more likely in those who have bacteraemia)
  • Pleural Effusions, Empyema, and PleurisyPneumonia can cause the pleura to get swollen (pleurisy), creating a sharp pain when you breathe in, if you don’t treat the swelling the pleura may fill with fluid (pleural effusion), this fluid may get infected (empyema- when pus-filled pockets develop in the pleural space)
  • Respiratory FailurePneumonia increases your risk of your lungs filling with fluid, this decreases the efficiency of gas exchange, this will result in abnormal O2 & CO2 levels and less O2 reaching vital organs in the body
  • Kidney Failure(Rare) When the infection (e,g, septic shock) reduces the amount of blood being pumped to your kidneys
  • Heart Failure20% of people who are in the hospital for pneumonia also have heart problems, this could be due to bacteria entering the heart, the stress of the illness on the heart, or that not enough O2 is reaching the heart

Question 13

What are the mechanisms of antimicrobial resistance?

Answer 13

Question 14

What is the gold standard diagnostic test?

Answer 14

Question 15

What are the typical organisms that cause pneumonia?

Answer 15

Question 16

What are the atypical organisms that cause pneumonia?

Answer 16

Question 17

How does staphylococcus aureus cause infection?

Answer 17

Question 18

What is antimicrobial stewardship?

Answer 18

Antimicrobial stewardship refers to coordinated interventions designed to improve and measure the appropriate use of antimicrobials by promoting the selection of the optimal antimicrobial drug regimen, dose, duration of therapy, and route of administration

• Self-medication and unhealthy attitudes to health
• Only take antibiotics when needed, they are ineffective against viruses
• Do not share your medication with others or take other people’s medications
• Make sure you finish the full course of antibiotics
• Taking aspirin in healthy people
• Do not save medication for later. Talk to your pharmacist about safely discarding leftover medicines