[11] Pneumonia Flashcards
What is pneumonia?
An infection of the lower respiratory tract and lung parenchyma
What does pneumonia lead to?
Consolidation
To cause pneumonia, what must an organism do?
Bypass the host’s normal non-immune and immune defence mechanisms
What are the non-immune mechanisms?
- Aerodynamic filtering of particles
- Cough reflex
- Mucociliary clearance
- Secreted substances including lysozymes, complement and defensins
What carries out the immune mediated response?
- Macrophages
- Neutrophils
- Lymphocytes
What percentage of CAP cases in children are caused by viruses?
14-35%
What causes variation in the causative organisms?
Age
What are the common causative bacteria of pneumonia in neonates?
- Group B strep
- E. Coli
- Klebsiella
- Staph aureus
What are the common causative bacteria of pneumonia in infants?
- Strep pneumoniae
- Chlamydia
What are the common causative bacteria of pneumonia in school age children?
- Strep pneumoniae
- Staph aureus
- Group A strep
- Bordetella pertussis
- Mycoplasma pneumoniae
What are the risk factors for pneumonia in children?
- Congenital lung cysts
- Chronic lung disease
- Immunodeficiency
- Cystic fibrosis
- Sickle cell disease
- Tracheostomy
What features may be present in the history?
- Recent URTI
- Pleuritic chest pain
- Temperature >38.5
- Shortness of breath
- Cough with sputum in children > 7
What features may be present on examination?
- Signs of respiratory distress
- Desaturation and cyanosis
- General ill health and lethargy
- Auscultation signs of lobar pneumonia
What are some signs of respiratory distress?
- Tachypnoea
- Grunting
- Intercostal recession
- Use of accessory muscles for breathing
What signs may be present on auscultation?
- Dullness to percussion
- Crackles
- Decreased breath sounds
- Tactile vocal Freitas
- Bronchial breathing
What investigations may be necessary?
- Sputum culture
- Nasopharyngeal aspirates
- Blood cultures (in severe cases)
- Pleural aspirate culture (with significant pleural effusion)
- Viral titres
- CXR (not in mild/uncomplicated cases)
What may be seen on a CXR?
- Pleural effusion
- Fluid level
- Apparent round pneumonia
- Cavitation
- Hilar adenopathy
- Calcification
What are the potential differentials for pneumonia?
- Bronchiolitis
- Asthma
- Pulmonary oedema
What is the treatment for pneumonia?
Antibiotics
How are antibiotics usually given in pneumonia?
Orally
When may IV antibiotics be required?
When the patient is unable to take oral antibiotics or symptoms are severe
What does the specific choice of antibiotic depend on?
- Age of the child
- Host factors
- Severity of illness
- Information about cultures if known
- CXR findings if known
What is the most likely pathogen in under 5 years?
- Strep. pneumoniae
What are the most common causes of atypical pneumonia in under 5’s?
- Mycoplasma pneumoniae
- Chlamydia trachomatis
