Pneumonia Flashcards
What is pneumonia?
Infection of distal lung parenchyma.
How can pneumonias be categorised? (x8)
- Hospital (nosocomial) and community acquired
- Aspiration pneumonia
- Pneumonia in the immunocompromised
- Typical and atypical
- Bronchial and lobar
How are hospital-acquired pneumonias defined?
After at least 48 hours after admission to hospital.
What are atypical bacterial pneumonias? (x3) Presentation?
Mycoplasma pneumoniae, Chlamydophila pneumoniae (Chlamydia pneumoniae), and Legionella pneumophila (air conditioning).
What is the aetiology of community-acquired pneumonias? (x10)
• Most infections caused by Streptococcus pneumoniae (aka pneumococcus; 70%); considered the prototype of typical pneumonia. • Haemophilus influenza • Moraxella catarrhalis • Chlamydia pneumonia • Chlamydia psittaci (contact with birds or parrots) • Mycoplasma pneumonia • Legionella • Staphylococcus aureus in recent influenza infections and IVDUs • TB • Fungal and parasitic infections occur less commonly but should be considered in immunocompromised patients or with travel history.
What is the aetiology of hospital-acquired pneumonias? (x2)
Gram-negative enterobacteria (Pseudomonas, Klebsiella), anaerobes (aspiration pneumonia).
What is the aetiology of viral pneumonia? (x6)
Influenza virus, respiratory syncytial virus (RSV), parainfluenza virus, SARS, MERS, COVID
What are the risk factors for pneumonia? (x5)
Age, smoking, alcohol, pre-existing lung disease, immunodeficiency.
What is the epidemiology of pneumonia: Incidence? Age?
Incidence 5-11 in 1000. Increased incidence with age.
What are the symptoms of pneumonia? (x5)
• Constitutional symptoms: fever, rigors, sweating, malaise • Cough and sputum (yellow, green or rusty in S. pneumonia) • SOB • Pleuritic chest pain • Confusion in severe cases, elderly or Legionella
What are the symptoms of atypical pneumonia?
Usually milder and present complaining mostly of constitutional symptoms e.g., headache, myalgia, diarrhoea/abdominal pain. Presentation is usually MILDER than community-acquired cases.
What are the signs of pneumonia? (x8)
• Pyrexia • Respiratory distress (tachypnoea) • Tachycardia, hypotension and cyanosis • Reduced chest expansion • Dullness to percussion • Increased tactile vocal fremitus • Bronchial breathing (inspiration phase lasts as long as expiration phase) • Coarse crepitations on affected side
How does pneumonia present on CXR? (x4 points)
• Lobar and patchy shadowing • Pleural effusion (costophrenic angle blunting) • Klebsiella often affects upper lobes • May detect complications: abscess (cavitation and air-fluid level)
What is the regime of CXR in pneumonias?
Repeat 6-8 weeks – if abnormal, suspect underlying pathology e.g., lung cancer.
What are the other investigations for pneumonia: Blood? (x5) Sputum/Pleural fluid? (x3) Urine? (x2) Serology? Bronchoscopy? (x3 indications)
- BLOOD: raised WCC, decreased Na+ (esp. in Legionella), blood cultures, ABG (assess pulmonary function), blood film (RBC agglutination by Mycoplasma causing haemolytic anaemia)
- SPUTUM/PLEURAL FLUID: microscopy, culture and sensitivity, acid-fast bacilli (group of bacteria identified by acid-based staining procedures)
- URINE: Pneumococcus and Legionella antigens
- ATYPICAL VIRAL SEROLOGY: raised antibody titres between acute and convalescent (recovered, at least 2 weeks post-onset) samples
- BRONCHOSCOPY and BRONCHOALVEOLAR LAVAGE: if Pneumocystis carinii pneumonia suspected, when pneumonia failure to resolve, or when there is clinical progression
How are non-resolving pneumonias managed? (x3 groups)
Non-resolving pneumonias are attributed to the following causes which should be considered and managed if identified: usually attributed to defects in host immune defence mechanisms, presence of unusual/resistant organisms, or diseases that mimic pneumonia.
