16 - LRTIs and Pneumonia Flashcards
What is pneumonia and pneumonitis?
Pneumonia: Inflammation of the lung parenchyma due to infection.
Pneumonitis: inflammation of the lung without infection, e.g due to physical or chemical damage
What is the common feature of all pneumonias and what would localised and diffuse pneumonia be called?
- Cellular exudate in alveolar spaces
- Lobar pneumonia (localised to one lobe)
- Bronchopneumonia (patchier)
What are some of the different organisms that can cause pneumonia?
- Bacterial
- Atypical
- Viral
- Fungal
- Protozoal
What are the pathological changes in pneumonia?
- Fibrin rich exudate
- Neutrophil infiltration
- Macrophage infiltration
What are some examples of classifications of pneumonia?
- Community-acquired
- Hospital acquired
- Aspiration
- Atypical (immunocompromised patient)
What are some of the organisms that cause typical community acquired pneumonia?
- Strep Pneumoniae (most common)
- H.Influenzae
- Moraxella Catarrhalis
- Klebsiella Pneumoniae
- Staph Aureus
What are some of the atypical organisms that can cause community acquired pneumonia?
- Mycoplasma Pneumoniae (most common)
- Chlamydia Pneumoniae
- Legionella Pneumophila
What is the definition of nosocomial pneumonia and what are the most common organisms causing this infection?
Infection of the lower respiratory tract in hospitalised patients occuring 48 hours after admission and was not incubating at the time of admission
Gram negative bacteria, MRSA, Staph aureus
What is aspiration pneumonia and what are the causative organisms?
- Aspiration of food, drink, saliva or vomit usually due to reduced level of consciousness, e.g anaesthesia, alcohol or drug abuse, neuromuscular disease, leading to infection
- Oral flora and anaerobes
What are the most common organisms to cause pneumonia in an immunocompromised patient?
- Pneumocystis jiroveci
- Aspergillus species
- Cytomegalovirus
What are some of the presentations of pneumonia?
- Dyspnoea
- Malaise
- Fever
- Productive cough
- Sputum will be purulent, rusty or flank blood
- Pleuritic chest pain
What would be abnormal on a respiratory exam with pneumonia?
What organisms most commonly case rapid onset pneumonia, often fatal if not treated quickly?
- Pneumococcal
- Staphylococcal
Atypical organisms like mycoplasma pneumonia usually are over a long period with symptoms for weeks
What tool can be used to assess the severity of pneumonia?
- Over 2 need hopsital treatment
- 2-5 then severe and consider ICU
Without doing a sputum sample, how can you make a guess at what organism is causing a patient’s pneumonia?
- Community or hospital acquired?
- Presence of chronic lung disease?
- Immunosuppression?
- Ownership of pet or travelled?
How do you diagnose pneumonia?
Chest X-ray: shadowing in at least one area of the lung field
Microbiology: gram stain and culture of sputum. If severely ill, blood culture. Nasal swabs
What factors can lead to a poor prognosis of pneumonia?
- Pneumococcal pneumonia in well patient only has 5% mortality but…
- High CURB65
- Older patient
- Very high or low WBC count
- Absence of fever
- Extensive x-ray shadowing
- Significant hypoxia
- Rise in blood urea
What antibiotics would you administer for each classification of pneumonia?
Community Acquired: amoxicillin (doxycycline if allergic) but if severe need hospital admission and co-amoxiclav and clarithromycin
Hospital Acquired: usually gram negative so IV co-amoxiclav, then piperacillin (broad spectrum) if not
Aspiration: see what happens as may just be clinical irritation then if severe co-amoxiclav
Atypical: do not respond to cell wall antibiotics, need ones that act on protein synthesis so macrolide (erythomycin) or tetracyclines (doxycycline)
What are some possible complications of pneumonia?
- Empyema
- Lung abscess
- Pleural effusion
What is the normal flora of the respiratory tract?
What defences does the respiratory tract have against infection?
- Muco-cilliary clearance (ciliated columnar epithelia)
- Cough and sneezing reflex
- IgA and IgG in mucous
- Macrophages in mucus
- Alveolar microbiota
What are some common upper respiratory tract infections and the organisms causing these?
- Rhinitis (common cold)
- Pharyngitis (usually virus like rhinovirus, parainfluenza, RSV)
- Epiglottitis
- Laryngitis
- Sinusitis (usually bacteria)
- Otitis media
What are the most common lower respiratory tract infections?
- Acute bronchitis: inflammation of medium airways. No change on CXR like in pneumonia. S.Pneumonia, H.Influenza, M.Catarrhalis. Bronchodilate, physio and antibiotics
- Chronic bronchitis: not due to infection
- Pneumonia: inflammation of lung alveoli due to infection
What are some differential diagnoses for pneumonia?
How can we prevent lower and upper respiratory tract infections?
- Immunisation: flu vaccine annually to high risk and pneumococcal vaccine every 5 years
- Prophylaxis: oral penicillin/erythromycin to high risk patients, e.g asplenic
- Smoking advice
