Lung infections Flashcards
What is pneumonia?
It is an infection that results in lung inflammation
What are the two main groups of pneumonia?
- community acquired
- hospital infection (nosocomial)
What causes community acquired pneumonia?
- viruses
- bacteria
- fungal
- unknown (lot of the causing agents are not known)
Give examples of pathogens causing community acquired pneumonia
- Strep. Pneumoniae
- Myxoplasma pneumoniae
- Staph. Aureus
- Chlamydophila pneumoniae
- Haemophilus influenzae
Give examples of pathogens causing hospital acquired pneumonia
- Staphylococcus aureus
- Pseudomonas aeruginosa
- Klebsiella species
- E. Coli
- Acinetobacter species
- Enterobacter species
Why is it important to distinguish between typical and atypical pathogens in community acquired pneumonia?
- Atypical bacteria are not covered by penicillin so a different antibiotic is required (macrolides)
What factors increase the likelihood of developing pneumonia?
- age (also higher mortality from pneumonia)
- social factors (e.g. overcrowding, poverty)
- medication (inhaled corticosteroids, immunosuppressants)
- medical history (COPD, asthma, heart disease, diabetes, HIV)
- demographic/lifestyle factors (excess alchohol consumption, age less than 2 and over 65, smoking)
- risk factors for certain pathogens (animal contact, healthcare contacts)
What can be seen in a chest x ray of a person with pneumonia?
- more white areas caused by inflammation
What things indicate that a person has pneumonia?
- New respiratory symptoms/signs
- Pleuritic chest pain
- Usually febrile
- Hypoxic
- Confused
- New X ray changes
- Severe enough to be admitted
What things suggest that a person has acute bronchitis?
- Cough
- Tracheal pain
- No new X ray changes
What are the BTS guidelines for diagnosing pneumonia?
- Acute lower respiratory tract symptoms
- New focal chest signs and, if in hospital, new CXR changes
- More than 1 systemic feature (fever, shivers, aches and pains, temperature >38)
- No other explanation for illness
How is it decided whether a person is admitted to hospital for CAP?
CRB65 severity score - confusion, respiratory rate, blood pressure and age over 65. Points given for each thing and 3-4 is high severity and 1-2 suggest referral should be considered.
How is pneumonia treated?
- antibiotics
- oxygen
- fluids
- analgesia
- nebulised saline (help expel phlegm)
- chest physiotherapy
What factors are considered when giving an antibiotics for pneumonia?
- CAP or HAP
- time of administration: for every hour delay in septic shock survival chance reduced by 7%
- treatment usually a week long
How do viruses affect the lungs?
- loss of cilia
- bacterial growth
- poor barrier to antigens
- loss of chemoreceptors
- local immune response
- cellular inflammation
- mediator release
Bird flu: what is it, symptoms and what caused it?
- close exposure to poultry (only human to bird transmission)
- Influenza A H5N1
- cough, shortness of breath, muscle pain, abdominal pain, vomiting, diarrhoea, renal failure
- deaths in 2-4 weeks despite antivirals from respiratory failure
What caused swine flu?
- Influenza H1N1
- Much more inflammation in those with severe disease
What factors affect the severity of disease?
- host, pathogens and the co-pathogens
- some people have genetics which mean they produce a particular type of cytokine in response to a pathogen which maximises damage
- some pathogen have more successful RNA
- If person has other pathogens may affect also
What factors are known to cause a more severe flu?
- Highly pathogenic strain of flu
- Absence of prior immunity: innate immunodeficiency, B cells and T cells
- Weakened host immune response: elderly, COPD/asthma etc.
RSV brochilitis
- viral infection can provide oppurtunity for bacteria - oppurtunistic
- ## some bacteria can make it easier for viruses to cause disease by causing viral entry receptor upregulation,
Why are commensal bacteria important?
Normally healthy microbiome help prevent infection as pathogens must compete with them
