Pneumonia symposium - upper airway infections Flashcards
name some upper airway infections
sinusitis tonsilitis pharyngitis tracheitis laryngitis bronchiolitis bronchitis
Which parts of the body are sterile?
urinary system
What are the innate immune system barriers to infection in the gut?
acid in the stomach enzymes commensal bacteria thick mucosal barrier GALT - gut associated lymphoid tissue
What are the innate immune system barriers in the vagina?
acidic pH
commensal bacteria
thick mucosal barrier
mucosal associated immune system
Which part of the resp tract is FAIRLY sterile if any?
the lower resp tract is FAIRLY sterile but the upper resp tract has some colonising organisms
What are the factors that promote colonisation of the resp tract with pathogens?
- thin barrier for gas exchange
- not a lot of immune cells as a heavy immune response in that area would be damaging
- large SA for gas exchange - 75m squared
- pathogens from the gut can enter the resp system in aspiration
How does the upper resp tract resist infection?
- commensal flora
2. normal swallowing reflex (neurological and anatomical)
What virulent bacteria can colonise individuals resp tract asymptomatically?
S. aureus S. pneumoniae H. influenzae S. pyogenes Neisseria spp
What are the commensals of the upper resp tract?
in upper resp tract eg S. aureus, S. epidermidis and Corynebacterium ( a gram +ve rod), colonisation of the oral cavity with streptococci, lactobacilli, colonisation of pharynx by streptococci and G- rods (sinuses are sterile)
What are the factors that aim to prevent infection of the lower resp tract?
- mucociliary escalator - ie cilia and mucus production
- cough reflex - nerve endings in the lungs
- sneezing
- soluble and cellular factors - eg IgA, defensins, lysozyme, surfactants (a direct bacteriocidal), alveolar macrophages, B and T cells, neutrophils
What factors make you susceptible to resp tract infection?
impaired swallowing change in colonisation of the upper airway immune dysfunction altered lung physiology comorbidities
What factors may cause an impaired swallow?
Stroke
MND
tumour obstructing the nerve
surgery
What factors cause an altered lung physiology?
instrinsic:
- CF
- Bronchiectasis
- emphysema
- ILD
extrinsic to airways (may affect ability to breathe and cough):
- spinal disease
- weakness
- obesity
- surgery eg difficult to breathe due to pain
What factors lead to immune dysfunction in the lung?
primary immunodeficiency eg complement deficiency
secondary immunodeficiency - HIV, immunosuppressant therapy
What are the viral causes of URTIs?
Rhinoviruses (45-50%) Influenza A virus (25-30%) Coronaviruses (10-15%) Adenoviruses (5-10%) Parainfluenza viruses (5%) Respiratory Syncytial viruses (5%)- causes bronchiolitis
What are some secondary complications from an URTI?
sinusitis pharyngitis otitis media bronchitis pneumonia these may be due to secondary bacterial infections ie bacterial superinfection
What is a key feature of influenza A?
muscle and joint pain
headache
GI symptoms eg diarrhoea
What are the indications for tamiflu?
the person is in an at-risk group: chronic respiratory disease - asthma, COPD heart disease renal disease liver disease neurologicalsymptoms DM
When is tamiflu given?
start treatment within 48 hours of the first sign of symptoms
Why is tamiflu given?
can help people at risk of severe flu
prophylaxis against spread of flu in a hospital
When does tamiflu not make a difference?
when a person has mild flu and they are otherwise healthy
How does tamiflu work?
interacts with key molecules on the surface of the influenza virus which prevent the virus from attaching to the resp epithelium, so virus is much less likely to replicate in the epithelial cells
Why should you do a HIV test for sb with suspected glandular fever?
as glandular fever looks like primary HIV
What are the causes of pharyngitis?
mostly viral - rhinovirus, adenovirus etc can also be EBV
bacterial:
- group A beta haemolytic strep - ie Strep pyogenes
- other streptococci and - M. pneumoniae -
- Neiserria gonorrhea due to oral sex
- Fusobacterium necrophorum is an anaerobic bacterium in the mouth and a cause of Leimierre’s disease - inflammation nda clotting in IJV enters RHS of heart and into the lungs, can cause embolic infection in the lung (give metronidazole)
- corynebacterium dipetheria
