CVR Resp Infection Flashcards
Types of respiratory tract infections
- upper respiratory tract infections
- lower respiratory tract infections
- pneumonia
symptoms of upper resp tract infection (5)
- coughing
- sneezing
- running/blocked nose
- sore throat
- headache
symptoms of lower resp tract infection (6)
- productive cough (phlegm)
- muscle aches
- wheezing
- breathlessness
- fever
- fatigue
symptoms of pneumonia (4)
- chest pain
- bluetinting of the lips
- severe fatigue
- high fever
how significant is the impact of respiratory infection?
in the top 10 causes of death globally
what are DALYs?
disability adjusted life year
-> a sum of years of life lost and years lost to disability
where does acute lung infection rank for global burden of disease when using DALYs lost?
first
why are respiratory infections not the leading cause of death globally, when they rank so highly for DALYs lost?
- the age of respiratory disease occurrence
- more likely to cause mortality in people >70
risk factors for pneumonia
-> demographic and lifestyle (3)
- 2>age or age>65
- cigarette smoking
- excess alcohol consumption
risk factors for pneumonia
-> social factors (3)
- contact with children aged <15 yrs
- poverty
- overcrowding
risk factors for pneumonia
-> medications (3)
- inhaled corticosteroids
- immunosuppressants (e.g.steroids)
- proton pump inhibitors
risk factors for pneumonia
-> medical history (11)
- COPD
- asthma
- <3 disease
- liver disease
- diabetes mellitus
- HIV
- Malignancy
- Hyposplenism
- complement or Ig deficiencies
- Risk factors for aspiration
- previous pneumonia
risk factors for pneumonia
-> RFs for certain pathogens (3)
- geographical location
- animal contact
- healthcare contacts
bacterial causative agents of resp infection (4)
- streptococcus pneumoniae
- mycoplasma pneumoniae
- haemophilus influenzae
- mycobacterium tuberculosis
viral causative agents of resp infection (5)
- influenza A/B
- respiratory syncytial virus
- human metapneumovirus
- human rhinovirus
- coronavirus
Which respiratory infection causes the highest annual mortality?
mycobacterium tuberculosis
What is the most commonly identified pathogen in individuals with respiratory illness?
rhinovirus
examples of community acquired pneumonia bacteria (5)
- streptococcus pneumoniae
- myxoplasma pneumoniae
- staphylococcus aureus
- chlamydia pneumonia
- haemophilus influenzae
examples of typical cause of pneumonia
- streptococcus pneumoniae
- haemophilus influenzae
- moraxella catarrhalis
examples of hospital acquired pneumonia bacteria (5)
- staphylococcus aureus
- pseudomonas aeruginosa
- kilebsiella species
- acinobater spp
- enterobacter spp
ventilator associated pneumonia
- pseudomonas aeruginosa (25%)
- staphylococcus aureus (20%)
- enterobacter
examples of atypical pneumonia bacterial causes
- mycoplasma pneumoniae
- chlamydia pneumoniae
- legionella pneumophilia
features of streptococcus pneumoniae
- gram positive
2. extracellular, opportunistic pathogen
what happens as a infection spreads lower into respiratory tract?
- bronchitis
- Bronchiolitis
- Pneumonia
What four things does pneumonia cause?
- lung injury
- bacteremia
- systemic inflammation
- immune response
what can lung damage cause?
acute respiratory distress syndrome (ARDS)
-> hypoxemia
what can bacteremia cause?
sepsis and deterioration
-> also organ infection
what can systemic inflammation influence
immune response and bacteremia
treatment for bacterial pneumonia
-> supportive (3)
- oxygen (for hypoxia)
- fluids (for dehydration)
- analgesia (for pain)
- > may also provide nebulised saline for expectoration and chest physiotherapy
treatment for bacterial pneumonia
-> ABs (2)
- penicillins e.g. amoxicillin
- macrolides e.g. clarithromycin
- > follow guidelines from local NHS trust
what type of AB in amoxicillin?
How does it work?
- beta lactam
2. binds proteins in the bacterial cell wall to prevent transpeptidation
How does clarithromycin work?
binds to the bacterial ribosome to prevent protein synthesis
what can be used to score pneumonia severity and guide treatment?
CURB-65
what type of bacteria do penicillins work against?
gram+
most important factor for increasing AB success
time of administration
-> then using an effective antibiotic
How many months of antibiotics are required (on average) to treat someone with TB?
3-6 months
what causes pneumonia when it’s not ‘caught’?
the bacteria that naturally reside your respiratory tract
-> opportunistic pathogens
what is the microbiota?
ecological communities of microbes found inside multi-cellular organisms
what are commensal microorganisms?
microbes that live in a symbiotic relationship with their hot. Provide vital nutrients to the host in the presence of a suitable ecological niche
what is a pathobiont?
a microbe that is normally commensal, but if in wrong environment can cause pathology
what is latent TB?
bacteria are living but inactive -> just not found inside granulomas within the resp tract
how many ABs are required and for what period to treat TB?
4 ABs, period of 6 months
is there such thing as a commensal respiratory virus?
nope
what does serotypes mean?
viruses which can’t be recognised by serum ABs
different viruses that cause upper respiratory infections (typical) (7)?
- rhinovirus
- coronavirus
- influenza
- parainfluenza
- respiratory syncytial virus
- adenoviruses
- enteroviruses
different viruses that cause upper respiratory infections (atypical) (2)?
- mycoplasma
2. chlamydia
why do viral infections cause disease? (7)
cause
- cellular inflammation
- local immune memory
- loss of chemoreceptors
- poor barrier to antigen
- bacterial growth
- loss of cilia
- mediator release
what is often causing the symptoms you see in respiratory infections?
the body’s immune response
what do influenza viruses bind to?
alpha sialic acids
what enzyme does SARS-CoV-2 affect?
Spike proteins binds angiotensin converting enzymes 2
why is avian flu (H5N1 more severe than influenza A (H1N1)?
avian flu binds alpha 2 and 3 sialic acids - flu A binds alpha 2 and 6 sialic acids. -
-> the 2 and 3 types are found deeper in the respiratory tracts (E.g. lungs vs trachea)
where is ACE2 found in resp system?
- nasal epithelium
- pneumocytes
- > raised in smokers
What do rhinoviruses bind?
ICAM-1 -> minor group LDL family of receptors
-> found in upper resp tract (trachea is lowest point)
What does respiratory syncytial virus F and G proteins bind?
glycosaminoglycans in receptors like IGFR1 and nucleolin
can you get re-infected with the same strain of RSV?
yes
can you get re-infected with the same strain of influenza?
no
what can indicate a severe lower resp infection on an xray
diffuse bilateral opacities
what leads to severe respiratory disease?
- innate differences
- immunodeficiency e.g. IFITM3 gene variant
- B cell
- T cells
- predisposing illness/conditions e.g. elderly, diabetes, obesity
what family of cytokines is v important in viral immune response?
interferons
How many groups of IFNs are there?
3 (I, II, III)
example of type I IFN
IFN-alphas
IFN-betas
example of type II IFN
IFN-gamma
example of type III IFN
IFN-lambda(?)
why are interferons named as such?
their ability to interfere with viral infection in vitro
who produces intereferons?
infected cells, activated immune cells
example of a receptor that interferons signal through
IFNAR1/2
what are induced when IFNAR1/2 are stimulated?
Interferons signalling genes (ISGs)
what immune compartment provides long term protection after vaccination and natural infection?
b cells
what is the leading cause of infant hospitalisation in the work, and what % of children are infected in year 1 and 3?
RSV
50% of children in year 1
All by year 3`
what percentage of children hospitalised with RSV develop severe bronchiolitis?
1%
can RSV repeatedly infect children?
yes
viruses similar to RSV but are at lower prevalence?
hMPV and PIV
risk factors for RSV in kids
- premature birth
- cogenital heart
- lung disease
presentation of RSV in babies (
- chest wall infection
- nasal flaring
- hyoxaemia/cyanosis
- croupy cough
- expiratory wheezing, prolonged expiration, rales and rhonchi
- tachypnea with apneic episodes
is RSV worse with inc/dec age?
dec
treatment options for RSV
- vaccines
2 monoclonal ABs - antivirals
what happens to RSV ABs after infection?
the wane very rapidly
-> same with corona
what type of infection can interact with viral infection?
bacterial coinfections
which sialic acids does influenza A bind in the respiratory tract?
alpha 2 and beta 3 sialic acids
How does the CURB-65 criteria work?
1 point for each parameter:
Confusion
Urea: BUN >7mmol/L
Respiratory rate: .30
Blood pressure: systolic <90 OR diastolic = 60
65: Age >65 yrs
What would the curb 65 score indicate?
0 or 1: outpatient care
2: inpatient
3 + : ICU
What is the leading cause of mortality in children under 1?
Lower resp infections- RSV most common
How many individuals are believed to have latent TB?
1 in 4
What pathogen accounts for majority for resp infections?
Rhinovirus
Why is there no RSV vaccine?
Poor immunogenicity (can get infected again) Vaccine-enhanced disease
