resp tract infection and immunity Flashcards
what is DALY – Disability-adjusted Life Year
Years of Life Lost (YLL) + Years Lost to Disability (YLP)
common cause of infant mortality in under 1y.o compared to 1-5y.o
under 1=LRTI (RSV-Respiratory syncytial virus)
1-5y.o= malaria
risk factors for pneumonia
-under 2, over 65
-close contact with kids (<15)
-overcrowding
-ICS
-immunosuppressants
-COPD/Asthma
-animal contact
Causative agents or respiratory infections: bacterial vs viral
Bacterial
Streptococcus pneumoniae
TB
Viral
Influenza A or B virus
Respiratory Syncytial Virus
Community acquired pneumonia- cause
Bacterial =Streptococcus pneumoniae
what is streptococcus pneumoniae
gram +ve
extracellular
opportunistic pathogen
common hospital acquired pneumonia
Staphylococcus aureus
Psuedomonas aeruginosa
E. coli
Acinetobacter spp.
Ventilator associated pneumonia
common causes
Psuedomonas aeruginosa
Staphylococcus aureus
what is atypical pneumonia
-Less frequent
-Mycoplasma pneumoniae
-different symptoms (ie. longer, milder symptoms)
different treatment:
-Penicillins= typical pneumonia,
+macrolides for atypical.
what is pneumonia
Inflammation and swelling of the alveoli
grading of potential bacterial pneumonia
CURB-65 (1 point each)
Confusion
Urea 7mmol/L+
Resp 30breaths/min+
BP: SBP< 90 OR DBP<60 mmHg
65 y.o +
Grading potential bacterial pneumonia- CURB 65. results meaning
0=low severity. Home treatment with Ab
1-2=moderate severity. consider hospital referral
3-4= high severity. Urgent hospital admission-> empirical ab
Treatments for bacterial pneumonia- supportive therapy
Oxygen
Fluids
Analgesia
Nebulised saline (may help sputum production)
Treatments for bacterial pneumonia- antibiotics in CAP and duration
CURB-65=0
Amoxicillin (or clarithromycin/doxycycline if pen. allergic)
CURB-65=1-2
Amoxicillin + clarithromycin (or clarithro./doxy.)
CURB-65=3-5
benzylpenicillin IV + clarithro. PO
5-7days (7-14 days for atypical)
Treatments for bacterial pneumonia- antibiotics in HAP and duration
CURB-65=0
doxycycline PO
CURB-65=1-2
Amoxicillin + clarithromycin (or clarithro./doxy.)
CURB-65=3-5
tazocin IV +/- Gentamycin IV
5-7days
what is Commensal
Commensal microorganisms are those that live in a symbiotic relationship with their host, providing benefits to the host without causing harm.
what is microbiota
collection of microorganisms that make up the ecological communities living inside a multicellular organism, such as humans.
what is Human microbiome:
100 trillion microbial cells populate our bodies at every barrier surface
what is opportunistic pathogen
microbe that takes advantage of a change in conditions (often immuno -suppression).
what is pathobiont
A microbe that is normally commensal, but can cause pathology if found in the wrong environment (e.g. anatomical site)
what causes severe disease in viral resp infection
- highly pathogenic strains (zoonotic)
2.absence of prior immunity - predisposing illness/conditions- (ie. fail, elderly, COPD)
-RNA sequence
-viral load
-DNA
-Environment
viral resp infection- resp Epithelial cells – the target and first line of defence for tight junction, mucous lining and antimicrobials. Explain how
Tight junctions – prevents systemic infection
Mucous lining and cilial clearance – prevents attachment, clears particulates
Antimicrobials – recognise, neutralise microbes and their products
most common cause of cold- viral resp infection
vs atypical bacteria
rhinovirus - in all ages
atypical= mycoplasma
what is a serotype
unique pathogen strains with outer surface differences that may evade antibodies from other strains
where do you find a lot of IgA-plasma cells vs Ig-G
nasal cavity
-Epithelial cells express many IgA receptor, allowing export of IgA to the mucosal surface
lungs
Thin-walled alveolar space allows transfer of plasma IgGs into the alveolar space
RSV, compared to Influenza, when does viral load peak
around day 7 in RSV- LATER,
compared to around day 3 in influenza
Recurrent re-infection with similar strains
No vaccine
Poor immunogenicity
what does this indicate
RSV
what does RSV stand for
Respiratory syncytial virus
RSV bronchiolitis in infants- symptoms
nasal flaring,
cyanosis,
croupy cough,
expiratory wheeze,
chest wall retraction
RSV bronchiolitis in infants- risk factors
Premature birth
Congenital heart and lung disease
RSV treatment-supportive and preventative
supportive therapy: oxygen, fluids, analgesia
preventative: vaccine- mRNA
therapeutic treatment for RSV
anti-inflammatory
-dexamethasone (steroid)
anti-viral
-remdesivir- broad spectrum antiviral
//Paxlovid
-monoclonal ab??
