Respiratory tract infections and immunity Flashcards
what are the signs and symptoms of upper respiratory infection
cough sneezing runny/stuffy nose sore throat headache
what are the signs and symptoms of lower respiratory tract infection
productive cough - phlegm muscle ache wheezing breathlessness fever fatigue
what are the signs and symptoms of pneumonia
chest pain
blue tinting of lips
severe fatigue
high fever
what is the most common respiratory infection
tuberculosis
what does daly stand for
disability adjusted life year
- years of life lost due to disability
what is the leading cause of mortality in infants
under 1s/5s
lower respiratory tract infections
what are some general risk factors for pneumonia
demographic and life style factors - young and old affected
social factors
medication
medical history
specific factors for certain pathogens e.g animal contact, geographical variations
what is the most common causative agent of respiratory infections
human rhinovirus
Which respiratory infections causes the highest annual mortality in the average year
tuberculosis
what are some common bacterial causative agents
strep pneumoniae
myx pneumoniae
haem flu
tuberculosis
what are some common viral causative agents
influenza a/b respiratory syncytial virus human metapneumovirus rhinovirus corona
how does pneumonia cause harm to human lung?
inflammation and swelling of alveolar space where gas exchange takes place
local and systemic inflammation that puts strain on cardiovasc system
how to grade potential bacterial pneumonia
crb/curb65 scoring if in hospital: confusion resp rate >30 breaths/min bp < 90 systolic >65 yrs
if in hosp
urea >7mmol/l
what does a score of 0 mean
likely suitable for home treatment
score of 1-2
consider hospital referral
score of 3-4
urgent hosp admission
antiobiotics if life threatening
what are some forms of supportive treatment for bacterial pneumonia
o2 - for hypoxia fluids - for dehydration analgesia - for pain nebulised salibe chest physiotherapy?
what are some forms of antibiotics to treat bacterial pneumonia
penicillins e.g amoxicillin - beta lactams that bind proteins in bacterial cell wall to prevent transpeptidation
macrolides e.g clarithromycin - bind to bacterial ribosome preventing protein synthesis
if curb is 0- 2 and cap what antibiotic recommended
amoxicillin
5-7 days
if curb is 3-5 and cap what antibiotic recommended
benzylpenicillin iv and clarithro
if curb is 0- 2 and hap what antibiotic recommended
doxycycline
can you catch pneumonia?
yes as bacteria found in:
human microbiome
microbiota
commensal
why do viral infections result in disease
cellular inflammation
mediator release
local immune memory
damage to epithelium - loss of cilia, bacterial growth, loss of chemoreceptors, poor barrier to antigen
what viruses can cause severe disease
highly pathogenic strains - zoonotic
absence of prior immunity
predisposing illness/condition
where do most respiratory viruses tend to preferentially adapt to bind to
upper respiratory tract if they have existed in humans for prolonged time
how does sars cov2 affect resp
spike protein binds to ace2 which is highly expressed in nose and alveolar cells therefore lots of nasal symptoms and damage and inflammation in alveoli - pneumonia
what is role of epithelial cells
first line of defence
how do epithelial cells act as first line of defence
tight junctions mucous lining and cilial clearance antimicrobials pathogen recognition receptors interferons pathways
what are serotypes
viruses which cannot be recognised by serum( really antibodies) that recognise another patogen
what immunoglobulins are commonly found in nasal cavity
igA
4 receptors
homodimer - extremelu stable in protease rich environment
what immunoglobulins are commonly found in lungs
igGs
thin walled alveolar space allows transfer of plasma igGs into alveolar space
points of flu
no reinfection by same strain
imperfect vaccines
rsv points
recurrent reinfection with similar strain
no vaccine
saes cov2 points
no prior immunity
newly licensed vaccine
what are some signs and symptoms of rsv bronchiolitis in infants
nasal flaring chest wall retractions hypoxemia and cyanosis croupy cough expiratory wheezing tachypnea
what are some risk factors for rsv risk factors
premature birth
congenital heart and lung disease
what is the leading cause of infant hospitalisation in developed world
rsv
general treatment options for resp infections
supportive therapy e.g oxygen
prophylactics - vaccine
antivirals
therapeutics - anti inflammatory
