Respiratory Tract Infections Flashcards
what are URT infections
primarily viral, everything above vocal chords to mouth and nose
- common cold, sinusitis, pharyngitis, laryngitis
- do not require antibiotics
what are the LRT infections
acute bronchitis, pneumonias, TB, influenza,
overview of acute bronchitis
50% viral, 25% bacterial, 25% mixed
- treat with antibiotics, measure PCT and CRP
- treat inflammatory component with ICS
- treat repiratory failure
- symptoms include cough with yellow-green phlegm
what is pneumonia?
a LRTI causing inflammation of lung tissue and sputum filling airways and alveoli
- when presenting say: signs of a LRTI (fever/cough or bronchial breathing) and CXR changes
how do you classify pneumonia?
community acquired = gram positive
hospital acquired = gram negative neg or staph aureus
fungi
unusual organisms / fungi
aspiration pneumonia
what is aspiration pneumonia?
from upper respiratory or GI tract
involves right lower lobe
what is hospital acquired pneumonia?
new onset of symptoms more than 48 hours after patients admission to hospital
what is ventilator acquired pneumonia
HAP in patients on mechanical ventilation
within 4-5 days of admission
how does pneumonia present?
SOB cough - sputum fever haemoptysis pleuritic chest pain delirium abdominal pain sepsis
what are the clinical signs of pneumonia
tachypnea tachycardia hypoxia fever confusion
how does pneumonia present on a chest x-ray
alveoli filled with neutrophils = consolidation
what can you hear in a patient with pneumonia?
bronchial breath sounds - harsh breath sounds loud on inspiration and expiration
focal coarse crackles
dullness to percussion bc consolidation
how do you assess the severity of pneumonia?
CURB-65
predicts mortality and score 1 = treat at home, score >1 hospital admissions
score >2 ICU
c- confusion
u-urea >7
R - resp rate >30
b - blood pressure
65 - age 65 and >
what are the common microbes causing pneumonia
strep pneumonia
haemophilius influenzae
moraxella catarrhalis: in immunocompromised patients
PA in CF patients and staph A as well
what is atypical pneumonia
organism that cannot be cultured and doesn’t respond to gram staining or penicillins
treated with macrolides or tetracyclines eg doxy
what are the organisms causing atypical pneumonia?
legionella pneumophila; can cause SIADH hyponatremia
in infected waters
mycoplasma pneumoniae (rashes)
chlamydia psitacci from infected birds
chlamyodphila pneumoniae: school aged with wheeze
coxiella burnetti: exposure to animals, have a flu
what is fungal pneumonia?
pneumocystis jivorecci
immunocompromised
dry cough, SOB on exertion, night sweats
co-trimoxazoles/ trimethoprim
what are the investigations for pneumonia?
CURB 0-1 = none
- CXR
- o2 sats, ABG
- FBC: WCC, Hb, platelets for inflammation
- viral swab!! and blood cultures
- urinary pneumococcal antigen
- CRP
- U&E’s
- LFT’s = sepsis
- lactate for sepsis
what is the treatment for CAP pneumonia
local guidelines
moderate, severe or septic: IV antibiotics then switch to oral
5 day (mild: amoxicillin or clarithryomycin) or 7 day course of dual amoxicillin AND macrolide
what is the treatment for HAP?
- broad spectrum b lactamase stable antibiotics such as co-amoxiclav together with a macrolide
what do you do if pneumonia is very hard to treat/not responding?
piperacillin-tazobactam
then change to narrow spec like benzylpenicillin
also continue clarithromycin to cover for atypical causes
what are the complications of pneumonia?
sepsis
pleural effusion = fluid in pleural cavity
empyema - pus in pleural space (drain and antibiotic)
lung abscess - pus in non pre-formed space
VTE
death
what causes pneumonia in children?
neonates: e coli, strep b and listeria
1-6 months: chlamydia trachomatis, staph a and RSV
6m-5 years is RSV and para-influenzae
what do CXR look like in diff conditions?
LOOK AT IMAGES
COVID: may be normal, peripheral bilateral consolidation
CAP - shadowing and consolidation
COPD: hyperexpansion an and reduced air markings
Lung cancer: pneumonia or recurrent infections
what is TB?
infectious disease caused by mycobacterium tuberculosis
descibe the TB bacteria
bacillus, wax coating
acid fast
zeil-neelsen stain
where is TB most common?
south asia, africa, immunocompromised
what are the RF for TB
known contact with active TB
immigrants from areas of high TB prevalence
immunosuppression
homeless people, drug users, alcoholics
what is the pathophysiology of TB?
bacteria are slow dividing with high oxygen demands
spread by inhaling infected droplets
spreads through lymphatics and bloods
granulomas containing the bac form around the body
what is active TB?
active infection in various areas
IS can clear it
normally IS may encapsulate site of infection and stop progression of disease = latent TB
reactivation - secondary TB
mostly affects the lungs bc the bacteria gets lots of oxygen there
what is extrapulmonary TB
affects lymph nodes = abscess
affects pleura, CNS, pericardium, GI, GUI, bones and joints
vaccine for TB?
BCG
intradermal
live attenuated
done on a negative mantoux test
what is the presentation of TB?
chronic, worsening symptoms lethary night sweats or fever weight loss cough lymphadenopathy erythema nodosum
how do you test for TB?
-mantoux test: inject tuberculin intradermally, after 72 hours >5mm is positive, then assess for active disease
interferon gamma release assays
CXR
sputum samples for cultures
what is the interferon gama release assay
mix blood sample w antigens from TB bacteria
previous infection = WCC sensitised so reaction
- used to test for latent TB
what does a CXR look like on someone with TB?
primary: patchy consolidation, pleural effusions and hilar lymphadenopathy
reactivated: consolidation with cavitation typical of upper zones
military: millet seeds, spread evenly throughout lung fields
how do you manage latent TB?
patients at risk of reactivation: isoniazid and rifampicin for 3 months
or
isoniazid for 6m
how do you manage acute pulmonary TB?
RIPE:
rifampicin and isoniazid for 6m
pyrazinamide and ethambutol for 2 months
pyroxidine prophylactically
what are the side effects of TB medication?
isoniazid: peripheral neuropathy hence propphylaxis of pyroxidine
rifampicin - red urine and tears bc p450 enzymes
- reduces pill effectiveness
ethambutol - colour blindness and visual acuity
how do you treat extrapulmonary TB?
corticosteroids
how do you assess for breathlessness?
MRC dyspnoea scale
1- only SOB on exercise
2-SOB when on hill or hurrying up
3- stops after 1 mile or 15 mins, slow walking
4 - stops for breath after 100 yards
5 - too breathless to leave house or do ADL
