Respiratory Tract Infections Flashcards
What does the term URTI cover?
Sinusitis
Tonsilitis
What does the term LRTI cover?
Bronchitis
Pneumonia
Empyema
Bronchiectasis
Lung abscess
Give 5 ways in which respiratory defences can be compromised
Poor swallow: CVA, muscle weakness
Abnormal ciliary function: Smoking, Kartagener’s
Abnormal mucous: CF
Dilated airways: Bronchiectasis
Defects in host immunity: HIV, Drugs
What is the abnormality seen here?
Double heart border “Sail sign”
Left lower lobe collapse
What is seen on CT here?
Densely consolidated + collapsed left lower lobe
18F
Left lower lobe pneumonia
Unwell
Raised WCC + CRP
What is the likely organism?
A. Pseudomonas aeruginosa
B. Mycobacterium tuberculosis
C. Legionella pneumophilia
D. Streptococcus pneumoniae
E. Staphylococcus aureus
D. Streptococcus pneumoniae
30-50% of CAP
Give 3 features of streptococcus pneumoniae under microscope
Gram +ve cocci (pairs + chains)
Alpha haemolytic
Optochin sensitive
List 4 symptoms/ signs of S. pneumoniae
Acute onset
Severe pneumonia
Fever, rigors
Lobar consolidation
What is S. pneumoniae almost always sensitive to?
Penicillin
What is pneumonia? How sick are patients generally?
Inflammation of lung alveoli
Community acquired or Hospital acquired
5-10% Mortality
20-40% admitted to hospital
Give 5 common signs/ symptoms of pneumonia
Fever
Cough +/- sputum
SOB
Pleuritic chest pain
Often localising signs + abnormal CXR
List 4 factors to consider when assessing possibility of pneumonia
Pre-existing lung disease
Immunocompromised
Travel, seasons, epidemics
Exposure to animals
List the 5 main causative organisms of CAP
Streptococcus pneumoniae
Staphylococcus aureus
Haemophilus influenzae
Moraxella catarrhalis
Klebsiella pneumoniae
How does age influence susceptibility to different causative organisms for CAP?
0-1m: E. coli, GBS, Listeria monocytogenes
1-6m: Chlamydia trachomatis, S aureus, RSV
6m-5y: M pneumoniae, Influenza
16-30: M pneumoniae, S pneumoniae
What are the typical causes of CAP? How many cases do they account for?
S pneumoniae
H influenza
85%
What 4 atypical organisms must be accounted for when treating CAP? Give a feature or exposure associated with each
Legionella: water exposure, A/C
Mycoplasma: barking cough, normal CXR
Coxiella burnetii (Q-fever): farm animals
Chlamydia psittaci: bird exposure
Give 7 signs that may be found on examination in a patient with CAP
Pyrexia
Tachycardia
Tachypnoea
Cyanosis
Dullness to percussion, tactile vocal fremitus
Bronchial breathing
Crackles
What investigations should be sent when suspecting CAP?
FBC, U+Es, CRP
BC, Sputum MC+S
ABG
CXR
Urinary antigen: legionella + s aureus
What is the CURB-65 score designed for?
Predicting mortality of CAP
Score 2: ?Admit
Score 2-5: Manage as severe
What are the elements of the CURB-65 score?
Confusion
Urea >7 mmol/l
RR >30
BP <90 sys, <60 dia
>65y
What is bronchitis? Which patients is it mostly seen in?
Inflammation of medium sized airways
Smokers
List 4 signs/ symptoms of bronchitis
Cough
Fever
Increased sputum production
Increased SOB
How does bronchitis appear on CXR?
Normal
List 4 organisms causative of bronchitis
Viruses
S pneumoniae
H influenzae
M catarrhalis
What is the treatment for bronchitis?
Bronchodilation
Physiotherapy
+/- Abx
What can be seen here?
Cavitation on LHS
56M
Left lower lobe pneumonia
Haemoptysis
Cavitation on CXR
What organism would you suspect?
A. S pneumoniae
B. H influenzae
C. S aureus
D. Klebsiella pneumoniae
B. H influenzae
Give 3 features of H influenzae under the microscope
Gram -ve Cocco-bacilli
Stain on Chocolate agar
May produce B-lactamase
Give 2 epidemiological features of H influenzae
15-35% CAP
More common with pre-existing lung disease
What is seen here?
Bilateral interstitial change
62M smoker
SOB
Confused
Bilateral interstitial change
Hyponatraemic
What is the likely organism?
A. Moraxella catarrhalis
B. Mycobacterium tuberculosis
C. Legionella pneumophilia
D. Cytomegalovirus
E. Staphylococcus aureus
C. Legionella pneumophilia
What similarity to atypical organisms share?
No cell wall
thus cell-wall active abx e.g. penicillin ineffective
Often extra pulmonary features e.g. hepatitis, low Na
How is legionella transmitted? What culture is required to grow it on?
Inhalation of infected water droplets e.g. A/C, fountain
Buffered charcoal yeast extract agar