Respiratory tract infections Flashcards
What are the 3 types of influenza?
A, B and C
Which influenza type is the commonest and most serious?
A is the most commonest and most serious
What is the genetic material in the influenza virus?
RNA
What does the influenza viral membrane have?
Viral membrane
with surface ‘spikes’
= glycoproteins:
– Neuraminidase (N)
&
– Haemaglutinin (H)
what do point mutations in the influenza virus lead to?
Antigentic drift which results in epidemics such as the seasonal flu
What does genetic reassortment lead to?
Antigenic shift which leads to pandemics
What organisms may cause pharyngitis?
Viruses – various
Strep pyognes (Group A Strep)*
Epstein-Barr Virus
Other Bacteria:
-Grp C G Streps
-Arcanobacterium
-Diphtheria
What investigations do we carry out for phatyngitis?
Throat culture (bacteria)
Monospot
EBV serology
ASOT (for Grp A Strep)
How do we diagnose group A strep?
Use a culture
How does Group A strep appear on culture?
Beta-haemolytic
What does group A strep react with?
Reacts with group A antiserum
What is group A strep sensitive to?
Bacitracin-sensitive
What is the usual bug for acute epiglottitis?
Haemophuluis influenzae = Hib
What age individuals does Hib affect?
Approx 6 months to 6 years
What other infections, other than Hib, cause acute epiglottitis?
Meningitis, Cellulitis,
Pneumonia
What do you do with patients with acute epiglottitis?
Intubate ASAP;
Antibiotics- Ceftriaxone
How does epiglottitis look like?
A thumbprint sign on an x-ray
What is croup?
Acute viral laryngo-
tracheobronchitis
What age group is affected by crop?
3 months to 3 years
What is the treatment for croup?
Steam etc – placebo value (?)
Steroids – beneficial – single dose
Antibiotics – no role
What is the pathophysiology of croup?
Inflammation &
oedema of larynx & trachea
Subglottic region –
least distensible part of
airway- prone to obstruction
Infants: airways more
compliant
-inspiration reduces
pressure in trachea
-collapses
-stridor
What is the single commonest cause of community acquired pneumonia?
Strep. pneumoniae
What is the most significant organism in very severe community acquired pneumonia?
Legionella,
Staph aureus
What are the lab tests for pneumonia?
– Sputum
– Blood Cultures
– Serum
– Urine (Antigen Kit)
– Throat swab (viral
testing)
What are the advantages and disadvantages of sputum sample tests?
-Can grown pneumococcus, staph aureus, coliforms and haemophilus
-However if there is a prior us of antibiotics, or mixture of salivary/mucoid makes test useless
What are the advantages of urinary antigen test for pneumonia?
-Quick
-Result not impacted by antibiotics
What are the causes of exasperated COPD?
-Bacterial infection
-Viral infection like RSV, flu, paraflu
-Non-infective causes like cold, allergens
What are the problems in investigations in COPD patients?
-Chronic sputum production
-Chronic colonisation with bacteria
What is the treatment for COPD exacerbation?
Maintain oxygenation
Treat (possible) underlying cause
Amoxicillin 500mg tds/doxycycline
Treat airways obstruction
– bronchodilators
– corticosteroids
Hydration/nutrition
