W6 27 respiratory infections including tuberculosis Flashcards
What can we split the respiratory tract into?
Upper and lower respiratory tracts
Upper - nasal and oral cavities, pharynx, epiglottis, larynx
Lower - trachea, bronchus, lungs, diaphragm
What is the normal state of the upper and lower RTs?
Upper usually has many bacteria and viruses present at all time but not causing infection
Lower is normally sterile
What defence mechanisms are in the respiratory tract?
Cilia, mucus production, cough, swallow mechanisms, immunoglobulins
When do URTI require antibiotics?
When bacterial aetiology is known or suspected (usually tends to worsen rather than resolve)
Systemically unwell
Features or high risk of complications
Are URTIs common?
Common, short lived, rarely serious, viral aetiology
What is acute coryza?
Nasal discharge, sneezing and cough (prolonged night cough with post-nasal drip)
What happens when there is pharyngeal compared with laryngeal involvement?
Pharyngeal involvement - sore throat
Laryngeal involvement - hoarse/lost voice
What is tracheitis/bronchitis?
Wheeze
When should we be worried about wheezing?
Wheezing upon breathing in = stridor, should prompt rapid investigation/treatment
What should nasal congestion, facial pain/pressure raise the possibility of?
Sinusitis
What are the common infections of the Nasopharynx, oropharynx, ear and larynx and trachea caused by?
(Don’t learn just be aware)
Nasopharynx - rhinoviruses (common cold), S. aureus
Oropharynx - Group A Strep (sore throat)
Ear - haemophilus
Larynx & trachea - parainfluenza
What is an important bacteria of the epiglottis, and what does it cause?
Haemophilus influenza type B
Causes acute onset of fever, sore throat, respiratory diseases
Is Haemophilus influenzae type B still around?
Nearly completely disappeared due to vaccine
What are worrying signs of Haemophilus influenzae type B?
Severe throat infection, with massive oedema of the epiglottis. Illness develops rapidly with high fever and difficult swallowing. AVOID MANIPULATION OF THROAT (call for help - ENT). Drooling and stridor should raise red flags
What is sinusitis and what causes it?
Inflammation of the lining of the sinuses
S. aureus, H. influenzae, and anaerobes (mainly gram +ve)
What is pharyngitis (sore throat/tonsillitis) caused by?
Can be viral or bacterial - difficult to differentiate
Streptococcus pyogenes: Group A streptococcal are most common bacterial cause
What is pharyngitis characterised by?
Inflammation, exudate, fever, tender cervical lymph nodes, red tender sore throat
What are some complications of pharyngitis?
Scarlet fever (characteristic red rash all over body)
Rheumatic fever
Post-strep Glomerulonephritis
What are the types of influenza?
A B and C
Type A and B cause most of the disease burden
The influenza virus is antigenically unstable and constantly changing. Describe what an antigenic drift is?
Antigenic DRIFT = minor changes to the amino acid sequence of the haemagglutinin (HA).
Happens fairly frequently, and people might still have some protection.
The influenza virus is antigenically unstable and constantly changing. Describe what an antigenic shift is?
Antigenic SHIFT = more major changes in the haemagglutinin or the Neuraminidase resulting in a large change in the virus. Shifts in the virus are associated with outbreaks of flu, with the population having little or no protective immunity.
Who are offered the flu vaccine?
Risk groups are offered it each year (eg over 65s, pregnant, at risk groups)
It is altered each year to reflect the most likely circulating strains but it is not always reactive.
How do you diagnose flu and what should you do if you suspect flu clinically?
Diagnose via a throat swab detection by PCR (but mainly just clinical)
If detected clinically - isolation precautions. Antivirals usually not necessary.
What is RSV?
Respiratory syncytial virus (RSV). It is transmitted by large droplets and secretions. It is a generally mild virus that occurs regularly each year, but can be severe in children (potentially developing bronchiolitis and pneumonia). Infection control in hospitals is critical to stop it. Disease in childhood does not give lifelong protection.
