1b Respiratory Tract Infections and Immunology Flashcards
What are the signs and symptoms of a upper respiratory tract infection?
A cough
Sneezing
Runny / Sore Nose
Headache
What are the signs and symptoms of a lower respiratory tract infection?
“Productive” cough
Muscle aches
Wheezing
Breathlessness
Fever
Fatigue
What are the signs and symptoms of pneumonia?
Chest pain
Blue tinge of the lips
Severe fatigue
High fever
What is DALY?
Disability adjusted life year - a sum of the years of life lost and years lost to disability
What happens to the rate of pneumonia with age?
Increases
What are the common bacterial causative agents for respiratory infections?
Streptococcus pneumoniae
Myxoplasma pneumoniae
Haemophilus Influenzae
Mycobacterium tubercolosis
What are the common viral causative agents for RTI’s?
Influenza
Human Rhinovirus
Corona Virus
Respiratory Syncytial Virus
Human metapneumovirus
What is CAP and HAP?
Community Acquired Pneumonia
Hospital Acquired Pneumonia
What is the most common cause of CAP?
Streptococcus pneumoniae
What gram is Streptococcus pneumoniae?
gram positive
What type of pathogen is Streptococcus pneumoniae?
Extracellular and opportunistic
What is the most common cause of HAP?
Staphylococcus aureus
What is bronchitis?
Inflammation and swelling of the bronchi
What is bronchiolotis?
Inflammation and swelling of the bronchioles
What is pneumonia?
Inflammation and swelling of the alveoli
What can pneumonia lead to?
Acute Respiratory Distress Syndrome
What is the CRB/CURB-65 scoring system?
Confusion
Respiratory Rate - 30 breaths / minute
Blood Pressure - 90 sys and 60 dia
65 - 65 years or older
In hospital - add Urea greater than2 7 mmol/L
What is the treatment for a CRB65 score of 0?
Home treatment
Antibiotics
amoxicillin
What is the treatment for a CRB65 score of 1-2?
Consider hospital referral
Amoxocillin and Clarithromycin
What is the treatment for a CRB65 score of 3-4?
Urgent hospital administration
Empirical antibiotics if life threatening
benzylpenicillin IV and claroithromycin
What are the three supportive treatments for bacterial pneumonia?
Oxygen
Fluids
Analgesia
What antibiotics should be used to treat pnuemonia?
Penicillin eg amoxicillin
Macrolides eg clarithromycin
What is meant by the microbiota?
ecological communities of the microbes found inside multi-cellular organisms
What are commensal bacteria?
Microbes that live in a symbiotic relationship with their host = providing vital nutrients to the host in the presence of a suitable ecological niche
What is a pathobiont?
A microbe which is usually commensal but if found in the wrong environment, can cause pathology
Why do viral infections result in disease?
Viral infection -> damage to epithelium -> results in cellular inflammation, local immune memory, mediator release, loss of cilia etc etc
What causes severe disease?
RNA sequence
Viral Load
DNA
Environment
have to consider all factors
Why might an infection lead to very severe disease?
Poor prior immunity
Highly pathogenic strains
Predisposing illness/conditions
What is the difference in protein binding between H1N1 and H5N1?
H1N1 - Haemogglutinin binds 𝛂2,6 sialic acids
H5N1 - Haemogglutinin binds 𝛂2,3 sialic acids
Where do viruses like to preferentially bind?
Most respiratory viruses can infect cells throughout the respiratory tract, but tend to preferentially adapt to bind cells of the upper respiratory tract if they have existed in humans for a prolonged time
Where is there the greatest proportion of 𝛂2,6SA found?
In the nasal cavity
Where is there the greatest proportion of 𝛂2,3SA found?
In the bronchi - lower respiratory tract
What is the role of the tight junctions?
Prevents systemic infection
What is the role of the mucous lining and cilial clearance?
– prevents attachment, clears particulates
What is the role of the anti-microbials?
recognise, neutralise and/or degrade microbes and their products
What is the role of the pathogen recognition receptors?
recognise pathogens either outside or inside a cell
What type of infection activates interferon pathways?
Viral infection
What are serotypes?
viruses which cannot be recognised by serum (really antibodies) that recognise another virus – implications for protective immunity
What does the interferon pathways activate?
Promotes upregulation of anti-viral proteins and apoptosis.
Which part of the respiratory tract is enriched for IgA?
Nasal cavity
What do the epithelial cells of the nasal cavity express?
ECs express poly IgA receptor, allowing export of IgA to the mucosal surface
Which part of the respiratory tract is enriched for IgG’s?
Bronchi
How are IgG able to enter into the alveolar space?
Thin-walled alveolar space allows transfer of plasma IgGs into the alveolar space
What are the risk factors for RSV bronchiolitis in infants?
Premature birth
Congenital heart and lung disease
What are the symptoms and signs of RSV bronchiolitis in infants?
Nasal Flaring
Chest wall retractions
Croupy cough
Expiratory Wheezing
Hypoxemia and Cyanosis
How does Remdisivir work as an anti-viral?
broad spectrum antiviral – blocks RNA-dependent RNA polymerase activity
What are some anti-inflammatory drugs?
Dexamethasone (steroids)
Tocilizumab (anti-IL-6R) or Sarilumab (anti-IL-6)
How does paxlovid work?
Paxlovid – antiviral protease inhibitor
How do casirivimab and imdevimab work?
monoclonal neutralising antibodies for SARS-CoV-2
Viral bronchiolitis is associated with the development of what?
Development of asthma
What is the most common cause of asthma and COPD exacerbations?
Rhinoviruses
