Respiratory Infections Flashcards
What are some symptoms of upper respiratory tract infection?
Cough Sneezing Runny/stuffy nose Sore throat Headache
What are some symptoms of lower respiratory tract infection?
Cough with phlegm Muscle aches Wheezing Breathlessness Fever Fatigue
What are some symptoms of pneumonia?
Chest pain
Blue tint on lips
Severe fatigue
High fever
How does age have an impact on respiratory infection outcome?
Very old people are at much higher risk and have a higher mortality risk
Very young children (eg under 2) also have a much higher risk
What are some risk factors for pneumonia?
Very young (under 2) Very old (over 65) Smokers Alcoholics Inhaled corticosteroids Immunosupressants PPIs COPD/asthma Heart/liver disease Diabetes mellitus
What is the most common respiratory illness causing pathogen
Rhinovirus
What respiratory illness causing pathogen most commonly causes mortality?
Mycobacterium bovis
What are the 2 ways pneumonia can be acquired?
Hospital
Community
Describe the characteristics of the pneumonia pathogen?
Gram positive
Extracellular
Opportunistic
What is the most common strain of community acquired pneumonia?
Streptococcus pneumoniae
What is hospital acquired pneumonia commonly associated with?
Ventilators
What is different about atypical pneumonia compared to typical?
The pathogens replicate a lot slower than usual and are sometimes more resistant to antibiotics that are commonly given in typical pneumonia
What infection may occur before pneumonia develops?
Bronchitis and bronchiolitis
What does pneumonia impair?
Gas exchange
What are some mechanisms by which pneumonia has bad outcomes?
Lung damage causes hypoxia and respiratory distress syndrome
Bacteremia causes organ infection and eventually sepsis
Systemic inflammation causes sepsis and deterioration
What is the first step in treating bacterial pneumonia?
Supportive treatments:
Oxygen for hypoxemia
Fluids for dehydration
Analgesia for pain
What is the second step in treating bacterial pneumonia?
Use of antibiotics
What type of antibiotic is penicillin?
Beta lactam
How do beta lactams work?
They bind to proteins in the cell wall and prevent transpeptidation
How do macrolides work?
They prevent protein synthesis by binding to the 50 s ribosomes
How can the success of antibiotics be increased?
Increasing the time to administration
Using an antibiotic that is effective (to find this refer to the NICE guidelines)
Give multiple together if needed
Is pneumonia contagious?
Not usually but it can be
What is an opportunistic pathogen?
A pathogen that takes advantage of a change in conditions eg immunosupression
What is a pathbiont?
A pathogen that is commensal but when found in the wrong environment (eg anatomical position), can become pathological
What does it mean when a pathogen is commensal?
When it lives symbiotically in the host
How common is latent TB?
Very, a lot of respiratory pathogens live in the upper respiratory tract without causing symptoms
What is the treatment for TB?
A combination of 4 antibiotics for 6 months
How is TB adapted to survive as a pathogen?
It has a very thick wall thats resistant to external molecules and factors
What are some ways viruses cause damage?
Cause cellular inflammation
Cause mediator release
They damage the epithelium causing loss of cilia, loss of chemoreceptors, and bacterial growth
How does infleunza A act?
Haemoglutinin binds to alpha 2,6 sialic acid
How does avain flu act?
Haemoglutinin binds to alpha 2,3 sialic acids
Where does infleunza A normally act?
Upper respiratory tract
Where does avian flu normally act?
Lower respiratory tract
What are the 2 groups of rhinovirus and what do they bind to?
Minor group binds to ICAM-1
Major group binds to low density lipoprotein
How does infection by influenza work regarding strains?
There is no reinfection by the same strain
How does vaccination for influenza work?
Vaccination is annual
It is possible but it isnt perfect
How does infection by RSV work regarding strains?
The same strain can infect someone multiple times, there are only 2 strains (A and B)
How many strains of RSV are there? What are they called?
2, A and B
How does RSV act?
F and G proteins bind glycosaminogylcans in receptors like IGFR1 and nucleolin
Where in the respiratory tract are the targets or RSV found?
All along the tract
How does vaccination for RSV work?
There is no vaccine
How does age change risk of RSV?
Infants and older individuals are at a much higher risk
How common is RSV in infants?
Its the most common respiratory tract infection in infants and a leading cause of hospitalisation
What are signs and symptoms of RSV in kids?
Hypoxemia Cyanosis Chest wall retractions Nasal flaring Expiratory wheezing Prolonged expiration
Infection by influenza can result in different symptom severity even in similar age, ethnicity- why is this?
The strain may be highly pathogenic
There may be prior immunity
There may be predisposing illness
Out of flu and RSV which has a faster emergence?
Flu
What is the main difference between infection by the flu vs RSV?
The same strain flu can’t infect you twice but the same strain of RSV can
What type of molecules are interferons?
Cytokines
What are the types of interferon and what are they called?
Type 1= interferon alpha/bets
Type 2= interferon gamma
Type 3= interferon delta
How do interferons work?
By inhibiting viral infection
What are ISGs?
Interferon stimulated genes- they inhibit viral replication inside cells when they are upregulated
What cells produce interferons and when?
Cells that are infected by viruses when they detect infection
What cells provide long term immunity?
B cells
How does pre existing immunity affect symptoms?
It greatly reduces them
What does RSV stand for?
Respiratory syncytial virus
