Upper respiratory tract Flashcards
what does the upper respiratory tract consist of
Upper respiratory tract includes the nasal cavity, pharyx and larynx
what are common URTIs
- Common cold – rhinovirus, coronaviruses, adenoviruses, myxovirsues, echoviruses
- Pharyngitis
what is more common bacteria or viruses for URTIs
- Bacteria infections can drive URTI but the most common cold is virsues
what is the most common virus that causes the common cold
rhinovirus
how can the common cold be transmitted
- Inhaling droplets in the air from sick people are major cause, due ot coughing sneezing or blowing their nose
- Touching a surface contaminated with the virus and then touching your eyes nose or mouth
- Inoculation of the mucosa lining of the upper airway
how long is the incubation time of the common cold
- varies depending on the virus
- Rhinoviruses = 1-5 days and respiratory syncytial virus may incubate for 7 days
define incubation time
this is the time before the onset of symptoms
what are the symptoms of the common cold
- Runny nose
- Sore throat
- Cough
- Sneezing
- Loss of appetite
- Low grade fever
- Watery eyes
- Headache
- Earaches
- Nausea sensation
- Rhinorrhoea (excess mucus filling in the nasal cavity) and nasal obstruction (mucosal lining) – major symptoms
what are the major symptoms of a common cold
Rhinorrhoea (excess mucus filling in the nasal cavity) and nasal obstruction (mucosal lining) – major symptoms
what leads to the feeling of congestion
- Nasal obstruction – this results in swollen cells and swollen blood vessels, the swollen blood vessels lead to the feeling of congestion
describe the pathophysiology of the human rhinovirus infection
- Airways are lined for the epithelial cells
- upon inhlation of the HRV, this is recognized by TLR in this example it is TLR 3
- binding to this leads to activation of a host of signalling mechanism this includes activation of the retinonic acid inducible gene-1-like receptor,
- this signals mechanism inside the cell which leads to the secretion and release of pro- inflammatory mediates such as TNF alpha, IFN, CXCL8, some of these are chemokines which attract neutrophils,
- APC cells happen, then there is a delayed immune signature of the B and T cells
what are the symptoms of inflammation
- Swelling
- Redness
- Temperature
- Pain
what two viruses are most popular for causing the common cold
- rhinovirus
- RSV (respiratory syncytial virus)
how does the respiratory syncytial virus lead to the common cold
Viral Replication (major target epithelial cells)
→ Recognition via Toll-like (TLR) & retinoic acid-inducible gene-I-like (RIG-I) receptors
→ Cellular infection triggers pro-inflammatory mediators (e.g. TNF-alpha, IFN & CXCL8)
→ Triggers & activates Innate & Adaptive response
what is CXCL8
major chemokine that recruits neutrophils to the area
what does the neutrophils do in common cold
this leads to increased vascular permeability and increased mucus hypersection which causes rhinorrhea and nasal obstruction(major symptoms)
how do viruses impede immune recognition
- High glycosylation & structural variability of surface G-protein = impedes immune recognition
- Viruses can not only change the cell surface marker but can release decoys as well (release of soluble G protein), this reduces the virus specific antibodies concentrations available for virus neutralisation
what is high glycosylation when the virus impedes immune recognition
Dendritic cells recognize surface proteins, viruses are good at variability of surface G proteins and can change it quickly therefore this can make the immune system redundant and unable to fight you this is high glycosylation
what is the impact of rhinovirus infections on people with asthma
- 50-80% of asthma exacerbations
- Factors favouring HRV infection severity in allergic conditions
what are you more likely to get an asthma exacerbation when you have a cold
Asthma (state of heightened immune & inflammatory response)
→ ↑ cytokine release (e.g. IL-4, -5, -10 & -13)
→ ↑intracellular adhesion molecule (ICAM-1, major HRV receptor)
→ more susceptible to HRV infection
how is COPD effected by virus causing the common cold
Viral infections may account for 60-80% of COPD exacerbations
- Worsening on resp symptoms – change in medication
- Increase in disease progression and hospitalization – this can lead to death
- Increased airway inflammation, worsening hyperinflation, lung function decline
Nasopharyngitis
what are the viral pathogens that cause COPD exacerbations
RV, Respiratory Syncytial Virus & Influenza virus
how do you prevent nasophayngitis from spreading
- Decrease infection risk
- Wash hands frequently
- Avoid contact with viral particles
- Avoid touching you eyes with contaminated hands
- Use disposable tissues
- Use instant hand sanitizers to stop the spread of germs
- Avoid touching your nose
how long does nasophayrngitis last for
- Duration up to 14 days, symptomatic 7-11 days
what are the symptoms of nasopharygitis
- Fever, sneezing, and sore throat typically resolve early whereas cough and nasal discharge are among the symptoms that last longest
how do you mange nasopharyngitis
- Nasal irrigation – clear pollutants and thin mucus
Nasal and or systemic steroids – reduce swelling
Decongestatns
how do decongestants work
- Site of action – blood vessels surrounding nasal sinuses
- Mechanism – alpha 1 adrenoreceptor agonist
- Pharmacological effect – vasoconstriction
- Decongestants reduce swelling of blood vessels around the sinuses and this reduces the congestion in the nose
- Alpha 1 agonist leads to vasoconstriction of the nasal blood vessels, this leads to a broad nasal pathway which leads to decongestion
what is pharyngitis
- This is a sore throat
- Pharyngeal and tonsillar tissue may look edematous or be ulcerated
- There is significant inflammation of the tonsils and there is also tonsillar exudate
what are the two scores used in the sore throat assessment
- fever pain score
- centor score
name the categories for the fever pain score
- If the person has fever above 38 degrees
- Purulence
- Attend within 3 days or less
- Severly inflamed tonsils
- No cough or coryza
name the categories for the centor score
- Tonsillar exudate
- Tender anterior cervical lymphadenopathy or lymphadenitis
- History of fever greater than 38 degrees
- No cough
how do you use the fever pain score and the centor score to work out if the patient should have an antibiotic or not
Fever pain is 0 or 1 do not offer antibiotic
Centor score 0 1 or 2 do not offer an antibiotic
Advice that sore throat can last around 1 week and to manage symptoms with self-care
Fever PAIN score 2 or 3 consider no antibiotic or a backup antibiotic prescription
FeverPAIN score 4 or 5 – consider an immediate antibiotic or a backup antibiotic prescription
Centore score 3 or 4 – consider an immediate antibiotic or a back up antibiotic prescription
what is the first line therapy and alternative first choices for pharyngitis
First line therapy
- Phenoxymethylpenicillin – 500mg four times a day or 1000mg twice a day for 5 to 10 days
Alternative first choice
- Clarithromycin – 250mg to 500mg twice a day for 5 days
- Erythromycin – 250mg to 500mg four times a day or 500mg to 1000mg twice a day for 5 days
what is the leading cause of nasopharyngitis (common cold)
human rhinovirus
