Colds and Allergies (Chapter 10) + Bermon Paper on URTI + Bonus Lecture Flashcards
What are the two main types of viruses?
rhinoviruses and coronaviruses
What are two diseases that colds are confused with often ?
Allergic rhinitis, or bacterial URTI
If someone has symptoms of a cold with a sore throat, what is it probably ?
Streptococcal infection (bacterial)
How are streptococcal infections spread ?
by airborne nasal discharge (sneezing), contact with hand
what are the complications of common cold ?
bacteria may appear in nose or ear because cavities are blocked
how many days does it take to get better from a cold ?
7-10
how long can viruses stay on inanimate objects for ? what happens to them ?
a few hours
oxygen can damage virus coating
how do viruses survive better ? what does this imply about the way they are usually transmitted ?
they usually survive better in liquids, therefore they need to contact the mucous membranes in order to more easily enter the body.
what is the difference between the way influenza and the common cold is transmitted ?
influenza is usually airborne
what drugs cure the common cold ?
none, they only alleviate the symptoms
what molecule is behind mucus production ? how ?
acetylcholine
released from cholinergic nerve, which increases mucus production
what effect does the common cold have on asthma ?
it may exacerbate asthma symptoms
is it ok to change asthma treatment if one is affected by a cold ?
yes, treatment may need to be increased to combat the increased symptoms
why do people have runny noses ?
mucus secretion trying to get rid of the virus
what is the symptom that may persist even after the end of the cold ?
cough
what is allergic rhinitis
a hypersensitivity reaction to an allergen which combines with an antibody, mainly IgE
explain the mechanism behind allergic rhinitis
antigen/allergen binds with antibody IgE
IgE then combines with mast cells at IgE receptors on the surface of the mast cell and basophils in mucosa of nasal passage. The granules which contain histamine and proteases are released into the outside.
when antigen present, cells degranulate, releasing histamine, prostaglandins, leukotrienes, platelet activating factor, bradykinin (inflammation)
what are the 5 things mast cells release in allergic rhinitis ?
histamine, prostaglandins, leukotrienes, platelet activating factor, bradykinin
why does inflammation occur in allergic rhinitis? what mechanism is behind it ?
tissues express H1 histamine receptor and receptors for leukotrienes, etc.
What do the proteases do in allergic rhinitis ?
The proteases directly kill tissues which release pain and inflammation mediators such as substance P, bradykinin, and arachidonic acid metabolites.
What are the immediate early phase symptoms of allergic rhinitis ?
rhinorrea (runny nose), vasodilation, sneezing, itching of nose and eyes
What are the late phase reactions of allergic rhinitis? What are they due to ?
Sneezing, congestion, enhanced responsiveness of other antibodies
Due to accumulation of the inflammatory cells (mast cells and basophils)
How do genes affect allergic rhinitis ?
If both parents have allergy, child has 50% change of getting allergies
If no parents have allergy, child has 10% chance
What is the counter-regulation theory?
That in developed countries, there are less parasites and infections, so the immune system is more sensitive than in under-developed countries in which the immune system becomes “harder to activate”