Anaphylaxis Flashcards
What type of hypersensitivity is anaphylaxis a complication of?
Type 1 hypersensitivity.
What is the main cell that causes anaphylaxis and where are these cells found?
Mast cell. Connective and mucosal tissues.
What is the main molecule that leads to anaphylaxis and how does it do it?
Histamine. Contraction of airway smooth muscle leads to constriction of airways. Dilation of blood vessels with increased blood flow to the surface. Increases movement of fluid out of bloodstream. This can lead to hypotension which can lead to shock.
What causes release of granules?
IgE mast cell crosslinking with allergen
What primes a mast cell.
Binding of IgE.
Apart from histamine what other molecule is prominent in anaphylaxis?
Leukotrienes.
What cells are responsible for IgE production in type 1 hypersensitivity?
Activation of CD4+ T helper cells (TH2) causes a switch to IgE production. B cells produce IgE.
In anaphylaxis what causes hives (urticaria)?
Stimulation of connective tissue mast cells causes vasodilatation leading to the red colour of the skin rash, and oedema leading to its raised appearance.
If an allergen is inhaled such as in hayfever what changes would occur?
Oedema in the epithelia lining the nose. Stimulation of mucus secretion. If the allergen reaches the bronchioles of the lungs then there will be contraction of smooth muscle reducing the diameter of the airways, as well as inflammation and increased mucus production.
If an allergen is ingested what would occur?
Mucosal mast cells in the intestinal tract stimulate smooth muscle leading to vomiting and diarrhoea.
What can inhaled allergens like hayfever result in?
Asthma.
How can adrenaline help someone suffering from anaphylaxis?
Adrenaline shot constricts blood vessels and redirects blood flow to organs. Relaxes smooth muscle leading to airway dilation.
How can you treat anaphylaxis?
Use of antihistamines and corticosteroids.
What can be used to monitor a patient who has suffered anaphylaxis?
Blood pressure monitor. Can prevent biphasic anaphylaxis.
