Rhinitis & Rhinorrhoea Flashcards
Define rhinitis
a common & often debilitating disease involving acute or chronic inflammation of the nasal mucosa
What four things is rhinitis characterised by?
- rhinorrhoea
- sneezing
- itching
- nasal congestion
State the three types of allergic rhinitis
- seasonal (winter and summer)
- perennial (all year)
- episodic
When the allergen is inhaled what antibody increases? What does it do?
IgE - binds to receptors and mast cells
What does re-exposure to the antigen cause?
Degranulation of mast cells and basophils
When inflammatory cells degranulate what is released?
Mediators
eg. histamine, cysLTs, tryptase, prostaglandins
Name three symptoms the release of mediators cause
itching, sneezing & nasal congestion
What other response contributes to congestion and obstruction?
recruitment of lymphocytes and eosinophils
What is meant by non-allergic rhinitis?
any rhinitis acute or chronic that does not involve IgE dependent events
Stat six causes of non-allergic rhinitis
- infection (viral)
- hormonal imbalance (pregnancy)
- vasomotor disturbances (idiopathic)
- non-allergic rhinitis with eosinophilia syndrome (NARES)
- medications (aspirin)
- genetic (CF)
Describe the mechanism behind breathing difficulty in rhinitis
Increased mucosal blood flow and increased blood vessel permeability increase the volume of nasal mucosa and cause difficulty breathing
Name four treatment targets
Anti inflammatory (glucocorticoids)
Mediator receptor blockade (H1 & CysLT1 receptor antagonists)
Nasal blood flow (vasoconstrictors)
Anti-allergic (sodium cromiglicate)
How do glucocorticoids work?
Reduce vascular permeability, recruitment and activity of inflammatory cells, release of cytokines and other mediators
What types of rhinitis can glucocorticoids treat?
SAR,PAR,NARES and vasomotor rhinitis
Applied topically as a spray
How do anti-histamines work?
Competitive antagonist s reduce the effect of mast cell derived histamine
- vasodilatation & increased capillary permeability
- activation of sensory nerves
- mucus secretion from submucosal glands
What types of rhinitis are anti-histamines effective for?
SAR, PAR and EAR
Administered orally or by intranasal spray. Second generation agents are preferred due to reduction in sedation.
What role does acetyl choline play in rhinorrhoea?
It is released from post ganglionic parasympathetic fibres which activates muscarinic receptors on nasal glands causing watery secretion
In what types of rhinitis do anti-cholinergic drugs reduce rhinorrhoea?
PAR and SAR but have no influence on the other symptoms
Ipratropium is administered intranasally but may cause dryness
How do CysLT1 receptor antagonist work?
Reduce the effects of CysLTs upon the nasal mucosa - equi-effective with H1 receptor antagonists in treating PAR and SAR
What is an example of a CysLT1 receptor antagonist?
Montelukast
How do vasoconstrictors work?
Mimic the effect of noradrenaline to produce vasoconstriction via activation of alpha 1 adrenoreceptors to decrease swelling in vascular mucosa
What is an example of a vasoconstrictor?
Oxymetazoline
