Drug Treatment in Rhinitis and Rhinorrhoea

Question 1

outline the pathology of rhinitis

Answer 1

common and often debilitating disease
acute or chronic inflammation of the nasal mucosa characterised by;
rhinoorohea (runny nose - watery mucus accumulation in nasal cavity)
sneezing
itching
nasal congestion and obstruction (swelling of nasal mucosa lately due to dilated blood vessels - cavernous sinusoids)

both rhinitis and rhinorrhoea involve increased mucosal blood flow, increased blood vessel permeability, or both - these increase the volume of the nasal mucosa and cause difficulty breathing in

Question 2

describe the similarities between allergic rhinitis and asthma

Answer 2

allergen inhaled increases specific IgE levels
IgE binds to receptors inmost cells and basophils
re-exposure to allergen causes mast cell and basophil degranulation
released of mediators including histamines, CysLTs, tryptase, prostaglandins, causing acute itching, sneezing, rhinorrhoea and nasal congestion
delayed response caused by recruitment of lymphocytes and eosinophils to nasal mucosa contributes to congestion and obstruction

Question 3

describe the varied drug classes used to treat allergic and non-allergic rhinitis and comment upon the nasal symptoms that are affected - glucocorticoids

Answer 3

anti-inflammatory;
reduces vascular permeability, recruitment and activity of inflammatory cells and the release of cytokines and mediators
mainstay therapy for SAR and PAR and are of vale in NARES and vasomotor rhinitis
sprayed to the nasal mucosa or given orally in severe intractable cases
effective monotherapy - reduces all symptoms of rhinitis including nasal congestion
combined with anti-histamines in moderate to severe rhinitis e.g. beclometasone, fluticasone, prednisolone (oral)

Question 4

describe allergic rhinitis

Answer 4

classified as;
seasonal (SAR)
perennial (PAR)
episodic (EAR)

Question 5

describe non-allergic

Answer 5

any rhinitis, acute, or chronic, that does not involve IgE dependant events
causes are diverse and include;
infection - infectious rhinitis (largely viral)
hormonal imbalance - hormonal rhinitis (pregnancy)
vasomotor disturbances - vasomotor rhinitis (idiopathic)
nonallergic rhinitis with eosinophilia syndrome (NARES)
medications - drug induced rhinitis

Question 6

describe occupational rhinitis

Answer 6

involves both allergic and non-allergic components

Question 7

describe the varied drug classes used to treat allergic and non-allergic rhinitis and comment upon the nasal symptoms that are affected - H1 receptor antagonists

Answer 7

mediator receptor blockade/anti-histamines;
competitive antagonists that reduce effects of mast cell derived histamines including;
vasodilation and increased capillary permeability
activation of sensory nerves
mucus secretion from submucosal glands
effective in SAR, PAR an EAR (less so in non-allergic rhinitis)
less effect upon congestion than other symptoms
oral or nasal spray (e.g. azelastine)
effect monotherapy
available as first or second generation agents. Latter preferred due to reduced sedation (does not cross blood brain barrier) and lack of anti-cholinergic effects
e.g. second generation - ioratidine, fexofenadine, certirzine (mild anti-inflammatory action)

Question 8

describe the varied drug classes used to treat allergic and non-allergic rhinitis and comment upon the nasal symptoms that are affected - anti-allergic/anti-cholinergic

Answer 8

anti-cholinergic (muscarinic receptor antagonists);
ACh released from post-ganglionic parasympathetic fibres activates muscarinic receptors on nasal glands causing water secretion that contributes to rhinoorhoea - blocked by muscarinic antagonists
reduce rhinorrhoea in PAR and SAR but has no influence upon itching, sneezing and congestion (the anti-cholinergic activity of first generation H1 blockers may contribute to their ability to suppress rhinorrhoea)
intra nasal spray - can cause dryness of nasal membranes
e.g. ipratropium

anti-allergic
purportedly mast cell stabilisation (uncertain)
maintenance treatment of allergic rhinitis with onset action of 4-7 days but weeks required for full effect
nasal spray (less effect than corticosteroids)
e.g. sodium cromoglicate

Question 9

describe the varied drug classes used to treat allergic and non-allergic rhinitis and comment upon the nasal symptoms that are affected - nasal blood flow

Answer 9

Cytseinyl Leukotriene Receptor Antagonists;
CysLT1 receptor antagonists reduce effects of CysLTs upon nasal mucosa
equi-effective with H1 receptor antagonists in treating PAR and SAR, their effect may be additive
oral
considered for patients with allergic rhinitis and asthma
montelukast sole agent used in this class

vasoconstrictors;
act as directly, or indirectly, to mimic effect of noradrenaline
produce vasoctonriction via activation of alpha1-adrenoceptors to decrease swelling in vascular mucosa
oxymetazoline, a selective alpha-adrenoceptor agonist (intra nasal), effective, short term in reducing congestion in allergic rhinitis