Rhinitis Flashcards
what is the clinical name for a common cold?
acute coryza
what is the most common respiratory cause of the common cold?
rhinoviruses.
what is the incubation period for the common cold?
between 12 hours to 5 days.
what are the clinical features of the common cold?
tiredness, slight pyrexia (fever), malaise and a sore throat and pharynx. sneezing and profuse, watery nasal discharge are followed by thick mucopurulent secretions that may persist for up to a week.
how is rhinitis clinically defined?
Sneezing attacks, nasal discharge or blockage occurring for more than an hour on most days.
what are the two types of rhinitis?
seasonal/intermittent - for a limited amount of time a year.
perennial/persistent - throughout the whole year.
what is seasonal rhinitis often called? (but it is not entirely accurate)
‘hayfever’
what is the commonest allergic disorder?
seasonal rhinitis.
what is the prevalence rate of seasonal rhinitis worldwide?
2-20%
what are the symptoms of seasonal rhinitis?
nasal irritation, sneezing and watery rhinorrhoea. many also suffer from itching of the eyes and soft palate. occasionally itching of the ears. 20% suffer from seasonal wheezing.
what are the symptoms of perennial rhinitis?
50% of patients, symptoms of sneezing and watery watery rhinorrhoea predominate. other half complain mostly of nasal blockage. may lose sense of smell or taste bur rarely have throat or eye problems. sinusitis occurs in about 50% of cases due to mucosal swelling that obstructs drainage from the sinuses.
what are the three types of perennial rhinitis?
perennial allergic rhinitis
perennial non-allergic rhinitis with eosinophilia.
vasomotor rhinitis
what is the most common cause of perennial allergic rhinitis? second most common cause?
faecal particles of house dust mites.
pets.
what is a occupational cause of perennial rhinitis?
industrial dust, vapours and fumes.
how can perennial non-allergic rhinitis with eosinophilia be identified?
no extrinsic allergic cause can be identified from the history or on skin testing but eosinophilic granulocytes are present in nasal secretions.
what are most patients with non-allergic rhinitis with eosinophilia intolerant to?
aspirin/non-steroidal anti-inflammatory drugs (NSAIDs)
what are watery secretions and nasal congestion triggered by in patients with vasomotor rhinitis? and why?
cold air, smoke, perfume or newsprint, possibly because of an imbalance of the autonomic nerves controlling the erectile tissue (sinusoids) in the nasal mucosa.
what are nasal polyps?
round, smooth, soft, semi-translucent, pale or yellow, glistening structures attached to the sinus mucosa by .a relatively narrow stalk or pedicle.
in what types of patients do nasal polyps occur in?
patients with allergic or vasomotor rhinitis.
what do nasal polyps contain?
mast cells, eosinophils and mononuclear cells in large numbers.
what do nasal polyps cause?
nasal obstruction, loss of smell and taste, and mouth breathing, but rarely sneezing, since the mucosa of the polyp is largely denervated.
what does mucus production result from?
parasympathetic stimulation.
what do sympathetic fibres maintain in terms of the sinuses?
tonic contraction of blood vessels, keeping the sinusoids of the nose partially constricted and aiding nasal patency.
what does stimulation of the parasympathetic do to the sinus?
dilates its blood vessels.
what kind of antibodies are produced by B cells against allergens? what does the antibody do?
IgE. binds to mast cells via high-affinity cell surface receptors, whose cross-linking causes degranulation and release of histamine, proteases (tryptase, chymase) prostaglandins (PGDs), cysteinyl leukotrienes (LTC4, LTD4,LTE4) and cytokines.
what does sneezing result from? when does it start after exposure to allergen?
stimulation of afferent nerve endings (mostly via histamine) and begins within minutes of an allergen entering the nose.
when are nasal exudation and secretion and eventually nasal blockage driven by?
increased epithelial permeability, mostly due to histamine.
what are allergens presented to T cells via?
antigen-presenting cells - dendritic cells.
what happens after allergens are presented to T cells?
release of IL-4 and IL-13 , which further stimulate the B cells, and also IL-5, IL-9 and granulocyte macrophage colony stimulating factor (GM-CSF) switching from a Th1 to a Th2 response to activate and recruit eosinophils, basophils, neutrophils and T lymphocyte. these cause chronic swelling and irritation which leads to nasal obstruction, hyper-reactivity and anosmia.
what is the clinical term for loss of smell?
anosmia
what management options are there for rhinitis?
allergen avoidance H1 anti-histamines decongestants anti-inflammatory drugs corticosteroids leukotriene antagonists immunotherapy
what is most common therapy for rhinitis?
H1 anti-histamines
what are H1 anti-histamines effective against? what are they not effective against?
effective against - sneezing and itching of the eyes and palate.
not effective against - rhinorrhoea and nasal blockage
why should first generation antihistamines no longer be used? what are example of these?
they cause loss of concentration and sedation in all patients. examples are chlorphenamine and hydroxyzine
what are examples of second generation antihistamines? what doses should be taken?
loratadine - 10mg once daily
desloratadine - 5mg daily
cetirizine - 10mg daily
fezofenadine - 120mg daily
how are decongestants taken?
can be taken orally but more commonly as nasal drops or sprays.
what are examples of decongestants which are widely used?
xylometazoline and oxymetazoline.
what are examples of anti-inflammatory drugs? how do they act?
sodium cromoglicate and nedocromil sodium. they block and intercellular chloride channel and influence mast cell and eosinophil activation and nerve function.
what is the most effective treatment for rhinitis?
corticosteroids
examples of corticosteroids for treatment of rhinitis?
beclometasone
fluticasone propionate
fluticasone furoate
mometasone furoate spray
what is a side effect of cortisteroids prescribed for rhinitis.
nosebleeds (epistaxis)
what is prescribed for rhinitis if antihistamines and topical steroids are not effective?
leukotriene antagonists e.g. montelukast 10mg daily in the evening.
when is immunotherapy used?
when patients do not respond to standard drugs.
