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Selasa, 01 Mei 2018

Rhinitis Medicamentosa! - YouTube
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Rhinitis medicamentosa (or RM) is a condition of rebound nasal congestion brought on by extended use of topical decongestants (e.g., oxymetazoline, phenylephrine, xylometazoline, and naphazoline nasal sprays) and certain oral medications (e.g., sympathomimetic amines and various 2-imidazolines) that constrict blood vessels in the lining of the nose.


Video Rhinitis medicamentosa



Presentation

The characteristic presentation of RM involves nasal congestion without rhinorrhea, postnasal drip, or sneezing following several days of decongestant use. This condition typically occurs after 5-7 days of use of topical decongestants. Patients often try increasing both the dose and the frequency of nasal sprays upon the onset of RM, worsening the condition. The swelling of the nasal passages caused by rebound congestion may eventually result in permanent turbinate hyperplasia, which may block nasal breathing until surgically removed.


Maps Rhinitis medicamentosa



Pathophysiology

The pathophysiology of RM is unclear, although several mechanisms involving norepinephrine signaling have been proposed. RM is associated with histological changes that include: an increase in the number of lymphocytes and fibroblasts, epithelial cell denudation, epithelial edema, goblet cell hyperplasia, increased expression of the epidermal growth factor receptor, increased mucus production, nasociliary loss, inflammatory cell infiltration, and squamous cell metaplasia.

Direct acting sympathomimetic amines, such as phenylephrine stimulate alpha adrenergic receptors, while mixed-acting agents, such as pseudoephedrine can stimulate both alpha and beta adrenergic receptors directly and indirectly by releasing norepinephrine from sympathetic nerve terminals. At first, the vasoconstrictive effect of alpha-receptors dominates, but with continued use of an alpha agonist, this effect fades first, allowing the vasodilation due to beta-receptor stimulation to emerge.

2-Imidazoline derivatives, such as oxymetazoline, may participate in negative feedback on endogenous norepinephrine production. Therefore, after cessation of prolonged use, there will be inadequate sympathetic vasoconstriction in the nasal mucosa, and domination of parasympathetic activity can result in increased secretions and nasal edema. Evidence suggests that if oxymetazoline is used only nightly for allergic rhinitis (instead of more frequent dosage as may be directed on product label), it may be used longer than one week without high risk of rhinitis medicamentosa especially with use of intranasal steroid like fluticasone furoate.


藥物性鼻炎:長期使ç
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Treatment

The treatment of RM involves withdrawal of the offending nasal spray or oral medication. Both a "cold turkey" and a "weaning" approach can be used. Cold turkey is the most effective treatment method, as it directly removes the cause of the condition, yet the time period between the discontinuation of the drug and the relief of symptoms may be too long and uncomfortable for some individuals (particularly when trying to go to sleep when they are unable to breathe through their nose).

A benefit of the gradual "weaning" approach is that it helps preserve normal nasal airflow during the withdrawal process. United States Patent Number 5,988,870 was issued for a method and apparatus used to facilitate the precise titration and gradual withdrawal of decongestant nasal sprays containing addictive compounds. The system is sold under the brand name Rhinostat.

The use of over-the-counter (OTC) saline nasal sprays may help open the nose without causing RM if the spray does not contain a decongestant.[8] Symptoms of congestion and runny nose can often be treated with corticosteroid nasal sprays under the supervision of a physician. For very severe cases, oral steroids or nasal surgery may be necessary.

For RM caused by topical decongestants, there are anecdotal reports of persons having success by withdrawing treatment from one nostril at a time.[1][9]

A study has shown that the anti-infective agent benzalkonium chloride, which is frequently added to topical nasal sprays as a preservative, aggravates the condition by further increasing the rebound swelling.[10]


Overuse Decongestant Nose Drop Induced Rhinitis with Sinusitis ...
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Causes

Common issues that lead to overuse of topical decongestants:

  • Deviated septum
  • Upper respiratory tract infection
  • Vasomotor rhinitis
  • Cocaine use and other stimulant abuse
  • Pregnancy (these products are not considered safe for pregnancy)
  • Chronic rhinosinusitis
  • Hypertrophy of the inferior turbinates

Allergic Rhinitis. - ppt video online download
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See also

  • Topical decongestant

Chapter 41: Physiology of Olfaction - ppt download
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References


Chapter 41: Physiology of Olfaction - ppt download
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Further reading

  • Bernstein IL: Is the use of benzalkonium chloride as a preservative for nasal formulations a safety concern? J Allergy Clin Immunol 2000 Jan; 105(1 Pt 1): 39-44.
  • Black MJ, Remsen KA: Rhinitis medicamentosa. Can Med Assoc J 1980 Apr 19; 122(8): 881-4.
  • Brunton L, Parker K, Blumenthal D, Buxton I (2008) Goodman & Gilman's Manuel of Pharmacology and Therapeutics, Chapter 10, Adrenergic Agonists and Antagonists, McGraw-Hill, New York.
  • Elwany SS, Stephanos WM: Rhinitis medicamentosa. An experimental histopathological and histochemical study. ORL J Otorhinolaryngol Relat Spec 1983; 45(4): 187-94.
  • Fleece L, Mizes JS, Jolly PA, Baldwin RL: Rhinitis medicamentosa. Conceptualization, incidence, and treatment. Ala J Med Sci 1984 Apr; DA - 19840716(2): 205-8.
  • Graf P: Adverse effects of benzalkonium chloride on the nasal mucosa: allergic rhinitis and rhinitis medicamentosa. Clin Ther 1999 Oct; 21(10): 1749-55.
  • Graf P, Hallen H, Juto JE: Benzalkonium chloride in a decongestant nasal spray aggravates rhinitis medicamentosa in healthy volunteers. Clin Exp Allergy 1995 May; 25(5): 395-400.
  • Lin CY, Cheng PH, Fang SY: Mucosal changes in rhinitis medicamentosa. Ann Otol Rhinol Laryngol 2004 Feb; 113(2): 147-51.
  • Mabry RL: Rhinitis medicamentosa: the forgotten factor in nasal obstruction. South Med J 1982 Jul; 75(7): 817-9.
  • Wang JQ, Bu GX: Studies of rhinitis medicamentosa. Chin Med J (Engl) 1991 Jan; 104(1): 60-3.

Source of article : Wikipedia