Acute viral nasopharyngitis pathophysiology: Difference between revisions

Jump to navigation Jump to search
No edit summary
m (Bot: Removing from Primary care)
 
(32 intermediate revisions by 7 users not shown)
Line 1: Line 1:
__NOTOC__
__NOTOC__
{{Acute viral nasopharyngitis(common cold)}}
{{Acute viral nasopharyngitis(common cold)}}
{{CMG}}
{{CMG}};{{AE}}{{AY}}
 
==Overview==
[[Rhinovirus]] (the most common cause of common cold) is usually [[Transmission (medicine)|transmitted]] via [[aerosol]]<nowiki/>s generated by [[coughing]] or [[sneezing]]. The entry point is usually the nose, however viruses can enter the body through the lacrimal ducts. Following [[Transmission (medicine)|transmission]], the [[virus]] invades [[epithelial cells]] and causes a release of [[Cytokines|inflammatory cytokines]], leading to the various symptoms of the common cold. The body responds using cellular and humoral immunity in addition to the role of bacterial flora in the defense against the organism.


==Pathophysiology==
==Pathophysiology==
===Virus===
===Virus===
Common colds are most often caused by infection by one of the more than 100 [[serovar|serotypes]] of [[rhinovirus]], a type of [[picornavirus]]. Other viruses causing colds are [[coronavirus]], [[human parainfluenza viruses]], [[human respiratory syncytial virus]], [[Adenoviridae|adenoviruses]], [[enterovirus]]es, or [[metapneumovirus]].<ref name="Merck">{{cite web | title = Common Cold (Upper Respiratory Infection) | work = The Merck Manual Online | publisher = [[Merck & Co.]] | date = November 2005 | url = http://www.merck.com/mmpe/sec14/ch188/ch188c.html}}</ref><ref name="CKS">{{cite web | author = CKS | year = 2007 | title = Common Cold (Topic Review) | publisher = Clinical Knowledge Summaries Service | url = http://www.cks.library.nhs.uk/common_cold/view_whole_topic_review}}</ref>
Common colds are most often caused by one of more than 100 [[serovar|serotypes]] of [[rhinovirus]]<nowiki/>es, a type of [[picornavirus]]. Other [[viruses]] that can cause colds are [[coronavirus]], [[human parainfluenza viruses]], [[human respiratory syncytial virus]], [[Adenoviridae|adenoviruses]], [[enterovirus]]es, and [[metapneumovirus]].<ref name="Merck">{{cite web | title = Common Cold (Upper Respiratory Infection) | work = The Merck Manual Online | publisher = [[Merck & Co.]] | date = November 2005 | url = http://www.merck.com/mmpe/sec14/ch188/ch188c.html}}</ref><ref name="CKS">{{cite web | author = CKS | year = 2007 | title = Common Cold (Topic Review) | publisher = Clinical Knowledge Summaries Service | url = http://www.cks.library.nhs.uk/common_cold/view_whole_topic_review}}</ref><ref name="pmid10567986">{{cite journal |vauthors=van Kempen M, Bachert C, Van Cauwenberge P |title=An update on the pathophysiology of rhinovirus upper respiratory tract infections |journal=Rhinology |volume=37 |issue=3 |pages=97–103 |year=1999 |pmid=10567986 |doi= |url=}}</ref>


===Transmission===
===Transmission===


The common cold virus is transmitted between people by one of two ways:
The common cold virus is [[Transmission (medicine)|transmitted]] between people by one of two ways:
* In aerosol form generated by coughing, sneezing, or
:# [[Aerosols]] generated by [[coughing]] and [[sneezing]]
* From contact with the saliva or nasal secretions of an infected person, either directly or from contaminated surfaces.
:# [[Saliva]] or nasal discharge, either directly or from contaminated surfaces


Symptoms are not necessary for viral shedding or transmission, as a percentage of asymptomatic subjects exhibit viruses in nasal swabs.<ref name=gsacc>{{cite web | url=http://dh.sa.gov.au/pehs/Youve-got-what/ygw-common-cold.pdf |type = pdf | title=Common Cold | publisher=Department of Health, Government of South Australia | year=2005}}</ref> The infectious period (time during which an infected person can infect others) begins about one day before symptoms begin, and continues for the first five days of the illness.
* [[Asymptomatic]] patients can transmit the infection, too.<ref name="gsacc">{{cite web | url=http://dh.sa.gov.au/pehs/Youve-got-what/ygw-common-cold.pdf |type = pdf | title=Common Cold | publisher=Department of Health, Government of South Australia | year=2005}}</ref>
* The infectious period (i.e. the time during which an infected person can infect others) begins about one day before symptoms begin and continues for the first five days of the illness.
* The [[virus]] enters the [[cell (biology)|cells]] of the [[epithelium]] of the [[nasopharynx]] and rapidly multiplies.
* The [[virus]] enters the body mainly through the [[nose]]. Other entry points include the [[Eye|eyes]] through drainage of [[tears]] from the [[lacrimal ducts]] into the [[nasopharynx]].
<br clear="left" />


The virus enters the [[cell (biology)|cells]] of the lining of the [[nasopharynx]] (the area between the nose and throat), and rapidly multiplies. The major entry point is normally the nose, but can also be the eyes (in this case drainage into the nasopharynx would occur through the [[Nasolacrimal duct]]).
{{#ev:youtube|GoRhRJXp0j8}}
 
[[Image:Aerosol from Sneeze.jpg |thumb|275px|left|Cold viruses are spread by aerosols created when a patient sneezes]]
<br clear="left"/>


==Pathogenesis==
* [[Viruses]] undergo frequent changes in their [[Antigenic|antigenic coat]]. This helps them evade the [[immune system]] and enables them to cause recurrent infections.
** [[Rhinovirus]] binds to [[ICAM-1]] receptors on [[epithelial cells]] and makes them release [[Cytokine|inflammatory cytokines]], but does not cause damage to them.
** [[Respiratory syncytial virus|Respiratory syncytial virus (RSV)]] does not cause any release of [[cytokines]]. Instead, it replicates in the nose and [[pharynx]]. In many occasions, it can spread to the [[lower respiratory tract]].<ref name="pmid27251607">{{cite journal |vauthors=Blaas D, Fuchs R |title=Mechanism of human rhinovirus infections |journal=Mol Cell Pediatr |volume=3 |issue=1 |pages=21 |year=2016 |pmid=27251607 |pmc=4889530 |doi=10.1186/s40348-016-0049-3 |url=}}</ref>
** [[Human parainfluenza virus]] causes [[inflammation]] of the respiratory tract, so [[Parainfluenza virus|parainfluenza]] infection is much more severe than other [[viruses]].
* The body fights the offending [[virus]]es using both [[humoral immunity]] (i.e. [[IgA]] in the [[epithelium]]), and [[Cell-mediated immunity|cell mediated immunity]] (i.e. different [[inflammatory cells]] in the [[adenoids]] and [[tonsils]]).<ref name="pmid10567986">{{cite journal |vauthors=van Kempen M, Bachert C, Van Cauwenberge P |title=An update on the pathophysiology of rhinovirus upper respiratory tract infections |journal=Rhinology |volume=37 |issue=3 |pages=97–103 |year=1999 |pmid=10567986 |doi= |url=}}</ref>
* [[Normal flora]] inhabitants in the [[nasopharynx]] also play an important role in eliminating the infection.
==References==
==References==
{{reflist|2}}
{{reflist|2}}
{{WikiDoc Help Menu}}
{{WikiDoc Help Menu}}
{{WikiDoc Sources}}
{{WikiDoc Sources}}
[[Category:Disease]]
[[Category:Disease]]
[[Category:Needs overview]]
[[Category:Needs overview]]
Line 29: Line 41:
[[Category:Viral diseases]]
[[Category:Viral diseases]]
[[Category:Inflammations|Nasopharyngitis]]
[[Category:Inflammations|Nasopharyngitis]]
[[Category:Pulmonology]]
[[Category:Otolaryngology]]
[[Category:Pediatrics]]
[[Category:Up-To-Date]]
[[Category:Infectious disease]]
[[Category:Infectious disease]]
[[Category:Pulmonology]]

Latest revision as of 20:17, 29 July 2020

Acute viral nasopharyngitis Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating acute viral nasopharyngitis from other diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

X-ray

CT

MRI

Ultrasound

Other imaging findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Acute viral nasopharyngitis pathophysiology On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Acute viral nasopharyngitis pathophysiology

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

National Guidelines Clearinghouse

NICE Guidance

FDA on Acute viral nasopharyngitis pathophysiology

CDC on Acute viral nasopharyngitis pathophysiology

Acute viral nasopharyngitis pathophysiology in the news

Blogs onAcute viral nasopharyngitis pathophysiology

Directions to Hospitals Treating Osteoporosis

Risk calculators and risk factors for Acute viral nasopharyngitis pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Ahmed Younes M.B.B.CH [2]

Overview

Rhinovirus (the most common cause of common cold) is usually transmitted via aerosols generated by coughing or sneezing. The entry point is usually the nose, however viruses can enter the body through the lacrimal ducts. Following transmission, the virus invades epithelial cells and causes a release of inflammatory cytokines, leading to the various symptoms of the common cold. The body responds using cellular and humoral immunity in addition to the role of bacterial flora in the defense against the organism.

Pathophysiology

Virus

Common colds are most often caused by one of more than 100 serotypes of rhinoviruses, a type of picornavirus. Other viruses that can cause colds are coronavirus, human parainfluenza viruses, human respiratory syncytial virus, adenoviruses, enteroviruses, and metapneumovirus.[1][2][3]

Transmission

The common cold virus is transmitted between people by one of two ways:

  1. Aerosols generated by coughing and sneezing
  2. Saliva or nasal discharge, either directly or from contaminated surfaces
  • Asymptomatic patients can transmit the infection, too.[4]
  • The infectious period (i.e. the time during which an infected person can infect others) begins about one day before symptoms begin and continues for the first five days of the illness.
  • The virus enters the cells of the epithelium of the nasopharynx and rapidly multiplies.
  • The virus enters the body mainly through the nose. Other entry points include the eyes through drainage of tears from the lacrimal ducts into the nasopharynx.


{{#ev:youtube|GoRhRJXp0j8}}

Pathogenesis

References

  1. "Common Cold (Upper Respiratory Infection)". The Merck Manual Online. Merck & Co. November 2005.
  2. CKS (2007). "Common Cold (Topic Review)". Clinical Knowledge Summaries Service.
  3. 3.0 3.1 van Kempen M, Bachert C, Van Cauwenberge P (1999). "An update on the pathophysiology of rhinovirus upper respiratory tract infections". Rhinology. 37 (3): 97–103. PMID 10567986.
  4. "Common Cold" (PDF) (pdf). Department of Health, Government of South Australia. 2005.
  5. Blaas D, Fuchs R (2016). "Mechanism of human rhinovirus infections". Mol Cell Pediatr. 3 (1): 21. doi:10.1186/s40348-016-0049-3. PMC 4889530. PMID 27251607.

Template:WikiDoc Sources